MH-CHP
MINGHUNG
1. Core Concept
Continuous Production: Unlike traditional batch-operated multi-daylight presses, continuous flat presses operate uninterruptedly. Formed fiber mats are fed continuously into the press inlet, undergo heating, pressing, and curing while moving through the press, and emerge as solid panels continuously from the outlet.
Flat Pressing: Pressure is applied perpendicularly to the panel surface, ensuring uniform thickness and smooth, flat surfaces – essential for high-quality MDF.
Hot Pressing: Simultaneously with pressure, heat (typically from oil- or steam-heated platens) is applied to rapidly cure the resin binder (e.g., urea-formaldehyde) and bond the wood fibers.
2. Main Components & Working Principle
Steel Belt System: The defining feature. Two long, robust, high-strength continuous steel belts (upper and lower) form the conveying and pressure-transfer surfaces for the mat/panel.
Heated Platen System: Positioned inside the steel belts along the press length are large heated platens (often divided into multiple heating zones). These platens contain channels circulating hot oil or steam, transferring heat through the belts to the mat. They are the primary heat source.
Hydraulic Cylinder System: Generates the immense pressure. Hundreds or even thousands of hydraulic cylinders are densely arranged along the length and width outside the platens. Their piston rods act through pressure beams or frames to apply force uniformly to the platens, which transmit it via the steel belts to the mat.
Drive System: Powerful motors drive sprockets or rollers that synchronously and steadily move both steel belts, pulling the mat through the entire hot pressing zone.
Inlet/Outlet Sections: Precise feed mechanisms (e.g., leveling rolls, metering rolls) ensure uniform, continuous mat entry. Discharge mechanisms remove the pressed panel at the outlet.
Frame: Massive, robust steel structure designed to withstand enormous pressures and equipment weight.
Control System: Highly automated PLC/DCS system integrating control of pressure, temperature, belt speed, panel thickness, and other critical parameters.
3. Advantages of Continuous Presses:
High Production Efficiency: Continuous operation eliminates batch cycle downtime, enabling significantly higher output rates than batch presses.
High and Consistent Product Quality: Precise control of pressure, temperature, and speed results in tight thickness tolerances, uniform density distribution, consistent physical/mechanical properties, and excellent surface quality.
High Automation Level: Facilitates fully automated production lines, reducing manual intervention and enhancing process stability.
Relatively Lower Energy Consumption: Continuous operation avoids the large energy spikes associated with frequent opening/closing of batch presses, improving thermal efficiency.
Ideal for Large-Scale Production: The standard equipment for modern, high-capacity MDF/HDF production lines.
1. Pressure Profile (Along the Press Length - Direction of Production):
High-Pressure Inlet Zone (Compaction Zone): This is the zone of highest pressure. As the loose fiber mat enters, it needs to be rapidly and forcefully compressed towards its target thickness. Maximum pressure is required here (often utilizing the press's peak capability) to overcome air resistance between fibers, establish intimate fiber contact quickly, and set the stage for heat transfer and resin cure. The maximum pressure capability exceeding 30 MPa is primarily utilized in this zone.
Stable Middle Zone (Curing/Solidification Zone): Once the mat reaches near-target thickness, pressure is reduced and maintained relatively stable (though still significantly above atmospheric pressure). The primary task here is to provide sufficient heat and time for complete resin cure. Pressure is maintained at an optimal level – high enough to ensure good fiber contact for heat transfer and bonding, but not so high as to cause excessive density, high internal stresses, or "over-pressing" that degrades properties. Pressure typically ranges between 10-25 MPa, adjusted as needed.
Pressure Reduction Outlet Zone (Setting & Cooling Zone): As resin cure nears completion towards the outlet, pressure is gradually and controllably reduced. This stage aims to:
(1)Precisely Control Final Thickness: Fine-tune pressure for exact thickness tolerance.
(2)Relieve Internal Stresses: Allow controlled stress relaxation within the panel to minimize deformation (e.g., warping) risks.
(3)Initiate Cooling: Some designs incorporate cooling in this zone. Pressure eventually drops close to zero before the finished panel exits. Pressure here decreases from the mid-zone level down to a few MPa or lower.
2. Pressure Adjustability - The Key Feature
Core Capability: One of the most powerful features of continuous flat presses is the high degree of pressure adjustability, both along the length and across the width. This is achieved through a zoned hydraulic cylinder control system.
Lengthwise Zoning: The press length is divided into multiple independent pressure control zones (e.g., 10, 20, or more). Each zone has its own group of hydraulic cylinders controlled by independent servo or proportional valves. The control system can individually set and adjust the target pressure for each zone.
Crosswise Zoning (Transverse Profiling): Within each lengthwise zone, the cylinders can be grouped across the width (e.g., left, center, right columns). This allows fine-tuning pressure across the panel width ("crosswise pressure profiling"). It compensates for potential transverse density variations ("density profile") caused by uneven mat formation, steel belt deflection, or platen temperature differences, ensuring uniform density across the entire panel width.
