CNC Turret Punching
Sheet metal enclosure cut via turret punching
Bracket cut by turret punching
CNC turret punching creates shapes in sheet material by successively punching a series of basic shapes such as circles and rectangles. The basic shapes are selected from a rotating turret under CNC control.
CNC turret punching is a cost effective method for cutting sheet metal in moderate to long runs. Edges are usually very good due to the shearing action. CNC turret punching can produce 2D shapes including cutouts. Example applications include:
Normally all the tooling needed are stock items but special tooling may
be needed for inside angles less than 90 deg and unusual shapes. CNC turret punching is commonly applied to:
Cost optimization options for turret punching include:
- Replacing outside arcs such as rounded corners with chamfered corners
- Reducing the number of different hole sizes
- Minimizing use of complex curves
- Use of hole sizes corresponding to stock tooling
- Requesting custom tooling for high volume runs
- For lowest cost use circles of inch diameter 7/64, 1/8, 9/64, 5/32, 11/64, 3/16, 13/64, 7/32, 15/64, 1/4, 9/32, 5/16, 3/8, 1/2, 1 or 2; inside arcs of inch radius 7/128, 1/16, 9/128, 5/64, 11/128, 3/32, 13/128, 7/64, 15/128, 1/8, 9/64, 5/32, 3/16, 1/4, 1/2 or 1; and limit outside arcs such as rounded corners.
CNC Turret Punching Design Considerations
- Avoid thin fragile shapes
- Warping may occur if many holes are punched or much material is removed from the sheet
- Minimize use of very small holes
- Bottom side features may have a few thousandths of an inch more material than the top dimensioned side.
- Some edges may show minor signs of the successive punching process, less so on the bottom side.
