Applications
Thermoforming machines transform heated plastic sheets or films into rigid packaging, trays, technical components and medium-to-large volume structural parts.
The typical process involves preheating the material, shaping it using a mould,applying vacuum or pressure, and cooling it until the final shape solidifies. The versatility of the process allows the use of multiple polymers (ABS, PP, PET, PVC) and complex geometries in competitive cycle times, provided that each stage is rigorously controlled.
Requirements:
Measurement of moulding and closing forces
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Heating circuit control
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Thermoforming process control
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Moulding circuit air pressure monitoring
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Requirement:
Measurement of moulding and closing forces
During thermoforming, controlling the clamping and forming forces is essential to avoid unwanted deformation and ensure the correct distribution of the material on the mould. The pressure exerted on the plastic sheet must be constant and adapted to the type of polymer and the mould design.
Excessive forces can cause cracks or crushing, while insufficient pressure compromises detail definition and surface quality. Accurate measurement allows the cycle to be optimised, maintaining constant parameters and reducing waste.
- Stainless steel construction for high strength
- Thermal compensation for measurement stability even with temperature variations
- High precision in the detection of applied forces
- Reliability in harsh environments, typical of thermoforming processes
Requirement:
Heating circuit control
In thermoforming, the heating of the plastic sheet must be uniform and repeatable to allow for controlled deformation. Temperature differences between zones can cause uneven thicknesses and visual defects.
Traditional electromechanical relays, which are subject to contact wear, do not offer the repeatability required in high-frequency cycles. It is therefore essential to use solid-state devices that ensure fast, silent and maintenance-free switching, with integrated diagnostics for load monitoring and fault prevention.
Solution:
Requirement:
Thermoforming process control
The thermoforming process involves several stations that must operate in perfect synchronisation: preheating the sheet, shaping it on the mould, maintaining pressure or vacuum, and controlled cooling. Each stage requires precise adjustments of temperature, timing and movements to ensure uniform thickness and absence of defects.
Non-integrated management can lead to instability, sub-optimal cycle times or variations in quality between batches. Centralised and flexible process control, on the other hand, allows parameters to be quickly adapted to different types of materials and products, reducing waste and setup times.
Solution:
- Internal PIDs for thermal zone control
- Remote I/O modules for real-time management of actuators and sensors
- Open architecture compatible with Docker applications
- Integration with MES systems and predictive maintenance functionality
- Improved quality and overall OEE
Requirement:
Moulding circuit air pressure monitoring
During pressure forming, compressed air is the main means of forming the material against the mould and ensuring faithful reproduction of the profile. The pressure must be controlled dynamically: too high a value can deform or puncture the sheet, while insufficient pressure leads to dimensional defects or incomplete moulding. Pressure stability directly affects product quality, cycle repeatability and mould life. It is therefore essential to have a robust and accurate measurement system that can provide constant feedback to the machine control system.
Solution:
- Compact stainless steel structure for high robustness and easy integration
- KS-I version with IO-Link for advanced diagnostics and status monitoring
- Compatibility with safety circuits thanks to SIL2 certification
Operating principle
The thermoforming cycle begins with the preheating of the plastic sheet, which is brought to a temperature close to the glass transition point of the material, making it malleable but not melted. The heated sheet is then transferred to the forming station, where it takes the shape of the mould thanks to the combined action of vacuum,pressure and, in some cases, mechanical thrust. At this stage, temperature distribution and deformation control are crucial to ensure uniform thickness and prevent defects such as creases,collapses or localised thinning. The forming system can be vacuum-based, in which air is removed from the mould to make the material adhere to the walls, or pressure-based, where compressed air pushes the sheet into the mould, ensuring greater detail definition. Some machines combine both techniques, also using a piston or counter-mould to pre-stretch the material and improve polymer distribution. Once the part has been formed,controlled cooling of the mould stabilises the geometry and allows the part to be removed, which can then be trimmed or perforated. The entire process is cyclical and automated, requiring precise control of temperature, pressure, vacuum and axis movement to ensure productivity and consistent quality.
