Archive for wireprocess

Bend Angle. Addressing Insertion Force in Connectors.

A wire harness has a few basic qualities, critical to performance and longevity of the device it is installed into. Low electrical resistance through the harness reduces heat and improves overall electrical performance. But as important is the ease of installation and the effect installation may have on electrical performance.

As we consider the critical elements of wire harness assembly and in particular the wire to terminal crimp process, a number of variables can make or break the performance of the most important aspect of a wire harness. Bend Angle is one of those variables which is receiving more scrutiny as we work to improve overall wire harness quality.

So what is Bend Angle?

Bend Angle is the condition caused by the crimping of the terminal. The pressure on the terminal from the press (and crimp applicator) causes the terminal to extrude outward. Extrusion is a natural occurrence of material (wire and terminal) being formed under pressure. The terminal actually can lengthen slightly during the crimp process. But excessive pressure can also cause the terminal to bend upward, in the shape of a banana. The banana shape is a measured attribute which is called Bend Angle.

So why is Bend Angle critical to the wire harness? It is important for two primary reasons.

First in the fit and function of terminals loaded into a multi-wire connector. When terminals are not straight, there can be mis-alignment between the pin and receptacle. On it’s own, one matching terminal pair can be harder to mate when the terminals are fixed in a housing. Consider the compounding effect of inserting multiple (unmatched) mating pairs in a housing. This can cause installation issues for the customer who is installing the wire harness.

Second is the potential of high electrical resistance at the mating point between the two terminals. We work to reduce electrical resistance of the terminal crimp by the proper crimp and crimp tool design along with a wire range rated for the crimp. Even with close attention to the proper wire/terminal match and recommended crimp height, high resistance can occur at the mating point.

It should be noted that bend angle is not as a factor with terminals that are not encased in a connector. More ‘forgiveness” in installing terminals that are not forced to mate in a confined space.

Reducing Bend Angle.

As mentioned extrusion during the crimp process is normal and some bend angle can occur. But ultimately reducing bend angle is important. Let’s consider some of the factors that can cause bend angle.

  • Crimp Height Too Low.
  • Worn Crimp Tools.
  • The Wrong Crimp Tools.
  • The Wrong wire size for the terminal.

Not only can these issues cause bend angle, they can also affect the electrical performance of the crimp.

Measuring Bend Angle and Parallelism.

There are actually two possible measurements: Bend Angle and Parallelism.

Bend Angle is measured from the top surface of the conductor crimp to the terminal body. Bend Angle can be measured from the top and side as pictured.

Bend Angle Side View

Bend Angle Top View. 

Parallelism is a “go/no go” measurement. Parallelism ensures all points are within a tolerance window in relation to a datum point. In the case of a terminal, measuring parallelism of both the insulation and wire crimp is possible. The datum line is placed on  the conductor body and a set of parallel lines are placed on the wire and insulation crimps. The wire and insulation crimp must be enclosed within the parallel lines.


Bend Angle and Parallelism dimensions are established by the terminal supplier. And by the customer when supplier dimensions are not available

Bend Angle is an emerging issue which is expected to be introduced into crimp standards such as USCAR-21. Regardless the existence of a mandated standard of not, the condition exists for multi pin/receptacle connectors. If high connector insertion or electrical resistance are an issue, perhaps evaluating bend angle is a variable that could be checked.

Need to measure Bend Angle? We are prepared to help. Whether in house capability or ad hoc requirements, we can supply your own solution or provide this as a service through Crimp Quality Solutions. Connect Your Way to WPS to find out more.

Terminal Pull Test. Putting it into Perspective.

Pull Testing, measuring the Tensile Test of a wire to terminal crimp has been a measurement of quality since the advent of pressing a wire to a terminal for electrical assembly.

Pull Test Methods have varied from weights, fish scales, portable and benchtop manual and motorized digital. I have even heard stories of an acceptable pull test being performed by pulling the terminal by the teeth. A dentist’s nightmare.

