Selecting the right injection molding machine is critical for producing quality parts at the right cost. This guide covers machine types, key specifications, how to calculate required clamping force, and a comparison of major machine brands used in China and globally.
Traditional hydraulic machines use hydraulic oil to power the clamp, injection, and ejection systems. They remain the most common type in Chinese factories due to their lower purchase price and proven reliability.
Advantages: Lower initial cost (30-50% less than all-electric), high clamping force capability (up to 8,000+ tons), robust and proven technology, suitable for large and deep-draw parts
Disadvantages: Higher energy consumption (30-50% more than electric), slower cycle times, hydraulic oil maintenance requirements, temperature fluctuations affect repeatability, oil leaks are possible
All-electric machines use servo motors for all axes (clamp, injection, ejection, carriage movement). They are increasingly favored for precision parts, cleanroom applications, and high-volume production.
Advantages: 30-60% lower energy consumption, faster cycle times (0.5-2 second reduction per cycle), higher precision and repeatability (±0.01 mm), quieter operation (65-75 dB), no hydraulic oil (cleanroom suitable), parallel movements reduce overall cycle
Disadvantages: Higher initial cost (30-50% premium), lower maximum clamping force (typically up to 650 tons), less suitable for high-wear applications, more expensive repairs if servo motors fail
Hybrid machines combine hydraulic systems (for clamping force) with servo-driven injection units. They offer a balanced approach between cost and performance.
Advantages: 20-50% energy savings over full hydraulic, better precision than hydraulic (approach electric quality), lower cost than all-electric, retrofittable on existing hydraulic machines
Disadvantages: Still uses hydraulic oil (not cleanroom-compatible), not as precise as all-electric, more complex than pure hydraulic
| Specification | What it means | Typical range |
|---|---|---|
| Clamping force (tonnage) | The force holding the mold closed during injection | 30 to 8,000+ tons |
| Shot size (oz or grams) | Maximum volume of material the machine can inject per cycle | 5-10,000+ grams (PS) |
| Screw diameter | Determines plasticizing capacity and shear rate | 18-120 mm |
| Injection pressure | Maximum pressure the screw can apply | 1,500-2,500 bar |
| Injection speed | Rate of material injection | 50-300+ mm/s |
| Platen size | Mold mounting area dimensions | 300-2,500+ mm |
| Tie bar distance | Space between tie bars (mold size limit) | 250-2,000+ mm |
| Mold height (min/max) | Range of mold thickness the machine accepts | 150-1,200+ mm |
| Daylight (open stroke) | Maximum opening between platens | 300-2,000+ mm |
Use this formula to estimate the required machine size:
Clamping Force (tons) = Projected Area (cm²) × Cavity Pressure (bar) / 1000Projected area = The area of the part + runner system as seen from the direction of mold opening
Cavity pressure depends on material and wall thickness:
| Material | Thin wall (< 1.5 mm) | Medium wall (1.5-3 mm) | Thick wall (> 3 mm) |
|---|---|---|---|
| PP, PE | 400-600 bar | 300-450 bar | 200-350 bar |
| ABS, HIPS | 450-650 bar | 350-500 bar | 250-400 bar |
| PA, POM | 500-700 bar | 400-550 bar | 300-450 bar |
| PC, PC/ABS | 550-800 bar | 450-600 bar | 350-500 bar |
| PMMA | 500-700 bar | 400-550 bar | 300-450 bar |
Example: A 200×100 mm ABS part (1.5 mm wall) with a single-cavity mold: Projected area = 200 cm², Cavity pressure ≈ 450 bar. Clamping force = 200 × 450 / 1000 = 90 tons. A 100-ton machine is appropriate.
| Brand | Country | Type | Tonnage range | Price level | Market position |
|---|---|---|---|---|---|
| Haitian (海天) | China | Hydraulic, Electric, Hybrid | 60-8,800 tons | $ (Budget to mid-range) | World's #1 by volume (35%+ global share) |
| Yizumi (伊之密) | China | Hydraulic, Electric, Hybrid | 30-4,500 tons | $ (Budget) | Strong in two-platen technology |
| Chenhsong (震雄) | China (HK) | Hydraulic, Electric | 20-6,500 tons | $ (Budget) | One of China's oldest press makers |
| Tederic (泰瑞) | China | Hydraulic, Electric | 30-2,000 tons | $ (Budget) | Fast-growing, exports to Europe |
| Cosmos (富强鑫) | Taiwan | Hydraulic, Electric | 30-3,200 tons | $$ (Mid-range) | Strong in multi-material molding |
| Brand | Country | Type | Tonnage range | Price level | Market position |
|---|---|---|---|---|---|
| Engel | Austria | Hydraulic, Electric, Hybrid | 28-8,000 tons | $$$ (Premium) | Top-tier precision, tie-bar-less technology |
| Arburg | Germany | Hydraulic, Electric, Hybrid | 12-650 tons | $$$ (Premium) | Gold standard for precision small parts |
| Fanuc | Japan | All-Electric (Roboshot) | 15-450 tons | $$$ (Premium) | Ultimate precision and speed, all-electric pioneer |
| KraussMaffei | Germany | Hydraulic, Electric, Hybrid | 50-4,000 tons | $$$ (Premium) | Strong in large parts and PUR technology |
| Sumitomo (SHI) Demag | Japan/Germany | Electric, Hybrid | 15-1,000 tons | $$$ (Premium) | Excellent for liquid silicone and thin-wall |
| Nissei | Japan | Hydraulic, Electric | 10-650 tons | $$ (Mid-premium) | Reliable, good for precision molding |
| Milacron | USA | Hydraulic, Electric, Hybrid | 35-4,000 tons | $$$ (Premium) | Strong in packaging and closures |
Consider these factors when selecting a machine for your project:
In China, you will encounter machines of varying ages. A typical factory fleet includes a mix:
Always ask about the age and maintenance records of the specific machine that will run your mold. A well-maintained 10-year-old Haitian machine can outperform a poorly-maintained 3-year-old premium machine.
We operate a fleet of injection molding machines from 60 to 1,600 tons, including Haitian (primary), Engel, and Fanuc Roboshot machines. Our machine park is calibrated annually with SPC documentation available for all production runs. We maintain separate cleanroom zones for medical and food-grade production.
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