Calmont

A Short History and Review of Shielded Cables

calmont — Tue, 04 Aug 2009 07:19:24 +0000

Effective shielding prevents interference from entering or emanating from a cable

In the late 1800s, as the use of electricity was first being used for communications, interface reared its ugly head. The imperative for some form of mitigation became apparent. The first attempts involved using custom cable for wire spacing. Bare wires entered buildings and were forced closer to each other, twisting the pair was the preferred technique for reducing interference says military wire specialist. Look at early pictures of New York City; the sky is dark with thousands of wires for telegraph and telephone wires. Then radio came along, and radio broadcasts could be heard coming from the telephone wires. The need for shields became a problem begging for a solution. Wrapping the cables similar to military cable with grounding wires (a simple served shied), worked or fixed installations; but when the cable was subjected to flexing, the wrapped wires separated and interference returned. Enter the braider. Braiders were invented in the mid – 1800’s to manufacture shoe laces and other textile items. Tinsel wire, a flattened wire wrapped around a cotton or flax yarn, was used for the epaulettes on military uniforms. Early telephone engineers discovered that this was great, very flexible conductor for telephone earpiece cords. The tinsel wire could also be braided over the conductors in the earpiece cords to reduce radio interference. When the custom extrusion cable was not subjected to high flexing conditions of a telephone cord, tinsel wire could be replaced by simple strands of wire.

These days, the purpose of a shield is to prevent interference from entering or emanating from a cable. The three types of interference radio are: radio frequency interference (RFI), electromagnetic interference (EMI) and electromagnetic pulse (EMP). RFI was the earliest type of interference that engineers had to deal with, Early radio signals easily found their way into devices. Coaxial cables and shielded twisted pairs using copper eliminated most of this type of interference. Today, EMI has become more problematic because of high power transmission lines; higher magnetic fields, such as MRI machines in hospitals; and other high power applications. Copper may not offer much resistance to higher magnetic fields; therefore,the use of magnetic materials such as high permeable irons may be required. EMP is produced by the detonation of nuclear devices. When the hydrogen bombs were tested in the 1950s at Bimini Atoll in the South Pacific, circuit breakers at power stations in Hawaii were tripped by the EMP

wave from the detonation. Critical military and civilian circuits must be protected from

an EMP condition. These shields require the use of both high and low permeable materials

to reduce the effect of an EMP.

Terminating Ultraflexible and High-Strength Cables

calmont — Thu, 02 Jul 2009 07:44:04 +0000

Foot soldiers in our modern Army now are “walking computers.” Night visiongoggles, GPS receivers, computers and radios are becoming commonplace. The interconnecting military cable must be lightweight and strong, but still contain all of the circuit conductors to carry out their mission. The military wire can be snagged on environmental hazards such as bushes or protrusions from vehicles. Increased strength demand means that the addition of

strength members, such as Kevlar or PPO fibers, are now the “norm.” Satellite custom cable need to have lightweight shields while still maintaining the same or higher shield effectiveness. Aracon, which is nickel- or silver-plated Kevlar, can assist in these applications. As a plated fiber that will spread across the cable core, it can easily give greater shield coverage than can be obtained with flat or round copper wires. Ground support equipment, while relying more and more on radio communications, still has the need for robust cables between communication huts. Fiber optics can pass large amounts of data, but there is still the need for power to the equipment. Composite cables can do both. The need for high tensile-strength members to keep the cables from pulling apart as well as crush-resistant materials to protect the fibers calls for tougher materials.

The design process starts with a source control drawing (SCD), as most harsh environment cables do not conform to the old MIL-spec system. Many military and medical cable designs use the material and physical properties and testing requirements from existing MIL-specs as a starting point and then delineate the additional requirements on the SCD granted waivers from the RoHS by the European Union (EU). When the conductor size gets smaller than 30 AWG, consideration

of moving to stainless steel as a conductor material needs to be reviewed. Often, for short conductor lengths, the increased resistance of stainless steel can be tolerated. If not, gold or silver plating can be done on the individual strands of a conductor to bring the resistance down to acceptable levels. For terminations, soldering to stainless

steel is difficult, whereas the gold or silver-plated wire can easily be soldered. Crimp contacts can easily be attached to stainless steel. Table 1 lists the strength and conductivity of alloys that can be considered when copper is not strong enough. After the conductor has been determined, the insulation must be chosen. The environmental considerations determine the temperature rating, solvent resistance and physical characteristics. Many programs

now prohibit the use of PVC. Thermoplastic elastomer’s (TPEs) have taken the place of many PVC materials. Also, to replace PVC, companies such as GE Plastics have created flexible versions of NORYL that can be extruded to ground support equipment, while relying more and more on radio communications.

May is National Stroke Awareness Month

calmont — Thu, 28 May 2009 08:07:14 +0000

According to HealthYes!, a leading mobile medical screening provider it is critical to follow the “3’R’s” – reduce risk, recognize symptoms and respond immediately. Following these steps could limit the number of Americans who die or are disabled each year by a stroke. Also helpful are new treatments and today’s technological advanced medical wire and military cables built with exacting specification. With years of researching, developing, manufacturing and testing high-performance EKG patient cables, custom cable assemblies in turn provide the ideal material for satisfying medical and military wire equipment needs.

