Omnetics’ Contribution to Cochlear Implants & Conductive Bone Hearing
Omnetics offers many of the smallest fine wire interconnect cables used in the assisted hearing industry. Years of materials study and process design have helped Omnetics produce extremely thin wall overmolded insulation and connector jacketing in the industry.
Our ears and brain work together to help us hear 
through a three step process. Sound waves pulse through the air and are received by the Outer Ear, which is simply a collector and tubular router for channeling sound into the Middle Ear. Our Middle Ear is made up of the ear drum and a few tiny bones that resonate and transfer tuned audio vibrations into the Inner Ear. Hearing losses within these first two sections are often called conductive hearing loss. This kind of loss is often a simple issue such as an ear infection or a hole in the ear drum, which can be aided by a hearing aid or middle ear implant. As sound is processed into the Inner Ear, we have key apparatus such as the cochlea and auditory nerve. These apparatus begin to add more intelligence and understanding to the sound as it is passed onto the auditory nerve. Sensorineural hearing loss is often a result of missing or damaged hair cells in the cochlea and is usually permanent. These types of severe losses are more often solved with cochlear implants. If there is even more severe damage, such as a missing auditory nerve, nearly total loss occurs and cannot be solved with cochlear devices because the nerve conducts the key electrical signals to the brain for understanding and processing.
Our ears and brain work together to help us hear through a three step process. Sound waves pulse through the air and are received by the Outer Ear, which is simply a collector and tubular router for channeling sound into the Middle Ear. Our Middle Ear is made up of the ear drum and a few tiny bones that resonate and transfer tuned audio vibrations into the Inner Ear. Hearing losses within these first two sections are often called conductive hearing loss. This kind of loss is often a simple issue such as an ear infection or a hole in the ear drum, which can be aided by a hearing aid or middle ear implant. As sound is processed into the Inner Ear, we have key apparatus such as the cochlea and auditory nerve. These apparatus begin to add more intelligence and understanding to the sound as it is passed onto the auditory nerve. Sensorineural hearing loss is often a result of missing or damaged hair cells in the cochlea and is usually permanent. These types of severe losses are more often solved with cochlear implants. If there is even more severe damage, such as a missing auditory nerve, nearly total loss occurs and cannot be solved with cochlear devices because the nerve conducts the key electrical signals to the brain for understanding and processing.
Both Conductive and Sensorineural hearing devices contain electrical devices to help them operate and adapt to active daily lives of those using them. New conductive hearing-assist devices are also being developed that look like single headbands for audio entertainment assistance and during sporting and TV watching. More serious systems using cochlear designs with implanted stimulators are being used more regularly and have significantly benefitted from improved technology.
Omnetics’ special processing 
techniques, miniature cabling, and miniature connectors help in the systems design and functional daily use for many users of cochlear type hearing devices. Our Nano connector technologies are used on the external sound processosr of cochlear implant devices for their small size and durability. Cables and connectors utilized by cochlear implants must be light weight, offer simple connection ease, and maintain use for long periods of time. The external component of a cochlear implant can be used for up to five years, so durability and comfort are top design priorities. Omnetics’ rugged flex pin design secures the connectors in place and allows for long-term use of the implant. Omnetics also uses extremely precise ultra-thin over-molding systems with 100% coverage to keep the cable connectors as small as needed for the application. Santoprene and other special polyurethanes such as Evoprene materials are used to help serve this medical grade community of products, which allow for waterproofing and sterilization. When designing very thin wall over-molding or unique shapes of small connectors and cables, consider Omnetics Connector Corporation. We are masters of this niche in the cable technology world.
Overmolding Connectors and Cable Assemblies
Expanding the Options for Instrument and System Designers
Connectors and cable 
assemblies are now capable of withstanding the most demanding environments, thanks to advancements in technology and the development of materials for mold compounds. As a result of these new developments, cable assembly overmolds are used in almost every industry and application. Cable assembly overmolds allow for a soft tactile feel, provide surfaces that can be held onto while using gloves, bond to the backshell and cable to provide ingress protection from water and dust (IP67 & IP68 sealing), provide strain or bend relief to protect the termination points and contacts, provide shock and vibration protection to eliminate fatigue and other damage, and provide resistance to physical abuse and abrasion from rugged environments.
