Form Follows Function for Optimal Connectivity

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Posted On:
November 04, 2020
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Balancing want versus need

Form Follows Function for Optimal Connectivity

3 Scenarios to Avoid on your Next Custom Cable Design

Designing custom cable and wire solutions for your end application can be a balancing act. Depending on the device, you may be considering a number of factors when putting the design together. Everything from environment to life expectancy to specific functions of the product should be considered when choosing the materials used in the cable, the components and construction, and even the colors specified. When it comes to custom cable for critical applications, it is recommended that the principle of form follows function is utilized. It seems like an obvious recommendation, but below are 3 examples that Northwire’s Cable Design Engineers encounter on a regular basis where a customer is coming to them to solve a connectivity issue because the form follows function principle was, in fact, not followed.

1) Size

A common problem we see is that engineers or product teams have focused their project on designing the device itself but have overlooked the significance of the cable and connector in the overall system design. As a result, you may end up with a very nice-looking device that is compact, however, there is no room for the cable and connector! We have had engineers come to us in a panic because a door will not shut when the cable and connector is plugged in. We have also helped engineers that did not consider how or where the cable and connector would plug in, so the angle is too severe, and the planned assembly will not plug in correctly. A device without any connectivity cannot perform its intended purpose.

As many industries make a move toward smaller, more compact devices, the trend toward smaller cables follows suit. That could include combining multiple cables into one cable with multiple functions. When this is done, the connectivity requirements of the application need to be kept in mind. As you make the cable solution smaller and smaller, often you end up with an increase in heat generation from putting more into a smaller space. This can lead to continuity loss and a loss in overall longevity. Work with your Cable Design Engineer to select proper stranding configurations and other materials that will mitigate heat generation and allow for heat dissipation.

When it comes to the cable and connector connection point, some may be tempted to minimize the size of the strain relief. The motivation may be to get it to fit inside of a cabinet, as mentioned earlier. However, you will want to make sure you are not sacrificing longevity when doing so. Keep the reasoning behind the purpose of the strain relief in mind when altering design to ensure you do not lose functionality.

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Cable with broken inner conductors sticking out of the cable jacket

2) User habits

How will the device be handled, stored, or cleaned in the field? User habits can vary greatly from what the planned use of a device may be. Think of your vacuum at home. Are you guilty of pulling the cable from the other end of the hallway to unplug the cord? Or perhaps from the bottom of the stairs? Are you guilty of coiling the cord haphazardly around the outside rather than coiling around the specific cable holders? If aesthetics were chosen over function in the design of these cables, then the user may experience failures in the field. Inner conductors can break if not protected correctly. Conductors can even pull out of connectors if they are not terminated appropriately. Keep in mind that what is right for one application and end user experience may not be correct for another. Custom cable design varies depending on the end application and the environment in which it is used! Function should always be kept top of mind!

3) Cost

As stated earlier, the cable and connector assembly solution is often the last consideration on a new product development project, so cost can be a major factor. Perhaps the project manager is already approaching the end of their budget, but they still need a way to connect their device to other systems or to transmit data and power! In this type of last-minute scenario where cost is a limiting factor, an inexpensive PVC may be chosen over a more robust material with a superior temperature range and durability such as a TPE or TPU. What may seem like the more cost-effective solution initially can turn into a much more costly and time-consuming endeavor in the long run. Dealing with failure and trying to fix a ‘cheap’ design can add a lot of time and money to a project when you consider testing requirements, product sign offs (whether internal or at the end customer), and especially any required certifications or standards that need to be met.

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Table showing jacket material benefit comparison

​​​​​​Typically, one would not think to complain about getting more than they asked for. However, if gold plating your cable design is leading to failures or unnecessary components and materials, you may want to conduct a design consultation. Northwire’s Cable Design Engineers have solved design flaws leading to cable and assembly failures as well as reduced the cost of the cable by redesigning it to include the materials and other components that are necessary for the device to function correctly and leaving out the extras. At first, it may seem like it would be faster and easier to try and make a standard, off the shelf cable work. However, when an application requires consistent connectivity and failure could mean line down, a cancelled surgery, or data loss to critical systems, you want to be certain form follows function for your cable and assembly design.

Think of the cable and connector solution as the nervous system of your device. Without it, the device does not have power or a way to send and receive data, rendering the device unusable.  Therefore, it is so important to consider connectivity early on in your product development life cycle. You will save yourself and your project team a lot of time and money if you keep the cable and connector requirements in mind when designing your next device. It is too important not to. What may seem like a way to save space or weight, may lead to more work and ultimately, more cost down the road. Whether you are at the napkin sketch stage of your next device, or at the other end of the spectrum with a device and no connectivity, Northwire’s cable design experts are available for a design consultation to review the needs of your specific end application and ensure form follows function

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