Given today’s demands for higher reliability and failure rate approaching zero, how does the Pull Test process fit in with the other testing methods being deployed? Are you even performing pull tests properly? This article will answer these questions and more as we put Pull Testing Into Perspective.

Pull Testing Defined.

Pull Test is a destructive test designed to determine the mechanical strength of a terminal crimp. A good mechanical crimp assures the crimp can withstand the normal handling and installation process.

Considering a cross section of quality standards, typical process parameters for pull test include:

  • Disengaging the insulation support so the pull force reading is based on the wire crimp alone.
  • Pull at a constant rate of 50 to 250mm/minute.
  • Wire should be taut prior to applying pull force. Remove slack from the wire.

But Pull Test is not the whole picture.

Pull testing is not a measurement of electrical performance. A quality crimp includes a secure mechanical crimp with low electrical resistance.  Low electrical resistance comes from a crimp with a wire under compression. Terminal suppliers validate crimps by optimizing the crimp barrel size to match the wire. Crimp tool profile is also a critical factor. Using the proper crimp tool profile, the wire and terminal are compressed together. Pull and electrical resistance reading are made and the recommended conductor crimp height is established and published. It is the responsibility of the end user to follow the crimp guidelines in order to assure an optimum performing crimp. Which includes conductor crimp height as a primary measurement with mechanical pull test as a secondary standard.

A few facts to consider:

  • Pull test and electrical resistance measurements rarely follow in tandem. Typically pull strength peaks before electrical resistance. Therefore it is possible to meet a minimal pull test while not optimizing electrical resistance. There will always be a compromise between Electrical Resistance and Pull Test.
  • Pay careful attention to how the wire separated from the terminal. This is an indication of the wire compression. Strands completely broken at the wire crimp indicate over compression. Conversely strands which completely pull out of the wire crimp still in a round shape indicate severe under-compression. Crimps with good compression should primarily break outside of the wire crimp.

Depending on Mechanical Strength as your primary crimp quality measurement leaves you open for premature crimp failure. And the consequences can be wide ranging. Even a single failure can be costly. Large scale recalls (not uncommon today) can cripple even a large company.

Crimp Quality Solutions provides the resources to take your crimp processing to the next level. Connect with us today.


Objective Evidence Part Two: Do you really know?

Assumptions may be a tool used in financial forecasting in absence of actual facts but is hardly a good practice to apply to actions around product quality.

This is the conclusion of our series on Objective Evidence as it applies to the terminal crimp process.

Objective Evidence is an important concept to ensure actions from decisions are causing positive results. To review from part one:

Objective Evidence defined: “Information based on facts that can be proved through analysis, observation and other such means of research.” Source:

In this article we explore the production and process monitoring of the terminal crimp process. Ensuring the pre-production validation process continues into production and controls that are in place, effectively reduce the chances of non-conforming assemblies leaving the production facility.

Assuming everything is working simply because you implemented a new monitoring process can lead to unacceptable outcomes. From material rework locally and goods returned from a customer to product recalls. Non conforming (or poorly performing) materials that are introduced into the supply stream can be costly, in monetary and non-monetary ways.

The CFM cycle (click to view video) is an example of an incorrect assumption that simply introducing a crimp monitor on it’s own does not guarantee non-conforming crimps. The reality is Crimp Monitors Do No Solve Your Crimping Problems.

Here are a few important areas to check:

Are your Crimp Monitors detecting crimp defects?

The ability to effectively monitor crimping using a Crimp Monitor (CFM) is affected by a number of factors. The terminal/wire match is one factor, considering Headroom which can influence the sensitivity of crimp monitoring. Equipment condition is another.

  • Duplicate an crimp error like strands missing. Determine if the threshold of the crimp defect detection is acceptable based on your requirements.

