Thermex Thermatron’s RF preheater systems are widely acclaimed for their rugged durability and engineering advantages. The unique characteristics of RF heating in achieving uniform, rapid and controlled heating throughout a given mass has never been more successfully applied than in the preheating of pultrusion resin / reinforcement. Today’s Thermex equipment brings a new standard of precision, economy and automation to the use of RF heating.

RF Pultrusion Preheater Single Electrode

RF Pultrusion Preheater Single Electrode

Pultrusion preheater ovens use one of the most cost-effective and fastest growing methods for production of composite materials. In this continuous process a fiber reinforcement material is pulled through a resin bath then through a set of preform plates to begin to shape the bundle. On parts with a thin cross section, the bundle is then pulled through a heated die to cure the resin. A cured part exits the die, ready to be cut to length.

For parts with a thicker cross section, companies have found it advantageous to add dielectric heating equipment such as the Thermex RF Pultrusion Preheater to the Pultrusion line. The RF Pultrusion Preheater is used to heat the inside of the part before it enters the heated die, increasing the line speed while helping to produce a better quality product by reducing or eliminating stress-cracking of the part.

The Thermex Pultrusion Preheaters are available in both single-electrode and multi-electrode models. The single-electrode model offers similar output power, voltage and input power KVA as the multi-electrode, but with a smaller spatial footprint.

Common Uses:

Preheating of thermosetting plastics for pultrusion

Applications:

Tool handles • sucker rods for petroleum • electrical insulators for power distribution • composite structural components • large diameter fiberglass rods

RF Pultrusion Preheater Single Electrode Features & Option

Features

  • Continuous RF power available when using a material suitable for RF heating
  • Cooled by shop air drawn in through replaceable air filter
  • Nominal frequency of 75 MHz
  • Includes plate, grid current and DC Kilovolt meters

Options

  • Laser
  • PLC
  • Remote start / stop function
  • IR temperature sensor and display integrated into the control panel

 


RF Pultrusion Preheater Multi Electrode

RF Pultrusion Preheater Multi Electrode

As previously stated, the Pultrusion Preheater ovens use one of the most cost-effective and fastest growing methods for production of composite materials. Thermex offers the Pultrusion Preheater ovens in both the single and multi-electrode model to provide a range of options for companies looking to implement this method in production. The multi-electrode model provides higher frequency and adjustable electrode height in a spatial footprint that is only slightly larger than the single-electrode model.

Common Uses:

Preheating of thermosetting plastics for pultrusion

Applications:

Tool handles • sucker rods for petroleum • electrical insulators for power distribution • composite structural components • large diameter fiberglass rods

RF Pultrusion Preheater Multi Electrode Features & Options

Features

  • Continuous RF power available when using a material suitable for RF heating
  • SCR Controller for uniform fine adjustment of power applied to all loads
  • Cooled by shop air drawn in through replaceable air filter
  • Nominal frequency of 80 MHz
  • Includes plate, grid current and DC Kilovolt meters

Options

  • Laser
  • PLC
  • Remote start / stop function
  • IR sensors with digital media display and over-temperature alarm

 

 


RF Preheater

RF Preheater

RF Preheaters preheat molding materials uniformly, rapidly and with greater efficiency. Materials such asphenolic, melamine and urea compounds have a low heat transfer property and high moisture absorption. These materials are being processed either by compression molding or transfer molding. Therefore, molding these materials without preheating lengthens molding time, and increases tooling wear resulting in deterioration of product quality and increase of rejects.

In the past, electric or infrared heating was used to reduce these problems, but today high-frequency preheating is the method of choice. Unlike the conventional heating which transfers heat by conduction from the outside of the material to the inside – high-frequency heating generates heat inside the material. The alternative high frequency electric field generated inside the RF Preheater causes the polar molecules of the material to be heated to continuously align themselves with the field. The friction resulting from molecular movement causes the material to rapidly heat throughout its entire mass.

Common Uses:

Preheating of thermosetting plastics (phenolic, melamine, polyester, and similar thermoset resins) for compression molding

Applications:

Preheating and curing of polyester, urethane, epoxy, urea, silicone, synthetic rubber and phenolic resins • Adhesive curing • SMC (Sheet Molding Composite) Bonding • General drying • Testing/heating studies • Bulk or granular solids

RF Preheater Options & Features

Operation: Preforms are placed on the sliding tray provided with the Preheater. Optional rotators are available to enhance heating uniformity. An adjustable timer stops the preheat cycle; the operator then pulls the tray open and removes heated preforms.

Controls: Indicator Lamp features include: Power On, Ready, RF On and Fault. Power output is controlled by adjusting the electrode spacing.

Meters: All units include both plate and grid current meters.

Cycle Timer: Electronic cycle timer is provided to control the heat time; optional heat delay timer is also available.

Optional Equipment:
Perform Rotators for one (1) to four (4) rows of preforms
Heat Delay Timer
IR Temperature Sensor Integrated into the Heat Cycle
Remote Cycle Start/Stop Function

 


RF 1.0 kW Preheater

RF 1.0 kW Preheater

For manufacturing processes focused on preheating and for curing of material like polyesters, urethanes, epoxies and silicones, engineers turn to the more petite Thermex RF 1.0 kW Preheater. This workhorse provides all the advantages of our larger Thermex RF Preheaters but with a smaller spatial footprint. However, despite its smaller size, it still features 1.0 kW of power, and a 2″ maximum preform diameter.

Common Uses:

Preheating of thermosetting plastics for compression molding

Applications:

Preheating and curing of polyester, urethane, epoxy, urea, silicone, synthetic rubber and phenolic resins

RF 1.0 kW Preheater Features & Options

Features

  • Continuous output power
  • Power output controlled by adjustable electrode
  • Equipped automatic overload protection
  • Standard voltage of 240V 60Hz
  • System cooled by shop air drawn in thru replaceable furnace-type air files
  • Process Time
  • 120 CFM Exhaust Fan
  • Interlocked applicator drawer and cabinet panels for safety

Options

  • IR temperature sensor integrated into heat cycle
  • Preform rotators for one (1) to four (4) rows of preforms
  • Analog and discrete outputs for external data collection
  • Remote cycle start / stop function
  • Arc suppression