Punching

• Space your holes 1.5x the material thickness apart. Cluster tools create holes at a distance of 1x material thickness, where single hit hole tools need additional material to maintain the same hole quality.
• Design your smallest holes at 1.2x material thickness.
• Minimize the number of unique punch-formed feature sizes/shapes throughout your design. Using the same sized features saves on machine setup time (and possible tooling costs).
• Specify typical punch feature tolerances within a range of +/-.005in. (+/- 0.127mm). It is important to keep in mind that tolerances in the flat state differ from those in the formed state.
• Consider the dimensional length of any progressive punch features (e.g. ribs, louvers, cluster patterns). Extensively long features can result in quality issues such as warping.
• Keep all your formed features facing a uniform direction. Designs that include form and form down features are at risk for quality issues.

The additional punching design guidelines below can be a useful resource in achieving dimensionally accurate and quality punched parts.

• Maximum formed feature height: 4x material thickness.
• Tool station diameters directly correlate to recommended space between punch-formed features. For feature spacing, we recommend using 50% of the tool station diameter: