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Design Guidelines
CNC Milling Process
Protomold uses CNC milling to produce its molds; part designs will benefit from the consideration of the mold-milling process.
It is difficult to maintain accurate milling control with long tools. Steep walls make the use of longer tools necessary. Whenever possible, avoid placing small detailed features adjacent to steep walls.
Drafted walls allow the use of shorter tools, which results in greater milling accuracy and detail.
Whenever possible, avoid placing small detailed features adjacent to steep walls.
Drafted walls allow the use of shorter tools, which results in greater milling accuracy and detail. |
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Because Protomold employs an automated CNC milling process to make the mold for your parts, some part corners will end up with a radius rather than a sharp edge.
This does not usually require a change to the model, but the designer is made aware of these radii before the mold is made.
A. Part model
B. Actual corner radius
C. Desired corner geometry
D. Tool |
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Avoid deep & thin ribs if possible
Deep ribs require draft and clearance in order to allow the milling tool access. The max tool lengths average between 8-12 times the tool diameter.
Also worth noting is that deep, thin ribs tend to increase the mold milling time and make hand polishing difficult and time consuming.
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Sometimes deep, thin ribs may result in potential collisions and/or geometry issues at the bottom of the mold cavities. |
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Final part shape can be affected when this occurs. |
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