Tag Archive for Crimp Quality

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.

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.

Crimp Quality: Scaling it to Fit.

“Quality is never an accident. It is always the result of intelligent effort” – John Ruskin

I am sure this quote from a 19th Century English Art Critic was applicable in the era it was written.  But it is no less applicable today.

“Quality is never an accident”. Nor does Quality simply happen. It takes effort to create, build and maintain an effective quality system. The stakes are higher today than any other time in history. The cost of a reject or recall can cripple a company. No company of any size is immune from the effects of a reject claim. Can you afford the risk?

“It is always the result of intelligent effort”. Yes, you must invest time and resources. People in the company from the top to the bottom need to be actively participating in efforts to create a quality system. Ask yourself these few questions:

  • What does our existing quality system look like?
  • Is it contributing to reduced internal rework costs?
  • Is it effective to reduce the risk of defective goods leaving our facility?
  • Do we have sufficient internal resources to improve our Quality System?
  • Do we need to consider outside sources to ensure we are keeping up with emerging trends in Quality Management?

Putting it into perspective, a quality system needs to fit the company’s size and structure. What is critical to large companies with big supply contracts and the associated requirements to fulfill may not be applicable to a smaller company. But even a small company should have a basic system of Quality which should be enhanced over time. Let’s get specific and drill down to the topic of Crimp Quality. Considering the pre-production validation and process monitoring, consider the essential tools for a basic Quality System:

Validation

  • Crimp Height Micrometers
  • Blade Micrometers (or Digital Calipers)
  • Pull Tester
  • A system of recording measurements

In-Process Monitoring

  • Validation Tools above
  • Crimp Force Monitors on bench and automation mounted crimp presses.
  • Visual Inspection Requirements
  • Requirements for Frequency of Measuring production

What Else?

Knowing what a good crimp is (and isn’t) is not evident with a visual external inspection. You need to look inside. Often a view of the interior of the crimp can quickly provide clues to conditions which can affect quality and contribute to increased processing costs of rework. For example:

  • Constant Crimp Force Monitor Alarms (avoid the CFM Cycle)
  • Wire assembly failures. High electrical resistance which can cause an overheard electrical connection.

For this you need to Cross Section the Crimp. This gives you a view into the material matching (wire/terminal) as well as the process tooling.

Bend Angle is a condition from the terminal crimp process. As a wire is crimped to a terminal, material is extruded outward and can cause the terminal to bend (banana shape). This condition can cause mating issues when connectors are mated together. Also, a potential of high electrical resistance in extreme cases of mating miss-alignment. An emerging measurement requirement in USCAR 21 for automotive wire harnesses.

Networking Crimp Quality.

Software and hardware networking are becoming more economical solutions to handling data. The right automated solution can reduce pre-production validation time and errors from manual data entry. Also, it removes subjectivity from validation and in-process monitoring (it looks like a good crimp therefore it is a good crimp – a big mistake in thinking). Do you Trust or Validate?

What about Equipment Maintenance?

Most companies have a maintenance program for their processing equipment. But is it effective enough? How many crimps from a set of tooling? I have calibrated our crimp press(es) but have I determined its (their) capability to produce repeatable crimp force and shut height?

Knowing comes before Doing.

Let’s face it, we are not experts in everything. Nor should we pretend to be. It is easy to start without the knowledge of what is needed. But is it effective? Industry Experts can come alongside your personnel to guide the process and provide critical advice to focus your efforts.

Scaling Crimp Quality is important in all companies who process wire assemblies. One size does not fit all. If you already have a crimp quality system (which we hope you do), what knowledge and tools do you need to make your system better. If you do not have a crimp quality system and no reported quality failures, the clock is ticking for one which could come. Don’t take the risk, obtain the knowledge of what is needed and get started with the basic tools.

Crimping Solutions could help you. Connect with us and Let’s Get Started with an assessment of your current condition.

Quality on the Plant Floor: Trust or Validate? 

We live in an environment of automation. Everywhere there are new developments in systems for making our lives more convenient. Our smartphones have become “smarter” with virtual assistants that have the right answer at the right time. Casual dialog is filled with terms like “virtual reality”, “artificial intelligence” and “the internet of things”. People are more connected now than any time in human history.

