With custom cable it is not uncommon to hear “Copper prices just dropped, why didn’t my cable price go down?” Copper prices are a major factor affecting custom wire and cable prices but not the sole factor.  Custo

m cable is normally made to order and many times in smaller quantities which is affected by the prices of materials at the time of ordering.  “Off the shelf” commodity wire is usually made continuously and in large volumes which absorb day to day cost fluctuations of copper/metals, compounds and labor/set up keeping the price more stable.

Here are just a few factors which affect the prices of custom wire and cable products

Petroleum prices-      Which can range from transport and freight costs to the actual compounds      which are made from petroleum products.beside copper:

   
• Material shortages-      An example is the fluoropolymer (FEP), earlier this year due to the      earthquake in Japan affected production for Daikin and DuPont which are      the only manufacturers of fluoropolymers in the world today. In addition      with China cutting back on their fluorospar exports which happened at the      same time resulted in an increase of 20-30% for the compounds.
 
• Material minimums-      Custom cable designs sometimes use conductors      and compounds which are not commonly used and are subject to minimum buys      which are factored into the per foot price of the cable.
 
• Set up-      Setting up equipment takes time and material, the higher the volume the      less the set up costs affect final price.

There are ways to help keep your cost down, for example:

 
• Plan ahead      – Placing blanket orders, scheduling orders over multiple shipments over      time.  Buying higher volumes helps      absorb minimums by amortizing material, set up and labor costs. Sometimes      the overall cost for ordering 1000 feet is less than ordering 200-      500 feet. Ask for price breaks to evaluate your options.

 
• Request samples      – Custom wire is usually specialized to the design however you can check      to see if your manufacture has a similar item they can sample you. This is      helpful when you need prototype of proof of concept quantities.  Many      custom cable manufacturers have      sample stock and overruns available which may be similar to what you need.

 
• Wait for it-      If you time to wait, ask your cable manufacture if they have any upcoming      jobs using the same material. Running your order along with another may      save you on set up costs and/or minimums. It's a long shot, but can be      done if your material is a more common one.

 
• Substitutions-      Ask what is driving the price.  If a material minimum is involved,      find out if there is a substitute material which may be readily available      you can use. Sometimes just changing the plating or strand count can make      the difference.

Medical wire and cable is different than wire and cable

used in other applications. Design engineers need to keep this in mind when specifying their cable. Often time custom medical cables are needed due to bio-compatibility, sterilization and possibly smaller sized device requirements.

When specifying a medical cable one needs to keep in mind several factors such as:

 
• Sterilization techniques autoclave, gamma, alcohol?
 
• Will this be a disposable cable?
 
• Will the cable come in contact with the patient? Bio      compatibility.
 
• Flexibility requirements.
 
• How will the device be used day to day?

Due to time constraints many times engineers will sometimes settle for a readily available off the shelf cable for prototypes or proof of concept, which is fine for the short term. When it comes to field and clinical trials a prototype should be made with wire or cable specifically designed for the application to better measure longevity and functionality. Medical cable applications fall into several categories; handheld medical devices are a large segment of medical cable applications.

Medical Hand Piece Cables

Cables for medical hand pieces must carry the power, control, sensor and data to and from the hand piece.  The cable may be as simple as a two-conductor cable, providing power to a cut & cauterize scalpel or a multi-conductor power, control and sensor cable used on an orthopedic surgery device.  Cables for handheld medical lasers likely contain lumens for cooling.  Ablating hand piece cables can also contain lumens for irrigation and suction removal.

The design of medical hand pieces falls into two categories: re-useable and disposable.  See below for information on Disposable Medical Cables and Re-useable Medical Cables.

Disposable Medical Cables

Disposable medical cables are made from the lowest cost materials that will meet the design needs of the device. Conductor cost is dictated more by the number of strands used to make the conductor.  The higher the strand count the more flexible the wire becomes.  A marketing trade-off is often made for disposable cables, i.e. increase stiffness can be tolerated by the need to hold cost down.  7 or 19 strand conductors can be used, where in re-useable cables the strand count can be well over 50.  The use of plating is reviewed and bare copper is the most often used.  Tin plating is used only to enhance solder ability. Crimping the wires is often the cheapest means of terminating the conductor.  Silver plating is rarely used for disposable cables.  Conductor sizes are determined by the current needs of the device.

Insulation and jacket materials are chosen by cost.  Low cost materials such as Poly Vinyl Chloride (PVC) or Thermo Plastic Elastomers such as poly urethane are often used.  Polyethylene can be used as insulation.  Insulation and jacket thickness are determined by the voltage ratings of the signals in the cable.