Strand Missing from Crimp

Crimp Monitors provide real time monitoring of the crimp process and as stated above the sensitivity of the monitoring process is affected by each element of the crimp process. The wrong tolerance setting whether set too high intentionally or by mistake increases the risk of introducing non-conforming crimps into your product.

Visual and Physical Measurements.

Take a batch of processed wires and fan them out. Check wire position in the crimp to ensure insulation is not in the wire crimp, the bell mouth and brush positions are correct. Measure wire crimp height and pull test and confirm they meet the manufacturer’s specs.

Crimp Height and Pull Test

Operator Bias: Removing Subjectivity from the Crimp Process.

Let’s face it. After a long period of time, operators and set up people can form their own bias towards quality. Left unchecked, this bias can be a problem in improving process quality. And be a process variation itself.

Lock down the validation and monitoring process. Connect your bench and automated crimp machines into a network. Process parameters do not change over time and should be stored in a central database. Create a process where validation of process parameters is required before machines are released for production. Then monitor the process to ensure ongoing conformity to the validated process parameters.

C&S MPN-100 Network

The stakes are never higher than they are today. Exposure to liability from non-conforming products can be reduced by following a repeatable process.

Crimp Quality Solutions is end to end support for the terminal crimp process. Connect with WPS to get started.


Objective Evidence Part One: Do you really know?

Companies make countless decisions each and every day. Micro decisions affecting short term operations and macro decisions affecting the company’s big picture over the long term. Whether micro or macro, good business decisions are made using factual information. And those decisions are generally based on objective analysis and free of subjective influence.

In this series, we are going to uncover questions which can be used in an assessment of a quality system for terminal crimping.

Objective evidence is a term which applies to a wide range of situations and are a basis for an effective decision. The audit process irregardless of what is being audited use objective evidence.

Objective Evidence defined: “Information based on facts that can be proved through analysis, observation and other such means of research.” Source:

Part one will deal with questions surrounding the validation and pre-production process. Part two will cover the production and process monitoring. Here are some questions to consider.

Material Verification.

  • Are the right materials picked and introduced into production?
    • Surprisingly, the introduction of the wrong materials into the production stream is a cause of defects and rework. Hopefully caught before leaving the facility, a major issue if caught by the customer. Is your system set up to eliminate the possibility of employee error when picking materials for production?

Applicator Set Up.

  • Has the applicator been prepared for production?
  • Was the applicator inspected after the last production run?
  • Are the tooling capable of producing crimps that meet quality specifications?

Applicator Installation.

Crimp Measurements.

  • Are you following the recipe?
    • The recipe or defined measurements for crimp validation include wire crimp height, crimp width, pull test and visual factors. Pull test alone exposes you to the potential of crimps with high electrical resistance. Wire Crimp Height is the primary method terminal suppliers specify to measure crimp quality.

Remember it is not enough to ask good questions.  Acting on the answers to those questions are critical in managing a system of people, processing equipment and process monitoring tools.

Part two will focus on questions to ask during processing.

Upstream Quality Factors: Wire

A wire termination is a very simple process: take a wire and terminal, force them together using a range of crimping tools and voila, a crimped wire.

A quality crimp is altogether different. Not so much in the crimp process, it is is somewhat the same. But ensuring the wire performs well over the life of the product and the process to assemble that wire with repeatable quality requires specialized knowledge. And application of that knowledge to the crimp process. This is very critical in electrical assembly today with the cost of failure (rejects, re-work, loss of customer confidence, liability) being so high. Which is precisely why we publish this technical blog: to arm you with the knowledge and processing tools needed.

We have covered a number of topics directly related to crimp quality. Such as Headroom, wire to crimp process sensitivity. Also Crimp Tool Setup Variability. Using tools such as Crimp Cross Section Analysis and Crimp Monitors to validate and monitor crimp quality.

In this post, we are going to move “upstream” and consider the effect of the wire itself to the crimp process. Considering the elements of the wire and the effect on process variation. Also the process (cut and strip) to prepare the wire for crimping.

