Welcome to Shanghai Metal Forming Machine CO.,LTD.

			Tolerances Please observe the tolerances and exact fixing when installing the tools. The tolerances of the tools are designed to ensure secure fixing. Important: the stripper should not touch the tools, otherwise there is a risk of tool breakage due to transverse forces. It is essential that the alignment tolerance should be maintained between the punch and die (see mode of installation). These tolerances ensure the flexible bearing which is so important for the process.

Testing: The round point allows non-destructive testing, depending on the condition of the tools. The control dimension represents the remaining bottom thickness of the round point.



The measurement should be performed using measuring calipers, e.g. type B011, between the wear marks on the die side. Checking is also necessary via component or breaking tests. The control dimension is contained in the test report and has a tolerance of ?15%. For sheet thicknesses of less than 0.8 mm, this tolerance is reduced (see test report for precise details). During its service life, the bottom of the die may drop. This has no effect on the quality of the point, provided the tolerance is observed. If readjustment is necessary, the durability must be tested.


Chisel test: In welding technology, durability is tested, for want of a better method, by driving a chisel between the sheets at the welding spot. In the case of the point, this procedure would destroy the geometry and durability of the point.

Process monitoring: Continuous monitoring can be achieved using our electronic process monitoring system. See information sheet.

Stripper: Strippers are necessary on both the punch and die side and must be placed directly on the tool. See test report for stripping force. In the case of multiple point tools with a common stripper plate, this value should be multiplied by the number of points.

The stripping distance on the punch side should be > the penetration depth (PD) of the punch neck. On the die side, it should be > the die depth (DD). See test report.



Calculation of ET = penetration depth ET = S1 + S2 + MT - X S1 = thickness of material punch side S2 = thickness of material die side MT = die depth X = control dimension X see test report

Withdrawing the punch or die violently without the stripper can cause deformation of the point and space needed reduce its durability. There is also a risk of breaking the tools. Excessively high stripping forces affect the shaping process and reduce durability.

For the drive, pneumatic, hydraulic or mechanical equipment can be used. Thanks to its special action, our pneumatic-hydraulic drive, the owerpack, is ideally suited for this purpose, and offers a number of decisive advantages.

Operational monitoring
If the pressing force is too low, no joint will be formed, but if it is too high, this can lead to breakage of the tool. The owerpack provides an optimal monitoring facility for ensuring the right pressing force. When the set pressing force is reached, the return stroke is initiated via an impulse from an oil high-pressure switch. If the pressing force is not reached, e.g. due to a pressure drop in the pneumatic system, this switch-over does not take place and the owerpack stops. This provides an ideal way of checking the pressing force for each point.

Operating safety precautions:
Tools must not be closed without material. Without material, the surface pressure at the centre of the tool is too high and leads to deformation of the die or tool breakage. This can be easily avoided by setting stroke limiters. Stroke limiters should basically be applied so that the control dimension is obtained when the tool is closed. This ensures that the punch and die never touch and cannot be destroyed even if operated without material.

The compressive strength of the holding fixtures must be able to stand up to the pressure loads of the tools in continuous operation. See test report for pressing force. The area varies according to the tool shank diameter or bearing surface. Pressure load = 350 N/mm² (Conforms to safety S = 3)

Punch designation

	10.	25.	149012
	outside Ø in mm	length number	item number (6-digits)

Die designation

	10.	25.	148917
	outside Ø in mm	length number	item number (6-digits)

In addition to this information, we also require the test report number.

The point elevation causes the component to move upon withdrawal.

This problem can also be solved by swinging the die out of the way.

In the case of heavily oiled sheets, we recommend that you install the dies at the top or blow them through. The tools can also be equipped with an oil discharge hole.

There is a risk of breakage as the tool shank hits the bending radius. The shoulder of the tools should not make contact with the sheet.

Equipment with circular tool movement.

Punch should be placed vertically on the sheet. This ensures similar retention forces to those of a linear tool feed.

If components are bowed or do not lie flat, please let us know.