Staying Connected - March 2013

Ingress Protection of Medical Cables

It is generally desirable and often necessary to require protection against the intrusion of foreign objects, dust, or water into medical devices - including cables and connectors.  The International Electrotechnical Commission (IEC) standard 60529 established and documents standard degrees of ingress protection.  Titled “Degrees of protection provided by enclosures,” it is commonly referred to as the Ingress Protection or “IP” Code.



IEC 60529 Establishes and defines standards for
Ingress Protection of electrical devices

When discussing ingress into medical devices, protecting against ingress of liquids or moisture is often what is first thought of.  However, equally important is keeping solid objects, such as fingers or tools out of a device or connector.  Protection against both is addressed in the IP standard.

IEC 60529

IEC 60529, second edition defines degrees of ingress protection for enclosures including:

  • protection of persons against access to hazardous parts inside the enclosure
  • protection of the equipment inside the enclosure against ingress of solid foreign objects
  • protection of the equipment inside the enclosure against harmful effects due to the ingress of water

The standard details requirements and designations for each degree of protection and the tests to be performed to confirm that the device meets the requirements.  It is also significant that IEC 60529 specifically addresses “harmful” ingress, whether it is by a solid or liquid.


Example of IP rating on medical device



The Ingress Protection Rating

The Ingress Protection Rating is more commonly referred to as the IP code.  The IP code as defined in IEC 60529 pertains to the broad category of electrical enclosures.  An electrical enclosure may be an electric or electronic device, an electrical component, or a medical connector or cable assembly.  The IP code should not be confused with the term “IP address,” used in data communications.

IP ratings are generally presented as two digits; the first digit refers to protection against ingress by solid objects and the second digit refers to protection against ingress by moisture or water.

Solid Objects

For protection against solid objects level 2 is designed to prevent fingers or similar sized objects from accidentally touching hazardous components, such as electrical contacts.  Level 4 protection prevents contact by objects 1mm or greater and is often referred to as “tool-proof.”  Levels 5 and 6 offer dust protection, with level 6 providing complete protection against solid objects including fine dust.



Devices with an “IPX4” or higher rating
should withstand liquid ingress during
cleaning except for submersion

Moisture and Liquids

The second digit of the IP rating refers to protection against harmful ingress of fluid or moisture.    Level 4 protection will prevent liquid splashed onto the enclosure from any direction from causing harm.  A device with level 4 ingress protection should withstand cleaning with liquids except for submersion.  The IP rating does not indicate that the materials are able to withstand various cleaning solutions; only that moisture from those solutions will not enter the device in an amount to be harmful.

The IP Rating Code Table

Solid Ingress Liquid Ingress
Level

Protected against

Details

Level

Protected against

Details

0

None

No protection

0

None

No protection

1

> 50mm

Protection against accidental contact by hand

1

Dripping water

Water dripping vertically will not cause harm

2

> 12.5mm

Protection against accidental contact by finger

2

Dripping water when tilted up to 15°

Water dripping vertically will not cause harm when the devices is tilted up to 15°

3

> 2.5mm

Protection against accidental contact by most tools

3

Spraying water

Water sprayed at an angle up to 60° from vertical shall not cause harm

4

> 1mm

Protection against accidental contact by small tools and wires

4

Splashing water

Water splashed from any direction shall not cause harm

5

Dust protected

Complete protection against moving parts and protection against harmful deposits of dust

5

Water jets

Protection against low pressure water jets from all directions snall not cause harm

6

Dust tight

Protection against penetration of dust

6

Powerful water jets

Protection against direct spray from all directions shall not cause harm

 

7

Submersion to 1 meter

No harmful ingress of water when submersed up to 30 minutes

8

Submersion beyond 1 meter

No harmful ingress of water with conditions specified by the manufacturer


Ingress Protection vs. Touch Proof

For medical cable assemblies and connectors, ingress protection for solid objects and a touch proof design are similar, but have different design goals.  DIN 42-802 details the design of touch proof plugs and receptacles while IEC 60529 establishes degrees of protection, leaving the design undefined.


Recessed pins in custom medical
connector meet DIN 42-802
touch-proof standard


An Inner mold helps provide protection
against ingress of fluids or moisture from
the cable side of the connector

DIN 42-802 achieves a touch-proof design by establishing overall dimensions and a 1.5mm set-back of contacts for plugs and a 1mm set-back of contacts for receptacles.  The DIN standard goes beyond safety in attempting to establish interchangeability between manufacturers.

