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- Design the part to be machined in the fewest number of clampings possible
- Radii should usually be greater than 1/8". A 1/8" end mill is a common small end mill size
- Features requiring an end mill longer than 4 times it's its diameter are usually difficult to machine
- Fillet internal corners
- A boring bar can be used on the student shop manual mills to bore large diameter holes
- External radii are usually difficult to machine accurately on a manual mill but you can alway use a file to add cosmetic fillets
- Steel is more difficult to machine than aluminum
- Tight tolerances will likely increase cost and manufacturing time
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- Welds should be easily accessible: welding out of position is difficult and welding in tight corner is sometimes impossible.
- Aluminum is far more difficult to weld than steel
- Welding can distort the geometry of your part
Solidworks
Sketch Geometry
- PUT THE ORIGIN IN A USEFUL POSITION
- Try to use relations whenever possible. For example, if you want to put a hole in the middle of an object use center-lines and midpoint relations rather than dimensions.
- Don't do fillets or chamfers in sketches
Fasteners and Off the Self Parts
- We will be using metric fasteners whenever possible
- Do not use toolbox fasteners. Try to use fastener already in trunk whenever possible. Otherwise find a CAD model on McMaster and download the model. Make sure to delete the default custom fields and add the VendorNo field. Fasteners should also have "Y" set in the "IsFastener field"
- Try to spec Spaenaur fasteners whenever possible. If you want to use a fastener that Spaenaur does not sell, check with a Mech lead first.
- Make sure to suppress threads in fasterners.
- Save the fastener according to the naming convension if you are adding it to trunk. Update the drawing number registry accordingly.
In Context Mates
- In context mates should be used when two parts are propertly mated
- These mates can help make the models more dynamic
Fits
Press Fits
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Design for Assembly and Installation
Consider how the final product will be assembled:
- If you have bolts, make sure there is room to fit a wrench or socket on the bolt head and nut.
- Think about how all of your parts are connected together. A good way to do this is write a brief "installation manual" on how everything would fit together, and the order that they would be installed
- Think about the final placement of the part. Does it need to be attached to the ground? If so, do you have an attachment point (ie. floor anchors)? How will it be moved to it's final location?
Design for Repair and Maintenance
- Consider the consumables and limited life components. Try to place these in areas that are easily accessible for anyone who has to repair your part in the future. If this isn't possible (for example, some grease points), try to find another suitable part (oil impregnated bearings) or alternative method (grease lines or automatic greaser)
Design for Shipping
During shipping, parts will experience extreme temperatures and unexpected loads. Also consider the size of your part, and what can be assembled at the final destination.
Fits
Press Fits
Press fits are typically defined using ISO-standard fits when designing metric parts. Press fits for components under 6mm in diameter should use an M7 fit, while components over 6mm in diameter should use an N7 fit.