Stamping: reliable double sheet prevention with new monitoring system – also as a retrofit

Stamped and hybrid parts are standard equipment in demanding sectors such as the automotive, electronics and household appliance industries. Over the last few decades, not only has production evolved – progressive dies enable the manufacture of complex parts – but also quality assurance: integrated sensor technology (optical, piezoelectric, inductive) in conjunction with tool and process monitoring systems guarantees tight tolerances and high process reliability during stamping.

Double sheet detection plays a special role here: if stamping waste is not completely discharged downwards, the tool may tilt; this is why it is referred to not only as double sheet detection but also as tilt detection. Kistler's analog inductive sensors have proven to be particularly advantageous for detecting double sheets: In combination with the KCA 400T analog controller, these distance sensors detect even the smallest stamping waste in the tool and thus prevent component damage and possible tool breakage.

With the new KCA 400T from Kistler, analogue sensors installed in the stamping tool can be conveniently parameterized and connected to the stamping machine or its monitoring system respectively. The analog controller has four inputs for analog sensors (0 to 10 V) and a digital output (PNP). All sensors can be set with different tolerances (in the range 10 to 200 µm) via the large touch display. Error messages are now displayed in plain text and with additional explanations – in addition to German, English, French and Italian, now also in Chinese and Spanish.

In AUTOSET mode, the KCA 400T automatically reads the signals from the connected sensors. After starting the press, a comparison is made between the stored set values and the actual values determined during the run. If all actual values are within the set tolerance, a PNP output signal is sent to the downstream tool monitoring system. If one or more sensors exceed the set tolerance, no output signal is generated and the tool monitoring system stops the press. Thus, the analog controller’s function is monitored with every stroke. The corresponding error message is shown on the display.

The double sheet control implemented with analog inductive sensors is more accurate than with digital (switching) sensors, for example, and offers the possibility of achieving very high monitoring accuracy and therefore the highest quality in stamping, even for older stamping machines.

Best tool protection when stamping – also as a retrofit

The new KCA 400T can be combined with all tool and process monitoring systems available on the market – existing monitoring systems can be easily retrofitted. If more than four analog sensors are integrated into a stamping tool, several Kistler KCA 400Ts can be used in parallel and connected to the monitoring system. Each analog controller only occupies one input, so that one digital input of the monitoring system becomes four analog measurement inputs.