Conductive Heat-Shrink Tubing for EMI/RFI Issues in Cable Assemblies
September 12, 2023
Heat-shrink tubing can provide a versatile EMI RFI shielding solution in Industrial, Mil/Aero, & Medical applications.
Downers Grove, IL USA:
The proliferation of electronic circuits & controls is virtually everywhere today and with the emergence of AI (Artificial Intelligence) we will soon have robotic personal assistants folding our laundry and doing our taxes. Seriously, AI and IoT (Internet of Things) are finding ways into factories, transportation, food processing equipment, and even medical devices. Now, when electromagnetic energy gets disrupted for any reason the expected electrical performance of a device or material can be adversely affected and this is called electromagnetic interference (EMI) or radio frequency interference (RFI). It is a growing problem and a design challenge. In today’s world of ubiquitous sophisticated electronic systems, this susceptibility can affect performance in one of two ways: conducted EMI/RFI which causes the system to malfunction from within, or radiated EMI/RFI, which causes other nearby equipment to malfunction.
If your electronic system needs a cable assembly connection, shielding that cable is often needed to mitigate EMI/RFI problems. Common solutions include using a metal or metallized plastic connector and soldering the cable shield to the connector or, alternatively, wrapping the junction with copper tape and then soldering it to the cable shield. More robust solutions involve metal braided sleeving and tubular expandable braided cable shielding which is used primarily in the electrical wire interconnect industry to protect cables from electrostatic and electromagnetic interference. Even though these types of solutions may work, they are costly and labor-intensive.
A cost-effective solution to this problem is to use shielded conductive heat- shrink tubing with a metallic conductive ink coating on the inside of the tube. The inner coating provides electrical continuity and EMI, RFI, and ESD shielding around the joints being connected. This tubing can solve a number of EMI/RFI problems easily and inexpensively.
In use, the appropriate diameter of tubing is simply placed over the components or assemblies to be shielded, and heat from a heat gun, an oven, or any other conventional heating device is applied to the tubing. After the tubing shrinks, the inner metallic layer provides an electrical connection between the outside surface of the objects that are joined by the tubing, thereby creating an almost 100% effective, 360° circumferential shield.
The versatility of heat-shrink tubing and its shielding effectiveness have been demonstrated in diverse applications. One such military application is its use in a soldier’s high-tech helmet. The manufacturer had developed a new design incorporating advanced systems such as night vision, heat sensing, and two-way communications into the helmet. However, when the helmet was manufactured the various electronic systems in the finished product were in proximity and were interfering with each other. The resulting crosstalk was so bad that it was impossible to use more than one component of the system at a time. Using heat-shrink tubing to cover the cables running inside the helmet easily solved the crosstalk problem.