The carriage of a lathe

The carriage of a lathe has several parts that serve to support, move and control the cutting tool. It consists of the following parts: 1.Saddle 2.Cross-slide 3.Compound slide or compound rest 4.Tool post and 5.Apron Saddle The saddle is an H-shaped casting that fits over the bed and slides along the ways. It carries the cross slide and tool post. Some means are generally provided for locking the saddle to prevent any movement when surfacing operations are carried out. The cross slide The cross-slide comprises a casting machined on the under aside for attachment to the saddle and carries locations on the upper face the tool post or compound rest. The crosspiece of the saddle is mechanized with a dovetail way, at right angles to the center axis of the lathe, which serves to guide the cross-slide itself. The compound rest The compound rest or compound slide is a mounted on the top of the cross-slide and has a circular base graduated in degrees. It is used for obtaining angular cuts and short taper as well as convenient positioning of the tool to work. By loosening two setscrews, which fit in a v- grove around the compound-rest base, the rest slide may be swiveled to any angle within circle. There is no power feed to the compound rest and it is hand operated. The compound rest handle is also equipped with a micrometer dial to assist in determining the depth of the cut. After necessary setting the compound slide is locked solid with its base. The tool post This is located on the top of the compound rest to hold the tool enable it to be adjusted to a convenient working position. Following are the common tool post: 1.Single screw tool post 2.Four bolt tool post 3.Open side tool post 4.Four way tool post The apron The apron is fastened to the saddle and hangs over the front of the bed. It contains gears, clutches, and levers for operating the carriage by hand and power feeds. The e apron also contains function clutches for automatic feeds. In addition, there is a split nut which engages, when required with the lead screw, when cutting either internal or external threads. The lay out of the apron includes an inter locking device which prevents the simultaneous engagement of the feed shaft and the lead screw. The apron handle wheel can turned to move the carriage back and forth longitudinally by hand. The complementary motion to this is obtained by the cross- feed handle, which moves the cross- slide back and forth across the saddle. The handle wheel is connected via a pinion meshing with a rack fitted to the lathe bed Usually a chasing dial or thread cutting dial is fitted either to the side or top of the apron and consists of a graduated dial. It has entirely independent drive provided by a worm wheel, which is a constant mesh with the lead screw. 

fr. NTTF ( NETTUR TECHNICAL TRAINING FOUNDATION)

