Terminal Crimp Quality is one of the most critical factors in a wire assembly. Your wire assembly has numerous connection points, and most of them have a connector to facilitate this connection. It only takes one bad connection to render an entire electrical assembly inoperable.

The wire-to-terminal crimp is composed of several elements. Each element has its own process capability. The crimp itself has physical factors which contribute to an acceptable electrical connection and mechanical strength. Crimp Physics are well established and essential to ensure an electrical connection with low electrical resistance and high tensile strength (as demonstrated by pull tests).

Conductor Crimp Height and Pull Test are the two primary measurements used in validating a crimp. Conductor Crimp Width is also an essential factor when considering overall crimp quality. But how does it fit in with these two primary measurement factors?

Crimp Tools are engineered and produced to form a terminal around a wire. Each crimp tool set (Conductor and Insulation punch and anvil) have a profile which produce the desired crimp shape. Wire is pressed into the terminal and the overall height and width assure the conductor strands are deformed at a proper compression ratio while achieving acceptable mechanical strength.

A terminal typically is designed to accommodate a few adjacent wire sizes that can be crimped without compromising electrical integrity or mechanical strength. The crimp applicator has a dial that sets the conductor and insulation crimp height to the rated wire size.

Conductor Crimp Width is not adjustable and is the same for all wire sizes within a terminal’s wire range. Where applicable, crimp height is further adjustable by a shut height adjustment on the press.

Over time, tools wear. As tools wear, the ability to maintain the height and width ratio are compromised. Small adjustments in shut height can compensate for tool wear, but the tool width is fixed. The sides of the crimp tool profile will wear to the point where the crimp height to width ratio is not met.

What are the implications of the Crimp Width being out of Spec?

• Loss of Conductor Compaction
• High Electrical Resistance
• Low Tensile (Pull Test) force.

Maintaining Conductor Crimp Height and Width is critical to assuring the proper conductor compression. Replacing tooling before the crimp height and width are compromised is very important. Despite the tendency to defer to the economics of tool costs and use tooling past their ability to maintain the proper measurements. Deferring to the latter raises the risk of crimp failure in the field.

Measuring conductor crimp width should be a parameter that maintenance tracks to determine when tools should be replaced. Conductor Crimp Width is measured using a dial caliper or Blade Micrometer.

A well equipped factory includes well maintained and capable processing equipment. Additionally a well equipped factory should also include validation and monitoring tools to assure repeatable quality. But even the best processing tools and quality tools are completely worthless without adequate worker training. Training is required for all levels of the organization, from management and supervisors to operators and maintenance. Crimping Solutions by WireProcess Specialties provides end to end support for the terminal crimp process. Visit Crimping Solutions or Connect to WireProcess to get started.

We are living in an age where communication between people is real time and instant. Now you can communicate across the globe with anyone, at any time just by picking up your favorite device.

Machines are also capable of talking to one another. What once was science fiction, is now a reality. Phrases such as IOT (Internet of Things) and AI (Artificial Intelligence) are a regular part of our vocabulary. We still have a long way to go before the Smart Factory becomes a reality across all industries. But the pieces are now available to create the factory of today and tomorrow. But like all areas of development in a company, laying out the integration starts with the right plan. And all plans require the right knowledge and the right people to ensure successful launch and operation. So where do you start? You always start with the Why.

Why Should You Network your Processes?

We are living in an area of extreme complexity. So much complexity, the average person cannot deal with the breadth of details required. So our ultimate goal should be to create simplicity out of complexity.

Our ultimate goal should be to create simplicity out of complexity.

Most tasks have some repeatable components to them. Components that can be automated so the main task can be completed with more efficiency.

Every process has its human element. When workers process their assigned task, two things can occur: errors and simple bias. Removing as many points where errors can occur is a critical factor in network and automation. Considering the following points:

• Selecting raw materials and processing tools. Have the right tools and materials have been selected?
• Are the processing instructions clearly laid out?
• Is Quality data available and as important, is it the current revision?

