Automatic Resistor Spiral Cutting Machines

The ohmic value R of a resistive element is determined by R = l /kA.

Where k is the conductivity, l is the element length and A is the cross sectional area of the element.

Performance and evaluation data colleted over the years and after a lot of empirical analysis, has provided MFR with at an appropriate cutting factor chart for determination of the final value of Resistor which can be trimmed from an initial resistor value for establishing high reliability and long term stability in the product.

In the cutting process a spiral (helical) groove is cut using a diamond slitting disc, which the resistor is displaced in a controlled manner with a combination while the slitting operation is going on. The cut results in the increase in the path and simultaneous reduction in the cross sectional area thereby multiplying the resistors value multi fold.

The machine is designed to accept a resistor only if the set value is attained and the length of cut is between 60 to 85% of the length availability for cutting. Rotary mercury contacts are used for measuring the value while the process is underway. MFR has standardized norms for determining the pitch groove width and depth quality of cut.

Strict in process inspection to ensure adherence to standard is specified by our QAP and enforced by the Quality Department.

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