Manufacturing
MJR is a high-tech windows &door manufacturer integrated with R&D, production and sales.
1.Raw Material Preparation and Formula Design
Thermal Stabilizers: Prevent PVC decomposition during processing, commonly used are lead salts, calcium-zinc composite stabilizers, etc.
Impact Modifiers: Improve low-temperature impact resistance of profiles, typically using CPE (chlorinated polyethylene) or ACR (acrylate)
Fillers: Mainly calcium carbonate, reducing costs and improving dimensional stability
Lubricants: Divided into internal and external lubricants, improving processing flowability and preventing mold sticking
Colorants: Mainly titanium dioxide, providing whiteness and weather resistance
Processing Aids: Improve melt strength and surface quality
2.High-speed Hot Mixing and Cold Mixing Process
Process Description:
Hot Mixing: Add prepared raw materials to a high-speed hot mixer, mix at 100-120℃ for 5-10 minutes. Friction heat enables PVC resin to absorb liquid additives, forming uniform premix
Cold Mixing: Transfer hot-mixed material to a cold mixer, rapidly cool to 40-45℃, preventing agglomeration and thermal degradation while removing volatiles
Equipment Parameters:
Hot mixer speed typically 800-1200rpm
Cold mixer speed 200-400rpm
Batch processing capacity generally 200-500kg
3.Extrusion Molding Process
Process Description: The mixed dry blend is fed into the extruder through a vacuum loading system, going through the following stages:
Conveying and Compression: Material is conveyed forward by screw propulsion and gradually compressed
Plasticization and Melting: Under heating and shear forces, material temperature rises to 180-200℃, completely melting into homogeneous melt
Homogenization and Metering: Melt is further homogenized, passing through the die with stable pressure and flow rate
Extrusion Equipment:
Tapered Twin-screw Extruder: Most commonly used, with good mixing effect and lower shear heat
Parallel Twin-screw Extruder: Used for high-speed production
Die System: Includes die head (determining profile cross-section shape) and calibration die (preliminary cooling and shaping)
4.Vacuum Calibration and Cooling
Process Description: High-temperature profiles extruded from the die immediately enter the vacuum calibration table:
Vacuum Calibration: Profiles pass through precisely dimensioned calibration molds, tightly adhering to the mold cavity under vacuum adsorption, obtaining accurate dimensions and surface finish
Water Cooling: Calibrated profiles enter cooling water tanks, reducing temperature below 50℃ through spray or immersion, completing final shaping
Cooling System Features:
Multi-stage gradual cooling to avoid internal stress from rapid cooling
Cooling water temperature typically controlled at 15-25℃
Cooling length generally 3-6 meters, ensuring sufficient cooling
5.Pulling, Cutting and Stacking
Process Description:
Pulling: Use crawler pullers to pull profiles at constant speed (typically 1-3m/min), maintaining stable extrusion process
Length Cutting: When profiles reach set length, cutting saw automatically cuts, requiring smooth cuts without burrs
Automatic Stacking: Cut profiles are automatically stacked by turning racks or manipulators, preparing for subsequent processing
Quality Control Points:
Synchronization of pulling speed and extrusion speed to prevent profile deformation
Cutting accuracy controlled within ±1mm
Prevent surface scratches during stacking
6.Quality Inspection and Packaging
Inspection Items:
Dimensional Tolerance: Using calipers, projectors to inspect profile cross-sectional dimensions
Mechanical Properties: Including tensile strength, impact strength, weld corner strength tests
Thermal Properties: Vicat softening temperature, thermal cycling tests
Weather Resistance: Artificial accelerated aging tests
Appearance Quality: Color uniformity, surface finish, free of impurities and bubbles
Packaging Requirements:
Wrapped with plastic film or woven bags
Corner protectors added to prevent transportation damage
Marked with model, length, production date and other information
