CNC Academy · Setup
CNC Workholding and Zeroing: Keep the Part Where You Planned It
The code can be perfect and still make a bad part if the material moves or the machine starts from the wrong reference. Workholding and zeroing deserve the same attention as the toolpath.
Visual lesson
The coordinate check
Inputs
- Material position
- Hold-down plan
- Design origin
Shop process
Secure stock → set zero → verify clearance
Result
Parts cut where the drawing expects
Choose the holding method for the operation
Screws, clamps, tabs, vacuum, spoilboard tape, fixtures, and pins solve different problems. Select a method that resists the cutting forces without putting hardware in the tool path.
Treat zero as a physical location
Mark the stock reference, decide whether zero is a corner, center, top, or spoilboard surface, and confirm that the drawing, CAM setup, and machine use that same reference.
Plan for the last part of the cut
Small parts, through-cuts, and thin offcuts can shift when they are released. Use appropriate tabs, onion skin, fixtures, or sequence planning to keep the final cuts controlled.
On the machine or at the bench
Use this checklist before you run.
- Map clamps, screws, tabs, or fixtures before CAM.
- Confirm toolpaths avoid all hold-down hardware.
- Mark the stock reference face and origin.
- Verify X, Y, and Z zero against the drawing.
- Plan how small parts remain secure during through-cuts.
Use the tool