Dynamic Adjustment: Based on pre-set process curves (defining pressure vs. position for different products, thicknesses, density targets) and real-time feedback (e.g., thickness gauges), the control system dynamically and precisely adjusts cylinder pressures in each zone to achieve the desired pressure distribution pattern.
Capability Demonstration: A maximum pressure exceeding 30 MPa signifies the press has the capability to exert extremely high pressure, particularly in the inlet compaction zone. This is crucial for producing High-Density Fiberboard (HDF), specialty boards (e.g., lightweight cores requiring high surface density), or processing difficult-to-compress raw materials (e.g., high bark or recycled content). High pressure ensures rapid and effective compaction of the fluffy mat to high density.
Not the Constant Operating Pressure: Crucially, this absolutely does not imply the press operates continuously at 30 MPa! 30+ MPa represents the upper limit of the equipment's capability.
Adjustment Based on Need: The actual pressure applied is entirely determined by specific production requirements:
Target Panel Density: The inlet pressure needed for standard MDF (~750 kg/m³) is much lower than for HDF (>800 kg/m³, even >1000 kg/m³). Higher density demands higher inlet pressure.
Raw Material Properties: Fiber morphology, moisture content, resin content, etc., influence compressibility.
Mat Structure: Different pressure profiles might be needed for layered mats (e.g., fine fibers on surfaces, coarse in core).
Production Line Speed: Higher speeds reduce dwell time in the inlet zone, potentially requiring higher instantaneous pressure to achieve the same compaction effect.
Resin Type & Curing Behavior: Different binders have varying pressure/temperature requirements for optimal cure.
Process Optimization: Operators or process engineers define an optimal pressure curve within the press control system based on the product specification and actual production conditions. This curve dictates the target pressure for each zone from inlet to outlet. Except for the inlet zone potentially approaching or reaching the maximum (e.g., 25-30 MPa for HDF production), pressures in all other zones are significantly below 30 MPa and are meticulously adjusted and set according to specific process needs.
Founded in 1983, Shandong MINGHUNG OSB&MDF Machinery Equipment Manufacturing Co.,Ltd., specializes in continuous press solutions for over 40 years.
MINGHUNG is a leading company in the industry of OSB&MDF making machine. With a strongfocus on producing high-quality machinery, we specialize in manufacturing thecomplete production line of Medium density fiberboard (MDF), High densityfiberboard (HDF),Particle board (PB), Oriented strand board (OSB), andVeneerable super strong particle board (LSB).
If interested please contact us for a quote.
Whatsapp: +8618769900191 +8615589105786 +8618954906501
Email: osbmdfmachinery@gmail.com
1. Core Concept
Continuous Production: Unlike traditional batch-operated multi-daylight presses, continuous flat presses operate uninterruptedly. Formed fiber mats are fed continuously into the press inlet, undergo heating, pressing, and curing while moving through the press, and emerge as solid panels continuously from the outlet.
Flat Pressing: Pressure is applied perpendicularly to the panel surface, ensuring uniform thickness and smooth, flat surfaces – essential for high-quality MDF.
Hot Pressing: Simultaneously with pressure, heat (typically from oil- or steam-heated platens) is applied to rapidly cure the resin binder (e.g., urea-formaldehyde) and bond the wood fibers.
2. Main Components & Working Principle
Steel Belt System: The defining feature. Two long, robust, high-strength continuous steel belts (upper and lower) form the conveying and pressure-transfer surfaces for the mat/panel.
Heated Platen System: Positioned inside the steel belts along the press length are large heated platens (often divided into multiple heating zones). These platens contain channels circulating hot oil or steam, transferring heat through the belts to the mat. They are the primary heat source.
Hydraulic Cylinder System: Generates the immense pressure. Hundreds or even thousands of hydraulic cylinders are densely arranged along the length and width outside the platens. Their piston rods act through pressure beams or frames to apply force uniformly to the platens, which transmit it via the steel belts to the mat.
Drive System: Powerful motors drive sprockets or rollers that synchronously and steadily move both steel belts, pulling the mat through the entire hot pressing zone.
Inlet/Outlet Sections: Precise feed mechanisms (e.g., leveling rolls, metering rolls) ensure uniform, continuous mat entry. Discharge mechanisms remove the pressed panel at the outlet.
Frame: Massive, robust steel structure designed to withstand enormous pressures and equipment weight.
Control System: Highly automated PLC/DCS system integrating control of pressure, temperature, belt speed, panel thickness, and other critical parameters.
3. Advantages of Continuous Presses:
High Production Efficiency: Continuous operation eliminates batch cycle downtime, enabling significantly higher output rates than batch presses.
High and Consistent Product Quality: Precise control of pressure, temperature, and speed results in tight thickness tolerances, uniform density distribution, consistent physical/mechanical properties, and excellent surface quality.
High Automation Level: Facilitates fully automated production lines, reducing manual intervention and enhancing process stability.
Relatively Lower Energy Consumption: Continuous operation avoids the large energy spikes associated with frequent opening/closing of batch presses, improving thermal efficiency.
Ideal for Large-Scale Production: The standard equipment for modern, high-capacity MDF/HDF production lines.