Shields, when required, are usually of a spiral type rather than braid to hold the cost down.  Spiral shields may lose shield effectiveness during repeated flexing, but the number of flexes for disposable cables is limited.

Jacket colors usually are chosen by the program.  The need for gamma sterilization may limit the color shades available.  Colors can change during gamma sterilization and are usually required to be stable for less than 10 cycles to allow for re-sterilization when repackaging is needed.

Re-useable Medical Cables.

Medical cables designed for re-useable devices have to use materials that will withstand several cycles of sterilization by alcohol based agents or autoclaves.

Conductors are made from high strand count conductors for maximum flexibility and often they are made from high strength copper alloys.  The size of the conductors is determined by the current they must carry to the device.  To withstand the rigors of sterilization, plating’s of tin or silver plating may be required.

Insulation must also withstand the rigors of sterilization and are often either Teflon’s such as FEP, PFA or Tefzel® or Silicone Rubber.  The use of lower cost materials may be made on a case by case basis.

When shields are required, they must be made from materials resistant to many sterilization cycles and are often silver plated copper or silver plated high strength copper alloys.  Shield construction is usually of a braid rather than a spiral, as spiral shields can move during flexing and compromise the shielding effectiveness.

The more popular choice for cable jackets are made from Santoprene™ TPE which is good for up to 100 cycles of autoclave, or Silicone Rubber.

Medical cable applications also include implantable, medical robotics, therapeutic devices, sensors and monitoring equipment.

To find out more or discuss your applications with medical wire and cable please contact Calmont Wire & Cable.

Please feel free to leave your comments; we would enjoy hearing from you.

Custom wire and cable is not readily available or stocked by distributors or manufacturers. Simply put, custom wire and cable is anything that is made to order specifically for a customer. Hypothetically, let's say you have a commodity cable that you use regularly but now your product design has changed and you need one or two more conductors. You check with your distributor and the manufacture doesn't offer that construction. You now need to turn to a custom wire and cable manufacturer which is set up to run special construction cable with little or no minimums

.Yes you will pay a little higher per foot than you do with the commodity wire however, you get exactly what you need and the performance you require. Prices between custom and commodity cable can't be compared as the construction and materials are different and the quantity produced are much lower with the custom cable. In the end it's all about having choices available to make a better product.

A few benefits of using custom wire and cable include:

 
• Engineered specifically for      your application
 
• Custom configurations
 
• Custom colors and/or printing
 
• Improved performance

You have choices! When having a custom wire or cable designed you a wide range of options to assist in building the right wire or cable for your needs. Some options include:

 
• Gauge sizes, smaller gauges      available
 
• Insulation and jacket materials     
 
• Type of shielding and      construction
 
• Conductor stranding,      plating and type

Reverse engineering is used in situations where the origin of a cable is unknown or there is no information about the wire or cable. Engineers in most cases will carefully dissect the wire or cable taking measurements and noting the construction of conductors, cable lay, shielding, fillers and other vital information. A series of tests are performed to determine the insulation and jacket materials. At this point if a customer would like to see improvements in the cable's performance such as a more flexible cable, or higher flex life it should be mentioned to the engineers so changes can be made to the design.

So who uses custom cables? Just about every industry including medical, robotics, aerospace, music/audio, and more. Building a better mousetrap often means designing a product that will exceed its expected performance and the wire and cable needs to be considered as well.

 

If you do not know much about wire and cable properties, don't be alarmed. Custom cable manufacturers have engineering resources to assist you with every step of the way starting with deermining the right materials and construction based on your application and requirements.

 

If you have questions about custom wire and cable or a project that you need assistance with, contact Calmont for assistance.  Feel free to post any questions or comments you may have. If you enjoyed this article please feel free to share it.

In the medical device industry a lumen is a term used to describe tubing which is typically used to transfer liquids, gases/air or even other cable components such as fiber optics and cameras. Lumens can be manufactured in a variety of configurations and incorporated inside a cable with multiple lumens (multi-lumen).

If you have been to the dentist then you have had experience with lumens. The handpiece used for air and water has lumens within the cable. The suction piece placed in your mouth is a disposable lumen. Other uses for lumens include micro-surgical instruments and pressure transducers. Cables for handheld medical lasers likely contain lumens for cooling. Ablating handpiece cables can also contain lumens for irrigation and suctioning.

Lumens are not limited to the medical cable industry. Lumens are used in many industries and are often called other names such as tubing or hose.