National Stroke Awareness Month is a great opportunity to educate your employees, friends, family and community about stroke. Knowing the symptoms of stroke and acting quickly can make the difference between life and death. Just remember, every second counts!

According to the American Stroke Association, below are the warning signs of stroke:

Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
Sudden confusion, trouble speaking or understanding
Sudden trouble seeing in one or both eyes
Sudden trouble walking, dizziness, loss of balance or coordination
Sudden, severe headache with no known cause

Advanced military technology for our frontline troops

calmont — Mon, 27 Apr 2009 08:04:58 +0000

Each year millions of dollars are poured into military technology for accuracy and advancement. With the advent of many new technologies, there has been an improvement in the U.S. defense programs. Improvements are toward advanced military wire and cable for support in weaponry, propulsion, sensor systems and automation. Unique custom cable and wire products designed are developed specifically for such military applications. These cables utilize the highest quality materials and the most advanced processing technology. The result is exceptional military cable capable of withstanding the harshest military conditions, from extreme temperatures to severe exposure to chemicals, fuels, lubricants and radiation.

Typical military and defense applications also include:

Ground Support
Communications
Fire Control
Digital and Analog Data
Field Radios
Shipboard
Training Aids
Low Smoke/Zero Hal

To get more information on military and medical cable, please visit: www.calmont.com

Medical Infrastructure – Increasingly User Defined

calmont — Mon, 16 Feb 2009 18:09:43 +0000

As medical equipment gets more sophisticated, there is a growing cry amongst users to make them more user-friendly. Right from a medical cable to an expensive defibrillator, current trends mean that increasingly the patients themselves will use the equipment.

Even two decades back, regular monitoring of blood pressure or diabetes needed trips to doctors’ offices. Not any more, and the trends indicate increased customization from a custom cable for a personalized EKG equipment to other types of medical device design..

As a result, large medical manufacturers for ultrasound, electrode, defibrillator, EKG, dialysis, handheld instrument, catheter, implant and other applications are pushing their vendors to improvise and provide flexibility in their product lifecycle – from product design engineering and Prototype Cable Design through full production.

Developing Medical Devices in a Consumer-Driven Market

calmont — Sun, 15 Feb 2009 18:40:47 +0000

I recently read an article on the captioned theme. It mentioned how devices like a medical cable needs to be safe and effective, and each custom cable or custom wire has to have the look and feel like electronic equipment.

The article mentions how the US Medical Devices Design market is becoming increasingly consumer driven, and medical devices are becoming more easily accessible and used by the general population.

Safety and Design issues therefore become paramount as many medical device manufacturers start targeting the end user directly, as opposed to targeting medical professionals. This will have a far reaching impact – whether it is prototype extrusion design or a custom cable design.

Following is the excerpt of the article which I found the most fascinating:

The following headlines and popular medical blogs reflects this growing trend:

“An Open Letter to Steve Jobs,” Diabetes Mine.¹ Blog discusses the need for devices such as insulin pumps to look more like iPods.

“Wireless Health Monitoring Comes to Life,” medGadget.²

“Medtronic Automates Pain Relief with Palm PDA,” Business Week.³

“Borrowing from Apple Playbook, Medical Device Makers Focus on Design, Consumer Appeal,” TheDeal.com.⁴

Consumer wants and needs are dictating that personal medical devices look and feel like everyday electronics. For years, device developers have offered insulin pumps that look like pagers, monitoring devices that feel like personal digital assistants, and medical electronics on wearable platforms, but consumers are asking for more. Patients want to minimize the stigma of their reliance on medical technology, and they want their medical devices to have the same kind of design appeal as iPods. This push for convergence of the medical and consumer market spaces brings a complex set of challenges to device designers. These challenges include widely divergent product life cycles, varying scenarios of use, and safety and efficacy concerns.

Formorinformation,pleasevisitthearticle : http://www.devicelink.com/mddi/archive/09/02/002.html

Disclaimer: This blog or article is for information purpose only, and should not be treated a professional advise or price protection guarantee. This blog is mainly used for search engine optimization and other commercial purposes and it is advised that readers seek professional consultation in the field of interest for more information

Dynamic Aerospace and Military Cables.

calmont — Fri, 26 Dec 2008 06:55:50 +0000

Aerospace, medical and military requires state of the art cables that are highly efficient with design support capability to qualify for usage. Depending on the application, medical cables maybe have to be rugged, handle high voltages or be ultra miniature cables to be used in applications that are quite diverse.

Medical device design and cables offer aerospace and military customers a full range of rugged, flexible and low outgassing jacketing options. Polyurethane, silicone rubber and thermoplastic rubber are just some of the materials used in these applications.

When beneficial, companies incorporate commercially available QPL subcomponents into custom designed cables. This allows customers to take advantage of readily available approved material, but at the same, address unique requirements for nonstandard shielding, jacketing and other components. Noncommercial materials such as nickel plated Kevlar® are utilized for weight critical satellite applications.

Disclaimer: This blog or article is for information purpose only, and should not be treated a professional advise or price protection guarantee. This blog is mainly used for search engine optimization and other commercial purposes and it is advised that readers seek professional consultation in the field of interest for more information

Hello world!

calmont — Fri, 26 Dec 2008 06:51:15 +0000

Welcome to Nestblogs.com. This is your first post. Edit or delete it, then start blogging!