The technical requirements for plastic injection moulding automotive parts are usually that there must be no defects such as peaking, dissatisfaction of injection molding, flow lines, pores, warping, silver lines, cold materials, injection lines, etc., and they must comply with ROSH environmental protection requirements.
Plastic Injection Tooling Design Of Injection Moulding Automotive Parts
Before designing the mold, the mold opening direction analysis is required. The mold opening direction analysis and selection are the most important links in determining the mold design scheme. The three elements of the mold design scheme are gate, ejection and parting line. The mold opening direction analysis is closely related to the ejection and gate design of the plastic injection moulding automotive parts. The selection of the mold opening direction is the basis and premise of the parting surface design.
Only after the mold opening direction is correctly selected can the parting surface be correctly selected. For parts with the same shape but different sizes, the size value will affect the selection of the parting surface. The selection of the parting surface is related to the mold structure. Qualitative analysis can only summarize the general rules, and quantitative analysis needs to be combined with the size of the plastic part.
For some plastic injection moulding automotive parts, the selection of the parting surface is not complicated, and the parting surface is even a plane in the middle of the product. The difficulty lies in the selection of the mold opening direction, that is, which side of the plastic part is placed in the movable mold and which side is placed in the fixed mold. This problem is sometimes difficult to judge, and even experienced engineers may make mistakes.
The correct judgment will leave the side with strong sticking force in the movable mold to facilitate the ejection and demolding of the plastic injection moulding automotive parts, and design the pouring system on the other side. We call this problem the selection of mold opening direction. Sometimes, the simpler the shape of the plastic automotive part, the more difficult it is to determine its mold opening direction. Round products, which seem to have simple shapes, have more complicated mold opening direction selection.
Three Elements That Determine The Tooling Design
The three elements that determine the mold design are gate, ejector and parting surface. Mold design is a systematic design. The three elements must be considered comprehensively and analyzed comprehensively to find a reasonable mold design. As mentioned above, before the parting surface is determined, the mold opening direction should be determined first. On both sides of the parting surface, arrows are used to mark the fixed mold and the movable mold, which are usually replaced by letters. CAV represents the fixed mold and CORE represents the movable mold.
The parting line is the parting surface. Small triangles are marked on both sides to make the parting surface intuitive and eye-catching, and it looks clear at a glance. PL is marked on the parting surface. The parting surface is a complete and closed parting line on the product. This line cannot intersect itself. Therefore, no matter how complex the automotive plastic part is, the parting surface is quite complex, or ups and downs, or curved surfaces and gaps, etc., the expression of the parting surface should be complete, correct and unique. There should be no ambiguity or ambiguity.
On the parting surface expression drawing, the parting line of the slider should also be drawn in detail. If the slider does not affect the parting surface, for example, the buckle position of the plastic part is below the parting surface, mark the slider with an arrow and mark SLIDE1, 2, 3… At the same time, the position of the ejector and gate should also be added. If necessary, the position of large inserts should also be drawn on this drawing.
The buckle position of the core side can be released out by force or by designing an inclined ejector. The actual mold design adopts the inclined ejector method, and the inclined ejector structure is shown in Figures 5 and 6. Since the stroke of the inclined ejector is very small, a small stroke and small inclined ejector can be designed and manufactured using quenched steel. The ejection of the plastic part adopts a combination of straight ejector and inclined ejector.
Reliable Supplier for Injection Mould Automotive
Yuanfang Technology manufactures high-quality molds for the injection moulding automotive industry. Our molds are designed to meet the highest standards for interior, exterior and under-the-hood applications. If necessary, we can analyze the shape of automotive plastic parts to meet customers’ unique requirements. For many years, we have been solving automotive parts mold life and time issues for customers.
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