In the commercial wire, cable and harness industry, much of the manufacturing work is performed by automated machinery or at the very least, semi-automatic tooling and is becoming even more automated as time progresses. This means that the main focus of production work for manufacturing companies is setups and maintenance. Today we are going to look at the setup side of production and the many aspects that go into creating a high quality certified product for commercial use in North America.

Believe it or not, although we use mil-spec crimp dies with super tight tolerances that can be edited by .001″, there is still variability in the finished product and overall quality. With automated machinery, grippers, belts, movements, materials and users can all create variability in the wire as it is processed. Let’s look deeper into each aspect to understand how we can limit variability in resulting products:

Cutting Variability

Machinery

The tooling machine itself is the most important aspect of a quality wire lead or harness. This remains true whether considering a multi-function automated lead making machine or a benchtop crimp press. Particular companies have stood strong against the test of time in the high grade Lead Maker industry and have become industry standards for high quality certified work. The ability of a machine to stay accurate over multiple thousands of cycles means everything to the finish of the end wire product, and certain brands are just better at it.

Build quality comes into play here, where heavier duty servo motors, belt drive systems and power controllers are used in the machine designs to maintain tight tolerances. At C-T Wire Prep, we prefer USA made Artos machinery because of their longstanding production capabilities in our own facility as well as an industry affection for their quality. As for benchtop crimp tooling, the Amp G series press is the breadwinner for making the absolute highest quality crimps.

It is imperative to know the right tooling options which can automatically usher in higher quality production.

Grippers

During automated wire cutting, a length of wire is pulled through the machine work area by either some kind of gripping device that clamps the wire at a specific location or a feed belt system that pulls the wire to correct length for the cutter module to slice accurately. As machinery runs, there is heat created by the friction of moving parts, the production material moving through the machine as well as other temperature variables created by atmosphere or other nearby devices.

As a production run is completed, the grippers can slowly become looser or in the case of belt drives, the rubber on the belts slowly disintegrates. These physical changes to the pulling mechanism for the cut can cause variability in finished wire length, and even has implications in crimp quality when wire stripped ends are inaccurate.

Wire Material Back Pressure

With older automated wire cutting machinery, electrical flywheel prefeeders were employed to help get the wire into the machine fast enough for accurate production work. Prefeeder Motor speeds were timed with wire pull devices to ensure the wire was not pulled too tightly while being measured and cut. These systems were unable to perform to the even higher standards of the digital servo designs we have available today in the market and thus a better technology has replaced it. On newer belt driven cutting machines, any sway or variation in back pressure on the wire as it is fed into the cut area will cause length errors. It is absolutely vital you run a capable prefeeding device prior to this type of cutting machine to maintain acceptable quality.

Another aspect affecting wire back pressure is straightening wheels. Electrical wire comes in a circular form either in a barrel or on a spool. Straightening devices help to straighten the wire back out before it is processed by automated machinery, otherwise many cut errors arise from bent wire. Even wire spool core diameter matters to the quality of the straightness so we limit our suppliers to larger diameters to mitigate quality issues.

Material Quality

jump to: Common Issues Found During Production

We are seeing many companies doing certified CSA & UL work who are beginning to define the specific suppliers they will allow to supply the raw goods that go into their products. As a manufacturing company completing processes in between the raw material creator and the finished product, we have to take special care in maintaining certain relationships with suppliers who we know to be high quality that we can offer other companies. Over our 30 years in business we have curated a rather short list of suppliers who are in the highest levels of the wire industry and at the highest quality levels possible to maintain our quality standards.

Wire core centricity is a large determining factor in selecting a wire supplier for certified work. This means how centered the conductors are inside the round insulation thickness. Some wire producers can have issues maintaining this material quality.

Nominal Thicknesses of the diameter of wire are everything for creating high quality wire products. Even a few thousandths of an inch difference can mean crimp pull test failure if conductor thicknesses are not exact. We have an entire article about metallic terminal-to-wire bonding during a crimp and how high quality crimps are created here

Crimp Variability

There are a handful of variables that come into play during the crimping or lugging of a terminal to a wire end during production. Let’s take a look at what causes them and how to limit crimp variability.

What causes Crimp Variability?

The Press itself

whether referring to a benchtop press or a press affixed to an automated lead maker, they operate on the same basis. Different presses have different accuracies pertaining to throw distance. How accurately a press ram can drop to a specific height and then back up at a high speed determines the crimp quality. Some older presses do not have the ability to be changed for their cycle depth, where newer servo motor designs allow tweaking of the drop height of the ram as well as sensing devices that monitor the quality. Crimp force monitoring makes sure the correct force is being applied to bond the metals, as well as machine vision and machine learning to visually check terminations for failures. These presses can be spec’d with and without the added features that help ensure high quality.

Crimp Dies

The actual device touching the terminals to apply them to the wire. These dies are very, very accurate at applying a terminal in the same exact way every time. The issue causing variability is, there’s also a thousand parts on the die all with the ability to adjust them.

Having a great setup tech is key to a crimp die operating properly. Every aspect of the material from feeding the terminals into the fixture, positioning, application and cutting off of the terminal from the carrier reel can create variability in the finished product if everything is not aligned, sharp and accurate.

Users

Employee training and expertise is the most important aspect of producing high quality wire products. There are techniques to be learned with handling wire to get a repeatable crimp. Everything from the angle that the wire is presented to the terminal during crimping, to the steadiness of the operator’s hand can change crimp quality. Certified terminals in our experience have rarely if ever caused crimp failures, so we put a certain amount of faith into the material itself. It is usually a user error or a setup issue that causes variability so focus must be placed on how the product is made physically and by whom. With the right amount of information and practice, most users can become proficient.

Die Maintenance & Alignment

It is important that the many pieces that make up a die are in the right spot all the time. These dies go into a press capable of 1.5 tons of force onto a 1 inch surface area so extreme pressures. If there are misaligned parts, the minimum error will be a bad crimp. The worst cases we have seen dies blown apart that were set up wrong. The ability of the engineering teams to accurately keep dies in spec is everything for creating the high quality wire crimps. That is why we meticulously maintain, test, audit, check and re-check every die every time we use them at C-T Wire Prep Inc.

Product Variability

When we look at variability in wire products, business model matters. Manufacturing companies who keep their client lists lower and produce the same types of products every time tend to produce the same quality over time, whereas it is more challenging to be in the custom market and maintain quality because of the amount of changes being made to assembly lines and tooling.

As a custom wire lead and harness manufacturer every aspect of the business process is locked down from material vendors to advanced reporting systems, tooling upgrades and physical quality checks before, during and after production in order to maintain that same quality edge, while creating custom products.

We hope this article has been useful in understanding the quality variability in wire products and who to go to for high quality.