Question

14) Generate a Tool design checklist for designing an injection mold.

Answer 1

The tool design checklist for designing an injection mold are as follows:

1) Whether a material and grade has been specified before designing tool? If yes, then proceed to wall thickness and if no then there is a problem.

2) Walls cool at variable rate based on thickness. Thus, this aspect need to be taken into account when designing your part, mainly at the junctions between thick and thin portion. If this aspect has been taken then proceed to draft angles otherwise part might suffer from sink and warpage.

3) Have you given one degree draft for all non-textured wall, ribs, bosses and any other feature created in the line of tool opening? If it is not given then there will be requirement of additional part which will add on the cost.

4) Have you added atleast three degrees to all shut out faces (places where tool surface touch), for example part openings? If not then tool wear might increase.

5) Have you enhanced draft angles accordingly incase of textured part?

6) Are the ribs that you have specified for strength - to avoid warpage and to add functionality - no more than 50% of the thickness of the walls with which they mate?

7) Are the ribs you have designed very thin or deep?

8) If you need bosses for screw fixings, have you specified a one degree draft angle and is the section on more than 50 % of the thickness of the wall with which it mates?

9) If internal undercuts are required for fixing and location features, or because part geometry is same in both side of mould tool, have you confirmed that the cores will move away from the undercut as the part is ejected?

10)T o produce the external undercuts required for holes and openings, or dictated by geometry of the total part, have you confirmed that the cores will operate as the tool opens?

11) Have you considered where the tool should be split so that it:
1. Follows a smooth path?
2. Can vent gases created during moulding?
3. Avoids cosmetic and functional faces?

12) The selection of an ejector type depends on part geometry and features such as bosses; have you considered how your part will be ejected from the mould?

13) To ensure optimum processing of the material, mould temperature must be correctly controlled; have you considered how the mould can be heated and cooled?