MH-CHP
MINGHUNG
The customized MDF high-speed continuous hot press mainly consists of the following core systems:
1. Frame and Framework System
The frame is the load‑bearing foundation of the entire press. It is welded from high‑strength steel plates into a closed‑frame structure capable of withstanding high pressure and heavy loads. The frames are arranged in groups according to uniform load distribution, ensuring stable dimensions and high precision. Frame movement uses sliding sleeves and tie rods to achieve thermal compensation. Some high‑end models also adopt a hinged frame design, allowing quick removal of rollers for easier maintenance.
2. Steel Belt and Drive System
The upper and lower heat‑resistant steel belts (typically 1.5–2 mm thick) respectively loop around the upper and lower press plate assemblies, running cyclically to clamp and convey the mat through the press. The steel belts are driven by drive rollers and equipped with deviation correction devices (such as a three‑dimensional correction system) to ensure operational stability and extend belt service life. An advanced passive steel belt roller structure makes assembly, adjustment, and maintenance easier.
3. Hot Platens and Heating System
The hot platens are the core heating elements of the press. They are generally made from solid rolled steel plates with deep‑hole drilling, featuring internal channels for heat transfer medium. The heating medium can be thermal oil or saturated steam. Thermal oil offers high heat capacity, uniform temperature, and the ability to reach high temperatures at atmospheric pressure; steam heating provides faster temperature rise. The surface of the hot platens is machined to extremely high precision, with flatness tolerance controlled within 0.1–0.18 mm and surface roughness of 3.2 μm. The temperature difference across the entire platen surface does not exceed 2–3 °C, ensuring uniform heating of the board. The transverse heating channel design makes heat distribution more reasonable.
4. Hydraulic System
The hydraulic system is the power source of the press, consisting of a hydraulic power unit, hydraulic cylinders, servo valves, sensors, etc. It uses dual pumps and cartridge valve control, featuring high efficiency, fewer control components, and reliable operation. High‑end models adopt a servo‑hydraulic system consisting of 200–400 independent cylinder units with closed‑loop pressure control servo valves, achieving control accuracy of ±0.1 bar and response time ≤10 ms.
5. Modular Structure
The continuous press is typically composed of four standard modules: the infeed module, center module, adjustment module, and outfeed module. Thickness calibration is completed in the adjustment module while the other three modules remain constant. Modular design not only facilitates manufacturing, transportation, and installation but also provides convenience for future maintenance and upgrades.
6. Control System
A PLC (Programmable Logic Controller) serves as the control core, together with an HMI (Human‑Machine Interface) touch screen, enabling real‑time monitoring and automatic adjustment of parameters such as temperature, pressure, speed, and thickness. The system supports both manual and automatic operation modes. Temperature and pressure signals are collected via analog input modules, and a fuzzy self‑tuning PID closed‑loop control algorithm ensures stable and precise process parameters.
The working principle of the customized MDF high‑speed continuous hot press can be summarized as “completing the heating, compression, and curing of the mat during continuous travel.” The detailed process is as follows:
Mat forming and infeed: Wood or plant fibers, after glue application and drying, are evenly spread by the forming machine to form a fiber mat with a certain thickness and density. The mat is pre‑compacted by pre‑press rollers to remove air, then enters the infeed of the continuous press.
Flexible infeed control: The press infeed is equipped with swingable upper and lower infeed mechanisms and infeed rollers, allowing flexible adjustment of the infeed opening according to mat thickness and process requirements, preventing mat stacking or blow‑out. Special transverse connection structures in the infeed section also facilitate mat degassing.
Zone pressing process: After entering the press, the mat passes through three stages: heating zone, curing zone, and cooling zone.
Heating zone (200–250 °C): Rapid heating activates the adhesive and begins surface curing of the board.
Curing zone (180–200 °C): Constant temperature and pressure allow heat to penetrate the core layer, fully curing the adhesive.
Cooling zone (150–170 °C): Gradual cooling suppresses spring‑back deformation and stabilizes finished dimensions.
Continuous pressing and outfeed: The mat is continuously conveyed through the entire press length clamped between the upper and lower steel belts. Under high temperature and high pressure, the fibers and adhesive fully bond to form a board. The finished board exits the press continuously, is cooled, and then cut to length by a flying saw according to the set dimension.