ASTM - Iron and Steel Products

Section 01 - Iron and Steel Products Volume 01.01, January 2005 Steel--Piping, Tubing, Fittings A0053_A0053M-04A Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless A0105_A0105M-03 Specification for Carbon Steel Forgings for Piping Applications A0106_A0106M-04B Specification for Seamless Carbon Steel Pipe for High-Temperature Service A0134-96R01 Specification for Pipe, Steel, Electric-Fusion (Arc)-Welded (Sizes NPS 16 and Over) A0135-01 Specification for Electric-Resistance-Welded Steel Pipe A0139_A0139M-04 Specification for Electric-Fusion (Arc)-Welded Steel Pipe (NPS 4 and Over) A0178_A0178M-02 Specification for Electric-Resistance-Welded Carbon Steel and Carbon-Manganese Steel Boiler and Superheater Tubes A0179_A0179M-90AR01 Specification for Seamless Cold-Drawn Low-Carbon Steel Heat-Exchanger and Condenser Tubes A0181_A0181M-01 Specification for Carbon Steel Forgings, for General-Purpose Piping A0182_A0182M-04A Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service A0192_A0192M-02 Specification for Seamless Carbon Steel Boiler Tubes for High-Pressure Service A0193_A0193M-04B Specification for Alloy-Steel and Stainless Steel Bolting Materials for High-Temperature Service A0194_A0194M-04A Specification for Carbon and Alloy Steel Nuts for Bolts for High Pressure or High Temperature Service, or Both A0209_A0209M-03 Specification for Seamless Carbon-Molybdenum Alloy-Steel Boiler and Superheater Tubes A0210_A0210M-02 Specification for Seamless Medium-Carbon Steel Boiler and Superheater Tubes A0213_A0213M-04B Specification for Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes A0214_A0214M-96R01 Specification for Electric-Resistance-Welded Carbon Steel Heat-Exchanger and Condenser Tubes A0234_A0234M-04 Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service A0249_A0249M-04A Specification for Welded Austenitic Steel Boiler, Superheater, Heat-Exchanger, and Condenser Tubes A0250_A0250M-04 Specification for Electric-Resistance-Welded Ferritic Alloy-Steel Boiler and Superheater Tubes A0252-98R02 Specification for Welded and Seamless Steel Pipe Piles A0254-97R02 Specification for Copper-Brazed Steel Tubing A0268_A0268M-04A Specification for Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing for General Service A0269-04 Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Service A0270-03A Specification for Seamless and Welded Austenitic and Ferritic/Austenitic Stainless Steel Sanitary Tubing A0312_A0312M-04B Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes A0320_A0320M-04 Specification for Alloy-Steel and Stainless Steel Bolting Materials for Low-Temperature Service A0333_A0333M-04A Specification for Seamless and Welded Steel Pipe for Low-Temperature Service A0334_A0334M-04A Specification for Seamless and Welded Carbon and Alloy-Steel Tubes for Low-Temperature Service A0335_A0335M-03 Specification for Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service A0350_A0350M-04A Specification for Carbon and Low-Alloy Steel Forgings, Requiring Notch Toughness Testing for Piping Components A0358_A0358M-04 Specification for Electric-Fusion-Welded Austenitic Chromium-Nickel Stainless Steel Pipe for High-Temperature Service and General Applications A0369_A0369M-02 Specification for Carbon and Ferritic Alloy Steel Forged and Bored Pipe for High-Temperature Service A0370-03A Test Methods and Definitions for Mechanical Testing of Steel Products A0376_A0376M-04 Specification for Seamless Austenitic Steel Pipe for High-Temperature Central-Station Service A0381-96R01 Specification for Metal-Arc-Welded Steel Pipe for Use With High-Pressure Transmission Systems A0403_A0403M-04 Specification for Wrought Austenitic Stainless Steel Piping Fittings A0409_A0409M-01 Specification for Welded Large Diameter Austenitic Steel Pipe for Corrosive or High-Temperature Service A0420_A0420M-04 Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Low-Temperature Service A0423_A0423M-95R04 Specification for Seamless and Electric-Welded Low-Alloy Steel Tubes A0426_A0426M-02 Specification for Centrifugally Cast Ferritic Alloy Steel Pipe for High-Temperature Service A0437_A0437M-04 Specification for Alloy-Steel Turbine-Type Bolting Material Specially Heat Treated for High-Temperature Service A0450_A0450M-04A Specification for General Requirements for Carbon, Ferritic Alloy, and Austenitic Alloy Steel Tubes A0451_A0451M-02 Specification for Centrifugally Cast Austenitic Steel Pipe for High-Temperature Service A0453_A0453M-04 Specification for High-Temperature Bolting Materials, with Expansion Coefficients Comparable to Austenitic Stainless Steels A0498-04 Specification for Seamless and Welded Carbon Steel Heat-Exchanger Tubes with Integral Fins A0500-03A Specification for Cold-Formed Welded and Seamless Carbon Steel Structural Tubing in Rounds and Shapes A0501-01 Specification for Hot-Formed Welded and Seamless Carbon Steel Structural Tubing A0511-04 Specification for Seamless Stainless Steel Mechanical Tubing A0512-96R01 Specification for Cold-Drawn Buttweld Carbon Steel Mechanical Tubing A0513-00 Specification for Electric-Resistance-Welded Carbon and Alloy Steel Mechanical Tubing A0519-03 Specification for Seamless Carbon and Alloy Steel Mechanical Tubing A0522_A0522M-01 Specification for Forged or Rolled 8 and 9\% Nickel Alloy Steel Flanges, Fittings, Valves, and Parts for Low-Temperature Service A0523-96R01 Specification for Plain End Seamless and Electric-Resistance-Welded Steel Pipe for High-Pressure Pipe-Type Cable Circuits A0524-96R01 Specification for Seamless Carbon Steel Pipe for Atmospheric and Lower Temperatures A0530_A0530M-04A Specification for General Requirements for Specialized Carbon and Alloy Steel Pipe A0539 Specification for Electric-Resistance-Welded Coiled Steel Tubing for Gas and Fuel Oil Lines A0540_A0540M-04 Specification for Alloy-Steel Bolting Materials for Special Applications A0554-03 Specification for Welded Stainless Steel Mechanical Tubing A0556_A0556M-96R01 Specification for Seamless Cold-Drawn Carbon Steel Feedwater Heater Tubes A0587-96R01 Specification for Electric-Resistance-Welded Low-Carbon Steel Pipe for the Chemical Industry A0589-96R01 Specification for Seamless and Welded Carbon Steel Water-Well Pipe A0595-04A Specification for Steel Tubes, Low-Carbon or High-Strength Low-Alloy, Tapered for Structural Use A0608_A0608M-02 Specification for Centrifugally Cast Iron-Chromium-Nickel High-Alloy Tubing for Pressure Application at High Temperatures A0618_A0618M-04 Specification for Hot-Formed Welded and Seamless High-Strength Low-Alloy Structural Tubing A0632-04 Specification for Seamless and Welded Austenitic Stainless Steel Tubing (Small-Diameter) for General Service A0660-96R01 Specification for Centrifugally Cast Carbon Steel Pipe for High-Temperature Service A0671-04 Specification for Electric-Fusion-Welded Steel Pipe for Atmospheric and Lower Temperatures A0672-96R01 Specification for Electric-Fusion-Welded Steel Pipe for High-Pressure Service at Moderate Temperatures A0688_A0688M-04 Specification for Welded Austenitic Stainless Steel Feedwater Heater Tubes A0691-98R02 Specification for Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at High Temperatures A0694_A0694M-03 Specification for Carbon and Alloy Steel Forgings for Pipe Flanges, Fittings, Valves, and Parts for High-Pressure Transmission Service A0707_A0707M-02 Specification for Forged Carbon and Alloy Steel Flanges for Low-Temperature Service A0714-99R03 Specification for High-Strength Low-Alloy Welded and Seamless Steel Pipe A0727_A0727M-02 Specification for Carbon Steel Forgings for Piping Components with Inherent Notch Toughness A0733-03 Specification for Welded and Seamless Carbon Steel and Austenitic Stainless Steel Pipe Nipples A0751-01 Test Methods, Practices, and Terminology for Chemical Analysis of Steel Products A0758_A0758M-00 Specification for Wrought-Carbon Steel Butt-Welding Piping Fittings with Improved Notch Toughness A0771_A0771M Specification for Seamless Austenitic and Martensitic Stainless Steel Tubing for Liquid Metal-Cooled Reactor Core Components A0774_A0774M-02 Specification for As-Welded Wrought Austenitic Stainless Steel Fittings for General Corrosive Service at Low and Moderate Temperatures A0778-01 Specification for Welded, Unannealed Austenitic Stainless Steel Tubular Products A0787-01 Specification for Electric-Resistance-Welded Metallic-Coated Carbon Steel Mechanical Tubing A0789_A0789M-04A Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing for General Service A0790_A0790M-04A Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe A0795_A0795M-04 Specification for Black and Hot-Dipped Zinc-Coated (Galvanized) Welded and Seamless Steel Pipe for Fire Protection Use A0803_A0803M-03 Specification for Welded Ferritic Stainless Steel Feedwater Heater Tubes A0813_A0813M-01 Specification for Single- or Double-Welded Austenitic Stainless Steel Pipe A0814_A0814M-03 Specification for Cold-Worked Welded Austenitic Stainless Steel Pipe A0815_A0815M-04 Specification for Wrought Ferritic, Ferritic/Austenitic, and Martensitic Stainless Steel Piping Fittings A0822_A0822M-04 Specification for Seamless Cold-Drawn Carbon Steel Tubing for Hydraulic System Service A0826_A0826M Specification for Seamless Austenitic and Martensitic Stainless Steel Duct Tubes for Liquid Metal-Cooled Reactor Core Components A0836_A0836M-02 Specification for Titanium-Stabilized Carbon Steel Forgings for Glass-Lined Piping and Pressure Vessel Service A0847-99AR03 Specification for Cold-Formed Welded and Seamless High-Strength, Low-Alloy Structural Tubing with Improved Atmospheric Corrosion Resistance A0851 Specification for High-Frequency Induction Welded, Unannealed, Austenitic Steel Condenser Tubes A0858_A0858M-00 Specification for Heat-Treated Carbon Steel Fittings for Low-Temperature and Corrosive Service A0860_A0860M-00 Specification for Wrought High-Strength Low-Alloy Steel Butt-Welding Fittings A0865-03 Specification for Threaded Couplings, Steel, Black or Zinc-Coated (Galvanized) Welded or Seamless, for Use in Steel Pipe Joints A0872_A0872M-04 Specification for Centrifugally Cast Ferritic/Austenitic Stainless Steel Pipe for Corrosive Environments A0908-03 Specification for Stainless Steel Needle Tubing A0928_A0928M-04 Specification for Ferritic/Austenitic (Duplex) Stainless Steel Pipe Electric Fusion Welded with Addition of Filler Metal A0941-04A Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys A0943_A0943M-01 Specification for Spray-Formed Seamless Austenitic Stainless Steel Pipes A0949_A0949M-01 Specification for Spray-Formed Seamless Ferritic/Austenitic Stainless Steel Pipe A0953-02 Specification for Austenitic Chromium-Nickel-Silicon Alloy Steel Seamless and Welded Tubing A0954-02 Specification for Austenitic Chromium-Nickel-Silicon Alloy Steel Seamless and Welded Pipe A0960_A0960M-04A Specification for Common Requirements for Wrought Steel Piping Fittings A0961_A0961M-04A Specification for Common Requirements for Steel Flanges, Forged Fittings, Valves, and Parts for Piping Applications A0962_A0962M-04 Specification for Common Requirements for Steel Fasteners or Fastener Materials, or Both, Intended for Use at Any Temperature from Cryogenic to the Creep Range A0972_A0972M-00R04 Specification for Fusion Bonded Epoxy-Coated Pipe Piles A0984_A0984M-03 Specification for Steel Line Pipe, Black, Plain-End, Electric-Resistance-Welded A0988_A0988M-98R02E01 Specification for Hot Isostatically-Pressed Stainless Steel Flanges, Fittings, Valves, and Parts for High Temperature Service A0989_A0989M-98R02E01 Specification for Hot Isostatically-Pressed Alloy Steel Flanges, Fittings, Valves, and Parts for High Temperature Service A0994-03 Guide for Editorial Procedures and Form of Product Specifications for Steel, Stainless Steel, and Related Alloys A0999_A0999M-04A Specification for General Requirements for Alloy and Stainless Steel Pipe A1005_A1005M-00R04 Specification for Steel Line Pipe, Black, Plain End, Longitudinal and Helical Seam, Double Submerged-Arc Welded A1006_A1006M-00R04 Specification for Steel Line Pipe, Black, Plain End, Laser Beam Welded A1012-02 Specification for Seamless and Welded Ferritic, Austenitic and Duplex Alloy Steel Condenser and Heat Exchanger Tubes With Integral Fins A1014-03 Specification for Precipitation-Hardening Bolting Material (UNS N07718) for High Temperature Service A1015-01 Guide for Videoborescoping of Tubular Products for Sanitary Applications A1016_A1016M-04A Specification for General Requirements for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless Steel Tubes A1020_A1020M-02 Specification for Steel Tubes, Carbon and Carbon Manganese, Fusion Welded, for Boiler, Superheater, Heat Exchanger and Condenser Applications A1024_A1024M-02 Specification for Steel Line Pipe, Black, Plain-End, Seamless E0527-83R03 Practice for Numbering Metals and Alloys (UNS.

