Dimple Operation In Sheet Metal

Sheet metal design consideration dimple.

Dimple operation in sheet metal.

Draw dies create the part shape by controlling metal flow into a cavity and over the forming punch. The problems in volved in a sheet metal operation for the purpose of dlmpling a sheet for a fastener are two fold one to dimple the sheet without distorting the surface of the sheet and two in. Prevents die damage and downtime. The minimum distance between one dimple and another is four times the material thickness plus the inside radius of each dimple.

When dimple dies are used they are coining the sheetmetal so the harder the applied pressure the more accurate the flare will be with less metal spring back. The process uses a pair of rolls which are designed with rows of specially shaped teeth that deform the strip creating the dimple shapes from both sides of the plain sheet prior to the traditional cold roll forming process as shown in fig. The welker roll dimpler minimizes blank sticking by adding rows of small dimples to sheet metal in coil fed operations. Dimples prevent blanks from sticking together simplifying handling for operators and press feed robots.

The minimum distance that a dimple should be from a bend is two times the material thickness plus the inside radius of the dimple plus the radius of the bend. Eliminates the need for expensive air knife systems. This plate prevents the metal from wrinkling as it flows into the cavity.