1. Core technical principles and system composition of plastic thermoforming machines
Plastic thermoforming machines achieve plastic deformation of polymer sheets by precisely controlling thermodynamic processes. Its core process flow includes three stages: the sheet preheating stage uses mid-infrared radiation (wavelength 2.5~4μm) to make the material reach a viscoelastic state. Industrial-grade equipment is generally equipped with 16-32 independent temperature control zones, and the energy consumption of 0.5mm PP sheet from room temperature to 170℃ is controlled below 0.8kWh/m²; the molding stage relies on a multi-stage pressure control system, and the vacuum negative pressure (-0.098MPa) and compressed air (0.2~1.0MPa) work together to achieve micron-level deformation control; the cooling stage uses a dual-circulation heat exchange system, the main water circuit maintains 20±1℃ basic cooling, and is supplemented by a 5~10℃ deep cooling circuit to suppress crystallization shrinkage.
High-end models are equipped with a servo closed-loop system. The solution provided by Mitsubishi Electric of Japan can achieve:
Mold positioning accuracy ±0.005mm
Pressure fluctuation range <±0.15%
Temperature control fluctuation ±0.3℃
Such a system controls the wall thickness deviation of 0.25mm PET beverage cups within ±3%, which is much better than the industry standard of ±8%.
2. Key breakthroughs in material engineering of plastic thermoforming machines
Different types of polymers have different requirements for the molding process:
(1). Crystalline materials (such as PP)
The cooling rate (15~20℃/s) must be strictly controlled to prevent excessive growth of spherulites and decreased transparency. The quenching system equipped with Bruckner equipment in Germany can reduce the temperature from 170℃ to 60℃ within 0.8 seconds, keeping the haze value of PP lunch boxes <5%.
(2). Engineering plastics (such as PC)
To overcome the problem of high melt viscosity, oscillating pressure technology is used: 30Hz pulsating air pressure (0.3~0.5MPa) is applied within a 0.5-second molding cycle to fully stretch the molecular chain. This technology reduces the stress cracking rate of car lampshades to 7 parts per million.
(3). Bio-based materials
PLA composite molding requires a humidity control module (RH85%), combined with a 95°C preheating treatment to eliminate the risk of hydrolysis. Italy's Amut company uses mold surface micro-texturing technology (Ra0.08μm) to reduce the demoulding force of plant fiber reinforced materials by 42%.
WENZHOU RAYSHAPE MACHINERY CO.,LTD.We are mainly produces Plastic thermoforming machine and plastic sheet extrude machine .we were founded in 2016 and located in pingyang county,wenzhou city ,zhejiang province ,China.we have large-scale R&D organization in the same industry in China,a perfect production and marketing service network.
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