fr. ASTM

 

Pin Point Gate Plastic Injection Molding

Used mainly for thin walled products with a frequency-lawyer-an injection of at least 3-4 times per minute, or a maximum cycle time 15-20 seconds a mold cavity with pin point gate. Material which is the injection into the cavity directly derived from the nozzle G, where the drop in temperature as well as barriers pengalirannya very small, so the size of the gate can be made small. Table 3.1 above can be used as guidance in determining the diameter of the gate d. -injection material in the cavity before reaching the runners will pass through the channel C first. The longer the runner channel, the temperature of the material tip of the flow would be decreased, so it will be difficult to pass through the narrow gate. Pouch runner dimasudkan D material to trap and hold the channel tip, so the material that will go through the gate, pretty good. Regarding the size of the gate, but is determined by the weight of products such as Table 3.1 above, is also affected by the condition and the condition of the bend cross-section and length of the runner. As a measure of onset, can be taken from table 3.1 size plus 20%. After ditrial if showing signs of too little gate as described in advance, gate be enlarged as necessary

Ribs and Gussets

When designing ribs and gussets, it is important to follow the proportional thickness guidelines shown in Figures 29 and 30. If the rib or gusset is too thick in relationship to the part wall, sinks, voids, warpage, weld lines (all resulting in high amounts of molded-in stress), longer cycle times can be expected. The location of ribs and gussets also can affect mold design for the part. Keep gate location in mind when designing ribs or gussets. For more information on gate location, see page 66. Ribs well-positioned in the line of flow, as well as gussets, can improve part filling by acting as internal runners. Poorly placed or ill-designed ribs and gussets can cause poor filling of the mold and can result in burn marks on the finished part. These problems generally occur in isolated ribs or gussets where entrapment of air becomes a venting problem. Note: It is further recommended that the rib thickness at the intersection of the nominal wall not exceed one-half of the nominal wall in HIGHLY COSMETIC areas. For example, in Figure 29, the dimension of the rib at the intersection of the nominal wall should not exceed one-half of the nominal wall. Experience shows that violation of this rule significantly increases the risk of rib read-through (localized gloss gradient difference). 

Product and Mold Design

SMAW Welding

Welding is the process of switching between two or more metals by using heat energy. Metal around the welds / connections, will experience a rapid thermal cycling which leads to complex changes, metallurgy, deformation and thermal stresses. It is very closely related to the strength, weld defects, and so forth which in general will have a fatal effect on the safety of welded construction. Welding process involves heating and cooling, in general, the microstructure of the metal depends on the speed of the cooling of the initial phase formation temperature up to room temperature. Because of this structural change on its own mechanical properties owned are also changing. Basically the weld area consists of three parts, namely the weld metal (weld metal), heat affected area is often referred to as the Heat Affected Zone (HAZ), and a metal stem that is not affected by heat. Weld metal region is part of the metal during welding melts and then freezes. Regional influence of heat or base metal HAZ is adjacent to the weld metal during welding thermal cycles of heating and rapid cooling. Unaffected parent metal heat is part of the basic metal welding where the heat and the temperature did not cause changes in the structure and properties. In addition there are three parts of other parts of the area which limits the area between the weld metal and HAZ are called the limit of welding. All events during cooling of the welding process is similar to cooling in the foundry difference is: 1. Cooling in the welding speed is higher 2. In the weld heat source moves straight 3. Thawing and freezing in the welding occurs continuously 4. freezing of weld metal from the metal wall of the parent which can be equated with the walls of the casting mold, only in the welding, the weld metal should be the one with the parent metal, while the foundry should be otherwise.

Threads - Product Design Mold Design

Molded-in threads can be designed into parts made of engineering thermoplastic resins. Threads always should have radiused roots and should not have feather edges – to avoid stress concentrations. Figure 35 shows examples of good design for molded-in external and internal threads. For additional information on molded-in threads, see page 105. Threads also form undercuts and should be treated as such when the part is being removed from the mold i.e., by provision of unscrewing mechanisms, collapsible cores, etc. Every effort should be made to locate external threads on the parting line of the mold where economics and mold reliability are most favorable. 

