Flat heaters — panel and shaped heaters

What is a flat heater

Flat heaters are designed for direct contact heating of flat surfaces. They are primarily used on equipment where a cartridge heater cannot be installed — for example, when there is no blind bore to insert one, or when the surface to be heated is open or irregular. A flat heater is a relatively low-cost device that is easy to install and connect. With the correct type selected, it can operate for years without maintenance.

Main applications include industrial plastic forming equipment, heat presses, 3D printers, injection moulds, and medical or food equipment (where flexible silicone heaters are required). There are four main types of flat (panel) heating elements, each with distinct characteristics and applications.

Flat mica heaters

Flat mica (muscovite) heaters are made by layering dielectric sheets and winding a resistance wire or strip onto a mica sheet, which is then enclosed in a metal housing.

The sizes and shapes of flat mica heaters can be extremely varied. The straightforward construction allows easy fabrication with mounting holes, technical cutouts, L-shaped or U-shaped bends, and power connection points at any position per drawing.

The power density of flat mica heaters is moderate — up to 4 W/cm². The relatively low structural rigidity requires tight installation on a flat surface. The heater is therefore supplied with mounting holes, and clamping is provided by a rigid metal pressure plate. When correctly installed on a clean, flat surface, a mica heater can last for many years. However, severe deformation damages the internal insulating layers and causes immediate short-circuit failure.

Flat ceramic heaters

Flat ceramic heaters are made by threading a nichrome or kanthal coil through channels in ceramic insulators. Ceramic flat heaters are available both with and without a metal housing.

The range of sizes and shapes for ceramic flat heater is narrower than for mica heaters, limited by the ceramic segment dimensions. Insulators with 1 to 12 holes at 7.15 mm pitch are used for assembly. Additional holes are possible but affect heating uniformity and total power — the coil channel is interrupted, leaving part of the heater inactive. L- and U-shapes are possible, as are side cutouts.

ceramic flat heater power density reaches 8 W/cm² — twice that of mica. The heater is relatively fragile and susceptible to impact loads. No heavy metal clamping hardware is required — simple surface fastening is sufficient.

Cast flat heaters

Cast heaters are heavy, complex and expensive. They are made by casting aluminium or brass around a tubular heater in a flat mould, followed by machining and drilling. Their use is limited since ceramic or mica heaters can usually substitute. Key advantages:

• High thermal mass due to the metal body — holds temperature very steadily;
• High thermal inertia — slow cooldown, dampens temperature swings;
• Resistance to mechanical loads — withstands impacts and vibration;
• With correct temperature management, can last for decades;
• The monolithic construction enables use in hazardous areas (Ex-rated execution) after additional certification.

Cast flat heaters are used exclusively in industrial applications. They are most commonly installed on injection moulding machines and extruders where a massive, vibration-resistant heater is needed.

Flexible silicone heaters

Silicone heaters are a relatively recent type applicable not only to flat surfaces. These heating elements have a thin (from 0.3 mm) and flexible structure, enabling use in almost any application. Their flexibility allows installation on curved or contoured surfaces. Cost is higher compared to mica and ceramic — so they are still gaining market share.

Several base materials are available, differing in temperature rating, thickness and appearance:

• Silicone — max 230 °C, opaque (usually red), ~0.6 mm with fibreglass reinforcement;
• Polyester — max 105 °C, transparent, colourless, ~0.2 mm. Domestic use: heated trays, stands;
• Polyimide (Kapton) — up to 230 °C, transparent yellowish, ~0.2 mm. Electronics, aerospace;
• Hybrid — two different insulating layers (e.g., silicone + polyimide) — combined properties.

Manufactured by bonding two insulating layers around the heating element. Can be made in any shape, dimensions up to 3000 mm × 600 mm.

Mounting options: pressure-sensitive adhesive backing (reduces max temperature to 180 °C) or spring tensioners at edges for cylindrical surfaces.

Specific power of flexible silicone heaters is modest — 2–3 W/cm². Therefore they are not used on high-thermal-mass parts. Typical applications:

• Medical equipment (organ transport containers, incubators);
• Food industry (bain-maries, milk warmers, heated serving surfaces);
• Aerospace (wing de-icing, pitot tube heaters);
• Military (instrument heating in Arctic conditions);
• Manufacturing (barrel and vessel heating for high-viscosity products).

Voltage

Any voltage can be specified — from 6 to 600 V, AC or DC. 2- and 3-phase supply configurations are available when required.

Standard voltages for flat heaters: 110, 220, 230, 380 V. For non-standard voltages (e.g. 12 V / 6000 W for DC equipment or 600 V / 15 kW for heavy industrial systems) it is important to calculate the current and select appropriate lead wire cross-section.

Installation and design notes

The primary fixing method for flat heaters is through-hole clamping. The heater must therefore be designed with the fastening in mind from the outset. Installation must be on a clean, flat surface — this is the prerequisite for long, trouble-free service. Drilling holes in a finished heater element is strictly prohibited: even a thin drill will sever the resistance coil.

Thermocouple holes (with or without retainer) or an integrated thermocouple inside the heater body can be added on request. Use with a temperature controller is recommended for accurate temperature monitoring.

Order worldwide

Custom-manufactured to drawing — from 3 days, from 1 piece. Worldwide shipping via DHL, FedEx, SDEK. 1-year warranty on all products. In business since 2010. To order, Send us a sketch, a photo of an existing heater, or describe your requirements — we will work out the specifications and provide a price within 15 minutes during business hours.

Certification: GOST 13268-88, on request — DIN, IEC, ASTM. TEN-Miass, ul. Shota Rustaveli 82a, Tashkent, Uzbekistan 100000. Phone: +998 50 090 19 24.