Staying Connected - May 2009

Strain Relief Options and Considerations


Examples of two custom
overmolded solid strain reliefs
- smooth and segmented

Strain Relief Options and Considerations

One feature of a medical cable assembly that is important to both the electrical and mechanical integrity and performance is the strain or bend relief.  Connectors are typically rigid and the strain relief provides a transition from the stiffness of the connector to the flexibility of the cable. A good strain relief will prevent mechanical force applied to the exterior of the cable from being transferred to the electrical terminations within the connector, which could lead to failure.

Custom or Pre-manufactured Strain Relief

Strain reliefs can be either pre-manufactured or custom designed and over-molded. Pre-manufactured strain reliefs typically slip over the cable before the connector is terminated.  After the cable conductors are terminated to the connector, the strain relief is screwed or glued onto the connector assembly.  Pre-manufactured strain reliefs are available in a variety of colors and also a variety of sizes to match common cable diameters.  In virtually every instance, an overmolded strain relief will offer better flex life, tensile strength, and moisture protection performance than a pre-manufactured strain relief.


Example of pre-manufactured
slip-on strain relief

Pre-manufactured
spring-style strain relief

Flex Life and Tensile Strength Performance

Besides the construction of multi-conductor cable or single conductor wire, flex life performance is influenced by a number of factors including: design of the strain relief, the type of material the strain relief is made of and also the hardness or durometer of the material.  Material selection can play a large role in the performance of a bend relief.  Typically, softer materials give greater flex life performance but do not offer as high tensile strength.  Some materials offer a better adhesive bond between the strain relief and the cable than others, generally improving both flex life and tensile strength.

Additional tensile strength can be achieved relatively easily in an over molded strain relief by the addition of a cable clamp.  The clamp is typically crimped onto the cable jacket prior to molding.  When the clamp is embedded into the mold material, it greatly increases the tensile strength of the assembly.

Benefits of Segmented or Smooth Strain Reliefs

Overmolded strain reliefs can be segmented or smooth.  A segmented strain relief typically offers the greatest degree of flexibility, but can make cleaning more difficult.  Smooth strain reliefs are easier to clean, but generally do not offer quite as much flexibility as a segmented strain relief.  An over molded strain relief, either smooth or segmented, typically provides a higher degree of moisture resistance as compared to a slip-on strain relief.  This can be an important consideration for cables that are cleaned often or otherwise subjected to contact with liquids.

A well designed segmented strain relief will feature walls and spaces designed to allow the bend radius to increase a greater distance from the connector.  The size of the solid sections and the size of the gap between solid portions are varied to achieve the desired bend radius.  Segmented strain reliefs are generally designed so that the segment closest to the connector closes first and the segment furthest from the connector closes last.  This provides the greatest amount of bend relief, protecting the wire terminations within the connector.


Bend starts at connector

Bend completes at segment
farthest from connector
reducing stress on connector

The length of a strain relief also contributes to performance.  Generally, the longer the strain relief, the better the bend and tensile strength performance.  However, consideration should be given to how the cable will be stored in clinical use.  Experience has shown that cables are often left attached and wound around portable devices, placing continuous strain on the assembly.  In this instance, a shorter strain relief may be desired and may offer better performance than a longer strain relief.


Anticipating how a cable will be
stored when not in use is
important design considerations

Custom Overmolded or Off-the-shelf Strain Relief

It is generally accepted that an overmolded strain relief offers superior performance when compared to a pre-manufactured strain relief.  Two factors that may lead to selecting a pre-manufactured strain relief instead of a custom overmolded strain relief can be the cost of tooling and lead-time to design and fabricate tooling.  Over the past twelve years, Affinity has developed a selection of strain relief tooling that can be used by our customers.  Depending on the design of the connector and diameter of the cable jacket, some tooling can be used as-is with no additional cost.  Other molds may require modification but with less cost and time required than designing and fabricating tooling from scratch.  Affinity engineers can often guide customers design decisions allowing them to use available tooling, saving time and money.


Custom segmented
strain relief molded onto
off-the-shelf connector

Summary

Understanding performance and design requirements, the Affinity engineering team helps our customer-partners choose the appropriate bend relief system, whether it be an off-the-shelf or custom molded solution.  An appropriate strain relief can improve both the performance and life of a medical cable assembly.

Affinity Medical Technologies has the experience and expertise to assist you with custom medical cable assemblies including effective strain reliefs.  Let us become part of your design team.  Contact Affinity Customer Care at 949-477-9495 or email to customercare2@affinitymed.com.

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Meet Sue Alessi, Affinity Medical Materials Buyer and Production Planner


Sue Alessi – always smiling!

Sue Alessi joined Affinity Medical Technologies in June of 2002 in the dual position of production planner and materials buyer.  Sue’s previous experience in injection molding, materials management and scheduling made her a valuable addition to the Affinity Medical team.

