Dimple Operation In Sheet Metal

Draw dies utilize a special pressure loaded plate or ring called a draw pad or blank holder to control the metal s flow into the cavity.

Dimple operation in sheet metal.

The minimum distance between one dimple and another is four times the material thickness plus the inside radius of each dimple. Draw dies create the part shape by controlling metal flow into a cavity and over the forming punch. The welker roll dimpler minimizes blank sticking by adding rows of small dimples to sheet metal in coil fed operations. 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. 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. Aluminum sheet is the easiest common. Dimples prevent blanks from sticking together simplifying handling for operators and press feed robots.

This plate prevents the metal from wrinkling as it flows into the cavity. 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. 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.