In addition to the UST steel stripper, DAYstrip and the Posi-Strip DAYTON PROGRESS also offers polyurethane strippers (also called PU strippers).
Use of a stripping device
In dies, strippers are always found in combination with punches. As the name suggests, the stripper is used as an aid to hold and then remove the processed material from the punch during stamping. When this occurs, care must be taken that the material does not become deformed and that no marks are left behind. The stripper, therefore, keeps the workpiece in its defined shape when the punch is retracted.
PU strippers are placed over the punch and attached to the retainer by a backing plate (Figure 1). The brand new stripper is closed off at the end with the exception of an air hole. During the first punching process, the punch pierces through the polyurethane, producing a perfect fit around the punch. The structure of a stripping device consisting of retainer, punch and polyurethane stripper, as shown in the Figure 2.
Polyurethane strippers from DAYTON - operation mode
Basically, polyurethane strippers can be used with different types of punches such as headed punches, ball-lock punches as well as high-precision punches. The design connecting the backing plate and the retainer ensures that the stripper sits firmly in place and does not hinder the punching process. The shape has a closed end which serves to ensure that the punched material does not deform. Figure 3 shows what happens when the stripper is tubular and open at the end: the punch simply pulls the metal sheet up, leaving a dent. All DAYTON PROGRESS PU-strippers have a closed end and thus exert pressure on a larger surface area of the material.
PU strippers are compatible with DAYTON retainers and punches
DAYTON strippers USM and UHM are compatible with DAYTON retainers and punches of the headed and ball-lock punch groups. The retainers are ART, ARTS, BRT and CRT. In combination with ball lock punches, they fit to the lengths of 71, 80, 90 and 100 in the light duty range and to the lengths of 80, 90, 100 and 110 in the heavy duty range. Headed punches are available in the lengths of 71, 80, 90 and 100 and can be combined with PU strippers.