A crimp tool is an instrument used to make a connection between two pieces of metal, usually between a wire and a connector placed on its end. A compressive force is used to deform one or both of them in a way that causes them to clamp onto each other to create a permanent connection. Crimp tools are typically used for electrical and electronic connections and were developed as a quick, high-quality and low-cost way to replace soldered terminations. Crimp tools are extensively used within the aviation, automotive and other critical manufacturing industries.
There are various types of crimp tools depending on the die of the tool and the items being crimped. Manual, handheld crimp tools are the most common types as they are portable, inexpensive, and effective and they usually have interchangeable die-sets. There are also crimp tools that are electric or
Although a crimp tool is not a measuring device, the tool and dies should be calibrated and maintained in accordance with the required standards and manufacturer’s recommendations to assure crimp security and quality. Crimp tools should be calibrated annually or at approximately 10,000 crimps, whichever happens first.
Crimp Tool Calibration Process
There are 3 main tests that can be done to test the crimp tool to ensure that it is operating within its manufacturer’s specifications, the Go/No-Go Pin Gage Test, the Crimp Height Measurement Test, and the Crimp Pull Force Test. Some of these tests may not be appropriate for all crimper types, so the manufacturer documentation should be consulted to determine the correct tests for the crimp tool being tested.
Go/No-Go Pin Gage Test
The most common test to calibrate a crimp tool is to use a “Go/No-Go” Pin Gage to check the crimp tool dies, where one end of the gage should fit through the closed die of the tool and the other end should not. The manufacturer’s instructions should be consulted to determine the appropriate diameter pin gages to be used. Some crimp tools may come with a Go/No-Go gage that is supplied by the tool’s manufacturer.
To perform the test, the crimp tool handles should be squeezed until the crimping dies are completely closed. The crimp tool should never be closed directly onto the pin gage. This will most likely damage the tool die and make the tool unusable.
The Go Gage should be inserted straight into the crimping die opening. The Go Gage should pass completely through the crimping die opening with no excessive sloppiness or free play. The No-Go Gage should then be inserted straight into the crimping die opening while using minimal force. The No-Go Gage should not pass completely through the crimping die opening. It is acceptable for the No-Go Gage to enter the crimping die opening as long as it does not pass completely through.
For crimp tools with multiple dies, the steps should be repeated for all crimp dies that require testing by using the appropriate pin gage for the die opening. If required, most crimp tools have adjustments to allow the tool die to be adjusted back to within the manufacturer’s specifications
Crimp Height Measurement Test
The crimp height measurement test involves measuring the crimp assembly after a test crimp is completed to ensure that the measurements meet the manufacturer specification for crimp height. A blade or point type micrometer is required for this test.
To perform the test, place the contact and appropriate wire in the crimping die and close the crimp tool handle until the ratchet mechanism releases or the dies are fully closed. Remove the crimp assembly and measure all the required test points specified by the manufacturer with the micrometer. All measurements must be within the manufacturer specifications. Again, repeat the steps for each crimp die on the tool or if different wire sizes are required.
Crimp Pull Force Test
A crimp tool calibration may require a test crimp to be subjected to a pull test. The crimp is pulled in a Tensile Tester until the crimp breaks and the maximum force is recorded. A motorized Tensile Tester is typically used as the tester can apply a consistent force and speed to the test crimp.
The test crimp is attached to the Tensile Tester using a variety of adapters or clamps for different sizes and shapes of wires and connectors. Tension is applied to the test crimp until the crimp fails, the wire pulls from the connector or the reading on the tester readout exceeds 120% of the minimum pull force that is stated in the manufacturer’s specifications. Any failure of the test crimp must occur beyond the minimum pull force that is stated in the manufacturer’s specifications. Repeat the pull test for each crimp die on the tool.
IN-HOUSE VS. OUTSOURCED CALIBRATION
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