Mold Operation Manual

Extrusion Mold Instruction Manual

Compiled by: EKO MOLD

I. Company Introduction

Hongda Enterprise was established in 1993, specializing in plastic extrusion molds, integrating manufacturing, R&D, and customer service.
The company currently employs over 300 staff members and operates more than 400 sets of high-end manufacturing equipment, producing about 1,500 sets of extrusion molds annually.

Hongda possesses core technologies and advanced concepts in the extrusion molding industry, holds multiple national patents, and has received national-level funding support for high-tech enterprises.
The company has successfully undertaken large-scale extrusion system projects for both domestic and international enterprises.

Main Products:

• Plastic profile molds

• PP and PE wood-plastic molds

• PVC wood-plastic and PVC micro-foaming molds

• Hollow grid sheet molds

• PVC sheet and plate molds

• Other extrusion molds

Subsidiaries:

• Huangshi Hongda Plastic Mould Co., Ltd.

• Shanghai Eko Mould Co., Ltd.

II. Mold Operation Precautions

To ensure proper and safe use of the mold, maintain precision, and extend its service life, please read this manual carefully before operation.
Become familiar with the mold structure and precautions to ensure correct installation and debugging.

The mold must be operated by trained professionals.
Before use:

• Check that the extrusion equipment matches the mold requirements.

• Ensure correct connection between the mold and the extruder.

• Verify that all auxiliary systems (water, electricity, air, etc.) meet production needs.

• Confirm that the extrusion material matches the mold’s design material.

III. Mold Categories

1. Plastic Profile Molds:

   • PVC plastic-steel door, window, and fence molds

   • PVC soft/hard co-extrusion molds

   • PMMA, ASA, and other multi-material co-extrusion molds

   • PVC trunking, conduit, and communication pipe molds

   • PVC ceiling panel molds

2. PP Wood-Plastic and PE Wood-Plastic Molds

3. PVC Wood-Plastic and PVC Micro-Foaming Molds

4. Hollow Grid Sheet Molds:

   • PVC, PP, PE wood-plastic door panel molds

   • PVC window sill board molds

   • PVC grid board molds

5. PVC Sheet and Plate Molds:

   • PVC wood-plastic construction formwork

   • PVC wood-plastic furniture board

   • PVC celuka foam board

   • PVC rigid plate and sheet

6. Other Molds:

   • PS foaming

   • Wall panel molds

IV. Basic Structure and Principle of Extrusion Molds

Extrusion molds typically consist of three main parts:

• Die head

• Calibrating mold (dry calibrator)

• Water tank (wet calibrator)

The calibrator and water tank together form the calibration and cooling system.

Extrusion molding depends on four main elements:

1. Extrusion material

2. Molding process

3. Extrusion equipment

4. Extrusion mold

Among these, the mold is the key — it shapes the molten plastic into the desired product by heating, diverting, compressing, and forming it, followed by calibration and cooling.

V. Structure and Working Principle of Each Mold Component

1. Die Head

The die head connects to the front end of the extruder barrel.
It channels molten material through the flow path, compresses it, and extrudes it into a preform of the desired geometry.

Functions:

1. Further plasticize the melt in the flow channel.

2. Generate necessary melt pressure to ensure product density.

       3. Convert spiral flow to linear flow for uniform extrusion velocity.

       4.Form the desired product cross-section.

Main Components:
Flange, die body, support plates, flow divider cone, mandrel, and die lips.模头的结构

As shown in Figure 1:

1. Forming Plate (Die Lip I)

2. Preforming Plate (Die Lip II)

3. Compression Plate

4. Support Plate I

5. Support Plate II

6. Transition Plate

7. Die Body

8. Flow Divider Cone

9. Flange Plate

10. Machine Flange Plate

11. Transition Sleeve

12. Die Head Screw

13. Forming Plate Screw

14. Thermocouple Hole

15. Heating Plate

2. Calibrating Mold

After leaving the die head, the extrudate enters the vacuum calibrator, where vacuum suction helps the melt adhere closely to the mold cavity wall.
The flowing cooling water inside the calibrator cools and solidifies the profile.

Most plastic profiles use one or multiple connected vacuum calibrators.
They typically consist of a cover plate, mold plate, inserts, circulating cooling system, and vacuum chamber.

Calibrator Structure (see diagram):

1. Iron foot

2. Spacer block

3. Base plate

4. Alignment pin

5. Mold plate

6. Cover plate

7. Hinge

8. Water outlet nozzle

9. Air nozzle

10. Water inlet nozzle

3. Water Tank

After the profile is initially shaped in the calibrator, it enters the water tank for full cooling and further shaping.
Water tanks are of two types: standard water tanks and turbulent flow water tanks.

• Standard water tanks submerge the product in slowly flowing cooling water — suitable for simple or thin-walled products.

Water Tank Structure (see diagram):

1. Iron foot

2. Baffle plate

3. Positioning post

4. Water tank bottom plate

5. Water tank cover plate

6. Water tank hinge

7. Air nozzle

8. Vacuum gauge

9. Calibrating block

10. Regulating valve    

   The turbulent water tank operates by rapidly drawing out the incoming water from the front end through the outlet at the rear end of the tank. This increases the cooling water flow rate and creates a certain level of vacuum negative pressure inside the tank, which forces the product to adhere more effectively to the calibrating block. This helps reduce shrinkage and deformation, ensuring the desired appearance and dimensional accuracy of the product.

