Plastic Chair Making Machine Explained – Manufacturer’s Guide to Efficient Chair Production
2025-05-16 08:34:07
Chair making machine is a key piece of equipment used in the large-scale manufacturing of plastic chairs. These machines enable high-volume, consistent, and cost-efficient production of chairs that are used across homes, offices, schools, and public venues. This guide offers key insights into the machine, material, and manufacturing process behind plastic chair production.
A chair-making machine, essentially an injection molding machine optimized for chair production, is engineered for thermoplastic injection molding to inject molten thermoplastics into high-cavity molds capable of forming large, load-bearing parts.
The primary structure includes:
- Injection Unit: Responsible for heating and injecting molten plastic into the mold.
- Clamping Unit: Holds the mold closed with adequate pressure during the injection and cooling.
- PCL Control: Operates all process variables, including temperature, pressure, injection time, and holding pressure.
- Hydraulic or Servo System: Powers the movement of clamping and injection mechanisms.
A typical plastic chair mold demands a high clamping force to prevent flash, given the large surface area of the part.
| Chair Type | Clamping Force Range (tons) |
|---|---|
| Children's Chair (Small Plastic Chair) | Approx. 250–500 tons |
| Standard Household Chair (Monoblock Chair) | Approx. 600–1000 tons |
| Large Outdoor Chair (Oversized Thick Chair) | Approx. 800–1300 tons |
| High-end Engineering Plastic Chair (e.g., PC Material) | Approx. 800–1300 tons |
| Chair Type | Shot Weight Range (grams) |
|---|---|
| Children's Chair (Small Plastic Chair) | Approx. 500–1500 g |
| Standard Household Chair (Monoblock Chair) | Approx. 1500–3000 g |
| Large Outdoor Chair (Oversized Thick Chair) | Approx. 3000–5000 g |
| High-end Engineering Plastic Chair (e.g., PC Material) | Approx. 3000–6000 g |
| Chair Type | Cycle Time Range (seconds) |
|---|---|
| Children's Chair (Small Plastic Chair) | Approx. 60–90 sec |
| Standard Household Chair (Monoblock Chair) | Approx. 50–60 sec |
| Large Outdoor Chair (Oversized Thick Chair) | Approx. 90–120 sec |
| High-end Engineering Plastic Chair (e.g., PC Material) | Approx. 50–90 sec |
The most significant advantageis its capability to produce structurally sound, aesthetically uniform, and defect-free chairs in mass quantities.
- Stable performance over long production hours
- Quick mold change options
- Low scrap generation
- Compatibility with automation (robotic take-out, stacking conveyors)
The machine follows the injection molding cycle, optimized for chair production:
- Material Feeding: Polypropylene granules are fed into the barrel.
- Plasticizing: The granules are melted using heaters and screw rotation.
- Injection: The molten plastic is injected into a precision chair mold at high pressure.
- Cooling: The part cools inside the mold, solidifying its shape.
- Ejection: The mold opens and ejector pins push the chair out.
- Repeat Cycle: The mold closes and the cycle repeats for high-volume production.
Further reading: Injection Molding: Processes, Benefits, Applications, and Future Trends
Material selection for chair manufacturing directly affects durability, cost, and appearance.
- Polypropylene (PP)
PP is the material of choice for plastic chairs due to its lightweight, excellent fatigue resistance, and cost-efficiency. It offers sufficient rigidity for load-bearing and good resistance to environmental stress cracking. Injection grade PP with high melt flow rate ensures ease of processing, especially in multi-cavity molds.
- Talc-Filled or Glass-Filled Compounds
Some chair manufacturers opt for talc-filled PP or glass fiber reinforced composites to enhance stiffness and dimensional stability. These materials require machines with stronger screws and improved wear resistance, given their abrasiveness.
- Color and UV Masterbatches
Color consistency is vital for branding and aesthetics. Masterbatches introduce color, UV protection, and other additives without affecting flow properties. Uniform dispersion is essential to prevent streaks or swirl marks on visible chair surfaces.
Further reading: Understanding the 10 Most Common Injection Molding Materials
Click the image to watch a full cycle of a plastic chair being manufactured in a high-tonnage injection molding machine.
- High Output: Multiple chairs per minute, 24/7 operation
- Defect Reduction: Automated control minimizes flash, warping, and sink marks
- Customisation: Molds can be designed for different chair styles and logo placements
- Energy Savings: Servo motor machines save up to 60% of electricity
- Lower Labour Dependency: Integrated automation reduces manual involvement
Plastic chair making machines can manufacture a wide range of seating solutions:
- Monobloc chairs
- Dining chairs with armrests
- Stackable office or training chairs
- School and classroom seating
- Kids’ chairs and booster seats
- Outdoor plastic stools and patio furniture
- Public utility chairs (bus stations, railway platforms)
The optimal clamping force for producing a standard plastic chair typically falls within the 600 to 1000 tons range. However, the final tonnage selection should be based on several factors:
- Product Size and Weight: Larger or thicker chairs require higher tonnage to ensure full cavity filling and avoid flash.
- Mold Size and Projected Area: The total projected area of the mold (including runners and parting lines) determines the minimum clamping force needed to keep the mold securely closed during injection.
- Material Type: Materials with high injection pressure (e.g., PC, PC/ABS) may need higher tonnage to withstand the force.
- Multi-Cavity Mold: If producing more than one chair per cycle, a higher tonnage machine is necessary.
Yes, recycled plastic materials such as recycled PP or PE can be used in chair production, especially for economic-grade or non-load-bearing chairs. Many manufacturers adopt a blended approach, mixing recycled and virgin materials to balance cost, strength, and process stability.
However, not all materials are used in 100% recycled form, and most production lines only partially incorporate recycled content. Pure recycled plastic often lacks consistent melt flow, may contain impurities, and exhibits reduced mechanical properties, which can lead to warpage, surface defects, or even structural failure.
The lifespan of a plastic chair mold depends on several key factors:
- Mold Material:
- P20 steel molds: ~300,000 to 500,000 shots
- H13 or 2316 hardened steel molds: ~800,000 to 1,000,000+ shots
- Maintenance Practices: Regular cleaning, lubrication, and wear-part replacement can significantly extend mold life.
- Material Used: Molding abrasive or recycled materials can reduce lifespan due to increased wear.
- Cooling and Ejection Design: Well-optimized cooling and smooth ejection systems reduce stress on the mold during cycles.
The chair making machine is more than a tool—it is the engine that drives productivity, profitability, and quality in plastic chair manufacturing.As the industry evolves toward energy-efficient, automated, and high-output systems, investing in the right chair making machine will define competitive advantage in the future.
- Group Name: Huarong Group
- Brand: Huarong, Yuhdak, Nanrong
- Service Offerings: Injection Molding Machine, Vertical Injection Molding Machine, Injection Molding Automation
- Tel: +886-6-7956777
- Address: No.21-6, Zhongzhou, Chin An Vil., Xigang Dist.., Tainan City 72351, Taiwan
