Channel with a web width of ¾" or less are usually formed in a die set SCD0-1. Width of web does not permit spring pad in the die.
For channels with web over ¾", die set SCD2-3 is recommended. Both punch and die have release wedges for quick removal of part. The die has a pressure pad to help maintain accuracy and keep the web flat.
When considerable material spring-back is encountered in channel forming, overbending is necessitated and die set SCD4-5 is recommended. The spring pad actuates the rocker inserts near the bottom of the stroke, causing the overbending
Small U-channel with little spring-back can be formed in one stroke in die set SCD6-7. Rocker insert overbends shape to allow for spring-back.