MICRO TOOLING CHALLENGES
4/2/13 Tooling challenges in micro mold making:
Parting line match – when putting two halves of a mold together to make a molded part, the parting lines have to be prestine. You can’t have a mismatch creating a “step” in the part.
Surface finish – surface finish is extremely important to micro machined components, especially if they are going to be assembled to something else. Creating a rough surface finish is a good thing to do when it is going into another part because it creates an improved surface area to adhere the next part to. Our dust-speck sized parts don’t have a lot of surface area, so roughening up that surface is of value.
Optical finish – surface finish needs to be extremely smooth so these components don’t feel like they are scratching the eye when implanted.
Material selection – Material selection when making micro-sized parts is an important consideration. Wall thicknesses are reduced because the parts are smaller and the material may get stretched out in a molding process. We need to use a material strong enough to do what it needs to do and be able to withstand heat within the body for a long period of time and be subjected to the elements.
Venting – It is important for machined tools to be vented properly to vent the gas out of polymer going through it.
Once the time has been taken to mold these tools, care needs to be taken to make sure they don’t depreciate and they will survive for their shelf life.