Extrusion Blow Molding Machine Parts and Functions

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
1st Edition 2009

Read more........

What Is Computer-Aided Process Planning (CAPP)?

In this section we introduce the topic of CAPP, and review important components of this technology. Chang and Wysk (1985) define process planning as “machining processes and parameters that are to be used to convert (machine) a workpiece from its initial form to a final form predetermined from an engineering drawing.” Implicit in their definition is the selection of machining resources (machine and cutting tools), the specification of setups and fixturing, and the generation of operation

sequences and numerical control (NC) code. Traditionally, the task of process planning is performed by a human process planner with acquired expertise in machining practices who determines from a part’s engineering drawings what the machining requirements are.

Manual process planning has many drawbacks. In particular, it is a slow, repetitive task that is  prone to error. With industry’s emphasis on automation for improved productivity and quality, computerized CAD and computer-aided manufacturing (CAM) systems which generate the data for driving computer numerical control (CNC) machine tools, are the state-of-the-art. Manual process planning in this context is a bottleneck to the information flow between design and manufacturing.

CAPP is the use of computerized software and hardware systems for automating the process planning task. The objective is to increase productivity and quality by improving the speed and accuracy of process planning through automation of as many manual tasks as possible. CAPP will increase automation and promote integration among the following tasks:

1. Recognition of machining features and the construction of their associated machining volumes from a geometric CAD model of the part and workpiece

2. Mapping machining volumes to machining operations

3. Assigning operations to cutting tools

4. Determining setups and fixturing

5. Selecting suitable machine tools

6. Generating cost-effective machining sequences

7. Determining the machining parameters for each operation

8. Generating cutter location data and finally NC machine code

Traditionally, CAPP has been approached in two ways. These two approaches are variant process planning and generative process planning. In the following section we discuss these and other issues in a review of work in this field.

THE

MECHANICAL

SYSTEMS

DESIGN

HANDBOOK

Modeling, Measurement,

and Control

OSITA D. I. NWOKAH

YILDIRIM HURMUZLU

Southern Methodist University

Dallas, Texas

CRC PRESS

Boca Raton London New York Washington, D.C.

Read more........

Polymer molding

Thermoplastics are molded as viscous liquids. Injection molding and extrusion dominate, but all molding processes impose flow that can orientate the molecules; if the molding is cooled fast enough the alignment is frozen in (Figure 19.5).

If not, polymers mostly prefer to form an amorphous structure. In some polymers crystallinity may develop on slow cooling. All polymers shrink as the mold cools from the molding temperature to room temperature because of thermal contraction and the loss of free volume caused by crystallization. Allowance must be made for this when the mold is designed.

Materials

Engineering, Science,

Processing and Design

Michael Ashby, Hugh Shercliff and David Cebon

University of Cambridge,

UK

AMSTERDAM • BOSTON • HEIDELBERG • LONDON • NEW YORK • OXFORD

PARIS • SAN DIEGO • SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO

Butterworth-Heinemann is an imprint of Elsevier

Read more........

Design Process

Before any discussion of CAD, it is necessary to understand the design process in general (Fig. 3). What are the series of events that lead to the beginning of a design project? How does the engineer go about the process of designing something? How does one arrive at the conclusion that the design has been completed? We address these questions by defining the process in terms of six distinct stages: 1. Customer input and perception of need 2. Problem definition 3. Synthesis 4. Analysis and optimization 5. Evaluation 6. Final design and specification A need is usually perceived in one of two ways. Someone must recognize either a problem in an existing design or a customer-driven opportunity in the marketplace for a new product. In either case, a need exists which can be addressed by modifying an existing design or developing an entirely new design. Because the need for change may only be indicated by subtle circumstances—such as noise, marginal performance characteristics, or deviations from quality standards—the design engineer who identifies the need has taken a first step in correcting the problem. That step sets in motion processes that may allow others to see the need more readily and possibly enroll them in the solution process. Mechanical Engineers’ Handbook: Materials and Mechanical Design, Volume 1, Third Edition. Edited by Myer Kutz by John Wiley & Sons, Inc.