   The air connector (see part 7) located at the rear of the water tank is used to blow off residual water remaining on the surface of the product, preventing the traction belt from slipping due to surface moisture on the profile.

VI. Mold Installation

1. Pre-Installation Inspection

• Check that the mold is intact and undamaged.

• Verify that the die head, calibrator, and water tank share matching serial numbers.

• Ensure all accessories (heating rings, flanges, transition sleeves, etc.) are complete and undamaged.

• Confirm the extruder model matches the mold’s specifications.

2. Installation Steps

2.1 Die Head Installation

1. Remove fastening bolts, apply high-temperature grease to threads, and clean the flow channel thoroughly.

2. Tighten mandrel and flow divider bolts, reassemble, and check die gap with feeler gauge.

3. Preheat the die to the set temperature, then retighten bolts and reheat for 10 minutes before operation.

4. Install flange and (if applicable) transition sleeve; align using a level gauge and tighten bolts sequentially.

5. Attach heating plates/rings and thermocouples, ensuring tight contact. Calibrate temperature readings.

6. Heat in stages — first to 140°C, hold for 30–40 minutes, then raise to working temperature.

7. After reaching target temperature, re-tighten all bolts before starting production.

2.2 Calibrator and Water Tank Installation

1. Mount the calibrator on the calibration table, align it with the extrusion center, and secure it.

2. Mount the water tank in the same way, connecting it to the calibrator with positioning pins and M10 bolts.

3. Connect air and water inlets — front for water (blue gasket), middle for air (black gasket), rear for outlet (red gasket).

4. Connect the vacuum and water systems per the schematic.

5. The first calibrator should use an independent vacuum pump; subsequent ones may share pumps.

3. Installation Precautions

• Handle molds gently to prevent impact damage.

• Always use correct lifting rings during hoisting.

• Ensure balanced and safe lifting; prioritize operator and equipment safety.

VII. Working Conditions

1. Extrusion line must be in good condition.

2. Use a stable and proven material formula and extrusion process.

3. Maintain cooling water at 15–20°C, pressure >0.3 MPa, and sufficient flow.

4. Main profile typically requires 3 vacuum pumps, with vacuum pressure >-0.09 MPa.

5. For high-speed extrusion, ensure vacuum tanks and suction systems operate with fast water circulation under negative pressure.

6. Mold adjustment must be done under the supervision of equipment operators.

7. Operators should follow or refer to process parameters provided by technicians.

Operators must be familiar with the extruder in use, including:

• Screw characteristics

• Heating and cooling control

• Instrument functions

• Haul-off control

• Mold structure and assembly

Proper understanding of these aspects ensures accurate control of extrusion conditions and correct machine operation.

IX. Extrusion Production Operating Procedures

1. Before starting the machine, check whether the temperature control system is responsive, the instruments are functioning properly, and the cooling water circulation is smooth. These can be tested using a thermometer and by running cooling water through the system.

2. According to the extrusion operation regulations, heat the screw, barrel, and die head of the extruder. After the temperature reaches the set value, maintain it for about 10 minutes to ensure all machine parts reach a stable temperature.

3. Before starting extrusion, tighten all connecting screws and bolts of the die head while it is still hot. Before the material is extruded, operators must not stand directly in front of the die exit to avoid injury caused by possible bolt or screw breakage.

4. When starting extrusion, begin with a low screw speed, then gradually increase it to prevent overload and possible damage to machine parts.

5. At the start of feeding, add a small amount of material evenly, keeping the feeding stable. Closely monitor the torque and other instrument readings. When material begins to extrude smoothly from the die and is connected to the haul-off machine, gradually increase the feed rate until normal extrusion is achieved.

6. During the initial haul-off, ensure there is a proper distance between the calibrator and the die head to facilitate pulling. Turn on the water circuit (avoid spraying water directly onto the die head, as it may cause abnormal extrusion and material blockage). For complex profiles or small inner cavities, open the calibrator cover plate. Once material plasticization is confirmed to be normal, use the prepared traction rope to pull the material to the haul-off unit. Shorten the distance between the calibrator and the die head, close the cover plate, and start the vacuum pump. When the extrusion and haul-off speeds are balanced and the profile runs steadily, adjust the calibrator-to-die distance to the ideal position.

7. If the extrudate is not forming properly at the calibrator inlet, or if the inner ribs stick to the cavity wall, use a pointed tool to poke several small holes in the unformed or inner rib areas at the calibrator inlet. This allows air to enter small cavities, helping to create negative pressure and ensuring the extrudate adheres tightly to the calibrator wall.

8. If partial blockage (not complete) occurs, immediately move the calibrator backward or increase the haul-off speed—or do both simultaneously—then adjust processing parameters to restore normal production.
   If complete blockage occurs and the above methods fail, move the calibrator backward, cut the material along the calibrator, shut off the water and air supply, reduce haul-off speed, and slowly pull the profile out of the calibrator. If part of the profile remains inside, disassemble the calibrator and completely remove any residual material.