Sue earned a Bachelor of Arts degree in Business Management from Northern Michigan University.  She began her professional career as a retail buyer.  At one time Sue, who is 6’3”, considered starting her own tall women’s retail apparel business but an interesting career opportunity led her to move to California. 

While working for Tyco Healthcare/Mallinkrodt in Southern California, Sue received extensive training in Lean Manufacturing, Just-In-Time inventory strategies, Team Building and production planning.


Sue leading Affinity Lean
Manufacturing team

Sue was a member of Affinity’s first Lean Manufacturing training group.  She eagerly shared her knowledge and experience from earlier Lean training with the Affinity team.   She is an active member of Affinity’s Lean Team and has helped implement improved methods in purchasing, stocking, and production, which ultimately benefit our customers.

At Affinity, Sue works closely not only with the production team, but with Engineering, Quality Sales Engineering and Customer Care.  Sue works hard to buy raw materials and components at the lowest possible price which helps Affinity keep price increases to our customers at a minimum.  She also handles several Vendor Managed Inventory (VMI) programs for Affinity customers.

Sue supervises an assistant buyer and inventory control specialist and two production team members responsible for cable cutting. Her experience allows her to mentor them with on-the-job training and career development.

One of Sue’s main responsibilities is to work in conjunction with Kevin Kom, Affinity’s Manufacturing Manager, to schedule production so that every order is shipped on time.  In 2008, Affinity shipped 99.2% of orders on-time, somewhat short of its goal of 99.5% on-time delivery.  Sue, Kevin, and the entire production teams’ hard work paid off this April when 100% of Affinity orders were shipped on-time!


Sue at Affinity picnic

When asked what she likes most about her position at Affinity Medical, Sue replied, “I enjoy the small company environment and the great team that I work with.  We are all working together for one goal--to achieve customer satisfaction.  When orders are finished on time and cables meet our high quality standards, the entire team can see the immediate results of our efforts.” 

Sue is an avid gardener and also enjoys swimming and spending time outdoors. She and her husband, Adam, are the proud “young” grandparents of a beautiful baby grandson, Antonio, who they visit as much as possible along with their extended families.

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Affinity Celebrates 12 Year Anniversary

In mid May Affinity Medical Technologies celebrated its 12 year anniversary.  Affinity team members took a break from production on the 20th for a company hosted lunch and an update on the company by Affinity President Mary Phillipp.


The Affinity Medical team – May 2009

Part of the presentation was to honor those celebrating employment anniversaries with the company.  Affinity is proud of maintaining a very low employee turnover rate and many of those who joined Affinity in its first few years are still with the company.

Mary thanked Affinity team members for their dedication and hard work.  “We’re thankful for the confidence that our customer-partners have shown in us.  While many companies are struggling, Affinity continues to grow,” said Mary.  “Your dedication to quality and on-time delivery is appreciated by our customers.”

After lunch and a few brief presentations, it was back to work for Team Affinity.

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Announcements and Information


New Affinity website
premiers June 1st

New Affinity Website

Affinity will “go live” on its updated website June 1st.  Responding to requests from customers and prospective customers, Affinity has expanded information available on its website regarding capabilities, services and products.  Affinity has also added additional technical resources and will debut the Affinity Blog.

The Affinity Blog site will allow our customers and friends a more intimate look into the people and activities at Affinity.  We think you’ll like it!

On June 1st, check-out both our new website www.affinitymed.com and our new Blog www.blog.affinitymed.com.

Trivia

On May 11, 1993 police in Sao Paulo, Brazil arrested Rodrigo Almeida.  He was standing outside of the bank he’d just robbed and was waiting in line for a taxi to make his getaway!

On May 22, 1906 Orville and Wilber Wright received a U.S. patent for a “Flying Machine” with a motor!


Orville and Wilber’s “Flying Machine”
with motor – image source Wikipedia

Marmon Wasp – first car to win
the 500 mile Indianapolis race
– image source Wikipedia

On May 30th, 1911 Indianapolis hosted its first long distance auto race.  The length of the race was said to be determined by the speed of the cars at the time.  Five hundred miles was expected to take about seven hours.  Race supporters thought that was about the longest time fans would stay to watch an auto race!




Suzann Sitka and Candy Golding
the Affinity Customer Care team

Affinity Customer Care - Hours of Operation

Affinity Medical Technologies customer care specialists are available to assist you from 7:00 A.M. until 4:00 P.M. Pacific time, except holidays.

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Affinity Medical Technologies

1732 Reynolds Ave
Irvine, CA 92614  USA
Phone: +1 949 477 9495
Fax: +1 949 477 9499
Email: CustomerCare2@affinitymed.com
Website: www.affinitymed.com