Reviewing and controlling all factors in the crimp process makes for more consistent results. And a level higher sensitivity to allow for a CFM to pick up small differences in the crimp process.

It all starts with quality wire. Consistent and repeatable material is critical to consistent crimp quality. And by extension, the ability of a crimp monitor to detect other defects related to the wire to terminal crimp process. Lot by lot and supplier to supplier consistency is important. Some of the factors in process variation:

  • Wire Stranding
    • Dimensions and Material.
    • Wire Twist.
    • Strand Count.
  • Insulation dimensions and material.
  • Wire Concentricity. Concentric wire allows for closer stripping of the insulation and ultimately better strip quality. Non-Concentric wire means the strip blades must be positioned farther away from the wire stranding to ensure the wire is not contacted by the blades, causing nicks and scrapes to the strands. Plus strip quality if affected.

Non-Concentric Wire

It continues with consistent processing methods. Wire Cut and Strip methods contribute to crimp quality in a positive or negative manner. Today’s technology motorized processing machines handle wire in a precision far better than previous generation machines. But they are far from infallible. In addition no matter how precise they are, external forces can introduce process variation that can affect the crimp process. Here are primary variables in wire cut and strip processing:

  • Strip Length. Length variation can be random or consistently high or low. Random strip length variation can be affected by the back pressure from the wire source. Consistently high or low strip lengths are typically programming errors from the process setup. Strip length variation can come from the processing equipment itself but is more of a rare condition than the conditions mentioned above.
    • Strip length variation whether random or consistent directly affects crimp quality. The conditions are the same whether an operator presents the wire to a “wire stop” in the terminal applicator or a swing arm on an automatic cutter presents the wire to the applicator. A strip length that is too short presents a high insulation condition where insulation is embedded in the wire crimp. Low insulation means the insulation is partly or completely out of the insulation barrel.

Example of Normal Crimp Curve

Example of Crimp with High Insulation

  • Strip Quality. A few conditions can affect strip quality:
    • Wire Concentricity. See above.
    • Blade Type or condition. Dull blades can cause residual insulation to enter the wire crimp. Universal V blades are good for most applications. But in some cases, no matter how much the blade setup is tweaked, the strip quality is not good. This could be due to the wire type. An alternate blade profile might be a better option. Such as a radius V style which cuts around the full periphery of the insulation.
  • Dirty Wire. This condition does not show up in a visual condition or as an error condition with a crimp monitor. It can affect the electrical properties of the wire. High electrical resistance is possible where contamination is severe. Contamination can be oxidation from wire that has been stored for a long time. In addition, residual oils or chemicals used in the wire production can be present.

Awareness of processing variables is critical. Applying this knowledge is even more critical. Employee training is important and could be considered one of your last lines of defense in detecting crimp defects. Good validation and monitoring tools are invaluable to assist in process control and improvement. Especially when your production depends on automation systems with high production rates. A lot of wires can be produced that are not possible to detect fast enough by a human.

Automate your setup validation to improve production efficiency and reduce the chance of setup error from the wrong information.

Crimp Quality Solutions is your end to end support for the terminal crimp process. We have the tools in your drive to take your crimp process to the next level. Do you have Crimp Monitors installed but do not use them? You are in the CFM Cycle. Crimp Performance Optimization is our solution to reactivate the crimp monitors to monitor your crimp process. Connect with WPS.

Headroom: Understanding Crimp Sensitivity

Last month we introduced Crimp Force Monitoring: Optimizing Crimp Performance. The CFM Cycle as described is a real situation that a number of companies find themselves in. Optimizing the crimp process can help to exit the CFM cycle.

A terminal crimp as simple as it appears, involves several inputs. Wire, terminal, crimp tooling, the crimp press and operator (bench) or automated machine are all factors which can directly affect crimp quality and ultimately the performance and longevity of the product the wiring is installed in.

Headroom analysis is a valuable indicator of Crimp Sensitivity. Headroom isolates the wire and terminal and the match between the two.