Product Design Mold Design

Gears

Gear teeth are a repetitive feature similar to screw threads or splines. It is not necessary to show their full form. In non-sectional views, gears are represented by a solid outline without teeth and with the addition of the pitch diameter surface of a type G line. In a transverse section, the gear teeth are unsectioned whereas the body of the gear is. The limit of the section hatching is the base line of the teeth as shown in the drawing in Figure 3.17. In an axial section, it is normal to show two individual gear teeth unsectioned but at diametrically opposed positions in the plane of the section. All details of the gear type shape and form need to be given via a note. In a gear assembly drawing which shows at least two gears, the same principle as for individual teeth (above) is used but at the point of mesh, neither of the two gears is assumed to be hidden by the other in a side view. Both of the gears' outer diameters are shown as solid lines. The standard ISO 2203:1973 gives details of the conventions for gears. 

Engineering Drawing for Manufacture
by Brian Griffiths
Publisher: Elsevier Science & Technology Books
 

Tail stock or loose head stock

Tailstock is located at the inner ways at the right hand end of the bed. This has two main uses: 1) It supports the other end of the work when it is being machined between centers, and 2) It holds a tool for performing operations such as drilling, reaming, taping, e.t.c. To accommodate different length of work, the body of the tailstock can be adjusted along the ways chiefly by sliding it to the desired position where it can be clamped by bolts and plates. The upper casting of the body can be moved toward or away from the operator by means of the adjusting screws to offset the tail stock for taper turning and to realign the tailstock centered for straight turning. The body is bored to act as barrel which carries the tail stock spindle that moves in and out of the barrel by means of the screw when the tail stock handle is turned. The front of the spindle has taper hole into which the dead center or other tool fits. After the adjustment is made, the spindle is clamped in the position by tightening the locking bolt on spilt lug.

Container Design Extrusion Blow Molding

Performance Objective: Use design details that improve drop impact performance Radii: Long and Generous, especially around the base, to allow flash pinch terminations to be located up on container sidewall chime or within the base pushup Base Engravings: Shallow, with Smooth, Rounded Edges Base Shape and Pushup: Rounded and Shallow Footprint: Wide and Rounded with smooth transitions to base and sidewall Panels: wide sidewall panels with long radii Radii: long and generous everywhere, especially at the base to allow flash pinch terminations to be located up on container sidewall chime or within the base pushup Base Engravings: shallow with smooth rounded edges Base Shape and Pushup: Rounded and shallow Footprint: Wide and rounded with smooth transitions to base and sidewall Panels: Wide sidewall panels with long transition radii 

EASTMAN
Extrusion Blow Molding Presentation

Splines and serrations

Splines and serrations are repetitive features comparable to screw threads. Similarly, it is not necessary to give all the details of the splines or serrations, the symbology does it for you. The convention is that one line represents the crests of the serrations or splines and the other the roots. This is shown in the hypothetical drawing in Figure 3.17 where there is a spline at the right-hand end of the gear drive shaft. A note would give details of the spline. The standard ISO 6413" 1988 gives details of the conventions for splines.
Engineering Drawing for Manufacture
by Brian Griffiths
Publisher: Elsevier Science & Technology Books

Gate INJECTION MOLDING

Gate is a crack or hole is relatively very small, is the entrance of the plastic material is injected into the cavity in the cavity. After passing through the gate, the material will flow cavity fill to the brim. Material flow from the gate until the cavity is fully charged, will travel a certain distance depending on the position of gate placement. Distance is called the flow path. Gate placement. Placement of gate position becomes very important, so the above tiadak defects occur or at least reduced to a minimum. Below is shown the possibility of defects arising in connection with the placement of the gate. Placement on gbr.3.11a gate, causing the flow path length so that it requires high injection tekenan,. Besides, there is the possibility of trapped air c section corner, where the product will be perforated at the venue. For large-sized products will experience deformation, for example, oval, etc.. The placement of the gate like gbr.3.11b, is a solution that is relatively the most good, although the appearance of the product will be disturbed by the existence of small cuts ex-gate. Placement on gbr.3.12a gate, the direction of flow after passing through the gate will be split into two, where each end aliarn will meet at 0. on a great product, the temperature of the flow at both ends meet has been greatly decreased, whereby the material at the end of the flow close to freezing. In that case, the meeting (weling) from either end did not produce a strong bond, so that products in this section will be brittle or crack easily. This meeting is usually a line, and called the welding line. Fig 3.12b, an improvement of fig. 3.12a. Gbr.3.12c shows a modification to the product, namely a place opposite the gate, given the bag. End of the flow temperature is very down is inserted into the bag, so that the materials meet each other and are linked material flow behind the tip, which still has a better temperature. Gbr.3.12d is the best solution which will meet the end of the flow of material that is still quite fresh. Gate placement as gbr.3.13a, will result in what is called jetting. Spray stream grazed the wall cavity, where there will be a thin section of material that attach and freeze first. As a result of this jetting, the product will look scaly. At a lower injection rate, as a result of jetting can be a bumpy batikan visible on the walls of the product. Placement on gbr.3.13b gate, the product will be bent, can gbr.3.13c dipertimbangakan. From the few examples of the above in mind, that wherever the gate is placed, will always give defect, both in terms of its appearance which seems former gate, other aspects such as product pad crooked, etc.. Preformance this regard mold designer must understand about product requirements, whether in terms of appearance or the importance of prioritizing the functional aspect, ie the product is not crooked, not brittle, etc., are terms of appearance is sometimes overlooked origin bias is not too bad. The purpose of the pen-desig's mold, is that mold can print product made to specification in effectif and efficiently.

Technology-Push Products

In developing technology-push products, the firm begins with a new proprietary technology and looks for an appropriate market in which to apply this technology (that is, the technology "pushes" development). Gore-Tex, an expanded Teflon sheet manufactured by W L. Gore Associates, is a striking example of technology push. The company has developed dozens of products incorporating Gore-Tex, including artificial veins for vascular surgery, insulation for high-performance electric cables, fabric for outerwear, dental floss, and liners for bagpipe bags. Many successful technology-push products involve basic materials or basic process technologies. This may be because basic materials and processes are deployed in thousands of applications, and there is therefore a high likelihood that new and unusual characteristics of materials and processes can be matched with an appropriate application. The generic product development process can be used with minor modifications for technology-push products. The technology-push process begins with the planning phase, in which the given technology is matched with a market opportunity. Once this matching has occurred, the remainder of the generic development process can be followed. The team includes an assumption in the mission statement that the particular technology will be embodied in the product concepts considered by the team. Although many extremely successful products have arisen from technology-push development, this approach can be perilous. The product is unlikely to succeed unless (1) the assumed technology offers a clear competitive advantage in meeting customer needs, and (2) suitable alternative technologies are unavailable or very difficult for competitors to utilize. Project risk can possibly be minimized by simultaneously considering the merit of a broader set of concepts which do not necessarily incorporate the new technology. In this way the team verifies that the product concept embodying the new technology is superior to the alternatives. 
Development Processes and Organizations

References and Bibliography
Many current resources are available on the Internet via
www.ulrich-eppinger.net
Stage-gate product development processes have been dominant in manufacturing firms
for the past 30 years. Cooper describes the modem stage-gate process and many of its
enabling practices.
Cooper, Robert G., Winning at New Products: Accelerating the Process from Idea to
Launch, third edition, Perseus Books, Cambridge, MA, 2001.
 

