How to Place ejector Pins on Mold design?

There are some guidelines as below to place ejector pins on mold design.

1. Ejector pin location

1.1 The distance pin to the edge of the plastic part should be 0.04~0.10 inch.

1.2 To place the pin to bottom of part as A pin, and leave 0.01inch to the edge of core. Not good to place as B pin on top of part.

1.3 The locations as picture below, A better than B, B better than C.

If there is no choice, have to place pin at C location, then it’s better to add some small step on pin to increase the ejection force.

1.4 If must place pin on A location without better option.

1.4.1 Must make the pin lower the parting line 0.0005 inch, same as venting depth.

1.42 Add spring under the return pins to protect the ejector pin.

2. Pin fitting length and clearance.

3. Ejector pins should be locked if the pins placed on the non-flat surfaces of part.

How to Improve this Injection molding Defect gas Mark at Gate location?

On injected parts, the injected mark as picture below easily happened on the gate location with banana gate, especially on textured surfaces. due to resin flows through the gate with high pressure. 

How to improve this kind of gate marks on injected parts by adjusting molding parameters?

The most important thing is: find out the switch point on molding machine of resin flows at gate point. Use low injection speed to fill the area of gate location, then can change to high speed after that point to inject other areas. It's vital to get the exact injection switch point.

How to Define thickness For plastic Product on Industrial design?

The thickness of plastic product related to plastic material, part size, injection gate numbers and locations.

Same thickness may be fulfilled by PA resin, but it may not be workable for PC resin, due to different flowability of each resin.

There is a formula to calculate the plastic product thickness base on selected resin and the flow length = the distance from injection gate to end of the part. Please see image below: