How to become mold expert?
How to become injection mold expert?
No ejector pin marks (such as clear plastic parts) are allowed on the surface of the parts, and the surface has higher requirements of the rubber parts. The entire surface of the parts can be ejected by ejector pad, as shown in picture 8.4.1.
8.4.1 Mechanism point :
Ejector pad demoulding point：
1) The ejector pad should have higher hardness and smaller surface roughness; the selected material should have a certain hardness difference (usually above HRC 5°); the ejector pad needs nitriding treatment (except stainless steel is not suitable for nitriding) .
2) The matching clearance between the ejector pad and the insert is not subject to the overflow, and the sliding is required to be flexible; the sliding side of the ejector pad is provided with a lubrication groove.
3) The side of the push block and the insert should be tapered, and the straight face should not be used.
4) The pusher cone structure should meet the requirements shown in Figure 8.4.2; the ejection distance (H1) is greater than the rubber ejection height and less than half of the height of the push block.
5) Ejector pad push should be guaranteed to be stable, and more than two pushers must be set for larger ejector pad.
Ejector pad mechanism example:
1) The parts are shown in Figure 8.4.3, and the ejector mechanism is shown in Figure 8.4.4. This mechanism considers that the demolding block has a large demolding area and a uniform topping force, and the inner and outer ejector pads are used for ejecting to balance the demolding.
2) As shown in Figure 8.4.5, the plastic parts can not have marks ejector pin; the push block mechanism is shown in Figure 8.4.6. This mechanism uses the ejector pad of insert to release the mold and push the block evenly.
3) Clear plastic parts can not have thimble marks, and they are demolded by push block mechanism, as shown in Figure 8.4.7.