Headroom Defined.

Headroom is the difference in peak force between crimping the terminal with and without the wire. Headroom is typically expressed as a percentage. For example headroom of 85% means the wire represents 15% of the total peak force of the wire and terminal. The higher the headroom percentage, the more sensitive the crimp is for detecting small defects such as strands missing in the crimp. Conversely, the lower the percentage of headroom, the less sensitive the crimp process is.

What Can affect Headroom?

The terminal crimp size in relationship to the wire size is the main factor in overall headroom. If the majority of force is used to form the terminal only, then there is very little margin to add the force of the wire.

It is important to note that a wire of the same gauge but different strand count/strand thickness measure similar area. So headroom percentages are similar. But the strand count and individual strand thickness can affect the amount of strands a Crimp Monitor (CFM) can detect that are missing from the crimp. Here a few examples of headroom with different wire sizes and strand counts.

Crimp with Wire

Crimp without Wire

7 Strand Wire: Average Peak Force (wire and terminal) is 6.78 (kn). Average Peak Force (Terminal Only) is 3.82 (kn). Headroom is: 6.78 – 3.82/6.78 = 43.7%.

  • Each Strand represents 6.24% of the wire portion of the crimp. Using a +,- 3% CFM tolerance, this means the CFM can detect one or more strands missing.

19 Strand Wire: Average Peak Force (wire and terminal) is 10.9 (kn). Average Peak Force (Terminal Only) is 7.36 (kn). Headroom is: 10.9 – 7.36/10.9 = 32.5%.

  • Each Strand represents 1.71% of the wire portion of the crimp. Using a +,- 3% CFM tolerance, this means the CFM can detect two or more strands missing.

26 Strand Wire: Average Peak Force (wire and terminal) is 4.52 (kn). Average Peak Force (Terminal Only) is 2.70 (kn). Headroom is: 4.52 – 2.7/4.52 = 40.3%.

  • Each Strand represents 1.55% of the wire portion of the crimp. Using a +,- 3% CFM tolerance, this means the CFM can detect three or more strands missing. And randomly detect two strands.

These are three examples of headroom calculations. Each application will be different depending on the terminal crimp profile and wire.

It should be noted that the ability of a CFM to detect small variations is greatly affected by the capability of each input in the crimp process. What may appear to be a “false reading” on a CFM is actually variation observed by the CFM compared to the reference samples. For example, Press Shut Height or Crimp Force can cause variation when all other inputs are in control. So in some cases, it may not be possible to reduce the CFM tolerance to a lower percentage due to variation in one or more process inputs.

The terminal design can affect headroom. The overall crimp profile is affected by the end use of the terminal. In some cases the terminal may require a thicker base material and that can translate into more material mass being crimped. Making headroom less sensitive.

Headroom is one tool used to Optimize Crimp Performance. The CFM-Lite CFM for Bench Presses is from C&S Technologies. This is a powerful tool for not only monitoring the crimp process but helping to troubleshoot crimp applications. Headroom analysis is a part of the CFM-Lite platform.

C&S CFM-Lite

Crimp Performance Optimization is part of Crimp Quality Solutions, end to end support for the terminal crimp process. For more information on how we can support your crimp process or the CFM-Lite, Connect Your Way to WPS.

Crimp Force Monitoring: Optimizing Crimping Performance

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.

Crimp Quality 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.

Understanding Crimp Tool Setup Variability

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.

Applicator and Crimped terminals.

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.

An Appliance Recall. Breaking down the Cause of Electrical Failure.

As I write this, a name brand manufacturer of appliances is adding to the list of recalled Dishwashers from defective power cords. The power cord can overheat, causing a serious fire hazard. The recall extends several years and affects a number of models under different brand names. I am not going to name names, a simple internet search can give you all the information on this recall. What is significant about this recall is that there were five reports of property damage which has affected over 600,000 models. A relatively small cost part over five failures has created a massive recall involving two countries (USA and Canada). Risking hundreds of thousands of lives on top of monetary cost and cost to reputation.