When a process has been in place for many years, workers become comfortable with that process. So much that bias can enter in. In the case of product quality, who makes a decision what is  an acceptable quality component? Who decides whether to place the component in the good or reject pile? And how can you be assured that the rejects are not placed as part of good production?

Removing simple bias and reducing causes of error are reasons for Network Integration.

What about process tool capability? You depend on machines to process your materials into a quality component. These machines require routine maintenance and parts replacement. Some considerations:

• Are your machines capable of repeatable processing? Is there a process in place to ensure process capability?
• What is the life span of consumable tools (cutters, punches, forming tools etc.). Do you have a process in place to replace consumable tools to ensure process capability?
• Do you have a system to enforce routine machine maintenance and consumable tool replacement?

All of these factors are why you need to consider Network Integration. Let’s consider the critical factors in your planning and integration process.

Identifying the Processes to Integrate.

Integrating as many factory processes is important. Most processes are different so a common system of communication between machine processes is key,

In the case of a typical wire harness factory, here are a few examples of processing systems:

• Bench Top Terminal Crimp Machines.

• Ultrasonic Welders (Wire Splice and Terminal to Wire Welders). Telsonic TS3 pictured below.

• Wire Twisters.
• Automated Wire Processing Machines.

A common system of communication between machine processes is key.

Platform Independence

Your factory will not only have different processes being used, often you have machines of the same processing type from different vendors. When you introduce a new vendor solution, you don’t simply throw out what you have used in the past. So in reality, you can have older process machines operating next to newer technology from the same and often different companies.

Competing companies may have their own solution. But does that solution talk to machines from other companies? Communication Systems must cover all machines whether they are older legacy systems or newer systems from different vendors.

Platform independence is critical.

Connecting Processing Machines and Quality Validation/Monitoring Systems.

You should be considering networking not just your processing machines for communicating process instructions and collecting valuable processing data .But also connecting quality validation and monitoring processes. In the case of Wire Harness Processing and the critical process of terminal crimping:

• • Crimp Height Micrometers (Conductor Crimp Height).

• • Blade Micrometers or Calipers (Conductor Crimp Width and Insulation Crimp).

• • Crimp Cross Section Analysis.

• • Crimp Force Monitoring.

• • Crimp Cameras.

C&S MPN100 Network for Benchtop Crimp Presses

These and other tools are important to ensure production starts with a validated process. And to monitor the production process for good output and to remove defects from the production stream.

Let’s face it, you don’t have all the answers. That’s why you need external support. Selecting the right companies to partner with is an important first step. Companies who are able to consider your unique requirements. Companies that have highly knowledgeable and experienced personnel to provide guidance. Along the full journey of your plan.

Connect Your Way with WireProcess Specialties to hear how our Global Technology Partners are your answer to your processing problems. We specialize in WireProcessing Solutions and Crimping Solutions.

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.

It is the same story repeated in almost every company I visit.

“We have invested in crimp force monitoring (CFM) technology for our crimp process. Invested as part of a full process automation system or installed onto bench top presses. Everything started well, but we ran into trouble along the way. We were getting false readings. The monitor was signalling an error despite the fact the crimp looked fine. After some time, our operators by-passed the monitors and continued without the CFM’s.”

You have now entered the CFM Cycle.

Crimp failure might not have happened yet but it could be looming around the corner. And that corner could be close or it could be longer off. But with every non-monitored crimp performed, the higher the probability crimp failure will occur.

What are the causes?

Typically it is a lack of understanding of the crimp process itself. Also it is possible crimping is treated as an afterthought, an assumption what looks good on the outside is the same on the inside and will perform well under normal conditions for the life of the product that a wire assembly is installed into.

Let’s consider a few factors which have likely been part of the reasoning for not using CFM’s. Or de-activating them all together.

1. Crimp Monitors do not Solve Your Crimping Problems. Click to read. Unrealistic assumptions that all crimp setups are the same, that it will be business as usual when monitors are installed. And not not using a crimp monitor as a diagnostic as well as a monitoring tool.
2. When a crimp monitor signals an error and the crimp looks good on the outside, it is the fault of the monitor itself. This can be an incorrect assumption. Cross Section Analysis is one tool to evaluate a wire termination that is causing the monitor to signal an error.

