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.