The crimping process is a process of interaction among terminals, wires, tools, people, methods, procedures and environmental factors.

When this process is controlled, qualified crimping can be achieved.

Quality control is an important part of high quality crimping operation.

Tool setup or inspection won’t take you too much time, but it will avoid thousands of dollars in losses due to rework or remanufacturing.

Deviation is a slight change from one crimping to another.

There are two kinds of deviations: ordinary deviation or special deviation.

Deviation usually affects the consistency of crimping effect, and the deviation is caused by many small reasons.

The common deviation is caused by the inherent tolerance in the coiled wire or terminal.

It is also due to the natural error of stripping and crimping equipment.

Some special circumstances can cause special deviations, which are irregular and unpredictable.

Process capability

*PPM：The parts per million of potential defects.

At least 25 samples should be taken in the crimping process.

Calculate the average value and standard deviation of the sample.

Cp (competency Index) values can range from zero to infinity, and the higher the value, the stronger the process.

Values greater than 1.33 are considered acceptable in most applications.

Calculation formula of Cp: allowable error / 6X standard deviation

Cpk (process capability Index) indicates whether the process under test can produce a product that is less than the allowable error.

If the process is set to the average value of the specification, the Cpk value is equal to Cp.

If the Cpk is negative, the average value of the process exceeds the standard limit.

If Cpk is between 0 and 1, some six Sigma distributions are outside the allowable range.

If the Cpk value is greater than 1, the distribution range of six Sigma is completely within the allowable range.

Six Sigma is the goal of many companies because it represents almost zero defect.

Whether a company has the ability to reach the six Sigma level depends on the common deviation of its manufacturing process; manual crimping tools cause greater deviation than crimping machines.

Part of the crimping deviation is the measurement deviation, which is caused by the different measuring equipment and the different measuring methods of the same measuring personnel.

The crimping micrometer is more accurate than the representative caliper.

The measuring instrument must have sufficient accuracy.

If the data obtained from the production crimping is significantly different from the data obtained from the capability study, the capability of the crimping tool needs to be reconfirmed.

Production

The capacity level of the tool needs to be determined before it is ready for production.

Many wire harness manufacturers crimp only hundreds or thousands of wires at a time.

In this case, it is neither realistic nor cost-effective to measure 25 pieces of capacity for each tool set.

Visual detection

Operators should follow the standard operating procedures, manually separate each wire harness, eye inspection of trumpet mouth, conductor pretrudence, end position of insulation, tail cutting and insulation crimping, can also be tested by intelligent pressure management system.

Control chart

Crimping height is generally drawn as a control chart because crimping height measurement is a rapid non-destructive measurement and is critical to the electrical and mechanical reliability of terminals.

There are three main purposes of drawing control charts.

First of all, the number of samples collected for setting is usually very small, so its statistical value is limited.

Secondly, the occurrence of special circumstances in the process is irregular and unpredictable, and there must be a means to record deviations in a timely manner.

This prevents thousands of termination joints from being scrapped at the end of the operation.

Thirdly, and most importantly, the data is necessary to evaluate and improve the crimping process.

The only truly effective and cost-effective way to manage the manufacturing process is to understand, monitor and reduce the inherent sources of deviations in the process itself.

The purpose of the control chart is to identify the cause of the offset to determine whether the process should be adjusted.