As the plant floor is automated how do we mix people decisions with those made by machines? Do we continue to trust the good but perhaps biased intentions of a worker. Or do you free them from routine decisions with the assistance of machine based systems?

We will dive into this topic and specifically in the crimp validation process. What is the decision process for the wire termination your worker has in their hand before they start producing wires? That decision has far reaching implications. Here are a few points for consideration.

Good information is critical.

Quality standards are derived from the source of the material. In the case of electrical terminations the terminal supplier is your source for measurement standards. Factors such as crimp height and width for wire and insulation crimps, pull test and visual standards. Also associated tolerances.  This information should be collected for each process setup and can be stored into a server computer.

Although not a core part of this discussion, the proper tools are also critical. For Crimp Validation, use only Crimp Height Micrometers for measuring conductor crimp height and calipers or blade micrometers for conductor crimp width as well as insulation crimp height and width. Pull test as a secondary measurement of crimp secure-ness and Cross Section Analysis to verify the internal crimp shape.

A system to pass that information to the personnel on the plant floor.

Good information is useless unless it is available for proper pre-production validation. Connecting client computers at locations on the plant floor or data entry modules on the processing machines provides provides an access point to retrieve the validation standards required. Also a potential portal for entering validation data for trace-ability and analysis.

A process that removes subjectivity from the decision to start production.

The operator of inspector has a pre-production crimped wire in their hand. At this point how do you verify the wire has been measured and meets all of the established standards. Or a few measurements pass and a few do not.

Without adequate controls, subjectivity be the plant floor personnel can creep in. Perhaps the rush to get into production can pressure personnel to cut corners and accept parts which do not fully meet quality. No matter how well trained personnel are, they are the last line of defense in pre-production and opinions can affect judgement.

Locking the equipment out of production until pre-production samples pass quality test is an important move. It is important to assure your personnel that this is not personal against them. Rather it protects them from fall out in failure conditions.

A properly configured network system with modules on production equipment can perform the dual function of production validation and release of the processing equipment for production.

In-Process Changes affecting Quality

Any change during production is an opportunity to introduce variation into the process. In the case of a wire termination, changing wire (reel or barrel) and terminal (reel) can change the process. In the case of applicator tooling, when the applicator is removed for maintenance like crimp tool changes, this is also a possibility for variation.

This presents you with two options: you can continue without validation or validate when the process changes. Not validating represents a risk which is hard to quantify. Material suppliers and tooling can have varying effects. The safer option is to perform a validation to confirm the changed process matches the initial validation. Having the ability to lock out the process equipment after a material change or maintenance and forcing a validation is a good practice. This removes any subjective opinions from creeping in.

Measure, analyze and improve.

What gets measured gets improved.  Having good information as a baseline is a good first step. The next step is analysis. Considering the strengths and weaknesses. Focusing on those areas that can contribute to long (or short) term failure in a product. Then acting on the analysis. This is fundamental to any quality improvement process.

There is a great amount of information that can be pulled from validation and in process monitoring of production. The important factor is the system. You can pick a manual method or automatically collect data from production machines and other measurement sources. Choosing an automated method removes a significant amount of manual data entry not to mention the potential of transposition error.

Tying it all Together.

You likely have most of the piece in place to automate the quality process. From production equipment to the measurement tools to validate and monitor output. Having a central server with validation standards and production data is a gateway. Connecting the components together provides the pathway for good two way communication between the plant floor (people and machines) and the server with the data collection and analysis capabilities to turn raw data into useful information for analysis and quality improvement.

Crimping Solutions and our Global Technology Partnership with C&S Technologies is your source for the technology needed in an ultra competitive manufacturing environment.

Connect Your Way to WPS and Let’s Get Started.

How Do You Inspect Your Crimps? A Seminar Review

At the 17th Annual Electrical Wire Processing Technology Expo, Terry Curtis President of WireProcess Specialties presented the seminar “How Do You Inspect Your Crimps?”. This seminar was presented as a teamwork effort between WireProcess and our Global Technology Partner: Crimping and Stamping Technologies.

The seminar was presented to a capacity crowd at the Expo. This speaks into the need for more information on crimp validation techniques. Crimp Quality is a topic we as a company are passionate about.

Terry Curtis, WireProcess Specialties at the 2017 Electrical Wire Processing Technology Expo.

