Crimp Tool Calibration

Crimp tools are devices that are used to make a connection between two items made of metal. The crimp tool uses a force to compress and deform one or both of the items to create a physical bond between them. Crimping was developed as a quick and easy way to replace the need for soldering connectors to wires.

The most widespread use is to crimp an electrical connecter on to the end of a wire to allow the connection of the wire to various terminal strips or other connections. Crimp tools are also used to make secure connections for loops in cable ends to attach various hooks or clamps.

Crimp tools are used for various cable or wiring installations in the automotive, aviation communications, electrical and metal forming industries. Crimp tools can have a single fixed crimp opening, multiple fixed crimp openings, or a head that allows for the interchangeability of many different sized crimping dies.

Most crimp tools are handheld and are operated manually by compressing the handle with the force of the hand. These are generally used to crimp smaller electrical connections or for connections to lighter weight cabling. For connections on larger cables that require substantially more force, hydraulic or pneumatic crimpers are used. Many of these types of crimp tools are designed to be mounted on a bench for stability during the crimping.


Is Calibration Required for Crimp Tools?

Since crimp tools do not perform any type of measurements there are often questions on whether they need to be periodically calibrated.

Many critical industries, such as the automotive and aviation industries, require them to be calibrated as part of their calibration programs to meet their industry regulations.

Through their use, the crimp opening contours or interchangeable dies can wear resulting in inadequate terminations and loose crimps. The ratcheting gears of the handle can also become damaged or wear which will cause the handle pressure to be too light to crimp the connection properly.

Periodic calibration of the tools is the only way to identify if the crimp will meet its manufacturer’s specifications and maintain its designed properties. The frequency of calibration typically depends on how frequently the tool is used, but crimp tools should be calibrated annually at a minimum. The owner of the crimp tool should decide which is the best calibration frequency for their crimp tool.


Calibration Methods

There are several different methods used for the calibration of crimp tools.

The most common way to calibrate the crimp tool is to use a ‘Go/No-Go’ gauge to check the size of the crimp opening. The ‘Go/No-Go’ gauge will have two different pin gauge sizes installed based on the manufacturer’s specifications. For a proper opening, the ‘Go’ gauge must fit through the closed jaws of the crimp area and the ‘No-Go’ gauge should not fit.

The crimp opening should never be closed directly onto the pin gauges or damage to the crimp tool will likely result.

For crimp tools with several openings or that have multiple interchangeable dies, the “Go/No-Go” gauge check must be repeated for each opening or die separately by using the appropriate pin gauges for the size of the opening.

Depending on what the crimp tool is being used for, just testing the tool opening is not sufficient to test the full properties of the crimp. In many cases, an actual crimp is made with the crimp tool on the appropriate connector and the crimp is tested to determine various crimp characteristics. There are two main ways that the crimped connector is tested, either by a non-destructive or a destructive test.

Non-destructive tests involve either the measuring of the crimp dimensions or testing a minimum pull force. The crimp is first visually inspected for the quality and evenness of the crimp. The crimp dimensions are then measured with a caliper or micrometer to determine the crimp height of the crimp indentions. If the measurements do not meet the height specifications, the crimp fails. The other non-destructive test involves placing the connector in a pull tester and pulling the crimp to a minimum crimp force as specified by the manufacturer and holding that force for 1 minute. The crimp should maintain its connection throughout the full time of the test.

Many regulations require a destructive pull-out test where the crimp is pulled at a constant speed until the crimp separates from the wire. The force of the separation is recorded along with the type of the crimp failure, such as whether the crimp is pulled completely off of the wire or if the crimp breaks somewhere on the connector. These pull-out tests are the most reliable tests for determining the tensile strength of the crimp.

has the required equipment and expertise to properly calibrate many types of crimp tools from a wide variety of manufacturers. For more information on our crimp tool capabilities, contact e2b calibration.

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