Plastic chairs are large household plastic products with large size and weight, so we undoubtedly need to use larger injection molding machines for professional production.Chair injection molding Machine is the most mature plastic seat production equipment today.
For large plastic chairs, an injection molding machine of more than 1,000 tons is usually using, while for small and medium-sized plastic chairs, an injection molding machine of 80 tons to 500 tons can meet production needs.
Selecting the right size of injection molding machine for plastic chairs depends on the chair’s weight, dimensions, material, and mold design. Key parameters include clamping force, shot capacity, and mold dimensions. Below is a step-by-step guide to determine the appropriate machine size:
Key parameters of plastic chair injection molding machines
- Clamping Force
- Shot Capacity
- Mold Dimensions
- Material-Specific Requirements
- Machine Recommendations by Chair Size
- Additional Considerations
Clamping Force (Tonnage)
The clamping force must counteract the pressure generated during injection to keep the mold closed.
Formula:
Clamping Force (tons)=Projected Area (cm²)×Injection Pressure (bar)1000
- Projected Area: Area of the chair (including runners) in the mold, perpendicular to the clamping direction.
Example: A chair with dimensions 50 cm × 40 cm has a projected area of 50×40=2000 cm². - Injection Pressure: Typically 300–500 bar for materials like PP (polypropylene) or HDPE (high-density polyethylene).
Example Calculation:
For a chair with a projected area of 2000 cm² and injection pressure of 350 bar:
Clamping Force=2000×3501000=700 tons
Recommended: A machine with 700–1000 tons clamping force for large chairs (adjust based on part complexity).
Shot Capacity (Volume/Weight)
The machine must inject enough molten plastic to fill the mold, including the chair, runners, and sprue.
Formula:
Shot Weight (g)=Chair Weight+Runner/Sprue Weight
- Chair Weight: Typically 2–5 kg for a standard plastic chair.
- Material Density:
- PP: ~0.9–0.95 g/cm³
- HDPE: ~0.94–0.98 g/cm³
Example:
For a 4 kg chair (4000 g) with 500 g of runners:
Total Shot Weight=4000+500=4500 g
Shot Volume:
Shot Volume (cm³)=Shot WeightMaterial Density=45000.95≈4737 cm³
Recommended: A machine with ≥5000 cm³ shot capacity.
Mold Dimensions
- Platen Size: The machine’s platen must accommodate the mold dimensions (length × width).
Example: For a mold size of 1000 mm×800 mm, select a machine with a platen larger than this. - Tie-Bar Spacing: Ensure the mold fits between the machine’s tie bars.
- Daylight Opening: Sufficient space to open/close the mold and eject the chair.
Material-Specific Requirements
- Plastic Type: PP and HDPE are common for chairs due to their durability and flexibility.
- Screw Design: Use a general-purpose screw for PP/HDPE with an L/D ratio of 20:1–25:1.
- Melt Temperature:
- PP: 200–280°C
- HDPE: 180–280°C
Machine Recommendations by Chair Size
| Chair Size | Clamping Force | Shot Capacity | Platen Size | Example Machines |
|---|---|---|---|---|
| Small (2–3 kg) | 400–600 tons | 3000–4000 cm³ | 800×800 mm | Haichen HCK600 |
| Medium (3–4 kg) | 600–800 tons | 4000–6000 cm³ | 1000×1000 mm | Arburg 820, Haichen HCK800 |
| Large (4–5 kg) | 800–1200 tons | 6000–8000 cm³ | 1200×1200 mm | Haichen HCK 1200 Engel 1200 |
Additional Considerations
- Cycle Time: Larger machines may have slower cycles; balance speed with part quality.
- Hydraulic vs. Electric: Electric machines save energy and offer precision for large parts.
- Ejection System: Ensure sufficient ejection force/stroke for large chairs.
- Safety: Machines >500 tons require robust safety interlocks and guarding.
Example Workflow
- Calculate projected area of the chair mold.
- Determine clamping force using injection pressure (e.g., 350 bar).
- Calculate shot weight/volume for the chair + runners.
- Verify mold dimensions against machine specs (platen size, tie-bar spacing).
- Select a machine with 10–20% higher capacity than calculated values to accommodate variations.
For a standard 4 kg plastic chair, a 800–1000-ton machine with 6000 cm³ shot capacity and a platen size of 1200×1200 mm is typically ideal.
Haichen plastic chair injection molding machine
Haichen has configured complete plastic injection molding machines and production lines for weekly customers all over the world, especially in Mexico, Argentina, etc.
- Features of Haichen brand injection molding machines
- Related information about 700-ton injection molding machine
- Technical advantages of Haichen injection molding machine
- Process characteristics of plastic chair injection molding machine
- Market positioning and customer support
Features of Haichen brand injection molding machines
Haichen is a company specializing in the manufacture of injection molding machines. Its products include various models of injection molding machines suitable for production of different scales and needs.
For example, Haichen K series 700-ton injection molding machine is a servo-driven injection molding machine suitable for the production of medium and large plastic products such as plastic buckets and plastic chairs.
If you need to produce exquisite wedding chairs made of large PC materials, we recommend the HCK1000-1500 model.
In addition, Haichen also provides E series injection molding machines, covering a range from 110 tons to 1200 tons, suitable for the injection molding of plastic products such as PET resin, PVC pipes, PC chairs, etc.
Related information about 700-ton injection molding machine
HCK700-ton injection molding machine may be a fixed pump injection molding machine or a servo energy-saving injection molding machine.
This machine is suitable for the production of a variety of plastic products, including plastic chairs.
All kinds of large and medium-sized plastic furniture can be produced.
Technical advantages of Haichen injection molding machine
Haichen injection molding machine is known for its high precision, energy saving and intelligence.
For example, Haichen injection molding machine adopts servo motor control, which has the characteristics of fast response and high precision.
In addition, Haichen has passed a number of international certifications (such as CE certification) to ensure the safety and environmental protection of its products.
Process characteristics of plastic chair injection molding machine
The production of plastic chairs usually requires high-precision and stable injection molding machines.
The molds of Haichen’s plastic chairs need to be specially treated to improve durability, and constant pressure and temperature need to be maintained during the injection molding process to ensure product quality.
Haichen’s injection molding machine can meet these requirements, providing efficient production capacity and stable performance.
Market positioning and customer support
Haichen injection molding machines are widely used in the global market and support the production of a variety of plastic products.
The company provides comprehensive after-sales service and technical support to help customers optimize production processes and improve efficiency.
Haichen 1000T plastic chair injection molding machine may be a fixed pump or servo energy-saving injection molding machine, suitable for the production of medium and large plastic chairs and other products.
Its technical features include high precision, energy saving and intelligence, which can meet the high standards of plastic chair production.
At the same time, the comprehensive technical support and services provided by Haichen can help customers achieve efficient production.
You may need to know:
- What size injection molding machine do I need?
- What is the market size of injection molding machine?
- What is the size limit on injection molding?
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