WireProcess Specialties

There I said it. Let me repeat:

Crimp Force Monitors Do Not Solve your Quality Problems.

Now that it’s out there let’s back up a little. First of all, let me be crystal clear. Crimp Force Monitors (CFM) are an essential tool of a quality system for any company that is serious about providing quality wire assemblies. The ability to monitor your process with a crimp monitor is extremely valuable for a number of reasons which we will unpack in this article. But let’s put things into their proper perspective.

First of all, a crimp process that has excess variation exists that way with or without a CFM. A CFM does not resolve crimp problems but will provide plenty of notification to the operator of this condition. In the form of CFM alarms. It is what is done from this point that is critical.  If the tolerance is opened up to silence the alarms or (worse) the monitor is turned off, then the true value of the CFM is lost.

Second, a CFM works best with a process that is in control and shows little piece to piece variation. This provides sufficient room for detecting small defects in the crimp process. Excess variation adds “noise” to the detection process and a CFM will have a harder time in determining a defect or just normal process variation.

The video below is from the 2016 Electrical Wire Processing Technology Expo and the seminar co-sponsored by C&S Technologies and Applitek Technologies: Do You Really Know Your Crimp Process where we discuss the CFM Cycle, a scenario played out countless times as new CFM Technology is introduced.

So what value is a CFM in the crimping process?

First, real time monitoring is 100% effective in measuring the crimp process. Visual inspection is only 80% effective over time and 100% manual inspection is not practical. It also answers the question: “what is happening between the first off article inspection and spot in process inspection”.

Second, as a process analysis tool, a CFM is effective in improving the crimp process over time. This is done by analyzing the five elements of a terminal crimp. And improving each process. The direct effect is a process in greater control and able to detect smaller variation.

Finally, as part of an integrated network of processing machines, the CFM can feed valuable production quality data into a central database for archival and analysis. Also provide a level of production quality approval by preventing access to production equipment until quality measurements are within allowable parameters.

So the question is “Do you need a CFM equipped facility?” Consider the following and judge for yourself.

• Pull test and crimp height measurements are a static and one-time check of quality parameters. As important as they are to production quality, they are not sufficient in of themselves. A CFM is one example of dynamic quality measurement in real time. Press Analysis is another example of dynamic measurement.
• CFM’s remove subjective judgement of good or bad crimps from employees.
• CFM’s monitor the whole crimp process and the associated elements.
• Without crimp monitors, the risk of defective wire harnesses increases and the cost of rework (not to mention product liability) will exceed the initial investment of crimp monitor technology by a large margin. “It hasn’t happened to us so far” you may say. “We have crimped millions of parts over the years with no problem” is another one. The laws of probability will eventually catch up without effective dynamic crimp monitoring. Why take the risk?

Do not take the risk! Our Global Technology Partner: Crimping and Stamping Technologies is a global authority in the terminal crimp process. Connect Your Way to WPS for an analysis of your crimp quality requirements.

Terminal Cross Sectioning is a quality validation technique that is not new to Wire Processing. The use of cross sectioning has broadened over the past few years and cross section systems are now appearing outside of the quality lab and on the factory floor. This trend is expected to continue in the coming years. Cross section labs are expected to be as commonplace as a pull tester in most processing facilities.

In the past, quality tests of a terminal crimp were performed by only a pull tester and being a destructive test, it was a first off and spot in process inspection.  But it certainly did not take into account the inherent process variation of the crimp process itself. Later on as electrical performance demands increased, it was necessary to improve the quality inspection processes. At the same time, crimp design advanced and no longer was just pull test sufficient. Enter crimp compression.  Crimp compression standards were a result of studies into crimping and it was determined that a predictable percentage of crimp compression was needed to assure optimal electrical performance. Crimp Height is based on optimum compression of the wire during the crimp process.

With Cross Section analysis, we can now peak inside the crimp. This cross section analysis provides us with a great amount of detail into not only the materials (wire and terminals), but how they are crimped together.  Information that is used for documentation and archival purposes.  An important aspect of cross section analysis is process improvement. Some of the measurements available from cross sectioning a crimp include:

• Crimp Height
• Crimp Width
• Crimp Compression
• Crimp Height to Crimp Width ratio
• Capability Studies including crimp height.

Process Improvement is a necessary component of any company who wishes to reduce their processing costs (material waste and processing time) as well as improving overall productivity. Cross Section analysis can be a valuable tool in process improvement. For example, crimp monitor alarms. Crimp monitors signal an alarm when an element of crimp quality causes excess variation.  Often the suspect parts appear normal and acceptable. Production continues. Later on another alarm occurs.  Same condition.  Parameters are opened up and production continues without alarms. But the underlying problem still exists. Once this cycle starts, the monitoring system becomes less sensitive and at some point only gross errors can be detected.  And the risk of accepting defective parts also increases.

Cross Sectioning a crimp offers one way of detecting an issue that could be quickly assessed and a resolution put in place. See the illustrations below.

Crimp wings touching crimp floor.

Uncompressed strands and uneven strand distribution.

These are two examples of conditions which can cause variation which a crimp monitor interprets as a defect. Which can affect electrical performance.

Embracing Cross Section Analysis as a critical validation tool is important for companies in the future. Costs have come down to the point where most companies can justify a base system for plant deployment. The WPS Cross Section Service is another way to get your analysis completed while working out the deployment of system for internal use.

Connect Your Way to WPS.