Screw threads

Screw threads are complex helical forms and their detailed characteristics in terms of such things as angles, root diameter, pitch circle diameter and radii are closely defined by ISO standards. Thus, if the designation 'M8' appears on a drawing it would appear at first sight to be very loosely defined but this is far from the case. Screw threads are closely defined in the standard ISO 6410, parts 1, 2 and 3:1993. The 'M8' designation automatically refers to the ISO 68-1:1998, ISO 6410-1, 2 and 3:1993 standards in which things like the thread helix angle, the vee angles and the critical diameters are fully defined. Thus, as far as screw threads are concerned, there is no need to do a full drawing of a screw thread to show that it is a screw thread. This takes time and costs money. The convention for drawing an engineering thread is shown using a combination of ISO type A and B lines as shown in the drawings in Figures 3.1, 3.2 and 3.3. A screw thread is represented by two sets of lines, one referring to the crest of the thread (type A line) and the other referring to the roots of the thread (type B line). These can be seen for a bolt and a hole in Figures 3.5 and 3.6. This representation can be used irrespective of the exact screw thread. For example, on the vice assembly drawing in Figure 3.1, the screw thread on the bush screw (part number 5) and the jaw clamp screw (part number 6) are very different. In the real vice, the former is a standard vee-type thread whereas the latter is a square thread. Line thicknesses become complicated when a male-threaded bolt is assembled in a female-threaded hole. The thread crest lines of the bolt become the root lines of the hole and vice versa. This means that in an assembly, lines change from being thick to thin and vice versa. This is shown in the vice assembly drawing in Figure 3.1, with respect to the bush screw (part number 5)/jaw clamp screw (part number 6) assembly.

Engineering Drawing for Manufacture
by Brian Griffiths
Publisher: Elsevier Science & Technology Books
 

THEORETICAL BACKGROUND BLOW MOLDING

Blow Molding (BM) process makes it possible to manufacture molded products economically, in unlimited quantities, with virtually no finishing required. The basic process of blow molding involves a softened thermoplastic hollow form which is inflated against the cooled surface of a closed mold. The expanded plastic form solidifies into a hollow product. Blow molded components are now seen all over the markets and industries for traditional materials, particularly in liquid packaging applications. The last few decades saw the introduction of polyethylene (PE) squeeze bottles for washing liquids, polyvinyl chloride (PVC) for cooking oil and fruits squash bottles, and polyethylene terephthalate (PET) for carbonated beverage bottles. Nowadays, it is also used for the production of toys, automobile parts, accessories and many engineering components. Blow Molding Process is intended also for manufacturing of most automotive parts and accessories. Below are some of the car plastics parts that are being produced by blow molding process. The use of plastics parts make our car more light weight and helps our car run faster. Extrusion Blow Molding Machine Parts and Functions • Extruder Motor—Drives the screw in the barrel to rotate and push the melted material into the die head. • Gearbox—Reduces the speed of the extruder motor into a required speed enough to push the material into the die head. • Hopper—A feed reservoir into which the material is loaded. • Extruder—A part of the machine that accepts solid resin material, conveys it in a surrounding barrel by means of a rotating screw, melts the material by means of heaters, and pumps it under pressure into the die head. • Cooling Fans—Cools down the barrel during machine shut down to prevent the material from degradation. • Heating Bands—Device attached on the barrel and the die head used to melt the solid material at a required set temperature. • Die Head—Used to form the melted resin into a parison and also used for adjusting the characteristics of molten resin to create a stable parison. • Die & Pin—Used to align the flow of parison to get a good and centered parison. • Hot Cutter—Cuts the parison after the mold is closed for the blowing process. • Blow Pin—Used to blow compressed air into the parison to inflate it after the mold has been closed and form the desired design of the mold. • Mold—A hollow form or a cavity into which a molten plastic material, called parison, is introduced to give the shape of the required component. • Deflasher—Used to cut the excess material on the bottle which is called a flash material (top and bottom). • Post Cooling—A part of the machine that is used to cool down the inside of the bottle, to lessen the cooling time required inside the mold. • Article Discharge—A part of the machine used to take the bottle out.

Higher Institute for Plastics Fabrication
WORKBOOK for Extrusion Blow Molding
Practical Course
Prepared by
Extrusion Blow Molding Department

Flats on cylindrical or shaped surfaces

It is not always obvious that surfaces are flat when they are on otherwise curved, cylindrical or spherical surfaces. In this case, flat surfaces such as squares, tapered squares and other flat surfaces may be indicated by thin 'St Andrew' cross type diagonal lines. An example of this is shown in the entirely fictitious gear shaft in Figure 3.17. The extreme right-hand end of the shaft has a reduced diameter and approximately half of this cylindrical length has been flat milled to produce a square cross-section. The fact that the crosssectional shape of this region is square and not cylindrical is seen in the end view as a square and in the right-hand side elevation by the crosses. 

Engineering Drawing for Manufacture
by Brian Griffiths
Publisher: Elsevier Science & Technology Books
 

The headstock - The back gear LATHE

The headstock The headstock is secured permanently on the inner ways as the left hand end of the lathe bed, and it provides mechanical means of rotating the work at multiple speeds. It comprises essentially a hollow spindle and mechanism for driving and alternating the spindle speed. All parts are housed within the head stock casting. The spindle of headstock is made of carbon or nickel-chrome steel. The back gear The back gear is an additional feature of a belt driven lathe and is used to obtain wider range of spindle speeds, for the number of speeds obtained from “direct speeds” is limited to number of steps only. When the back gear is engaged, the spindle is speed is reduced considerably. So it is also used when it is necessary to have a slow speed of the spindle that cannot other wise be obtained by direct speed. A slow speed is necessary in the following cases. 1.In turning jobs of large diameter within the available cutting speed of the material 2.In turning jobs tough or hard material when the material is hard it becomes necessary to apply greater cutting force by the tool to shear out the metal. This increase in cutting force will require greater turning torque necessitating slower spindle speed. 3.In operations like thread cutting, reaming, e.t.c. 4.In taking deep cut as rough turning.
fr. NTTF ( NETTUR TECHNICAL TRAINING FOUNDATION)

Unscrewing System

To remove a product that is threaded on the inside, the mold that form the screw must be rotated in the opposite direction from the direction of threaded products. Player power can be generated by a straight motion from the mold openings are converted into rotary motion by means of transmission such as worm gear, or by adding a separate player. Below are shown examples of mold unscrewing system with its own player. As the player is connected to a motor. With through existing trnsmisi gears on the axle TSB core rotates in the direction opposite the direction of threaded products. At the base of cores threaded bushing installed with the direction and magnitude equal pitch screw threaded products. Because the threaded bushing above also serves as a nut, then the opposite direction when the screw rotated cores, cores will retreat and escape from the grip of the product, wherewith products are free from cores driven down by stripper plate. At the opening of the next mold, plates 1 and 2 open, runner pin sinking of the surface of the plate so that the runner down. To avoid co-rotating products during core spinning off product, at the end of the tooth or indentation formed male.