Good Crimp

Under Compressed Crimp

Let me be crystal clear about one point. The crimp process is one of (if not the) most critical processes in a wire assembly or harness. It only takes one defective crimp to render an assembly defective. And that defect may some take time over the life of the product to affect it’s performance. Don’t take the crimp process for granted, understand the crimp process, the elements that go into it and optimize crimp performance.

Crimping Solutions provides end to end support for the terminal crimp process. Crimp Performance Optimization is our program that offers support to companies who want to activate (or re-activate) Crimp Monitors. Crimp Performance Optimization leverages our decades long experience in the crimp process to provide the needed training and knowledge in terminal crimp technology. And the deployment of our tools to evaluate problem applications to improve crimp quality and the stability of the crimp process.

We are ready to help you to Optimize Crimp Performance. Connect with us to hear more.

In the past, set up of an applicator to crimp a terminal was a time consuming process. Applicators were often bolted into the crimp presses and a manual adjustment to the press ram was made in order to provide the proper pull test between the wire and the terminal. Companies would acquire a large quantity of crimp presses and most high volume applications were permanently fixed to a press to reduce set up time. But at a cost of facility floor space. This was also a time when run volumes of one application were larger and spanned days and often weeks. That was then.

Today we have presses and applicators designed around a universal press shut height. Press bases and ram assemblies accommodate quick change of applicators. The applicator adjust-ability is quick and the press is only adjusted to account for tool wear.

Despite the commonality of applicator setup, each setup needs to be treated as unique. This is even more important when crimp monitors are deployed and configured to detect small crimp variations. That does not mean significant extra time for setup. But extra effort to ensure the setup is done right and initial samples are validated and meet the quality specifications.

So what can vary from setup to setup? Let’s break those down.

Presses which are routinely adjusted to match the proper crimp height and pull test mean each application can vary from it’s intended crimp spec. As a general practice, the press should be returned to it’s calibrated shut height position after each job. When the press adjustment uses a graduated scale with positive adjustment points makes the change back to the calibrated position more predictable. When no positive adjustment of the shut height is available,then exact position of the shut height is not possible without re-calibration.

Micro-Adjustment of Crimp Press.

Presses have their own variation from press to press. If the applicator is installed in a different press, this is a source of variation. The way the applicator is installed in the press can affect the setup. Dynamic Press Analysis is a way to determine piece to piece variation within a press and between presses.

Applicator service and crimp tool replacement is a source of variation even when the same wire and terminal are used.

Wire of the same gauge but with different strand quantity and diameters is a source of variation. Crimp compression can affect electrical resistance and compression of the strands can vary with the stand thickness and number of strands. A wire with 19 strands will compress differently than a 41 stand wire.

Different wire gauges crimped to the same terminal. Each terminal has a range of wire it will crimp. The crimp geometry is designed to match the wire range. Generally speaking a terminal supplier will attempt to fit as many wires into one crimp size. Mainly to reduce the amount of terminals to produce and stock. A wide range of wires in one crimp section can affect headroom when using crimp monitors. Headroom is the difference between the force to crimp the wire and terminal and the terminal only. More headroom equals the ability to detect small crimp defects.

Different lots of terminals and wire. Variation can exist from lot to lot of materials.  Over the years, that lot to lot variation is smaller due to tighter process control by the supplier. But variation can exist so validation when materials (wire barrels/reels or terminal reels) change, a re-validation is recommended.

So why is this important? Consistency in setup is critical for consistent crimp quality. Especially when crimp force monitors are being used for in process monitoring. Crimp monitors can be affected by piece to piece variation from equipment wear, material matching and in process material changes. The more consistent these elements are, the more sensitive the process is for the monitor to detect smaller defects.

Conversely the less sensitive the process is, the more difficult it is to detect small defects. And the greater the risk of accepting defect parts.

Improving your current crimp process is ongoing. Reducing sources of variation gives a higher level of confidence in your ability to deliver a high level of quality assemblies to your customers.

Don’t know where to start? Crimp Quality Solutions can help.