Terry started the discussion by stating ” it only takes one bad crimp”. It only takes one miss-applied crimp to render a wire harness defective. There are a range of implications from repair of the affected harness to in house sorting of larger batches of harnesses. Certainly the customer relationship can be affected with legal liability a possibilities in severe cases. Can you company afford the risk?

A Quality Crimp: It All Starts Here.

A quality crimp starts with fundamental crimp specs, typically established by the terminal supplier. This includes the physical geometry of the crimp section, visual attributes and measurement standards. An emerging specification (bend angle and parallelism) which affects the mating of connectors was presented.

Bend Angle can cause interference issues with connector mating.

An excerpt of a comprehensive study into crimp compression as it affects electrical resistance was shared to illustrate the co-relationship between compression and electrical resistance and the effect compression has on mechanical crimp strength (Pull Test).

The take away from this section was the terminal suppliers based on their design and testing of crimp geometry produce a “Recipe” to follow. The end user’s task is to “Follow the Recipe”.

Apply the Recipe.

Pre-Production validation involves taking the “Recipe” and ensuring the specifications are met. Prior to production start. Required measurements, methods and the proper measurement tools were discussed. Visual inspection was also covered as well as a few tips on how to spot a wire under compression in a terminal were uncovered.

The shape of the terminal, measured through Cross Section Analysis shows how the crimp tools form the terminal and the distribution and compression of wire strands. A good indicator of crimp to crimp consistency and a factor in “false CFM readings” (which are not really false at all).

Production Monitoring.

Validation alone is not sufficient to assure the quality will be maintained through the production run. Factors which can affect quality during the production run were discussed. Also stressed was tools which are used in the validation process are also used to measure crimp quality during production.

A Crimp Monitor (CFM) is an essential tool in process monitoring. The CFM provides 100% real time monitoring of crimp force and detection of typical crimp defects.

The CFM Cycle, a topic introduced in our 2016 seminar outlines what can happen when constant alarms from a CFM are not investigated for their cause and CFM tolerances are opened up to stop the CFM alarms.

Applicator and Press Capability and Maintenance.

Applicators and Crimp presses are the two critical processing tools for the crimp process. Maintaining this equipment to ensure they provide statistically repeatable crimp performance.

Ensuring the Applicator crimp tools are within the manufacturer’s specifications is the most critical attributes of an applicator. Also important are feed and cut off system and general wear of the applicator body and feed track.

The press is the common factor and sees more wear and tear than an applicator which is removed after production. Assuring the shut height is calibrated is one factor. But statistically repeatable shut height and crimp force is required to assure consistency during production. Press Analysis is a very important aspect of equipment maintenance.

As illustrated below, a repeatable press (Shut Height and Press Force) equals smaller tolerances with the CFM which means the CFM’s ability to detect smaller defects is increased. The converse is true when a press is not repeatable. This equation also can apply to the Applicator.

Networking.

A validated crimp indicates the recipe is followed, and production monitoring assures the process stays within the validated tolerances during production. But what about your plant personnel? What happens when all of the materials and processing tools converge for production?

  • How can you be assured that the right materials and tooling are used? And what about validation specifications. Are they followed?
  • What about material and tooling changes, how do wire and terminal changes as well as applicator maintenance affect the initial validation?

Networked production equipment and measurement is a way to assure the right materials and tooling are deployed. Also measurements attributes are validated and re-validation occurs when process parameters change.

Management Support.

Any quality initiative lives and dies with Management support. Management needs to be actively involved in assuring resources are acquired and deployed, personnel are trained, systems are created and they measure the overall improvement of quality. Cooperation between functional areas (production, quality, set up and maintenance) are ensured.

How Do You Inspect Your Crimps? A fundamental understanding of crimp development and validation techniques is an important first step. Production Monitoring ensures validation specs are maintained through the Production cycle. Using the right tools for both Validation and Monitoring is very critical. Maintaining production equipment is also critical to assure consistent piece to piece results. Networking ties it all together and removes some of the routine decision making from plant floor personnel. Quality Improvement programs live and die with Management support.

If you are evaluating your current crimp quality system, get started right with Crimping Solutions. End to End support for the terminal crimp process. Ready to get started? Click here.

Connecting the Dots: Pre-Process Validation to Production Process Monitoring 

By their body language and words, companies say it all;

“Why monitor our crimp process with more than the most basic of tools? After all over the years, our products have performed with no problem without adopting more than is necessary?”
On the surface this may be true. But lurking under the surface are problem issues that can costing your company now and in the future.

Consider the following scenarios:

  • Internal process rejects or rework that goes unreported. Like a bad crimp that is simply clipped off and an operator re-strips the wire and crimps a new terminal to the wire. Adding variation to the process by manually processing the wire without validating the results.
  • Mismatched wire and terminals. A mismatch between the terminal and wire, especially the terminal being too big for the wire can cause excess variation in the crimp process and electrical performance issues like high resistance. Process variation is a hidden cost to production while high electrical resistance is a potential long term product failure.
  • Worn production tooling creating batches of parts which can create assembly issues upstream. Deformed terminals from compensating for worn tools are one problem.

Mainstream OEM terminal suppliers invest an extensive amount of resources to ensure the connector they design performs properly on the factory floor and in the actual product over it’s life expectantly. They provide the processing test requirements to assure the terminal is assembled properly. So why do so many companies not validate their assembly to the recommended specifications, never mind monitor their assembly process?

Consider the Cost of Inaction (the status quo) as a reason.

So let’s talk about the transition from pre-process validation to process monitoring. For that you need to think about this fact:

In a lab environment, processes are controlled and highly repeatable. In a production environment, external variation exists which can affect the final product quality.

Without real time process monitoring, depending on single or spot in-process inspections does not give you any solid information on the capability of the terminal crimp process. And that is a missed opportunity for process improvement which can provide improved efficiency and reduced process costs. Which is the Benefit to the Cost of Quality.

One important point to remember is that process monitoring tools do not improve quality in and of themselves. But they can raise issues on individual setups which should be reviewed at the time. Otherwise you can be trapped in the CFM Cycle.

Using the right tools in crimp development and validation in addition to process monitoring can provide the opportunity to improve crimp quality. Establishing a base line of quality and deploying a quality improvement strategy can reap great dividends in cost reduction, customer retention and potential for new customer acquisition.

Crimping Solutions provides end to end support with your terminal crimp process.

Crimp Quality Solutions: Training and Support Services

Training, Consulting and Support Services are an integral part of Crimp Quality Solutions, part of the WireProcess Specialties portfolio of solutions for processing wire assemblies.

One of the strengths of WPS for almost four decades has been in the supply of terminals, crimp tooling and crimp monitoring systems. It has become evident that a comprehensive offering to our customers is needed. Which is beyond the physical acquiring and deployment of components, processing and process monitoring monitoring equipment.

For example, consider this statement:  Installing a Crimp Force Monitor does not improve quality. See our article: Crimp Quality Monitors Do Not Solve Your Crimping Problems.

Our engagement starts first with an assessment of your current crimp process. We can perform this either in house or through a virtual connection.

Training material is custom tailored to the company’s needs with one or more of the following topics:

  • Pre-production crimp validation
  • Crimp Process equipment set up
  • Pre-production crimp testing
  • In-process monitoring
  • Documentation

Training can be performed in house or via webinar.

Crimp Quality Solutions Support Services are a vital link in the implementation of a Crimp Quality improvement strategy. Our in house Crimp Cross Section lab gives you a start in documenting crimp conditions. Crimp Press Analysis assesses the condition of your crimp presses, a critical component of your crimp process. Crimp Cross Sectioning is a vital tool in validating and process monitoring a crimp. Cross Section provides a peak inside the crimp and tells a lot about the performance of the crimp process and inherent variation.

Crimp Quality Solutions provides you with end to end support in your terminal crimp process. Let’s Get Started with your crimp process.

Crimp Quality Solutions: An Overview

Back in the day, training for personnel was readily available from suppliers or internal company experts.  Does it seem that access to training and has become scarce.  Do you sense the “brain drain” as knowledgeable people are retiring and not being replaced? Perhaps Crimp Quality Solutions is for you.

Crimp Quality Solutions is part of the WireProcess Specialties portfolio of solutions for companies processing wire harnesses and electrical assemblies which include a terminal crimped to wire.

Consider the following questions:

  1. We only make a quick measurement of crimp quality and a visual inspection pre-process.  We do not have any idea what the capability of our crimp process is.
  2. We have received a review request from a customer about our crimp quality or have had to address rejected wire harnesses with faulty crimps.
  3. We have installed crimp monitors to our bench presses or automated wire processing machines and have chronic error signals from one or more crimp applicator set ups. As a result, we have opened up CFM tolerances to stop the error signals or completely shut off the monitors.
  4. We want to establish a baseline of our crimp quality and improve quality over time.

If you answer yes to any of these questions then Crimp Quality Solutions is for you. We offer end to end support of the crimp process. Our support covers three areas:

  • Training and Consulting.
  • Support Services.
  • Quality Validating and Monitoring Technology.

We start with a free assessment of your current crimping process. We review the assessment and where required, consult with our industry experts and provide a proposal that covers one or more of the above areas of support.

If you do not measure crimp quality as part of your quality system, you are at risk of product failure, costly rejects or recalls and reduced customer confidence. Because it has not happened so far does not change the fact it could in the future. There is a cost of inaction when it comes to product quality.

There is a positive cost to action and we are ready to respond and support your crimping process. Let’s Get Started.

What can other industries learn from Automotive standard USCAR21?

USCAR21 Title

USCAR-21 is the quality standard that can strike fear into companies who deal with automobile assembly companies.  USCAR-21 is a universal standard which applies to suppliers of electrical assemblies to The Ford Motor Company, General Motors Corporation and Fiat Chrysler Automobiles.

Companies who are not involved with automotive wire harnessing can quickly dismiss this standard as not applicable to their business and industry. Although this is true, some of the components of USCAR-21 are valuable and can be directly applied to the validation of wire terminations for any industry. Companies not considering some of the key features of USCAR21 can miss out on the benefits to quality improvement.

We will drill down to reach those best practices which can be applied to your company.

Prior to the formation of USCAR-21, each automobile manufacturer had their own testing and validation standards. The adoption of a common standard meant more efficiency in the testing process, especially for suppliers who provided wire harness across a number of automobile OEM’s listed..

The USCAR-21 standard includes mechanical and accelerated environmental tests which are designed to duplicate potential operating conditions a wire to terminal connection can experience through the expected life cycle of an automobile. Demands on the electrical system are increasing with smaller wires carrying communication signals and larger wires used in current load in applications such as EV batteries. A comprehensive standard was required to address the performance requirements through the full range of harness size and complexity. At the same time, to reduce some of the bureaucratic burden from the supplier end.

Lets bring USCAR-21 down to it’s most basic objective: Electrical connections must maintain low electrical resistance through the expected life span of an automobile. This is achieved by adhering to critical crimp design and validation criteria.

Ultimately, monitoring the crimp process during production is important to ensure specifications from the validation stage are maintained.

Here are a few considerations to the actual electrical crimp.

  • The terminal supplier’s recommended crimp height and width is the starting point of all initial and pre-production crimp validation. Wire terminations should perform acceptably though the tolerance range of the recommended terminal crimp height.
  • Crimp compression, the process of encapsulating the wire into a crimp barrel with sufficient force to deform the strands from their round shape is a major factor in acceptable electrical resistance. Compaction of the strands by 15 to 20% provides the best opportunity to pass electrical resistance testing. There is a direct correlation between the amount of wire strand compression and electrical resistance. Especially leading up to and through the above compression range.
  • Crimp barrel and wire size must be carefully matched to ensure the optimal compression is achieved. In combination with the proper crimp tool design. Factors indicating a poor wire to terminal match:
    • Wire strands under-compressed.
    • Strands not evenly distributed in the crimp barrel
    • Crimp wings curl and touch the bottom (floor) or sides of the crimp barrel.
    • Crimp wings with a gap at the top, with strands not fully encapsulated in the crimp or pressed on top during the crimp process.
cross section (130)

Cross Section showing under compressed strands and voids.

  • Serrations in the crimp are designed to break oxides present on the surface of wire strands, providing better electrical connection. Also to assist in the mechanical secure-ness of the crimp.longitudinal cross section 5

Consideration of measurement methods.

  • Crimp Height is the primary test factor in a validation and in-process measurement.

CHT Mic

  • Tensile (Pull) testing is a secondary testing method to ensure the wire termination has “sufficient mechanical strength”. It is not a determining factor of electrical performance as low or high compression can affect not only mechanical but electrical performance.WhatsApp Image 2016-11-10 at 9.31.28 AM
    • In all cases, insulation support on terminal crimps must be peeled back or not crimped at all for pull testing. Pull test readings should be made on the wire to terminal crimp only.