We are going to drill down to the cause(s) of the component failure. Also the greater implications of all manufacturers of electrical components. And how preventative measures by applying tools and quality practices can greatly reduce the risk of component failure.

What Causes a Power Cord to Overheat?

High electrical resistance at any point along the length of the cord is a typical culprit for  excessive heat. High Electrical Resistance is caused by a number of factors. In the case of a wire assembly some factors are outlined below:

  • Wire size too small for the rated current that flows through it.
  • Connector Crimp and Wire are not properly matched.
  • Poorly crimped terminals
  • Crimp Equipment.
    • Not set up correctly.
    • Worn Tooling
    • Inconsistent Crimp Press Force.
    • Crimp missing strands.

Crimped terminals are a core connection in a wire assembly and can be a source of high electrical resistance.   High resistance in crimped terminals is directly attributed to too low and in some cases too high compression of the wire strands within the crimp. There is a direct correlation between crimp compression and electrical resistance. Crimp compression cannot be determined without cross section analysis. Pull test does not provide an accurate measurement of crimp compression (and by extension: electrical resistance). In some cases, pull test can actually decline slightly before resistance peaks.

There is a direct correlation between crimp compression and electrical resistance.

Terminals that have a crimp barrel that is too large for the terminal can cause low compression. Improper crimp tooling can also contribute to inconsistent crimp quality. Worn crimp tools, improper crimp tool setup and press force that can vary from piece to piece can also lead to inconsistent crimp quality.

Wire stripping equipment can also cause inconsistencies. Worn blades or improper machine setup can cause cut strands.  Cut strands can reduce the total compressed area in the crimp which can increase resistance.

Prevention is the Cure.

The difference between this recall taking on the dimension it has and not even happening at all could be simply a few missed checks in the assembly process. We are going to get really specific and focus on the terminal crimp process. Consider the following:

  • Knowledge of the assembly process is critical. But it is not enough. Assuming wire assembly is a simple process that does not require constant monitoring can be a critical mistake.
  • Understanding each factor in assembly and their inherent variability is important. In the case of crimping a wire to a terminal, there are five basic elements to consider. Any of these factor which are not in control can affect quality.

Where do you start?

Manufacturing Machines are well maintained and capable of repeatable piece to piece consistency. Static calibration and single piece measurement does not guarantee statistical capability. Dynamic measurement provides the way to measure process capability and repeat-ability.

Tooling is replaced before quality is affected.

Manufacturer’s Specifications are a critical start to a process validation.  Suppliers spend a significant amount of resources in developing components and the associated assembly instructions and quality standards. For example, quality standards for terminals include crimp height measurements and minimum pull test standards.  Crimp Height measurements are created which are based on optimum crimp compression.  Validate using Crimp Cross Section Analysis.

Use the Right Measurement tools. For terminal crimp height, use crimp height micrometers. Other measurements can be made by blade micrometers or dial calipers. Pull test as a secondary measurement. Cross Section Analysis for more in depth analysis of the wire under compression.

Crimp Height Micrometer

Correct Materials are used. Ensure the wire is matched to the terminal based on the supplier’s specifications.

Measure when material lots change. Materials within or between lots can cause variation in the crimp process. Re-Measure to assure there no changes in materials.

When a failure occurs of this magnitude, it can be a wake up call for the companies involved. But it also can be a valuable lesson to others.  Don’t take a chance with the future of your company. Ensure your crimp process is validated and monitored prior to and during the production process. Crimp Quality Solutions provides valuable tools and knowledge for the terminal crimp process.

Components and Processing Solutions for Large Cable Wire Processing.

