Continuation of 4 factors…. Basics for the tool.

In the previous articles we have looked at the part design and material selection process. Now let us discuss the basics of tool design.

With material selected we can now look at tool design, so that hopefully the tool is designed to a specific material. In more cases than not we go with generics so that we can run certain types of materials due to their shrinkage. To keep this fairly quick and simple a list.

1- What type of tool. Based on the class from SPI 101, 102 etc.  Basically how many parts are to be made from the tool?
2- Given that we now know the material, we can look at what the shrinkage needs to be the draft for that type of material, and what types of steels we may want. An example might be PVC or FR grade material we might want to go with a stainless steel. If glass filled have we compensated for the differential in shrinkage flow to cross flow?
3- Gate location, type of gate, runner system for material. Is it a hot runner system, valve gated or other type, which may call for more details?  Is the locations called out in the part design? Does the gate design pose a fill problem?
4- Venting, do we have these called out? Is there enough.
5-  Cooling, is it shown, are we uniform from our wall.
6-  Cooling, thick section, is it best to put an insert in the tool for these areas so we get same rate of cooling as we do with thinner section of the part?
7- When the design for the tool is done are we having a review with the molder, material person and others to be sure we have thought of all. Thus everyone has a bit of impute into the tool before steel is cut.
8- Have we set the size of the mold, height, and widths. Will it fit and function in the machine we planned on running it in? What is the flow to thickness ratio and estimated tonnage we need to keep the mold closed. Are the plates as thick as we need be and or do we have enough support pillars.
9- Are we calling out a radius on all inside corners of the part and calling these out to the mold with specific details and not general notes.
10- How is the ejector system for getting the parts out of the tool? Is the stroke correct, how is this in relation to the machine it will run in?
11- If we texture the part have we allowed for extra draft?

From the above which is not a concise list of all that needs to be check, there are many things within the tool that do need to be check and reviewed. Lists are available in many books and references. The above are just some highlights and or things to jog the memory.

Thanks for the time

Steven L Silvey

360-882-3183