Throughout the pressing process, the hydraulic system continuously applies pressure, the heating system controls zone temperatures, and the control system monitors and automatically adjusts all parameters to ensure stable board quality.
1. Passive Steel Belt Roller Structure and Deviation Correction Technology
The steel belts are passively driven, with drive rollers at both ends of the press. When the steel belts run on passive rollers, frictional resistance is low, improving transmission efficiency and extending belt service life. The three‑dimensional deviation correction system automatically adjusts the steel belt position in three directions, preventing misalignment and prolonging belt life.
2. Servo‑Hydraulic Precision Control Technology
Servo valves control the pressure of hydraulic cylinders, enabling real‑time switching of control strategies based on board thickness: for thin boards, position control (accuracy up to ±0.05 mm) is prioritized; for thick boards, uniform pressure (zone pressure difference <0.3 bar) is prioritized. The combination of pressing and lifting allows continuous adjustment of the upper platen bending curvature, achieving fine control over the board’s density profile.
3. Zone Temperature Control System
The hot platens are typically divided into 12–24 independent temperature control zones. Each zone is equipped with a thermocouple and PID controller, allowing independent setting and adjustment of temperatures to meet the differentiated temperature profile requirements of different board thicknesses. The temperature difference across the hot platen surface does not exceed 2–3 °C, effectively avoiding warpage caused by uneven heating.
4. Precision Thickness Control
Dual control technology combining longitudinal zone pressure regulation and transverse fine micro‑adjustment allows board thickness tolerance to be controlled within ±0.1 mm, meeting high‑end application requirements. The overall configuration of the hydraulic system keeps press technology nearly isobaric, producing thin boards with minimal thickness deviation, often requiring no sanding before further processing.
5. Intelligent Production Management System
Equipped with an Industry 4.0‑level intelligent production management system, it can collect production data online in real time (temperature, pressure, speed, thickness, etc.), automatically adapt to changing process conditions, optimize production processes, and support remote diagnostics and maintenance.
Parameter | Specification Range |
Press length | 23.9 – 48.8 m (customizable) |
Press width | 4 – 10 ft (approx. 1.2–3.2 m) |
Finished board thickness | 0.8 – 80 mm (depending on model) |
Finished board width | 915 – 3000 mm |
Finished board length | 1830 – 5490 mm (any custom length) |
Operating speed | Up to 2500 mm/s |
Daily capacity | 300 – 2500 m³ |
Board density range | 450 – 1100 kg/m³ |
Working pressure | 2 – 8 MPa (zone adjustable) |
Hot platen temperature | 150 – 250 °C (12–24 independent zones) |
Installed power | 2500 – 5000 kW |
Thickness control accuracy | ±0.1 mm |
Heating method | Thermal oil / saturated steam / electric heating |
1. Extremely high production efficiency
The continuous press eliminates auxiliary time for starting/stopping and loading/unloading boards associated with traditional batch presses. Its unit‑time capacity can be up to 15 times that of a single‑opening press and 23 times that of a multi‑opening press of the same specification, with a maximum annual output of 700,000 m³.
2. Excellent finished board quality
Tight thickness tolerance, uniform density profile, and high surface smoothness – many high‑end products require no sanding to meet downstream processing requirements.
3. Energy saving and reduced consumption
Zone temperature control of the hot platens and high efficiency of the hydraulic system significantly reduce energy consumption and raw material waste compared to batch presses.
4. Flexible product specifications
Maximum width up to 3000 mm, thickness from 0.8 to 80 mm, and theoretically unlimited length. It can produce MDF, HDF, particleboard, OSB, and other wood‑based panels.
5. High degree of automation
The PLC + HMI intelligent control system enables fully automatic operation, reducing manual intervention, lowering operational difficulty, and minimizing human error.
6. Easy maintenance
Modular design and advanced passive steel belt roller structure make assembly, adjustment, and maintenance convenient. Key components have long service life, resulting in low overall operating costs.
With its high‑speed, continuous, and intelligent characteristics, this equipment has become an indispensable core machine for modern wood‑based panel production lines and an important indicator of a manufacturer’s technological advancement.
