Introduction Cable Assembly Solutions Epec Engineered Technologies is a highly regarded supplier of cable assemblies used in a wide variety of markets including Medical, Industrial, Automotive, and Data Communications, to name a few. With a main focus to support Tier 1 and Tier 2 level companies, we manufacture custom cable assemblies for specific applications based upon customer design and print requirements. The performance requirements of the markets we serve are based on stringent regulations, which are intended to ensure delivery of high quality, reliable products on a repeatable basis. The Cable Assembly solutions that Epec offers include highly reliable products able to withstand the rigors of the application the assembly will be used in. Whether the assembly will be exposed to repeated flexing, exposure to fluids, or to the harsh environment of a manufacturing floor, our assemblies are built to meet the challenge. Inside our Cable Assembly Manufacturing Methods Ebook, you will discover several suggestions on ways to keep assembly costs under control. These suggestions will help you understand the many facets of designing a cable assembly that meets your expectations, but also ways to keep the costs of cable assemblies as low as possible.
Manufacturing Method #1 Don t Choose the Wrong Conductor for the Application: Utilize the conductor material best suited for the application. Match the number of strands that make up the conductor to the need the higher the number of strands used to produce a conductor, the higher the cost of that conductor. Most conductors have a standard strand count (i.e. 7 strands) which will be the least expensive. Use the correct plating Plating, or the coating applied to the strand, can increase the cost of the conductor. For some conductors, bare copper is more expensive than a coated conductor due to the lack of popularity, causing a loss of economies of scale in the production operation. The most common plating is tin, though other platings, such as silver or nickel, are also available. Match the size of the conductor to the electrical requirements of the application both voltage and ampacity needs will dictate the size of the conductor needed.
Base Material Conductivity Flex Life Relative Cost Advantages Disadvantages Copper +++ ++ $ Low Cost Oxidizes Copper Alloy ++ +++ $$$ Flex Life Cost Copper Weld +++ ++ $$ Strength Flexibility Plating Material Temperature Rating Conductivity Relative Cost Advantages Disadvantages Bare N/A +++ $ Low Cost Oxidizes Tin 150C + $$ Aids Soldering Silver 200C +++ $$$ Nickel 250C ++ $$$ High Frequency/ Temperature Characteristics High Frequency/ Temperature Characteristics Poor at High Frequencies Material costs significantly impact the overall price of an assembly. A properly designed assembly will use materials that will meet the needs of the application. DESIGN AN ASSEMBLY USING MATERIALS TO MEET THE EXPECTED NEEDS OF THE APPLICATION, DON T PAY FOR FEATURES YOU DON T NEED.
Manufacturing Method #2 Don t Design the Assembly to Meet Requirements That Aren t Needed of the Application: Choose compounds that will provide the proper level of performance of the installation. PVC is available in different formulations offering varying pliability, electrical properties, and temperature ratings, with the price range varying accordingly. Fluoropolymers have excellent thermal, chemical, mechanical, and electrical characteristics and are used in low-voltage applications though higher priced than PVC (roughly 8 10 times). Some fluoropolymers such as PTFE will require the use of a conductor with silver or nickel plating also driving up costs. Compounds are available that offer very good mechanical strength such as TPE/TPR. Match the components to the expected usable life of the equipment - if the equipment is expected to have a life expectancy of 10 years, avoid a design that will last for 30-40 years. The components needed to allow the assembly to be used for the extra 20-30 years will raise the cost of the assembly.
Material Use Temperature Rating Shore Hardness Relative Cost LDPE Insulation/Jacket 80C 55D $ HDPE Insulation 75C 65D $ Polypropylene Insulation 80C 58D $ PVC Insulation/Jacket 80-105C 16-46D $ TPE/TPR Insulation/Jacket 105-125C 14-30D $$ Polyurethane Jacket 80C 29-38D $$$ Teflon (FEP) Insulation/Jacket 200C 56D $$$$ Halar (ECTE) Insulation 150C 75D $$$ Kynar (PVDF) Insulation/Jacket 125C 67-70D $$$ PCV Alloy Insulation/Jacket 60-75C 58D $$ Non-Halogen Insulation/Jacket 75-105C 33-55D $$$ Compounds are the first line of defense for a cable assembly, protecting the internal components of the assembly from the environment the assembly is installed in. DESIGN THE ASSEMBLY TO MATCH THE LIFE EXPECTANCY OF THE EQUIPMENT IT WILL BE INSTALLED ON. A LONGER ASSEMBLY LIFE EXPECTANCY THAN THE EQUIPMENT IS A BAD INVESTMENT.
