Rapid, Clean, and Efficient: How Infrared Heat Lamps Are Working In Plastic Thermoforming

Principle of Vacuum Thermoforming

Vacuum thermoforming is a process that shapes thermoplastic sheets into specific forms.

The principle is as follows:

 

1. Heating and Softening: The plastic sheet is clamped over a mold and heated uniformly until it reaches a high-elastic (softening) state.

 

2. Vacuum Forming: Once softened, the air between the sheet and the mold is extracted through vacuum holes in the mold, causing atmospheric pressure to press the sheet tightly against the mold surface.

 

3. Cooling and Setting: The vacuum is maintained while the plastic is cooled, allowing it to solidify into the desired shape. The finished part is then demolded.

 

The core of the thermoforming process lies in heating the plastic sheet precisely, uniformly, and efficiently. Infrared heating technology, particularly quartz infrared heat lamps, has become the mainstream heating solution in thermoforming and laminating because of its rapid thermal response, high radiant efficiency, and the ability to match the material’s absorption spectrum. The quality of vacuum thermoforming heavily depends on the temperature uniformity and the softened state of the sheet. Traditional heating methods such as ceramic heaters or hot-air circulation suffer from slow heating, high thermal inertia, and significant energy consumption. In contrast, infrared radiation uses electromagnetic waves to directly excite molecular vibrations within the plastic, generating heat and achieving a temperature rise within seconds. Quartz infrared heat lamps, designed specifically for plastic thermoforming and laminating, deliver an instantaneous, precisely controllable radiant heat source, greatly enhancing molding efficiency and product yield.

 

Our Infrared Heating Lamps

 

1. Rapid Thermal Response and Instant Temperature Control

The high-temperature-resistant tungsten alloy filament can reach full power output within 1 second and stops heating immediately when switched off. This characteristic perfectly matches the reciprocating, intermittent operating mode of thermoforming machines, eliminating the need for constant heat preservation and reducing standby energy consumption. Using a PID or PLC control system, the heating lamp array can be regulated with stepless on/off control, achieving a temperature profile control within ±1°C on the sheet surface.

 

2. Matching Radiation Wavelength with Plastic Absorption Characteristics

Different thermoplastic materials (such as ABS, PS, PET, PMMA, and PC) have distinct infrared absorption peaks. The quartz infrared heat lamps provided by EdenLamp can be designed as fast medium-wave or short-wave types. For example, for thicker PS or ABS sheets, short-wave infrared radiation (1.0–1.4 μm) can penetrate the sheet to a certain depth. Heat is rapidly absorbed by the surface while the interior is simultaneously heated by the infrared radiation, enabling extremely fast heating. For thin PET sheets, fast medium-wave also achieves rapid heating, supporting high-speed production lines.

 

3. High Power Density and Zoned Heating Design

Quartz infrared lamps can be manufactured in single-tube or twin-tube configurations to achieve high watt density (30–60 W/cm), making them suitable for localized intensive heating. In the forming of large vacuum-formed parts (such as automotive interior panels and refrigerator liners), the heating area is often divided into multiple independently controlled temperature zones. EdenLamp’s lamps can be configured with different wattages and lengths. By comprehensively considering lamp spacing, reflector shape, and the lamp-to-sheet distance, heating stripes or cold edge zones can be avoided. This effectively covers or compensates for wall-thickness issues caused by varying draw ratios, significantly improving the structural strength of the finished product.

 

4. Cleanliness, Long Lifespan, and Easy Maintenance

The quartz glass tube used as the lamp envelope has extremely high chemical stability and resistance to sudden temperature changes. This heating method generates no dust and produces no airflow, keeping the sheet and mold clean. It is particularly suitable for applications requiring strict hygiene standards, such as medical devices and food packaging. Moreover, the optimized filament process and sealing technology give the lamp a working life of over 5,000 hours, reducing downtime losses caused by frequent replacement.

 

Single Tube Short Wave Halogen Infrared Lamps are widely used in high-efficient industrial fast heating applications. The halogen IR lamp is made of quartz single tube. The heating filament is tungsten alloy material. We have 10mm, 11mm, 12mm, 14mm, 15mm and 19mm single quartz tube for different customers. The total length of single tube IR lamp can be up to 2.5 meter. In order to better convey and focus on the heated material all the IR radiation emitted from the IR lamp, the special gold reflector or white reflector will be coated and fixed directly on the quartz surface.

Short Wave Single Tube IR Lamp
Peak wavelength	1.0-1.4μm
Response time	＞1 second
Diameter (mm)	10	11	12	14	15	19
Max. Length (m)	1.1	1.1	1.5	2.0	2.0	2.5
Reflector	White or Gold reflector
Burning position	Horizontal or Vertical

 

 

Twin Tube Short Wave Infrared Radiant Heat Lamps are widely used in high-efficient industrial fast heating applications. The IR lamp is made of quartz double tube. The heating filament is tungsten alloy material. We have 23×11mm and 33×15mm quartz twin tube for different customers. The total length of twin tube IR lamp can be up to 6.0 meter. In order to better convey and focus on the heated material all the IR radiation emitted from the IR lamp, the special gold reflector or white reflector will be coated and fixed directly on the quartz surface.