Staying Connected - October 2008

Ingress Protection and Medical Cables

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

Ingress protection is most often thought to mean protection against ingress of harmful water or moisture.  While moisture protection is one of the levels of ingress protection, keeping solid objects out of a device or connector is part of the standard and is often overlooked.

IEC 60529

IEC 60529, second edition is but one of many standards adopted by the International Electrotechnical Commission.  The standard defines degrees of ingress protection for enclosures including:

  • Protection of persons against access to hazardous components within the enclosure
  • Protection of components within the enclosure against harmful ingress of solid foreign objects
  • Protection of components within the enclosure from harmful effects to the ingress of water or moisture

It is important to understand that IEC 60529 specifically address harmful ingress, not all ingress of solid objects or water.

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 as related to Affinity, a medical connector or cable assembly.

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

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

The second digit of the IP rating refers to protection of the device against ingress of water or moisture.    Level 4 should prevent water splashed onto the enclosure from any direction from causing harm.  A device with a level 4 water protection should withstand cleaning with liquids except for submersion.  It is important to understand that an IP rating does not indicate 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 Code Table

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

 


recessed pins meet DIN 42-802
touch-proof standard

Ingress Protection vs. Touch Proof

For medical cable assemblies and connectors ingress protection for solid objects and a touch proof design are similar, but slightly 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.

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

Achieving Ingress Protection for Liquids


Inner overmold provides
high degree of protection against
ingress of liquids or moisture

Protection against harmful ingress by liquids or moisture is not difficult to achieve when addressed very early in the design stage.  Protection is commonly achieved by molding thermoplastic material over other components.  Providing ingress protection in either a plug or receptacle is somewhat easier than achieving the same level of protection when connectors are mated.

Many medical connectors consist of insulators with pins or sockets inserted into hard plastic.  When overmolded with common thermoplastic materials, the assembly achieves a high degree of protection against harmful ingress by liquids.  Providing the same degree of ingress protection when mated to another connector requires additional engineering and design considerations.

The most common method to achieve a high degree of ingress protection between two connectors is for one half to be made of a hard material and the opposite half to be made of a softer material.  The size and geometry of the softer material is designed so that it must be stretched over the mating component.


IP67 connector system showing
two groves in hard plastic receptacle
and soft outer grey TPR plug

To achieve a tight, waterproof fit, tooling is designed so that when first fabricated the fit of one component over the other is too loose, offering little ingress protection.  This tool-save method requires subsequent machining to removes material from the mold for the outer component.  Each time material is removed from the tool, the fit of the molded part becomes tighter and tighter until the desired feel and level of ingress protection is achieved.

To achieve an IP X6 or IP X7 rating and maintain reasonable un-mate force, additional ribs designed to fit into groves in the receptacle are commonly used.  These are also typically done in a tool safe manner with additional machining yielding the desired fit and ingress protection.

Summary

The need for ingress protection and the level of protection desired or required are elements that should be addressed very early in the design phase of medical connectors or cable assemblies.  Affinity has experience and expertise in designing and manufacturing devices which meet our partner’s ingress protection requirements.  If you would like to discuss ingress protection and how it relates to your cable or connector project, contact Affinity Medical.

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Meet Beatriz “Betty” Navarrete – Manufacturing Associate


Betty Navarrete always
has a smile on her face

One of the most familiar faces at Affinity Medical is Beatriz Navarrete.   Betty began her career at Affinity Medical four years ago as a manufacturing associate.  Recently, Betty was given increased job responsibilities including releasing production orders to the floor.  She has willingly taken on these additional responsibilities and proven her ability to multi-task while always showing a positive attitude.

Before immigrating to the United States from Mexico and joining Affinity Medical, Betty completed her studies in Psychology and received a university degree.  After graduation, Betty worked for the National Statistical and Geographic Information Systems of Mexico, and organization that compiles information about companies and their employees for the national census.  Betty was also trained and employed as an early childhood counselor in the Psychology department at the university where she earned her degree.


One of Betty’s duties is to
precision cut wire and cable

Betty supports production at Affinity by releasing and kitting production work orders.  Her Supervisor, Sue Alessi says; “Betty is a valued employee at Affinity Medical and she wears many different hats.”  In addition to her kitting and releasing work orders, Betty is responsible for inventory control and precision cutting of raw cable.

Betty was part of the team that recently reorganized Affinity’s warehouse.  She is now participating in “Lean Manufacturing” training.  The three month workshop is helping to establish more streamlined manufacturing procedures while increasing communication and efficiency in all areas at Affinity Medical Technologies.