1. Pressure Profile (Along the Press Length - Direction of Production):
High-Pressure Inlet Zone (Compaction Zone): This is the zone of highest pressure. As the loose fiber mat enters, it needs to be rapidly and forcefully compressed towards its target thickness. Maximum pressure is required here (often utilizing the press's peak capability) to overcome air resistance between fibers, establish intimate fiber contact quickly, and set the stage for heat transfer and resin cure. The maximum pressure capability exceeding 30 MPa is primarily utilized in this zone.
Stable Middle Zone (Curing/Solidification Zone): Once the mat reaches near-target thickness, pressure is reduced and maintained relatively stable (though still significantly above atmospheric pressure). The primary task here is to provide sufficient heat and time for complete resin cure. Pressure is maintained at an optimal level – high enough to ensure good fiber contact for heat transfer and bonding, but not so high as to cause excessive density, high internal stresses, or "over-pressing" that degrades properties. Pressure typically ranges between 10-25 MPa, adjusted as needed.
Pressure Reduction Outlet Zone (Setting & Cooling Zone): As resin cure nears completion towards the outlet, pressure is gradually and controllably reduced. This stage aims to:
(1)Precisely Control Final Thickness: Fine-tune pressure for exact thickness tolerance.
(2)Relieve Internal Stresses: Allow controlled stress relaxation within the panel to minimize deformation (e.g., warping) risks.
(3)Initiate Cooling: Some designs incorporate cooling in this zone. Pressure eventually drops close to zero before the finished panel exits. Pressure here decreases from the mid-zone level down to a few MPa or lower.
2. Pressure Adjustability - The Key Feature
Core Capability: One of the most powerful features of continuous flat presses is the high degree of pressure adjustability, both along the length and across the width. This is achieved through a zoned hydraulic cylinder control system.
Lengthwise Zoning: The press length is divided into multiple independent pressure control zones (e.g., 10, 20, or more). Each zone has its own group of hydraulic cylinders controlled by independent servo or proportional valves. The control system can individually set and adjust the target pressure for each zone.
Crosswise Zoning (Transverse Profiling): Within each lengthwise zone, the cylinders can be grouped across the width (e.g., left, center, right columns). This allows fine-tuning pressure across the panel width ("crosswise pressure profiling"). It compensates for potential transverse density variations ("density profile") caused by uneven mat formation, steel belt deflection, or platen temperature differences, ensuring uniform density across the entire panel width.
Dynamic Adjustment: Based on pre-set process curves (defining pressure vs. position for different products, thicknesses, density targets) and real-time feedback (e.g., thickness gauges), the control system dynamically and precisely adjusts cylinder pressures in each zone to achieve the desired pressure distribution pattern.
Capability Demonstration: A maximum pressure exceeding 30 MPa signifies the press has the capability to exert extremely high pressure, particularly in the inlet compaction zone. This is crucial for producing High-Density Fiberboard (HDF), specialty boards (e.g., lightweight cores requiring high surface density), or processing difficult-to-compress raw materials (e.g., high bark or recycled content). High pressure ensures rapid and effective compaction of the fluffy mat to high density.
Not the Constant Operating Pressure: Crucially, this absolutely does not imply the press operates continuously at 30 MPa! 30+ MPa represents the upper limit of the equipment's capability.
Adjustment Based on Need: The actual pressure applied is entirely determined by specific production requirements:
Target Panel Density: The inlet pressure needed for standard MDF (~750 kg/m³) is much lower than for HDF (>800 kg/m³, even >1000 kg/m³). Higher density demands higher inlet pressure.
Raw Material Properties: Fiber morphology, moisture content, resin content, etc., influence compressibility.
Mat Structure: Different pressure profiles might be needed for layered mats (e.g., fine fibers on surfaces, coarse in core).
Production Line Speed: Higher speeds reduce dwell time in the inlet zone, potentially requiring higher instantaneous pressure to achieve the same compaction effect.
Resin Type & Curing Behavior: Different binders have varying pressure/temperature requirements for optimal cure.
Process Optimization: Operators or process engineers define an optimal pressure curve within the press control system based on the product specification and actual production conditions. This curve dictates the target pressure for each zone from inlet to outlet. Except for the inlet zone potentially approaching or reaching the maximum (e.g., 25-30 MPa for HDF production), pressures in all other zones are significantly below 30 MPa and are meticulously adjusted and set according to specific process needs.
Founded in 1983, Shandong MINGHUNG OSB&MDF Machinery Equipment Manufacturing Co.,Ltd., specializes in continuous press solutions for over 40 years.
MINGHUNG is a leading company in the industry of OSB&MDF making machine. With a strongfocus on producing high-quality machinery, we specialize in manufacturing thecomplete production line of Medium density fiberboard (MDF), High densityfiberboard (HDF),Particle board (PB), Oriented strand board (OSB), andVeneerable super strong particle board (LSB).
If interested please contact us for a quote.
Whatsapp: +8618769900191 +8615589105786 +8618954906501
Email: osbmdfmachinery@gmail.com
