Flexible heaters are just that…heaters designed to be flexible enough to accommodate tight areas and intricate geometries that need heating properties. These highly-customized heaters are engineered specifically to meet your specific requirements. They’re thin, bendable, and can be designed using the most complex shapes, geometries, and curves to fit almost any type of application.

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Flexible Heater Overview
What They Are, Different Types, and
Where Are They Used

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Introduction to Flexible Heaters
 Flexible heaters are just that…heaters designed to be flexible enough
to accommodate tight areas and intricate geometries that need
heating properties.
 These highly-customized heaters are engineered specifically to meet
your specific requirements.
 They’re thin, bendable, and can be designed using the most complex
shapes, geometries, and curves to fit almost any type of application.

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Introduction to Flexible Heaters
 Flexible heaters have excellent heat transfer properties, have the
ability to be directly bonded to areas needing heat, provide quick
optimum temperatures, uniform heat distribution, and high-watt
densities without sacrificing efficiency or dependability.
 There are multiple types of flex heaters, but this presentation will focus
on the 2 most prevalent, silicone heaters and polyimide heaters.

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Silicone Rubber Heater
 Silicone rubber vulcanized around a wire wound element, or an etched foil
element.
 Can be designed to exact shape and size needed.
 Thin construction allows application fit in limited spacing.
 Moisture and chemical resistant to provide longer heater life.
 Heat transfer is rapid and efficient.
 Decreased wattage requirements
compared to conventional heaters.

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Polyimide Heaters
 Polyimide material laminated around an
etched foil element.
 Thin construction allows application fit in
limited spacing.
 Excellent tensile strength, tear resistance, and
dimension stability.
 Resistance to fungus and chemicals.
 Solvent resistant.
 Offers thermal stability over a wide
temperature range.

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Heater Specifications
Silicone Rubber Heaters Polyimide Heaters
Sizes from 1”x1” to 18”x24” 1”x1” to 12”x12”
Min/Max operating temperature -70˚F to 392˚F (Continuous) -70˚F to 266˚F (Continuous)
Nominal thickness .030” .007”
Maximum resistance density 200Ω/in² 450Ω/in²
Maximum watt density 50W/in² 30W/in²

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What is Watt Density?
 Watt Density equals heat flux. The amount of heat (watts) per unit area (in²).
 It’s expressed in watts per square inch of heater surface and determines the
heater's operating temperature for a given set of conditions.
 Low Watt Density - If the watt density is too low the heater operating cost will be
high
– Poor efficiency
 High Watt Density - If watt density is too high this could cause the heater to fail,
cause damage to the material being heated, or the element may burn out.
– Poor life
Tip: When in doubt between two-watt density choices, choose the lower one.

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Low Watt Density
2W/sq’’ 4W/sq’’
 Longer Heater Life
 Higher Price to Operate

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High Watt Density
8W/sq’’ 16W/sq’’
 Shorter Heater Life
 Cheaper to Operate

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Types of Heater Elements Design – Wire Wound
 Unlike etched foil element, there is
no restriction on overall size.
 Wire is high resistivity and usually
made of a nickel chromium alloy.
 Thicker and has reduced watt
densities compared to etched foils.

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Types of Heater Elements Design – Etched Foil
 Rectangular cross section exposes more
of the heating element to the contact
surface, than wire wound.
 Allows for thinner overall heater.
 Size is restricted to “etched panel” size,
typically 12”x12” (11”x11” actual foil
element), or less. Slightly larger sizes can
be reviewed for manufacturability.
 Etched foil allows tighter spacing element,
allowing for higher watt densities and
higher temperature operation.
 Multiple heat zones possible.

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Types of Elements
 Multiple metal and alloy options to meet
desired total resistance and correlating
wattage output based upon the voltage
applied.
 Wire wound elements are typically high
resistance nickel chromium alloys or
copper-nickel-manganese alloy.
 Etched elements, high resistance options
such as stainless steel 304 and Inconel
600 (Nickel Chromium alloy)
 Medium resistance option such as CuNi44.
 Low resistance options such as pure
copper foil.

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Mounting Methods
 The most popular form of mounting for
flexible heaters is pressure sensitive
adhesive (PSA).
 It should not be used for applications
exceeding 400°F (205°C) on silicone
rubber and 300°F (150°C) on polyimide.
 Heaters with PSA should be stored no
more than 6 months before installation.
 Other forms of mounting include RTV
silicone adhesives, rubber and nylon
grommets, and Velcro fasteners.

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Value Add Connectors and Designs
1. Application of connectors, such as Molex or Tyco.
2. Vulcanization to other materials such as aluminum, steel, etc.
3. Punch press capabilities for complex shapes.
4. PSA application for fixturing.

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Certifications and Compliancies
 Epec flexible heaters are UL and CE certified.
 Certified under UL standard KSOT2 (Heaters, Specialty - Component).
 Certified for UL, Canada.
 UL example = Manufacturing logo, heater type, manufacturing part #.
 If part is to have UL printed on it, it MUST be required at quote.
 CE certified under EMC Directive 2014/30/EU.
 Epec flexible heaters are ROHS and REACH compliant.

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Industry Applications
 Medical: Blood warmers, dialysis units, heated bedding.
 Automotive: Heated mirrors, heated batteries, heated gear boxes.
 Industry: Heated solutions and chemistries, heated raw materials.
 Consumer: Lithographs, aquarium equipment, lenses/video equipment.
 Refrigeration: Condensing trays, fan rings and motors.

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Q&A
1. What are the max/min operating temperatures for each heater type?
– Silicone -70˚ F - 392˚ F (continuous use) FEP adhesive
– Polyimide -70˚ F - 266˚ F (continuous use) FEP adhesive
2. What is the nominal thickness of the flex heaters?
– Silicone is 0.056” for wire wound and .030” for etched foil
– Polyimide is .007” (no PSA)
3. What are maximum watt densities?
– Silicone is 50 W/in²
– Polyimide is 30 W/in²
4. What are lead times?
– 20 days new part numbers, 15 days repeat orders, 15 days prototypes.

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Thank You
Check out our website at www.epectec.com.
For more information email sales@epectec.com.
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