WhatsApp Image 2016-11-10 at 9.33.24 AM

  • Crimp Cross Section un-covers the actual crimp condition from wire/terminal match and crimp tool profile. As well, crimp applicator setup can be checked (i.e.: terminal feed position).

cross-section-273

  • Visual inspection criteria ensures the proper machine setup provides the best crimp. Visual factors of an acceptable crimp are:
    • End of wire protruding on the contact side of the wire crimp. Known as brush.
    • Insulation and wire (roughly 50:50) present in the “window” between the wire and insulation crimp.
    • Bell mouth present on insulation side of the wire crimp to protect wire stands. Bell mouth can also be present on the contact side of the wire crimp.
    • Insulation crimp wings should not penetrate the insulation and make contact with the internal stranding and should fully encapsulate the insulation.

Electrical and Electronic devices that are not assembled into an automobile will have their own performance parameters. In most cases they are not subject to temperature and humidity fluctuations that are present in an automobile. But totally dismissing good crimping practices and not applying some of these best practices can expose your products to premature failure which carries a high cost (and liability). That’s the important factor when Acting on the Cost of Quality, understanding the Benefits and avoiding the risks of Inaction.

WireProcess is equipped and ready to deploy the tools you need to take your crimp process to the next level. Connect Your Way to WPS.

Counting the Cost of Quality: The Benefits

Every Decision has a cost.

This is the third and final part of our series Counting the Cost of Quality. In Part One, we discussed The Cost of Action, those decisions that are made on the basis of acting on information that has been provided. In Part Two, The Cost of Inaction covers the implications of not acting. Part Three will cover the Benefits.

As a company with a bias towards action, we consider the benefits of action far surpass the benefits of not acting. But acting after thoughtful analysis of the decision being considered. We acknowledge that any decision even a decision to act, carries some risk. Decision paralysis can take hold when the fear of making a decision is greater than not acting, part of the reason the cost of inaction can be high. We can consider as many variables as possible but there will never be enough information to completely mitigate risk from a decision.

So to consider the benefits of making a decision to act, let’s use an example of acquiring a Crimp Cross Section Lab to enhance your company’s quality process validation and monitoring capability. You have considered the upfront cost which includes the actual cost of acquisition, employee training and integration of this system into the company infrastructure. Consider the benefits which can apply to this decision:

Internally, individual employees directly involved with the new acquisition will be happy to see the company has provided new tools to help in their day to day work. As a collective, employees feel a higher sense of security that the company is investing in the company’s future.

As a company, new tools that are used can improve the overall quality of output. In the case of quality validation like our example, this provides a measurement tool to track the quality of output. Any tool to measure progress is critical (and may I say essential) to a company’s survival never mind growth.

Externally, existing customers will have a higher chance to keep existing business with your company when they see investment in infrastructure. Investments that can benefit them. And provide new opportunities to grow the business relationship through added contracts as they come up.

Potential customers will be more driven to work with you as they see investment in new infrastructure. In some cases, new processing or validating tools (like Cross Section Analysis as described) are minimum gateways to a business relationship even starting. For others, they will see your company set apart from your competition as internal investment in hard processing systems (capital) and training (human resources) are made. Where the investment is emerging and state of the art, you separate yourself from others who have not advanced as far as your company has.

These are just a few benefits to making the investment to improve quality. I am sure there are other direct and indirect benefits not mentioned.

This series was created to illustrate the opposing sides of a decision, to act on a decision or to stay the course (which in and off itself is a decision). You may not be in a position to be part of the decision making process of the company you are currently employed with. But regardless, you will be affected by any decision (or non decision) made.

In a perfect world all companies will err on the side of action and see the positive aspects of acting to improve the company. But some will stay the course and not act. And may not see any difference in the short term. The same with an action decision, there may not be a positive result in the short term. But the difference will lie in the long term implications. And if I were to consider the long term survival prospects of any company, the bias toward making positive action on decisions would make me more confident in that company’s future. Certainly that is the goal for our company.

WireProcess Specialties has many decades of experience in processing and validating technology for wire processing. We are here to help in making the right decision. Connect Your Way to start the dialog.