Flexible cable or non-flexible overview

Nowadays, cables are everywhere. Does a cable that is intended to be deployed in a flexible application environment, in essence, have to be a flexible cable? In fact, this is not necessarily true, although many readers may just regard it as grammatical. A simple definition, but in fact many flexible cables are not suitable for the continuous bending or flexible operating environment for which they are calibrated. In today's highly competitive and extremely complex electronics industry, the possibility of cable failure or any equipment failure should not exist, because companies cannot accept any downtime, nor can they accept expensive early replacement years before the expected life span. equipment, especially in the current market environment where competition comes from all over the world and profit margins are significantly reduced.

However, cable failures and system downtime still occur, why?

This article will discuss the differences between flexible cables and cables designed for constant bending, and examine why simply assuming that a flexible cable will be suitable for use in an extreme flexible environment can be a costly mistake.

Bendable or flexible?

There's a huge difference between bendable and flexible, and it's not just semantics. Of course, it’s also important that the cables are properly bent and arranged for a neat and aesthetically pleasing installation. Flexible cables can be used in projects that require routing according to a fixed design, making installation easier and simplifying troubleshooting within the cabinet or cable tray. It should also be noted that round cables are more reliable when bent because they are not limited to axial bending when bent.

With this in mind, cables with the correct "bend properties" should be selected when routing, because once the routing and installation are implemented, the cable will be static throughout its service life and, in this case, has good "bend properties." "Performance" standard cables fully meet the needs of use. However, in many production equipment and material handling equipment, cables need to be continuously bent during operation. Flexible cables that can withstand millions of bending cycles are much more complex than standard cables with "bend performance" and also require Consider a range of unique factors.

So, how do you choose the right flexible cable?

The first thing to consider is the type of bend the cable needs to handle, is it uniaxial, torsional or multiaxial? Each type requires some specific cable properties. For example, single-axis control cables requiring the most extreme performance (up to 14 million flex cycles) will require flexible cable construction, suitable for high-flex operation, and may also need to achieve shielding performance; while in less demanding single-axis environments Under this condition, cables with a minimum flex life of 1 million cycles and flexible construction can be used.

There are four common types of cable flex motion to consider when designing and applying high-flex cables:

• Rolling flexibility

• Flexural flexibility or “pendulum motion”

• Torsional flexibility

• Variable/random flexible movement

Different cable structures and materials are used depending on the way the cable bends. For example, a twisted cable has different torque and routing patterns than a rolled flex cable. Physical test data and statistical analysis are required to evaluate cable performance to determine a value commonly referred to as "flex life" and the overall reliability of the system. Understanding the correct application of cables will help designers select the most appropriate cables and reliably predict product service life and performance. In applications where the cable requires torsion or variable flexible movement (such as the operation of a robotic arm), special cables must be used that are resistant to torsion and have a torsion degree of ±360 degrees per meter.

Some cables today need to operate under extremely bending conditions. One situation is when a cable or drag chain experiences continuous bending or linear motion. Cables designed to carry these motions must use unique manufacturing processes or materials. This is because in a flexible motion environment, one of the main causes of cable failure is sheath rupture. Especially for shielded cables, the sheath is easily damaged due to the difference in bending radius between the inner sheath and outer sheath surfaces during movement.

Since there was no dedicated flex testing equipment that could fully quantify cable performance under conditions of continuous bending linear motion, Alpha Wire designed and manufactured dedicated testing equipment that is still in use to ensure that Alpha Wire's flex cables can handle extreme bending. Stringent requirements within the environment.

The equipment is capable of providing accelerated cable orbital motion for long periods of time and has been used to test a variety of highly flexible cables. The equipment has a fixed cycle of 17 times per minute and 1,836,000 fixed cycles per month, with the only variable being the bending radius of the installed cable chain. It has four tracks for mounting cables, two with a 4.5-inch bend radius and the other two with a 6-inch bend radius. In the test, the conductors of each cable are interconnected with each other and connected to a counter that records each completed cable bending cycle until one of the conductors in the cable breaks, which means the cable's useful life is over and Causes the counter to stop counting. In addition, if there is any obvious crack or break in the outer sheath of the cable, it also means that the cable has failed.

Although there is currently no conclusive evidence proving that this flexibility test is directly related to cable life, Alpha Wire believes that the conditions of this test are much harsher than most actually installed drag chain application environments. Perhaps the best way to demonstrate the importance of using the right cable is to use real-life application examples from real customers. The customer is a mature automobile assembly plant that has just purchased a number of spraying robots to automate the entire paint spraying process. However, when the robots were first put into use and tested for trial operation, the robots broke down one after another within the first few days. After many attempts and careful investigation, it was discovered that the cause was a repeated cable failure (not an Alpha Wire product).

At this stage, Alpha Wire was invited to participate in troubleshooting and solution implementation. Alpha Wire engineers analyzed the cause of the failure, checked the robot's movement trajectory, and consulted with staff involved in equipment installation to determine the exact cause of the failure and prevent the problem from recurring. Many problems were identified at the site, but the main reason was that the cable used on site had not been tested by the robot manufacturer, and only a common flexible cable was used.

This cable connects the cabinet to the robot, the wiring is very neat, and the wiring is routed in a very neat and beautiful looking device. However, this cable cannot achieve continuous bending in any plane, which means that the cable will fail within a short time after the robot reciprocates. By designing and manufacturing specially customized flexible cables, Alpha Wire solves this problem and meets the needs of its customers for applications within this unique environment. The new cables were first tested on one robot and rolled out to other robots, with the end result being that the robot has been running smoothly for almost two and a half years without changing the cables.

Summarize

Designers and system manufacturers should understand exactly what is required during the cable's lifetime to ensure that the cable does not cause any system failures. However, it is not always easy to understand in detail which cable is suitable for which application, so cable manufacturers need to solve this problem by making it as simple as possible to specify the correct cable type.

In summary, using the right cables from the start of a project can greatly reduce the risk of cable failure and ensure productivity and performance. With this in mind, the question “flex or not” becomes a critical decision! As Alpha Wire’s As an authorized distributor, Heilind can provide relevant services and support to the market. In addition, Heilind also supplies products from many of the world's top manufacturers, covering 25 different component categories. It attaches great importance to all market segments and all customers, and constantly seeks to expand product offerings to cover all markets. The above is an overview of the flexibility of cables. I hope it will be helpful to everyone.