Thu Dec 08 21:46:24 CST 2022
Abstract】The design characteristics of the mold structure are explained through the analysis of the shape of the plastic part.
1 Requirements of plastic parts
Figure 1 shows the plastic water bucket, the product requires a uniform wall thickness, smooth surface, no obvious defects, a mold cavity, the material is ABS
2 Injection mold design
From Figure 1, we can see that this product is simple in shape and large in size, so we should consider not only saving material, reducing the weight of the mold, but also making the mold strong and reliable:
The first consideration of this mold is two-plate structure, using direct feed, pneumatic ejector, the overall structure of three options, see Figure 2a, b, c.
Figure 2a mold is round, moving, fixed mold by the guide column connection, with a tapered surface to ensure the coaxiality of the upper and lower mold, this structure is easy to cause stress concentration at the guide column hole, and the shape is slightly small will make the mold is not strong, resulting in injection up mold deformation, or even cracking.
Figure 2b mold is square, moving and fixed die are connected by guide pillars, and the coaxiality is ensured by tapered surface. This mold is in the four corners for the guide pillar vacant position, the structure is slightly more reasonable than 2a, but still larger
Figure 2c mold is round, the moving and fixed die is directly connected by the tapered surface, because the moving and fixed die has no direction, the angle can be rotated, and the product release slope is large, as long as the tapered surface is properly raised, and pay attention to the assembly, without the guide role of the guide pillar will not make the core touch the cavity. The movable and fixed mold are equipped with connecting screws on both sides for easy installation in the injection machine. The structure is more compact, and the external dimensions are small, which reduces the weight of the mold and saves material.
The mold (see Figure 3) adopts multi-stage water cooling, and the stress is concentrated around the cavity in the cooling water hole, but the hole diameter is small. In addition, the movable mold is evenly stressed and strongly locked by the taper of the movable mold, so it is not easy to be deformed by the injection pressure and the mold structure is reasonable. This kind of mold has been applied for many times, and the effect is good.