Dimension lines

Various ISO standards are concerned with dimensioning. They are under the heading of the ISO 129 series. The basic standard is ISO 129:1985 but it has various parts to it. A dimensioning 'instruction' must consist of at least four things. Considering the 50mm width of the jaw and the 32mm spacing of the holes of the movable jaw drawing in Figure 3.15, these are" Two projection lines which extend from the part and show the beginning and end of the actual dimension. They are projected from the part drawing and show the dimension limits. In Figure 3.15, the width is 50mm and the projection lines for this dimension show the width of the part. They are type B lines (thin, continuous and straight). These lines touch the outline of the part. The projection lines for the hole-centre spacing dimension of 32mm are centre lines. They are type G lines (thin, discontinuous, chain) which pass through the drawing just past where the holes are located. A dimension line which is a type B line (thin, continuous and straight). In Figure 3.15, these dimension lines are the length of the dimension itself, i.e. '50' or '32' mm long. A numerical value which is a length or an angle. In the Figure 3.15 example the dimensions are the '50mm' and '32mm' values. If a part is not drawn full size because it is too small or too large with respect to the drawing sheet, the actual dimension will be the value which it is in real life whereas the dimension line is scaled to the length on the drawing. Two terminators to indicate the beginning and end of the dimension line. The terminators of '50' and '32' dimensions in Figure 3.15 are solid, narrow arrowheads. Other arrowhead types may be used. There are four types of arrowhead allowed in ISO, as shown in Figure 3.16. These four are the narrow/open (15~ the wide/open (90~ the narrow/closed (15 ~ and the narrow/solid (15~ An alternative to an arrowhead is the oblique stroke. When several dimensions are to be projected from the same position, the 'origin' indication is used, consisting of a small circle. These drawings are shown in Figure 3.16. An example of an origin indicator is shown in the movable jaw detailed drawing. Many dimensioning examples can be seen in the movable jaw and hardened insert detail drawings. The dimensions in these two drawings follow the following convention. All terminators are of the solid arrow type, all projection lines touch the outside of the part outline, all dimension numerical values are placed above the dimension lines and all dimension values can be read from the lefthand bottom corner of the drawings. 
Engineering Drawing for Manufacture
by Brian Griffiths
Publisher: Elsevier Science & Technology Books

The bed LATHE

Description and functions of lathe parts Following are the principal parts: 1 Bed. 2.Headstock. 3.Tailstock. 4.Carriage. 5.Feed mechanism. 6.Screw cutting mechanism. The bed The lathe bed forms the base of the machine. The headstock and the tailstock are located at either end of the bed and carriage rests over the lathe bed and slides on it. The bed should be seasoned naturally to avoid distortion or warp that may develop when it is cooled after the bed is cast. The guide ways of the lathe may be flat and inverted- v having included angle of 90. The bed material should have high compressive strength, should be wear resistance and absorb vibration cast iron alloyed with nickel and chromium forms a good material suitable for lathe.




fr. NTTF ( NETTUR TECHNICAL TRAINING FOUNDATION)

Sistem Stripper - Ejector

The principle of this system is that the initial release of the product is driven by a stripper and ejectors simultaneously. This system can solve problems of the emergence of large deformation on the product due to stripping of the stripper system or due to the ejection of ejector system above. But in fact this system is mainly used in products where the wall or double wall inner wall has a snap. The principle mechanism of product release. aiming to achieve the distance along the mold opening delimiter pos1, where the stripper plate postal 2 no longer move backwards are other parts of the mold such as male (core) headings 3, 4 male, pos5 support plate, the runner heading pin 6 etc., will continue to move backwards until the composition range of mold. In this position ejector plate and post plate rentainer 7 does not come to move backwards because of the nylon tip shaft 8 which entered the post stripper plate press in post 2. In this position the product has been separated from male post 4, is a wall that has a snap in the end of the ejector pin is still mencengkaram post 9. In a subsequent retreat, nylon ripped from the stripper plate 2 so that the ejector plate post and retainer plate 7 with post-sam ejector pin 9 post interesting in retreat, the product apart from the tip ejector pin post 9. Ejector plate and the retainer plate with ejector pin post 7 post 9 held not come to move backward, it can happen with nylon at the end of the shaft of the post 8. Nylon TSB entered the press with the press can be adjusted by adjusting the bolt conical body. If the bolt rotated to right, in this case the right threaded bolts, then the tuner will sink bolts and nylon will enlarge, press the stripper plate style will grow. This press style that causes the ejector pin go stuck. At the next retreat, ejector plate and the retainer plate 7 will be heading in the push back by the support plate heading 5, where the impetus is greater than the style press nylon, making nylon uprooted from the stripper plate ejector pin which then come to move backward. In addition to nylon, or the opening sequence of movements can also be made of them by wearing jiffy lock.

Design Process - Service design

Design Process Effective design can provide a competitive edge matches product or service characteristics with customer requirements ensures that customer requirements are met in the simplest and least costly manner reduces time required to design a new product or service minimizes revisions necessary to make a design workable Design Process (cont.) Product design defines appearance of product sets standards for performance specifies which materials are to be used determines dimensions and tolerances Service design specifies what physical items, sensual benefits, and psychological benefits customer is to receive from service defines environment in which service will take place

Stripper system

In the picture looks stripper mechanism, where the product is dropped by a plate drawn by the pull plate is fastened to the plate cavity. At an open mold, the core will open for the movement carried by the moving plate. runner or know by heart is also separated from the sprue, because of the undercut at the end of the run ner pin. The products also come loose at the pull out step plates. The system is relatively inexpensive but only for a simple product of a certain size. If the product has a wide or large diameters and thin walls, so after products on the strip off from the core (male), there is a possibility the product will be deformation (bending). This is because: - Vacuum at the upper inner wall of the product - Large diameter products that produce products cengkaram force on the core component is also large, while the thin wall product is not strong to overcome the vacuum's and grip style. Deformation is common in the soft plastic material such as PE, PP, etc.