Omnetics offers experience in the design and manufacturing of high quality overmolded cables for a variety of medical, military, and industrial applications that may require prototypes, quick turn, or low or high volume production. Our focus is on engineering overmolded cables using our in-house Milacron vertical injection molding machines that are built to meet or exceed your exact specifications. A wide range of physical and material properties are available:
| Material Properties | |||||
|---|---|---|---|---|---|
|
MATERIAL: |
Polyurethane |
PBT |
Santoprene |
TPE |
PVC |
|
RUGGEDNESS & DURABILITY: |
Very High |
Very High |
Moderate |
Moderate |
Moderate |
|
RIGGIDTY: |
Soft – Moderate |
Very Hard |
Soft – Hard |
Soft – Moderate |
Moderate – Hard |
|
AUTOCLAVE: |
Low |
Moderate |
High |
Varies |
Low-Moderate |
|
CLEANABILITY & STERILIZATION: |
Low-Moderate |
Moderate |
Moderate |
Good |
Moderate-High |
|
MAX TEMP (°C): |
90 |
140 |
135 |
Varies |
105 |
|
COST: |
Moderate |
Moderate |
Low-Moderate |
Low |
Low |
The material selection process is critical to meeting the demands of the engineer’s application, so Omnetics can work directly with design engineers to help choose the best material for his or her needs. Electrical properties are also critical; Polyurethane is one of the best materials for control of items such as high dielectric strength and resistivity while retaining resistance to wear, exposure to chemicals, and retaining flexibility. The dielectric constant, a measure of an insulator’s ability to store electrical energy, is the ratio of the electrical capacity of an elastomer to store electrical energy to the capacity of a similar material made mostly of air. One factor that influences the dielectric constant is frequency of the signals, and tests may be run from as low as 25 cycles per second up to many megacycles per second.
The power factor of an electrical insulation material indicates its tendency to generate heat in service. If a capacitor using an elastomer as the dielectric is charged by a direct current and then immediately discharged, there is an energy loss in the form of heat. The ratio of this loss to the energy required to charge the capacitor is known as power factor. It’s expressed as a decimal fraction or a percent of the charging energy, which ensures compatibility and that it is suitable for military and rugged applications cooling systems; per the ASNI/VITA specifications.
One example of Omnetics 
selecting an over molding material for a specific application is in the use of Polyurethane Estane for portable military electronics. This material is a halogenated flame retardant compound with good low temperature properties and strong cut resistance. It is injection overmolded onto cables and connectors that will experience high use, provide IP68 sealing, and be exposed to a wide range of rugged environments. Another advantage of this material is that it does not require massive thickness to function and protect the electronics.
Omnetics is also very experienced in the use of thermoplastic elastomers (TPE) compounds. Omnetics regularly uses Evoprene for cable and connector products being utilized on medical devices worn by humans. The Evoprene being overmolded is based on the widely specified SEBS (Styrene – Ethylene Butylene – Styrene). These polymers are fully saturated, so there are no double bonds. Evoprene also offers high resistance to oxidation, making it an excellent material for outdoor wear. This material lends itself to superior mold quality and finished surfaces, even when mold material is held to very thin coating. Flexibility and ruggedness of these ultra-thin connector assemblies cannot be surpassed with other materials.
Contact Omnetics today to learn more about our overmolding processes.
Omnetics’ Ruggedized Nano Strip Connectors
Nano Strip connectors at .025” pitch with high-reliability pin and socket systems offer proven reliability in extreme environments and provide fast and firm mating for high density circuits in miniature and portable electronics.
Applications using micro strip connectors have expanded greatly as circuits have gotten smaller and more portable. Ruggedness has become critical in many of the new uses for portable electronics. Unmanned aerial vehicles require low weight and small size but also demand rugged performance, especially during landing. Land based robotic circuits have high shock and continuous vibration requirements and contain field replaceable modules that need to be switched quickly. Missile systems use strip connectors that can handle the 1 amp of current in a small and low profile module during high speed vibration. Both single row and dual row Nano strip connectors can be used for high speed digital signals for data rates up to 5 Gbits per second.
High performance circuits remain in demand but are getting smaller and traveling constantly. Omnetics’ Nano strip connectors help reduce size and weight while remaining very rugged and offering high performance. High reliability strip connectors using ruggedized insulators and military quality Flex Pin® technology are focused on providing the best and strongest strip-style interconnections in the world. These units have proven both signal integrity and reliability in many of the most demanding instruments, including portable electronics for armed forces’ systems.
Connectors are designed and manufactured in the United States with performance and ease of use as the main feature. The ultra-low profile and rugged format makes it a perfect fit for inside-the-box applications and high-reliability board to board solutions. The key elements, pins and sockets, have passed QPL standard tests in complimentary designs by using a beryllium-copper spring metal-pin for mating and employ nickel and gold plating. The insulator body of high-strength polyphenylene sulfide provides excellent dielectric qualities to help manage signal quality and ruggedness to offer very low-profile interconnects for higher density stacked modules. Up to 30 gauge Teflon® insulated stranded wires are used to provide up to 1 Amp of current when needed. Wires are crimped to the contacts and sealed with an epoxy back-potting system that ensures wire retention and strain relief. Connector formats are available for board surface mount, through-hole, and cable to cable connections. Pin counts range from 2 to 60 positions in single row format and up to 48 positions in dual row format.
