Archive for November 2019

Crimp Force Monitors: Factors When Implementing In-Process Monitoring.

We have written about Crimp Force Monitors (CFM) many times over the past few years. The Crimp Force Monitor is a critical tool that provides real time monitoring of the crimp process.

Crimp Monitors can detect quality issues with upstream processes such as wire. Also Crimp Monitors provide valuable information on equipment conditions and variability in Crimp Tool Setup.

In this article we are going to discuss some of the important considerations for implementing a Crimp Monitoring Program. Whether it is on an automated cutter like the Megomat 600 or a benchtop crimp press, getting started properly will better ensure a successful implementation.

The first and most important point when implementing a CFM program is to understand what CFM’s are not.

Crimp Force Monitors do not solve your crimping problems. They will bring quality problems to the surface, problems you might not know actually exist. Awareness of issues in crimping is the first step to a consistent and repeatable crimp process. It is common when using Crimp Monitors for the first time to blame the Monitor when a crimp application experiences frequent CFM alarms.

Crimp Monitors do not solve your crimping problems, that is your job.

Culture Change. Consider this fact: things will be different after implementation. How you approached crimp quality before will change. This is a whole company effort not just the domain of a few quality people. Workers on the plant floor will need to be trained. Attitudes will need to change. Consistency is king. No more adapting to make it work, CFM’s require consistency in order to separate process noise (external variables) with the consistent factors and you need to work to eliminate those variables.

No Crimp Set up is identical.  Treating all crimp application as equal will lead to problems. Wire/Terminal match, crimp tool shape and condition are variables that differ from application to application. Some are naturally more sensitive than others.

Understanding the five elements of a crimp. A typical terminal crimp is comprised of five elements: Wire, Terminal, Operator, Applicator and Crimp Press. The match between the wire and terminal is critical. Mismatched terminals and wire can cause piece to piece variation due to the movement of the wire in the terminal during the crimp process. Crimp presses that are not maintained with loose ram movement and worn ram adapters/base plates is also a source of piece to piece variation.

Constantly improving the process. Identifying problem applications and prioritizing them for process improvement is important. Employing analysis tools can help to uncover core issues that cause inconsistencies. Cross Section Analysis is an essential part of quality improvement efforts. Headroom Analysis identifies the sensitivity of the crimp process based on the force to crimp the terminal with and without the wire. The C&S CFM-Lite includes built in Headroom Analysis.

C&S CFM-Lite

Creating a repeatable validation process. Validating your crimp process is a critical step. Considerations:

  • The right terminal and wire for the circuits being produced.
  • The right applicator tooling and just as important, well maintained and production ready tooling.
  • A Crimp Press that provides repeatable shut height and crimp force. Maintained and free of debris.
  • Calibrated Measuring Tools including:
    • Crimp Height Micrometers (Conductor Crimp Height)
    • Blade Micrometers (Conductor Width and Insulation Height and Width).
    • Pull (Tensile)Tester.
    • Cross Section.
    • Bend Angle (if applicable).

A system to record and maintain validation and in process measurements. This could include a manual record keeping system. Although cost effective, there are risks in workers transposing numbers incorrectly. Also pulling the wrong materials and tooling. In an age of the connected factory, consider network connected equipment and measurement tools that force critical validation elements to be checked.

Quality Parameters. Who makes the decisions?  Crimp Monitors use tolerances which are applied around a teach-in value (average of test pieces measured prior to production). These tolerances can be adjusted to suit each crimp application. Which can make the measurement of crimp force more or less sensitive. Access to the tolerance setting can be open or restricted.

When tolerance setting is left open, there is a risk of un-trained workers making adjustments that can allow for defective crimps to pass undetected. This can create a behavior we call the CFM Cycle.

Avoid the CFM Cycle. Restrict access to the tolerance setting to trained personnel. Address problem applications with analysis tools such as Headroom and Cross Section.

Summary. Creating an implementation process at the start prevents problems on the factory floor and with Crimp Quality.

Crimp Quality Solutions is a great place to start. With end to end support for the terminal process, we provide the knowledge and resources you need. Connect with WireProcess to start the conversation.