Achieving Ingress Protection for Liquids

Achieving protection against harmful ingress of liquids or moisture is best addressed early in the design stage.  Protection is commonly achieved by applying potting material or molding thermoplastic resin over components.  When done properly, a high level of ingress protection may be achieved without adding significant cost to the product.

Most medical connectors consist of insulators with pins or sockets.  Connectors designed to prevent moisture ingress will typically have solid pins or sockets that are pressed under pressure into the plastic insulator.  When the insulator with wire-terminated contacts is well potted or over molded, a high degree of ingress protection may be achieved.



Connector system showing groves in
pliable plug that mates with rigid receptacle

A common method to achieve a high degree of ingress protection between two mated connectors is for one side to consist of a rigid material and the opposite side to be made of a pliable material.  The size and geometry of the pliable material is designed so that it will be stretched over the rigid mating component, providing a seal against moisture ingress.

To achieve a tight, waterproof fit, mold tooling is designed “tool-safe” so that when first fabricated the fit of one component over the other is too loose, offering little, if any, ingress protection.  Subsequent machining removes material from the mold for the outer component.  Each time material is removed from the tool, the part becomes larger and the fit of the molded part becomes tighter.  This is done in small steps until the desired feel and level of ingress protection is achieved.

Another method to achieve a high level of ingress protection between connector halves that will be mated and unmated is to use O-rings or molded ribs that fit into a grove on one side of the connector pair.  Because O-rings can be displaced or lost, molded ribs are often a more reliable method.


Test fixture sprays water at zero to
ninety degrees for fluid ingress testing
as the device is rotated


Ingress Protection Testing

While Affinity has a well-equipped lab, ingress testing is contracted out to a third-party test lab with appropriate accreditations.   Such labs typically offer testing and reporting for solid ingress protection, including dust as well as testing for fluid ingress protection.

Summary

The need for ingress protection and the level of protection desired or required are elements that are best addressed early in the design phase of medical connectors or cable assemblies.  The Affinity engineering team has experience and expertise in designing and manufacturing devices which meet high levels of ingress protection.  If you would like to discuss ingress protection and how it relates to your cable or connector project, contact the Affinity engineering team via email to customercare2@affinitymedical.com or call us at +1 949-477-9495.

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Meet Affinity Maintenance Supervisor – Jesus Avila



Affinity Maintenance Supervisor,
Jesus Avila

Jesus brought enthusiasm, hard work and 23 years’ experience working in maintenance when he joined Affinity in 2009.  Earlier in his career, he spent nine years at local medical device maker, McGaw where he was exposed to FDA Good Manufacturing Practices (GMPs) and Standard Operating Procedures (SOPs).  At McGaw he also gained valuable experience participating in FDA and OSHA audits, as well as extensive experience servicing electrical, pneumatic, hydraulic machinery and equipment.

Immediately before joining Affinity, Jesus worked for Niagara Bottling for nine years.  At Niagara, he worked twelve-hour shifts, six days a week.  Even though he said he did not mind the hours, Jesus left Niagara to spend more time with his family.  “At Niagara, I was the “Machinery Doctor” and I loved what I did.  But, my wife and kids were my first priority and I wanted to find a job that allowed me to spend more time with them,” said Jesus.

Jesus posted his resume on-line and received a call-back from Affinity’s Manager of Manufacturing and Facilities, Kevin Kom.  Jesus said he was attracted to the company by the opportunity to build Affinity’s maintenance department and also by the work schedule.  When Jesus started he said, “Kevin was the whole maintenance department and he needed help.”

When asked what his first impressions of Affinity were, Jesus replied, “I was impressed by the fast growth of Affinity and also that everyone strived to do their best!  Growing and achieving excellence is the natural outcome when you do your part in a well-oiled machine like Affinity. The management is the best I have ever worked for.”

Asked about his biggest challenge so far, Jesus replied “Being invisible!  Because, maintenance well done is the maintenance that nobody notices!  If all of our facilities and machinery look and perform as when they were new, that means I am doing my job.  And, I firmly believe that the best maintenance is preventive and not corrective.  Currently there is an “I” on my team because it is just me!”


Jesus setting up job on milling machine


“One of my goals is to position Affinity’s maintenance department to more efficiently anticipate what is needed so that any maintenance will be taken care of before it causes down time.  We will be better able to serve our customers if every piece of equipment is always working properly.”

