Punch machine

A punching machine works like a hole punch for paper. The punch presses the paper against the support of the hole punch and finally into a round opening. The scrap from the punching collects in the hole punch container.

Punching works exactly the same way: the sheet is positioned between the punch and the die. The punch moves downward and plunges into the die. The edges of the punch and the die move past each other in parallel, cutting the sheet. Observed in detail, the punching process proceeds in four phases. When the punch touches the sheet, the sheet is deformed. Then it is cut. Finally, the tension within the material is so great that the sheet breaks along the contour of the cut. The cut-out piece of sheet - the so-called punching slug - is ejected downward. When the punch travels upward again, it can happen that it pulls the sheet along. In that case, the stripper releases the sheet from the punch.

The higher the fraction of cut on the sheet edge, the better the edge quality. For precise fits, for example, preliminary holes are punched and then the final diameter is punched out with a slightly larger tool. The fraction of cut along such an edge is then as high as 100%.
(Source : allproduct.com)

Starrett 248E Drive Pin Punch For Machine Shop And Motor Service Work, 8" Length, 3/8" Punch Diameter

Axial Forming

Felss has redefined what can be done in terms of industrial manufacture of splines.

In short: The axial forming technology offers improved possibilities to form high quality internal and external splines made chipless, fast, reliable, and cost-effective.

In more details, the special low-frequency modulated axial forming process ensures the net shape forming of splines to the highest quality (IT5 quality classification) even after the part has been hardened, and on a very thin tube wall. This part quality is given by the combination of the forming process, the shape of the die design and the high-stiffness tool system that also offers unique possibilities for fine adjustment of the carbide splining die. The tool system can actively control the splined part diameter with +/- 0.03 mm (measured as over-pin diameter).

The Felss axial forming process is largely independent of the pressure angle of the die. This unique feature means that one can design the spline profile more freely than would be possible with competing technologies, and without giving in on the general die performance and service life.

Both external and internal splines can be formed by the Felss axial forming machine technology. Here it is very important to mention that internal spline forming in blind holes is offered as a standard solution in the same machine and just with one clamping. Because of the special tool exchange system, one can also make for example three different spline profiles on the same part in the same clamping.

Another key benefit of the axial forming process is the higher strength of the teeth compared to what can be obtained with conventional metal cutting technologies. Forming does not break the grain structure of the work piece, and this significantly contributes to the static and dynamic strength of the splined profile.

The repeatability and predictability of the axial forming process is also a very important benefit to mention. Of course, depending on the actual part and work piece material, the die will form approx. 1.6 km splines.

The machine concept is flexible. It is within certain limitations possible to add a tool exchange system, or add a second NC axis for internal splining from the bottom side, if required for new part production.

Turbine Steam Path Maintenance & Repair, Vol. 2