Betty Navarrete leads the
Birthday Band with (l to r) Lulu,
Rosario, Dora, Micaela, and Betty

When asked what she likes most about working at Affinity, Betty replied; “There is opportunity to grow and develop my skills in new areas at Affinity.  I appreciate the chance to try new things so I thank Mary Phillipp and everyone else for their continued support.”

Betty is also the founder and leader of Affinity Medical’s “Birthday Band”.  The band consists of Betty playing a miniature accordion and three other manufacturing associates who cheerfully play tiny drums and noisemakers while serenading the team members who are celebrating their birthday.  The Birthday Band has become a regular and expected part of the birthday celebrations at Affinity.

In addition to her full time job at Affinity, Betty works three evenings and most weekends as a food service supervisor at a local hotel restaurant.  Betty enjoys dancing to rock and roll music and takes every opportunity to have fun with her friends at parties and local clubs.

Although she is always on the go working two jobs, Betty makes time to play her acoustic guitar.  She favors romantic songs that she says ”relaxes me and soothes my spirit.”

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ECG Snap Electrode Connectors


Affinity electrode snaps

Affinity produces a variety of ECG electrode snap and pinch connectors.  Each is designed to mate securely to a standard stud-type electrode.  Part of mating securely is mating in such as a way to not produce any unwanted noise when the pinch or snap is moved while attached to the electrode.

A snap connector is made up of the metal snap assembly which at Affinity is overmolded with thermoplastic rubber or polyurethane.  A flexible strain relief is part of the snap body and is molded over the leadwire terminated to the metal snap assembly.


Affinity’s proprietary metallic snap
assembly offers reliable performance

Affinity uses a proprietary metal snap assembly that has been proven for over ten years to provide reliable and long lasting performance. 

The strain relief is an important part of a snap connector.  Often it must absorb the substantial perpendicular force used to disconnect the snap from the stud when the leadwire is used as a removal device.  A well designed strain relief will absorb the force over its length, preventing the force from acting on the electrical termination within the snap assembly.


One of Affinity’s standard snap
configurations with segmented strain
relief and molded-in lead designations

Affinity Medical owns a variety of proprietary snap connector and strain relief designs.  These designs will accommodate leadwires with diameters of .060, .080, .090, .100, and .120 inches accepting both shielded and unshielded leadwires as well as tinsel Kevlar wire.

Defibrillation protection is often required in medical monitoring devices.  Defib protection resistors are most commonly built into the yoke of a patient cable, however when that is not possible or desired, they may be located within the snap assembly.  Affinity offers tooling to accommodate defib resistors in the snap assembly with only slight lengthening of the snap.


Unique custom electrode snap
with LED indicator

Besides standard electrode snap assemblies, Affinity produces a number of custom snaps for our OEM partners.  One unique custom product incorporates LED’s within the snap head giving the operator visual confirmation via a green light that the connection is good.

If you would like to see examples of our standard snap assemblies or discuss a custom snap, please contact Affinity Medical Customer Care at 949-477-9495 or email to customercare2@affinitymed.com.

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Announcements, Information and Trivia

.

Halloween is a holiday celebrated on the night of October 31.  Irish immigrants carried versions of the tradition to North America in the nineteenth century.  Halloween is celebrated in a number of countries in the Western world including the United States, the United Kingdom, Canada, Ireland, Puerto Rico, Japan, and New Zealand

To some, Halloween is about bats and ghosts and witches riding on brooms.  To most children, Halloween is about…GETTING CANDY!

Tootsie Rolls were introduced in 1996 by Leo Hirshfield.  He named them after his daughter whose nickname was “Tootsie.”

In 1920 the first “Baby Ruth” candy bar was sold.  It was named after President Grover Cleveland’s daughter.  Not, as many assume the legendary baseball player Babe Ruth!


The Snickers bar, introduced in 1930 by Mars Candy - is named after the Mars family favorite horse named…Snickers!


Suzann Sitka and Candy Golding
the Affinity Customer Care team


Affinity Customer Care - Hours of Operation

Affinity Medical Technologies customer care specialists are available from 7:00 A.M. until 4:00 P.M. Pacific Time Monday through Friday, except National Holidays.  You may reach all Affinity team members by phone at +1 949 477 9495 or by email.  Email addresses are first initial followed by last name @affinitymed.com.

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Affinity Medical Technologies

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