Choosing Between Machining and Fabrication For a Part
Most parts can be made either way. The cost difference between them is rarely small, and it is decided during design.
Tolerance Sets the Floor
Cut and formed sheet holds general tolerances well. When a feature needs a few thousandths, that feature is machined, even if the rest of the part is not.
Volume Moves the Line
Fabrication front loads programming and tooling and then runs cheaply. Machining scales more linearly. Somewhere between them is a crossover quantity worth calculating before you commit.
- Under fifty pieces, machining often wins
- Between fifty and five hundred, run both quotes
- Above five hundred, forming and welding usually win
- Weldments beat billet on anything large and hollow
Design For the Process You Chose
Bend reliefs, minimum flange lengths and inside radii are free at design time and expensive after the model is released.
Send the model to the shop before the drawing is final. Ten minutes of feedback there beats a revision cycle later.
A shop that does cutting, forming and machining will quote both paths honestly. A shop that does one will find a reason its process is right.