“Jesus is an absolute pleasure to work with,” said Affinity General Manager, Bob Frank.  “He has done a great job making sure everything in the building is in good working order.  And, when something does need service, everyone knows that Jesus will take care of it promptly and professionally.”

Jesus earned a degree as an Electrical and Mechanical Engineer from E.S.I.M.E.  (Superior School of Electrical and Mechanical Engineering) at I.P.N (Polytechnic National Institute) in Mexico City.  He also finished his G.E.D at Rancho Santiago College and has taken training courses on Injection molding, logic ladders, PLC and robotics.  This month, he will start a leadership training course at Rancho Santiago College.

Jesus grew up in Mexico City and moved to the U.S. when was 23 years old.  He and his wife Laura have been married 12 years and have two children:  eleven-year-old Joshua and six-year-old Samantha.  “They are my motivation and inspiration,” said Jesus.  He and his family live in nearby Santa Ana, California.

When not working, Jesus likes to, “read a good book” and work with his remote control (RC) cars.  “We love to visit our families in Mexico whenever we have the opportunity.”

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Medical Cable Assembly Nameplates



High quality multi-colored nameplates
provide necessary information and
meet regulatory requirements

Medical devices, including cable assemblies and wires, require labeling and marking for identification and to comply with regulatory standards.  One of the most common methods to label cable assemblies or custom connectors is to use high quality multi-colored nameplates.

Nameplates are commonly designed to fit into recessed pockets molded into the cable yoke or connector.  Nameplate labels printed on a durable material such as polycarbonate will resist cleaning agents and scratching.  Being placed a five to ten thousandths of an inch below the surface helps prevent the nameplate from being removed either accidentally or intentionally.  When attached using an appropriate adhesive, the nameplate is virtually permanent.


High quality nameplates allow company
branding to be prominently shown


One of the advantages of a nameplate is the ability to print brands and logos with intricate detail and in multiple colors.  The material and process used to produce nameplates lends itself to high quality printing.  A well designed nameplate can not only convey necessary information, but can help associate the cable assembly with the manufacturer’s brand.

The Affinity engineering team has helped OEM partners properly and effectively label cables and connectors.  If you would like to see examples or samples of high quality nameplates, contact Affinity at customercare2@affinitymedical.com or call us at 949-477-9495.

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Announcements, Information and Trivia




While Manatees are
often referred to as a
“sea cow,” they are a
close relative to
elephants


Armadillo means
“little armored one”
in Spanish

No February Issue – If you wondered why you did not receive a February Issue of Staying Connected you are not alone – there was none!  For the past six years, Affinity’s electronic newsletter has been published the last week of the month.  Beginning with this issue, Staying Connected will be published the first week of the month.

Animal Facts and Trivia

Koala Bears - The fingerprints of koala bears are virtually indistinguishable from the fingerprints of humans.

Donkey’s Eyes - The placement of a donkey's eyes in its' heads allows it to see all four feet at the same time making it a very sure-footed animal.
           
Lobsters - It takes a lobster approximately seven years to grow to be one pound.

Manatee - The closest relative to the manatee is thought to be the elephant. Some scientists think that elephants returned to the sea from land to become manatees.

Dinosaurs - Dinosaur droppings are called coprolites, and are not uncommon.

Pigs – Pigs are omnivores, meaning they will eat both plants and animals.  Pigs typically have a large head and a long snout which it uses to dig to find food.  It is anatomically impossible for pigs to lookup into the sky.

Armadillos – The word “armadillo” means “little armored one” in Spanish.  They are prolific diggers which may explain why armadillos get an average of 18.5 hours of sleep per day, being exhausted from digging!

Chilling Facts

The coldest temperature ever recorded on earth is −89.2 °C (−128.6 °F) at Vostok Station in Antarctica on July 21, 1983.  Vostok is located 3,500 meters (11,482 feet) above sea level.

Fastest temperature drop ever recorded was 27.2 °C (49 °F) in 15 minutes in Rapid City, South Dakota, U.S.A. on January 10, 1911.

The coldest inhabited place on earth is Oymyakon, a village in Oymyakonsky Ulus of the Sakha Republic in Russia.  It has the coldest monthly mean temperature: −46 °C (−51 °F), for the month of January.

The lowest temperature ever recorded in Hawaii was -11.1 °C (12 °F) at the Mauna Kea Observatory located at 4,198 meters (13,773 feet) on May 17, 1979.

The snowiest place in the United States is Valdez, Alaska, which receives an average of 8.3 meters (326 inches) of snow every year.