Wire comes in a multitude of sizes and configurations and is used in a vast number of electrical and electronic devices and assemblies.  In recent years, efforts to reduce overall weight of a wire harness mean smaller wire gauges and thinner wire insulation are being used.   At the same time electrical demands of some products have increased the requirement for larger cable, able to handle a higher current load.  The automotive industry is a prime example of the demands to address both ranges; smaller to bring weight down for more fuel efficiency and larger for emerging applications such as electric car batteries and hybrid fuel cells.

This article will focus on processes and components used in assemblies with large cables.

Defining Large Cable Processing.
For the purposes of this article, we will discuss processing (cut, jacket strip and wire end process assembly) on wire 6 awg and larger. Also multi-conductor cables with individual insulated wires encased in an outer insulation jacket or sheath. In general, as the wire size increases, the production volume decreases.  Production volumes typically dictate whether single or multi stage processing solutions are deployed.  We will outline single and multi stage processing solutions.

Single Processing Tools

Processing tools that perform a single function.

Wire Cut


The Wezag SH Series Hand cutter series features a ratchet action and can cut wire up to 350 mm in diameter.


The Model 31 from Carpenter Mfg is a lever style wire cutter designed to cut wire and other materials.  Featuring a guillotine blade, and adjustable wire guides, the model 31 can cut material 1″ in diameter and 4″ wide.  Wire up to 0 awg can be cut and (material dependent) up to 2/0.



Wire Strip

The Carpenter 72C is a dual blade rotary wire stripper.  The 72C processes a wide range of single and multi-conductor wire.  Quick change wire guides center the wire for nick free processing.




The Carpenter 77E wire stripper is a pneumatic heavy cable wire stripper.  The large wire grippers provide high pulling power for tightly bound insulation and large cross sections.  The 77E uses fully adjustable V blades and quick change wire guides for accurate and repeatable processing.  Form blades can also be used where V blades do not provide the desired results.


The Beri.Co.Megamax is a heavy duty programmable wire stripper capable of multi-stage precision wire stripping for cable up to 25.00 mm wire diameter. The Megamax can process large OD coaxial wire. The Megamax is one of three high capacity multi-stage wire strippers available through our partner Schaefer Megomat.

Wire Crimp


UP60Wire Process Specialties supplies crimp technology for loose and reel fed contacts.  The WDT (Wezag) UP60 shown at the left is a pneumatically activated crimping press that can crimp large terminals such as battery lugs up to 180 square mm.  Interchangeable adaptors with a wide range of die sets provide maximum flexibility.



Multi-Stage Wire Processing

Process machines that perform more than one function during a single machine cycle.


The Compu-Cut 42B is a heavy duty wire and tubing cutter with a 4″ wide blade and 1″ opening.  Flat cable and tubing as well as round wire and multi-conductor cable can be processed using the 42B.  Add additional wire separators and multiple rows of material can be processed to maximize production quantities.  The cutter head is pneumatically operated and the feed unit is electrically motor driven for accurate cut lengths.

The Compu-Cut 36A is an additional option for cutting heavy duty wire. With a special guided blade holder and a standard utility knife blade, the 36A makes precision cuts on large gauge wire as well as semi ridgid tube.

Terminals and Connectors

ETCO is a supplier of terminals and connectors.  ETCO has two manufacturing facilities in the USA for processing reel fed and loose piece heavy duty terminals.  ETCO terminals are manufactured to exacting quality requirements using state of the art fabricating equipment.

 The connector at left is a top post battery terminal.  This is one of many terminal styles for heavy cable and power cords.  ETCO can also supply custom fabricated connectors to your design.

Special Processes

The Judco FLG2 processes heat shrinkable tube around large cable, battery lugs or other connector systems.  The FLG2 is energy efficient and shrinks tube fast with low cost quartz halogen bulbs and mirrors to focus light energy around the material being processed.

These are a few solutions for processing wire and cable harnesses available from Wire Process Specialties, your authority in wire processing, connectors and terminal crimp technology.  Connect Your Way to WPS to see how we can help your company reduce cost and improve the efficiency of your wire assembly processes.