Manufacturing Method #3 Develop the Assembly for Ease of Manufacturability: Avoid the desire to specify extremely tight dimensional tolerances the tighter the tolerance, the more difficult the assembly is to produce, the more expensive the assembly will be. There will be applications where a tight tolerance is required. Such as when very specific electrical characteristics are needed which would drive controlling the primary insulator dimensions. Or if the assembly is to be routed through a predetermined opening which would drive controlling the dimensions of the diameter of the overall cable. In these instances, a tight tolerance is desired to ensure the assembly meets the application. In some applications adherence to published standards is acceptable, such as those dimensions stated in IPC/WHMA-A-620.
Design assemblies with characteristics that meet the need of the application. Tight tolerances can be attained but increase the cost of an assembly and may not be needed. THE MOST EFFICIENT ASSEMBLIES ARE THOSE THAT ARE DESIGNED WITH THE MANUFACTURING PROCESS IN MIND.
Manufacturing Method #4 Don t Over-Design the Assembly: Choose a color code for the primary insulation that aids in termination of the cable - choose contrasting colors and avoid light and dark colors (i.e. light blue, blue, dark blue). If shielding is needed, use the correct combination to meet the application. Unnecessary shielding adds cost to the cable assembly. Shield Type Flexibility Relative Cost Advantages Disadvantages Tape ++ $ Lowest Cost Poor Flexibility Braid +++ $$$ Excellent at Low Frequencies High Cost Spiral ++++ $$ Pig-Tail Termination Poor at High Frequencies Tape & Braid + $$$$ Best Possible Performance Highest Cost
The cable assembly should be designed to meet the requirements of the application, features that are nice to have will increase the cost of the assembly. WHEN DESIGNING A CABLE ASSEMBLY, REMEMBER, IF YOU DON T REALLY NEED IT DON T ASK FOR IT.
Manufacturing Method #5 Don t Specify Criteria That is Not Needed: If the assembly will be installed in a stationary application don t ask for a flexible assembly. To achieve flexibility, the assembly producer will build the cable with high strand count conductors and compounds developed for continuous motion - both driving up the costs. There are two ways to look at flexibility. One is to look at flexibility as it would be needed for routing during installation. The second would be to look at flexibility as it would be needed in a continuous movement application. Understanding the difference between the two will allow a designer to develop an assembly that is most efficient at meeting the needs of the application without asking for features that aren t needed.
There are applications that require an assembly to be able to withstand constant movement but there are also applications that require an assembly to be flexed only once during installation and the designs for each of these is very different. AS A RULE OF THUMB, THE MORE FLEXIBILITY REQUIRED OF A CABLE ASSEMBLY THE MORE THE ASSEMBLY WILL COST.
Manufacturing Method #6 Choose Connectors That Will Perform: Some connectors will provide form, fit, and function but do not address electrical performance. Match the connector to the need. If possible allow the use of substitute connectors. In most all instances, the substitutes will perform as well as the original connector. If at all possible avoid getting into a situation where the connector you ve chosen for use on a cable assembly is only produced by one manufacturer. This could lead to supply and pricing issues in the future.
If at all possible, choose a connector design that is made by several manufacturers, this will avoid supply and pricing issues in the future. THERE ARE MANY DIFFERENT TYPES AND STYLES OF CONNECTORS AVAILABLE, A CHOICE YOU MAKE TODAY WILL HAVE AN IMPACT ON THE ASSEMBLY IN THE FUTURE.
Manufacturing Technique #7 Pick the Correct Connector Material to Match the Application: For some applications a brass connector body is a good economical choice. For harsh environments a sealed connector should be used to avoid assembly failures in the future causing unexpected additional costs. Contacts should be made from high quality materials that are suited for the application. Brass, beryllium copper, or phosphorous bronze are acceptable.
The first step in choosing a connector is deciding how often it will be connected and disconnected. CHOOSE THE CONNECTOR RIGHT FOR THE PERFORMANCE NEEDED OF THE ASSEMBLY.
About The Author Brian Morissette Cable Assembly Product Manager Brian Morissette has over 32 years of experience working in the electronics/manufacturing industry and was Epec s Cable Assembly Product Manager. Brian directed and assisted in sales for cable assembly opportunities, working directly with customers to recommend the appropriate cable specifications for their applications. He oversaw the design and manufacturing of cable assemblies, working out any issues to ensure quality service and products to our customers. Prior to Epec, Brian held positions in both the business development and manufacturing areas. His most recent position was manager of product marketing, and he has also held various positions on the sales and manufacturing side of operations working for TE Connectivity, AMP, and Madison Cable. Brian holds an MBA from Nichols College. Visit Our Website @ www.epectec.com
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