Functional and non-functional dimensions

Although every aspect of a component has to be dimensioned, some dimensions are naturally more important than others. Some dimensions will be critical to the correct functioning of the component and these are termed functional dimensions. Other dimensions will not be critical to correct functioning and these are termed non-functional dimensions. Functional dimensions are obviously the more important of the two and therefore will be more important when making decisions about the dimension value. Figure 4.1 shows an assembly of a shaft, pulley and body. A shaft is screwed into some form of body and a pulley is free to rotate on the shaft in order to provide drive power via a belt (not shown). The details of the three parts of this assembly are shown below the assembly drawing. The important function dimensions are labelled 'F', and the non-functional dimensions 'NF'. The main function of the assembly is to allow the pulley to rotate on the shaft, driven by the belt. Thus, the bearing diameter and length of the bolt pulley are important and therefore they are functional dimensions because they define the clearances that allow the pulley to rotate on the shaft. The belt will be under tension and the resulting lateral drive force will be transmitted to the shaft. The stresses set up by this force must be resisted by the screw thread in the body. Therefore, the length of engagement of the thread in the body is a functional dimension.
Engineering Drawing for Manufacture

by Brian Griffiths
Publisher: Elsevier Science & Technology Books
 

The mechanism of injection molding product expenditures

To remove the product from the mold, the mold Should Be moved to open the form in the which the movement is a return of the plate and other parts of the mold is Carried by the backward motion of the moving plate. Backward movement or opening Should Be synchronous is imultaneously or sequentially with movements also That other parts of the mold so That the product apart and fell out of the mold. At the time the mold opens, the supporters in terms of weight,mold is Divided into two parts That come the moving plate (cavity) and the part the which joined the fixed plate (core). In general, the moving mold plate to function as participating forming the inner product, where in this section are the components or the driving mechanism of the release of the product. Currently participating fix the mold plate is Generally sebagain forming the outer product, and will of Those parts have sprue and runner system.

The Engineering Design Process

Engineering design is one of the processes normally associated with the entire business or enterprise. from receipt of the order or product idea. 10 maintenance of the product. and all stages in between (Figure 2.6). The design process requires input from such areas as customer needs. materials. capital, energy. time requirements. and human knowledge and skills. Two important societal concerns that an engineer must take into account are legal and environmelltal issues. Every business must operate within the law that governs their business. When designing. it is important that the engineer understand that legal issues may affect the designed product. Safety laws related to automobiles are an example of how government legislation can affect a design. Governmcnt regulations related to the cnvironment may also havc a bearing on the final outcome of the design. For cxamplc. the cmission requircments on an automobile cngine havc a great effect on the final design. An cxample of human knowledgc input is an cngineer's knowledge of graphics. mathematics. and the sciences. Such knowledge is used by the engineer to analyze and solve prohlems. An engineering design involves hoth a process and a product. A process is a series of continuous actions ending in a panicular result. A product is anything produced as a result of some process. As the design of a product or process is developed. the design team applies engineering principles, follows budgetary constraints. and takes into account legal and social issues. For example, when a building is designed. engineering principles arc used to analyze the structure for loads: determine the structure's cost. based on the materials 10 be used. the size of the structure. and aesthetic considemtions; and create a design that adhcres to the local laws. Graphics is an extremely important pan of the engineering design process. which uses graphics as a tool to visualize possible solutions and to document the design for communications purposes. Graphics or geometric modeling using CAD is used to visualize, analyze, d(X~ument. and produce a product or process. In fact. geometric modeling it,<;elf could be considere a process. geometric modeling produces final design solutions, as well as inputs to the production process, in the form of wrnputer databases. As a product. geometric modeling is a result of the engineering design process. 

The Engineering Design Process
Bertoline-Wiebe-Miller:
Fundamentals of Graphics Communication,3/e
The McGraw-Hill Companies,2001
 

Sectional views

There are some instances when parts have complex internal geometries and one needs to know information about the inside as well as the outside of the artefact. In such cases, it is possible to include a section as one of the orthographic views. A typical section is shown in Figure 2.16. This is a drawing of a cover that is secured to another part by five bolts. These five bolts pass through the five holes in the edge of the flange. There is an internal chamber and some form of pressurised system is connected to the cover by the central threaded hole. The engineering drawing in Figure 2.16 is in third angle projection. The top drawing is incomplete. It is only half the full flange. This is because the part is symmetrical on either side of the horizontal centre line, hence the 'equals' signs at either end. This means that, in the observer's eye, a mirror image of the part should be placed below the centre line. Note that the view projected (beneath) from this plan view is not a side view but a section through the centre. In museums, it is normal practice to cut or section complex parts like engines to show the internal workings. Parts that are sectioned are invariably painted red (or any other bright colour!). In engineering drawing terms, the equivalent of painting something red is to use cross-hatching lines which, in the case of Figure 2.16, are placed at 45 ~ The ISO rules concerning the form and layout of such section lines is given in Chapter 3. The method of indicating the fact that a section has been taken on the view, from which the section is projected, is shown in the plan view of the flange. Here, the centre line has two thicker lines at either end with arrows showing the direction of viewing. Against the arrows are the capital letters W, and it is along these lines and in the direction of arrows that the sectional view is taken. The third angle projection view beneath is a section along the line AA, hence it is given the title 'Section AN. This method of showing the section position with a thickened line and arrows is explained further in the following chapter on ISO rules. Other examples of sections are given in the assembly drawing of a small hand vice (see Figure 1.11) and the detailed drawing of the movable jaw of the vice (see Figure 1.12). In the case of the movable jaw detailed drawing in Figure 1.12, the front view is shown on the top-left and the right-hand side drawing view is a right-hand section through the centre line. In this instance there are no section lines or arrows to indicate that it is a section through the centre. However, in this case, it should be obvious that the section is through the centre and therefore it is not necessary to include the arrows. However, this is not the case for the inverted planned view, which is a complicated half-section with two section plane levels on the left-hand side and a conventional inverted plan (unsectioned) view on the right-hand side. Because this is a complicated inverted plan view, the section line and arrows are shown to guide the viewer. Note that the crosshatched lines on the two different left-hand planes are staggered slightly. A different type of section is shown in the assembly drawing in Figure 1.11. Here the movable jaw (part number 3), the hardened insert (part number 2), the bush (part number 4), the bush screw (part number 5) and part of the jaw clamp screw (part number 6) are shown in section. This is what is termed a 'local' section because the whole side view is not in section but a part of it. The various parts in the section are cross-hatched with lines at different slopes and different spacings. The section limits are shown by the zig-zag line on the movable jaw and a wavy line on the jaw clamp screw. Another type of section is shown on the tommy bar of the assembly drawing. This is a small circle with cross-hatching inside. This is called a 'revolved section' and it shows that, at this particular point along the tommy bar, the cross-sectional shape is circular. In this instance the cross-sectional shape would be the same at any point along the tommy so it doesn't really matter where the section appears. The ISO standards dealing with sectional views are ISO 128-40:2001 and ISO 128-44:2001. 

