Is it possible to think of any electrical or electronic system without cables or a cable assembly? Well, I thought so too. A cable assembly forms a crucial part of electronics and something that every electronics designer, enthusiast, or engineer needs to know. However, in most instances, it typically gets thought of and addressed last. This article canvasses everything related to the design, components, and other crucial aspects of a cable assembly.
Cable Assembly in Electronics
The importance of a cable assembly in electronics is apparent. Therefore, you have to think about and address it early enough during the development of the electronic design, especially if you want an excellent design that will function seamlessly. A cable assembly design contains numerous components that have a direct influence on the cable assembly outcome. Consequently, an under-designed or overdesigned assembly can have negative consequences when it comes to its performance. So as a designer, what should you do?
Comprehending the diverse components making up a cable assembly becomes crucial in designing and ordering quality cable assemblies. Therefore before looking for an ideal wire harness manufacturer, it becomes prudent that you know the different types of a cable assembly in existence, the components, and application areas. For instance, if the cable harness assembly is intended for dynamic installation, with plenty of anticipated flexing, the components need to withstand the anticipated flex. The same applies when the assembly’s targeted application area entails a harsh setting.
Diverse types of harness assembly exist, with different categorizations. For instance, most manufacturing companies will primarily produce custom cable assembly. However, going into specifics, you can always design and order a cable assy, rf cable assemblies, etc., based on your design and application needs.
Design Consideration Options for Your Cable Assembly
The need for an excellent harness cable calls for diverse considerations in designing the cable assembly. It should include top materials to deploy to ensure that the expectations set forth get met during the assembly installation. Additionally, you should also consider the correct termination method regarding the signal type you transmit through the assembly. Necessary safety certifications necessary for the assembly also need to get considered to ensure compliance, especially with the environment. All these are important considerations that we will address in this article as we seek to help you understand everything about cable assemblies.
Essential Cable Assembly Design Components to Consider and Pick for an Excellent Harness Assembly
As we had earlier mentioned, cable assemblies have diverse but crucial components. Each component plays an instrumental role in the functioning of the cable assembly product. To better understand it, let us now consider the various components and their impact on the quality of the harness cable.
- Circuits or Conductors
The type and number of conductors or circuits included in a specific assembly are determined by the assembly’s targeted application area. Various options exist for the conductive material type deployed, the stranding utilized during the conductor construction, and the specific plating applied or deployed to conductive materials.
Copper is one of the most widely used and versatile conductive materials. It comes as a compatible material with diverse coatings regarding retarding corrosion and aiding the termination process. Additionally, concerns such as the breaking strength get addressed by utilizing copper alloys and copper-clad steel, which often prove available in case of any need. While these materials essentially possess copper, they also incorporate elements like alloys (chromium, cadmium, and zirconium) or steel to enhance the conductor’s breaking strength and flex life. What’s more? You can also deploy stainless steel as a conductor, provided you plate it enhance its conductivity as it always proves a poor heat conductor compared to copper.
Using bare copper often proves unwise due to corrosion that results from atmospheric exposure. Therefore, most conductors need plating with diverse coatings to retard corrosion besides allowing the copper to get utilized in rigorous installations. Consequently, you will find Tin as a popular coating material for bare copper, and it is very affordable besides helping with the process of termination. Additionally, coatings like nickel or silver become applicable when the anticipated operating environmental temperatures are high. It can accommodate temperatures of up to 260°C
If you want to construct a cable assembly, then the conductors deployed can get constructed from a strand of conductive material or numerous smaller conductors. It applies because stranded conductors got developed to overcome the rigidity with which solid wires are provided. Further, it comes in diverse variations. Therefore, the assembly application will influence the construction type to deploy. It is, nonetheless, necessary to recall that the size of the conductor influences the number and the diameter size of the strands, which in turn affect the conductor’s flexibility.
Because of this, every conductor for your cable assembly needs to get designed for a particular use. For example, if the conductor aims to give power, it becomes helpful to consider the current-carrying capacity before establishing its conductor size. Additionally, if the conductor will need to allow the transmission of signals, aspects such as the signal speed and assembly length become crucial to determine for an accurate conductor construction.
- Primary Sheaths or Insulations
Insulators always come as thermoplastic or thermoset compositions. Aspects such as the material, type, and thickness similarly become essential to consider for the insulator (primary conductor) while considering the relevant cable assembly it has to operate in. Materials often prove available when it comes to meeting a diverse range of environments and applications. Critical for redress in this scenario includes the assembly’s operating temperature, the level and type of voltage the assembly needs to carry, the harshness extent of the assembly’s installation environment, besides the fluid/chemical types the assembly will get subjected to.
You might wonder if there are materials that can allow for an assembly operation in extreme temperatures. However, to allay your fears, it is true that diverse materials exist that can operate from -65°C to upwards of +200°C. However, it becomes vital to consider whether the assembly will prove static or dynamic, implying whether the assembly will get subjected to movement and at what temperature it does. It becomes crucial because an assembly in a state of dynamism and extreme temperatures requires rugged compounds to ensure its proper functioning compared to static and more reasonable temperature settings.