9. When stopping production, first feed cleaning compound or shutdown material to purge the production material inside the extruder, then stop the machine. While still hot, disassemble and clean the die and related components.

X. Disassembly and Cleaning of Extrusion Molds

1. Mold disassembly should be carried out promptly and efficiently.

2. After stopping the machine, first remove the heating plate and loosen the screws (part 12) on the die head and the bolts on the flange, but do not remove them completely. Attach the lifting screw, lift the die head securely, then remove the flange bolts and transport the die head to a designated cleaning area.

3. The die head should be disassembled on a dedicated wooden workbench. The bench should be sturdy, with a tabletop larger than 1200 mm × 650 mm. Prepare necessary tools such as wrenches, pin extractors, needle-nose pliers, brass pry bars, copper sheets, and air nozzles.

4. Disassembly and cleaning of the die head:
   4.1 First remove the flange plate (part 9), then the die head screws (part 12). Insert a brass wedge bar into the mold slot to remove the forming plate (part 1), preforming plate (part 2), and compression plate (part 3) together for cleaning.
   4.2 Remove the mold body (part 7) using a brass wedge bar to separate the support plate 1 (part 4), support plate 2 (part 5), transition plate (part 6), and mold body (part 7) for cleaning.
   4.3 When cleaning, use needle-nose pliers to grip any residual material, while blowing compressed air to cool and harden it for removal. Use soft tools such as copper sheets to clean fine gaps and grooves, being careful not to scratch the mold surface.
   4.4 Remove residual marks using metallographic sandpaper and fine oilstones, and polish the surface to its original finish.

5. Disassembly and cleaning of the calibration mold and water tank:
   5.1 When production stops or abnormal extrusion causes blockage, the calibration mold should be disassembled and residual material removed. During normal production, material deposits may adhere to the vacuum grooves and air holes, scratching the surface or obstructing air flow. These should be regularly cleaned with soft copper sheets.
   5.2 Before disassembly, shut off the vacuum pump and water valve, open the cover plate, and use a copper or hardwood rod to remove the residual material. Avoid damaging the surface or applying excessive force that could reduce alignment accuracy.

XI. Maintenance of Extrusion Molds

1. Maintenance during mold operation:
   1.1 Improper handling or cleaning during disassembly is one of the main causes of mold damage. Therefore, only trained personnel should perform these tasks.
   1.2 Use copper tools when disassembling and cleaning the die head.
   1.3 Clean sealing surfaces with fine oilstone or metallographic sandpaper.
   1.4 Before assembly, polish the flow channels to a low roughness and apply a thin layer of silicone ester to prevent corrosion during storage.
   1.5 During assembly, apply high-temperature grease to all bolts, screws, and contact surfaces.
   1.6 When disassembling calibration molds, handle carefully to avoid impact. Reinstall plates in numerical order.
   1.7 During routine water tank maintenance, ensure proper adjustment space remains after installing the calibration blocks.

2. Maintenance when molds are not in use:
   2.1 Never leave raw material in the mold—extrude all material before shutdown.
   2.2 Before storage, use compressed air to remove impurities and dry with hot air.
   2.3 Clean all parts and apply lubricant to sliding surfaces.
   2.4 Remove any rust caused by water or corrosive plastics; polish if necessary.
   2.5 After maintenance, thoroughly dry and apply anti-rust oil.
   2.6 Store molds in a dry environment.

3. Mold Packaging and Protection:
   Molds should be packaged in sturdy, wooden boxes that are durable, dustproof, and easy to handle. Before packaging:
   3.1 Clean thoroughly to ensure:

   • No material in die head channels.

   • No residue or burrs on die plate surfaces.

   • No filament residue on calibration mold surfaces.

   • No water or debris in the water tank.
     3.2 Seal the outlet of the forming plate with oil paper.
     3.3 Seal the inlet and outlet of the calibration mold with oil paper.
     3.4 Secure the mold firmly inside the crate to prevent shifting during transport.

4. Mold Storage and Preservation:
   4.1 Store molds in a clean, dry, and ventilated warehouse, away from corrosive materials.
   4.2 After use, clean, reassemble, seal with oil paper, and store properly.
   4.3 Place molds on dedicated racks to ensure safe and convenient access.

      5.Mold Maintenance Record Card

XII. Fault Phenomena, Causes, and Remedies During Extrusion Mold Production

Fault Description

XIII.Fittings name of extrusion tooling

XIV.Tooling parts/fittings name list

Die head

Die plate

Spider plate

Transition plate

Mandrel

Spreader

Die body

Flange

Transition bush

Heater plates

Thermocouple

Calibrator

Top cover

Drying side

Drying center

Calibrator bottom

Calibrator supports

Water bath

Baffle

Flowing channel

Flowing

XV.The above description of the company reserves the right to modify without prior 

notification.

HUANGSHI HONGDA PASTIC MOULD CO.,LTD

SHANGHAI EKO MOULD TECHNOLOGY CO.,LTD