Engineering Drawing for Manufacture
by Brian Griffiths
Publisher: Elsevier Science & Technology Books

Why are first and third angle projections so named?

The terms first angle projection and third angle projection may seem like complicated terms but the reason for their naming is connected with geometry. Figure 2.15 shows four angles given by the planes OA, OB, OC and OD. When a part is placed in any of the four quadrants, its outline can be projected onto any of the vertical or horizontal planes. These projections are produced by viewing the parts either from the right-hand side or from above as shown by the arrows in the diagram. In first angle projection the arrows project the shape of the parts onto the planes OA and OB. When the two planes are opened up to 180 ~ as shown in the small diagrams in Figure 2.15, the two views will be in first angle projection arrangement. When the part in the third quadrant is viewed from the righthand side and from above, the view will be projected forwards onto the faces OC and OD. When the planes are opened up to 180 ~ the views will be in third angle projection arrangement, as shown in thesmall diagrams in Figure 2.15. If parts were to be placed in the second and fourth quadrant, the views projected onto the faces when opened out would be incoherent and invalid because they cannot be projected from one another. It is for this reason that there is no such thing as second angle projection or fourth angle projection. There are several ISO standards dealing with views in first and third angle projection. These standards are" ISO 128"1982, ISO 128-30:2001 and ISO 128-34:2001. 
Engineering Drawing for Manufacture
by Brian Griffiths
Publisher: Elsevier Science & Technology Books
 

Design Aesthetic

Design is the process of conceiving or inventing ideas mentally and communicating those ideas to others in a form that is easily understood. Most often the communications tool is graphics. Design is used for two primary purposes: personal expression, and product or proccss dcvelopment (Figure 2.1). Design for personal expression. usually associated with art. is divided into concrete (realistic) and abstract dcsign and is uften a source uf beauty and intercst (Figure 2.2). Whcn a design servcs some useful purpose. such asthe shape of a ncw automobile wheel. it is classified as a design for product or process development (Figllre 2.3). Aesthetic design is concerned with the look and feel of a product. Industrial designers specialize in the aesthetic qualities of products. as well as other clements related to human-machine functionality. Functional design is concerned with the function of a product or process. Airflow over an automobile is an example of a fllnctional design element. Most engineers are con~~erned with functional elements (Figure 2.4). Many products will have both aesthetic and functional design elements. requiring the engineers and designers to work as a ieam to produce a product or system thaI is both runctional and aeslhetically pleasing (Figure 2.5). 

The Engineering Design Process
Bertoline-Wiebe-Miller:
Fundamentals of Graphics Communication,3/e
The McGraw-Hill Companies,200

Projection lines

In third angle projection, the various views are projected from each other. Each view is of the same size and scale as the neighbouring views from which it is projected. Projection lines are shown in Figure 2.14. Here only three of the Figure 2.12 views are shown. Horizontal projection lines align the front view and the left-side view of the block. Vertical projection lines align the front view and the plan view. The plan view and the left-side view must also be in orthographic third-angle projection alignment but they are not projected directly from one another. A deflector line is placed at 45 ~ This line allows the horizontal projection lines from the plan view to be rotated through 90 ~ to produce vertical projection lines that align with the left-side view. These horizontal and vertical projection lines are very convenient for aligning the various views and making sure that they are in correct alignment. However, once the views are completed in their correct alignment, the projection lines are not needed because they tend to complicate the drawing with respect to the main purpose, which is to manufacture the artefact. It is normal industrial practice to erase any projection lines such that the views stand out on their own. Often in engineering drawing lessons in a school, the teacher may insist projection lines be left on an orthographic drawing. This is done because the teacher is concerned about making sure the academic niceties of view alignment are completed correctly. Such projection lines are an unnecessary complication for a manufacturer and therefore, since the emphasis here is on drawing for manufacture, projection lines will not be included from here on in this book. 

Engineering Drawing for Manufacture
by Brian Griffiths
Publisher: Elsevier Science & Technology Books

Thermoforming

Thermoforming is a set of processes for forming a thermoplastic sheet or film around the mold by applying heat and pressure. In this process, the sheet is heated in the oven until softened but not to the melting point. Sheet is then removed from the oven, spread out around the mold and then the sheet is sucked by the vacuum process. Because the mold at room temperature, then the formation of the plastic mold will be in accordance with smoked During sheet in contact with mould. That the types of products generated with this process are Billboards, packaging, household applications. Product-open or hollow products can not be formed Because the pressure can not be maintained During the formation. Since thermoforming is the process of withdrawal and toning, as well as sheet metal forming, the material must have a high uniformity of strain, if not Will there be a failure. -Mould for thermoforming molds are usually made ​​from aluminum Because of the high fracture strength is not required. Tooling is not too expensive and quality considerations, including wear, unequal thickness is not too significant. (bid / multiple sources)

First angle projection

The other standard orthographic projection method is first angle projection. The only difference between first angle and third angle projection is the position of the views. First angle projection is the opposite to third angle projection. The view, which is seen from the side of an object, is placed on the opposite side of that object as if one is looking through it. Figure 2.13 shows the first angle projection layout of the bracket shown in Figure 2.12. The labelling of the views (e.g. front view, plan, etc.) is identical in Figures 2.12 and 2.13. Note that in first angle projection, the right-side view is not placed on the right-hand side of the front view as in third angle projection but rather on the left-hand side of the front view as shown in Figure 2.13. Similarly, the left-side view appears on the right-hand side of the front view. The other views are similarly placed. A comparison between Figures 2.12 and 2.13 shows that the views are identical but the positions and hence relationships are different. Another first angle projection drawing is seen in the title box in Figure 2.13. This is the truncated cone. It is the standard ISO symbol for first angle projection (ISO 128:1982). It is this symbol which is placed on drawings in preference to the phrase 'first angle projection'. First angle projection is becoming the least preferred of the two types of projection. Therefore, during the remainder of this book, third angle projection conventions will be followed. 

Engineering Drawing for Manufacture
by Brian Griffiths
Publisher: Elsevier Science & Technology Books

Rotational molding

Most thermoplastics and thermosets can be formed into products with a large cavity with Rotational molding process. Mould with thin metal walls are made in two pieces and is designed to rotate in two mutually perpendicular axes. Plastic powder that has been measured previously placed in a warm mold. Mould then heated in an oven usually large, while the mold is rotated in two axes. This process makes the powder pressed into a mold where the mold surface will heat the powder without melt. The types of products made with this process are tanks with a variety of sizes, trash, baket, housing, ball. The liquid polymer called plastisol (usually used vinyl plastisol) can also be used in slush molding process. Mold simultaneously heated and rotated. After contact with the wall of the mold material to melt and mold wall wrap. Products to be cold when it was still spinning and removed by opening the mold.