The good part… a start

When we all look at what we manufacture which may be a small component or a completed assembly what is it we wish to make?  Is it not a good part or component? One that does everything that we wish it to do?  Or the more critical aspect is that it does everything the customer wants, for its life. Similarly there are some whom mold acceptable parts that have no real critical functions… what could be called shoot and ship but these too need to perform to acceptable levels.

When looking at the finished part, there are four factors involved… Part design, Mold and or tool design, Material selection and processing.  In the past (20 plus years ago) we use to just walk into the tool shop with the old part and tell a toolmaker to make an 8 cavity tool and that the material is polystyrene.  Than 12 to 16 weeks later we had a mold, that upon shooting and a bit of a processing dance we made some parts… maybe 3 to 7 times going back and forth to the tool room would be needed to troubleshoot and debug the tool. In most cases we were able to produce an acceptable product and everyone was happy. That was than and today though we may still try to do some things by a guess and hope for the best, times have changed.

Today people want the mold and parts yesterday. And the tolerances are tight, and sometimes unachievable.  With the time frames most people want we all tend to skip what I would call the basics of getting all the parties together to discuss the best possible solutions to the opportunities presented.

Part Design:
When we look at the part, the first thing is to note the part design. From the designers standpoint they should design to what they want. Break the rules, put all the thought into the part. This is the initial concept, what may be called creative time frame to come up with the new design.
Now that we have this concept the steps should be to understand the function of the part or parts. What is it they do and must do. Basically called the second part, it is to understand the function.  Given this we can now alter the part design to be a good plastic part design, what with uniform walls, radius corners, holes away from sidewalls. It may also be important to state what dimensions are critical to the performance of the part function and which are for constructing the part. This is where two sets of prints are produced. One to create the part and one to check what is important.  Or the other concept is to highlight the areas of importance.

To be continued:
Thanks for the time.

Steven L Silvey
Sr. Technical Service
GP-ADC