Other industries using lumens include:

• Industrial
• Automotive
• Instrumentation and sensors
• Automation/ robotic

As products become smaller and more compact and it is more common to see tubing and cable incorporated into one component. A few examples outside the medical industry include hi-tech hand sprayers with electronic controller in handpiece, cables with hydraulic fluid tubes, pressure transducers and air controlled switches.

Often when designing a device or equipment with tubing or lumens a custom cable solution is needed. It is important to tell your cable manufacture as much information as possible about the application and its intended use.

Key information may include:

• Used for fluid, air or other?
• Will it be pressurized?
• Type of fluid or gas?
• Flexibility requirements?
• Bio-compatibility requirements?

The more your cable manufacture knows, the better the design will meet your needs. Working with a cable manufacturer early in your design phase will help to determine tubing size, material and construction to insure your project goes smoothly from the start.

Comments are welcome! Tell us about your lumen application or challenge.

These applications include:

• Aerospace
• Medical
• X-Ray and MRI
• Radar systems
• Photo copiers
• Robotics

Extruding the semi-conductive insulation and the outer jacket layers of silicone at the same time insures that there is no air or any contamination particles at the joining of the two layers. The use of a semi-conductive silicone layer over the copper conductor reduces corona by filling the space around the conductor with semi-conductive silicone to remove the air. The semi-conductive material also increases the effective corona inception diameter from that of one of the strands in the conductor to a diameter slightly larger than the total conductor diameter. This results in the higher corona inception values and increase effective radius of conductor found in co-extruded silicone wires.

Features and Benefits:

• Corona, moisture and ozone resistant
• Lightweight  and extremely flexible design
• Radiation resistance
• Excellent electrical characteristics
• Resistant to temperature extremes
• Lower      EMI

Increased Customer Benefits:

• Reduces noise on radar
• Spots on Xerox copies
• Error spots on medical x-ray's

Built in stripes

Other uses for Co-extrusionIn 1958, The Wham-O Company had a problem:  The stripe in the original Hula Hoop was painted on and was wearing off quickly after a short time of use. The Wham-O Company asked Calmont Wire & Cable's founder Bill Chilcote to find a solution to the problem.  Bill seized the opportunity and developed a co-extrusion process and built the equipment to add the stripe right into the tubing, which made the stripe permanent. The stripe has evolved over the years but the fundamentals of Bill’s technology are still being used today for the Hula Hoop and many other applications in a variety of industries.

Medical device, aerospace and automation manufacturers often require flexible cables for their products. Flexible wire and cable can have many interpretations. Sometimes a simple description such as, “the wire needs to be as limp as a wet noodle” is enough to understand your needs. The choice of type of conductor and insulation can greatly influence the flexibility of the cable performance. Understanding what the flexibility requirements are will help to determine the materials and construction for the flexibility of the wire or cable.

When specifying a flexible cable you need tell your cable manufacturer what the intended use will be.

• Do you need to route it through equipment or a tight space?
• Will it be subject to repetitive flexing?
• Do you need the cable to flexible during use?

There are several factors which make a cable flexible, a few are:

• Conductor stranding
• Shield types
• Cable lay
• Insulation materials.

Typically in conductor stranding, the more strands a conductor has the more flexible the wire will be. Normally “off the shelf” wire and cable is stranded in 7 or 19 strand configurations, is not flexible enough for most applications requiring flexible or high flex cycles. The general rule is the higher the strand count of the conductor, the more flexible the wire or cable will be. Stranded conductors are composed of un-insulated “strands” of wire twisted together. The advantages of stranded conductor over a single strand are increased flexibility and flex-fatigue life. When you see 22AWG (19/34) for example, what the description means is that there are 19 strands of 34 AWG making up the 22 AWG conductor. Other common options for a 22 AWG is a single strand (solid) up to 168/44 strands. The construction of the conductor also plays a role in the cable’s flexibility, for example a rope stranding is the most flexible. For repetitive flexing applications such as robotics and automation, the use of high strand alloy material is recommended.

Choosing the right insulation can add to the cable’s flexibility. Silicone is one the most flexible of the compounds used. Silicone wire is used to meet a variety of demands such as extreme high and low temperature requirements, flame resistance, flexibility, strength and purity. The application and environment also play a role when choosing jacket material. Harsh environments, chemicals, and abrasion will narrow down your insulation and jacket options. Discussing your flexible wire application with a cable manufacturer can help you choose the right materials for the performance and longevity of your product