Additionally, the insulation type of the primary conductor gets determined by the voltage or current that the cable assembly carries. It becomes pivotal because certain insulations cannot withstand carrying higher currents in extended periods.
If the cable assembly anticipates transmitting high-speed signals, some of the insulations are required to get “foamed” through gas injection or chemical foaming processes. It allows for the alteration of the insulation by developing air bubbles within the insulation. Consequently, it will enable high-speed signal passage without any impediment.
You can also opt to color and mark the primary insulation for easier identification, especially in cables that possess more than one conductor. It often gets completed by a colorant mixed during the primary extrusion. However, you can also incorporate an extra identification method by printing specific numbers on the insulation or stipes (longitudinal, ring-bands, or spiral)
- Cabling or Twisting of Conductors
Cable or wire twisting often becomes instrumental in canceling electromagnetic interference (EMI) for outside sources. The innovation came about in 1881, courtesy of Alexander Bell. So why is this crucial?
Suppose you have prior experience dealing with telecommunication cables. In that case, you will have noticed the typical noise problem in instances where the pairs of wires lie next to one another in one cable for long distances. Consequently, the proximity induces the crosstalk from one pair onto the adjacent pair, and with the addictive nature of noise throughout the cable length, it becomes unbearable. To counter this effect, twisting the cable pairs eliminates the noise as the pairs only lie next to each other for half twist distance. It, therefore, becomes necessary to determine the application of your cable assembly. If, for instance, the assembly will apply in the transmission of data signals or communication, then twisting of wire pairs becomes necessary to eradicate the existing risk of EMI or noise that can influence the assembly’s performance.
It also becomes important to cable together with the twisted pairs of conductors. Cabling infers to the operation during the manufacturing process where the conductors get helically wrapped together. Cabling has numerous reasons key among them the provision of a more flexible assembly. However, it also gives a round configuration, something that allows for an artistically pleasing assembly product.
The control of both RFI and EMI can get achieved further through shielding. Here, overall shields get applied after the cabling of the pairs of conductors. Diverse overall shield options exist though each has its benefits and drawbacks. For instance, among the most popular entails the foil shield: a metalized foil that gets adhered to some polyester backing. It comes as at an affordable cost with fairly decent flexibility. However, it does not possess a decent flex life and only proves decent at higher frequencies.
Another overall shield option entails the braided shield. It mainly gets composed of small but numerous diameter wires, all braided onto the core of the cable through braiders (specialized equipment for braiding). While it comes at a higher cost and proves problematic to terminate, this overall shield provides a better shield at lower frequencies besides a better flex life, which the foil shield cannot accomplish.
Another shield type entails the spiral shield that features small diameter cables or wires getting wrapped around the core of the cable. It offers incredible flexibility accompanied by lasting flex life though it often proves inferior when safeguarding the conductor at high frequencies and proving tough to terminate.
So how can you achieve the best protection? One of the best ways to protect against RFI/EMI is through a mixture of braid and foil shields. It offers incredible protection for every frequency and proves simple to terminate, albeit at a steeper cost.
- Outer Sheath
It often applies to post the construction of the cable core. The outer sheath jackets the cable core and serves as a protective layer through its flame-retardant and material toughness attributes. However, the outer sheath always proves flexible to allow for assembly movement during installation and throughout the relevant equipment’s life cycle. Additionally, it also comes as a chemically resistant layer, though with semi-conductive properties in specific applications.
The jacket or sheath gets developed from diverse materials, though the choice of material hinges on the intended installation environment of the assembly. A typical material used in this case is the PCV owing to its cost-effective nature. However, other materials that can get deployed as sheaths also exist. It includes urethane-based products, elastomer-based products, fluorocarbons, alloy-based materials, and non-halogen materials.
- Strain Reliefs or Connectors
Plenty of options exist for you as a cable assembly designer to pick from when it comes to connectors. However, the speed and type of signal getting transmitted should determine your connector choice. For example, whenever power gets sent through the cable assembly, picking a crimp-type connector becomes crucial. However, a welded or solder-type connection becomes necessary when a high-speed signal gets transmitted. Additionally, it becomes essential to note that the connector options are limited depending on the type of equipment the cable assembly will deploy. For instance, the equipment may have a pre-installed connector that the cable assembly needs to mate with, limiting your connector options significantly.
Additionally, as a cable designer, it helps decide whether a strain relief becomes necessary for your cable assembly design. It always offers a transition point between the cable and the termination area besides preventing the load from getting transferred to the terminations. It consequently prevents termination failure.
- Safety Certification
A key concern in the design of cable assemblies often features the intended application location or country. Every location has its regulatory standards regarding safety and environmental standards, often enforceable by the regulatory authorities in the respective regions or countries. Most countries have safety and regulatory standards of their own regarding testing and examination of electrical devices. It also includes the restriction on the use of substances that can get classified as hazardous.
Picking the correct components often starts the journey of ensuring a top-rate and quality cable assembly. Therefore, it helps to consider the details provided and talk to us- RayMing PCB and Assembly company for any inquiries regarding your electronic assembly needs.