Omnetics strip connectors are well-established products in our COTs and Standards family, and design options, sizes, and shapes are available and can be discussed. Omnetics is staffed with experienced engineers to work directly with the designer. Attention to detail early in the custom design stage helps save you time and money, while achieving the highest signal integrity and performance needed.
See more information on Nano Strip Connectors here.
From the Engineer’s Desk: High Speed Connector Design
Selecting the Right Insulation Material for Your Application
As featured in the December 2017 edition of Design World.
This article is a continuation of our series on connector design. This installment will focus on selecting the right insulation material.
Introduction
The insulation material is the material that surrounds the individual conductor wires. The purpose of an insulator is to protect wires from mechanical stress, and to prevent shorts and dielectric breakdown from nearby electrical signals.
| Cable Insulation Material Summary | ||||||
|---|---|---|---|---|---|---|
|
|
Cost |
Dielectric Constant |
Flexibility |
Temp Range |
Temp Range |
Outgassing |
|
Polyvinyl Chloride (PVC) |
Low |
5.0-8.0 |
Good |
60°C-105°C* |
Fair/Good |
Poor |
|
Polyethylene (PE) |
Low |
2.1 |
Good |
80°C |
80°C |
Poor |
|
Polypropylene (PP) |
Low |
2.2 |
Good |
80°C |
Fair/Good |
Poor |
|
Teflon (FEP) |
High |
2.1 |
Fair |
200°C |
Good |
Good |
|
Teflon (PFA) |
High |
2.0 |
Fair |
260°C |
Good |
Good |
|
Teflon (PTFE) |
High |
2.1 |
Fair |
200°C |
Good |
Good |
|
Teflon (XL-ETFE) |
High |
2.7 |
Poor/Fair |
150°C |
Good |
Good |
|
*Varies by formulation |
||||||
Key Considerations
There are several parameters that should be considered when selecting an insulation material:
- Dielectric Constant: The dielectric constant impacts the impedance and loss through the cable. The dielectric constant, however, does not impact the performance for low-speed signals, so it is only a concern for high-speed applications.
- Flexibility: Given the relatives sizes, the overall flexibility of the cable is influenced much more by the braid and jacket material. The flexibility of the insulation material still plays a role, but it is less critical.
- Temperature range: Temperature is important because it may impact the processability of the wires as well as the usability in the end environment. Processability is important because the insulation material must not melt if it needs to be soldered. Additionally, the material must not melt if a shrinktube is heated up and shrunk in the surrounding area.
- Flammability: Describes the ability of material to burn. Materials with good flammability ratings help minimize the amount of toxins released during fires.
- Outgassing: Outgassing consists of the releasing of gas from a material. This is primarily a concern in space where low outgassing materials are required in order to maintain a clean environment.
Insulation Material Options
There are many different materials that can be used for insulation material, but the vast majority of applications can use materials from the following three categories: PVC, Polyolefins, and Teflon.
- PVC: There are countless different PVC formulations, all with slightly different characteristics, so it is difficult to provide specific characteristics of PVC. That said, there are general parameters that are relatively similar across most formulations. PVC is generally the cheapest material and is used widely in commercial cables. PVC is not a good material for any applications with high-speed, temperature, or outgassing requirements.
- Polyolefins: The polyolefin family includes both polyethylene and polypropylene. These materials are also popular in commercial markets due to their low cost. The low dielectric constant is what separates polyolefins from PVC, and makes them a great solution for high-speed applications. However, the low temperature range and poor outgassing limit the applications where they can be used in.
- Teflons: There are many flavors of Teflon, but the most popular Teflons used for insulation materials are FEP, PFA, and PTFE. For the significant majority of applications, these Teflon materials provide the best characteristics, both electrical and mechanical. Not only do they have a low dielectric constant for high-speed applications, Teflon has a high temperature rating and low outgassing characteristics. The other Teflon option used is cross-linked ETFE (XL-ETFE). Despite slightly lower electrical and temperature characteristics, XL-ETFE has good cold flow and radiation resistance, which is important in aerospace applications. The downside of Teflon is that it can be up to ten times the cost of a material like PVC.
Conclusion
This article provides a summary of the various options to be considered in selecting the right insulation material. Understanding these variables should help engineers ensure their cable-connector assembly works optimally for their specific application.
Did you know?
More than 219,000 individuals worldwide have received cochlear implants (www.asha.org).
See Omnetics’ products optimized for the medical industry here.
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