120-Ton Injection Molding Machine: Technical Specifications and Selection Guide

120-ton Injection Molding Machine
Injection molding is the foundational manufacturing process for producing precise, high-volume plastic components. At its heart is the need for clamping force, or tonnage, to keep the mold secure against high injection pressures. The 120-ton injection molding machine is specifically recognized as the industry’s operational sweet spot, effectively balancing substantial clamping capacity with optimized cycle times and energy consumption.

 

This 120-ton capacity is typically selected for molds that require counter-pressure against an estimated projected area of 45 to 65 square inches—a range ideal for small to mid-sized, high-precision parts. This machine class is heavily utilized in producing essential items such as detailed automotive interior components, complex medical disposables, and compact consumer electronics housings.This comprehensive technical guide is designed for manufacturing professionals and will detail the precise operational specifications, mold size constraints, and performance variability, including the increasing dominance of all-electric technology for superior precision and efficiency, inherent to this critical machine class. Our analysis begins by establishing a clear understanding of the fundamental role that tonnage plays in maintaining mold integrity during the high-pressure injection phase.

Technical Specifications and Performance

Accurate assessment of the technical specifications of a 120-ton injection molding machine is mandatory for production planning and mold design. This machine class is engineered to deliver a robust balance of throughput and part quality across a defined working envelope.

Key Technical Parameters

These parameters define the machine’s capabilities and constraints, influencing mold design and material selection. The Nominal Configuration represents a typical, well-optimized machine build.

Clamping Unit Unit ES120
Clamping Force kN 1,200
Mold Opening Stroke mm 360
Min. Mold Height mm 180
Max. Mold Height mm 450
Max. Daylight mm 810
Platen Size (HxV) mm 670 × 620
Tie Bar Space (HxV) mm 470 × 420
Min.Mould Dimension mm 305 × 270
Max.Mould Weight t 1
Ejection Stroke mm 110
Ejection Force kN 40
No.of Ejector Pin Holes / 5
Injection Unit Unit IU180 IU260
A B C A B C
Screw Diameter mm 26 30 34 30 34 38
Screw L/D Ratio L/D 23 23 20 23 22.4 20
Theoretical Shot Volume cm³ 64 85 109 99 127 159
Injection Pressure MPa 283 212 165 272 212 169
Holding Pressusre MPa 226 170 132 217 169 136
Shot Weight (PS) g 58 77 99 90 116 144
Plasticizing Capacity (PS) g/s 10 13 16 13 18 23
Injection Rate (Standard/High) g/s 97 / 217 129 / 289 165 / 372 129 / 289 165 / 372 206 / 464
Injection Speed (Standard/High) mm/s 200 / 450 200 / 450
Plasticizing Stroke mm 120 140
Screw Rotation Speed rpm 400 400
Nozzle Contact Force kN 25 25
General Data Unit IU180 IU260
Total Power (Standard/High) kW 17.0 / 30.6 18.3 / 31.9 18.3 / 31.9 23.5 / 39.2 25.7 / 41.4 25.7 / 41.4
Heating Capacity kW 6.50 7.80 7.80 7.80 10.00 10.00
Motor Power (Standard/High) kW 10.5 / 24.1 15.7 / 31.4
Heating Zones / 5.00 5.00
Theoretical Weight t 5.80 5.90
Machine Dim.( L×W×H) m 5.0×1.4×1.7

All-Electric Injection Molding Machine: Dimensional Layout

Performance Profile

Core Capabilities

120-ton machines are optimized for medium-sized, highly detailed parts, ensuring high repeatability and minimal material waste.

  • Part Sizing: Effective projected area management up to 350 cm² (approximately 54 in²) to maintain mold integrity during peak injection.
  • Material Versatility: The standard 20:1 L/D ratio supports efficient plasticizing of commodity resins (e.g., PP, PE, PS) and engineering thermoplastics (e.g., ABS, PC, Nylon).
  • Production Volume: Capable of running multi-cavity molds (typically 2 to 8 cavities) for small components.
  • Speed Metric: Dry cycle times (clamp open to close) routinely achieve 2.0 seconds or less, enabling optimized molding cycles.

Limitations

Constraints must be factored into part design, particularly concerning volume and physical size.

  • Maximum Shot Weight Constraint: The theoretical shot volume restricts finished part weight, typically below 250 grams for thick-walled components.
  • Dimensional Constraint: Mold base size is strictly limited by the Tie Bar Clearance (470 x 420 mm Nominal), which prohibits large-format toolsets.

Energy Efficiency and Precision

Modern 120-ton machines prioritize energy management, with the adoption of specialized drive systems being the industry norm:

  1. All-Electric Systems: Offer the highest level of efficiency and control. Energy consumption is typically reduced by 50% to 70% compared to conventional hydraulics. They provide superior motion control for the most demanding parts, achieving repeatability below 0.01 mm.
  2. Servo-Hydraulic Systems: Provide a more economical balance, reducing power draw by 30% to 50% versus older fixed-displacement pumps while maintaining high clamping tonnage output.

These energy-saving technologies directly enhance the economic viability of the operation and ensure the sustained, long-term value of the equipment.

A comparative analysis of the energy management and efficiency of two 120-ton machine drive systems (all-electric and servo-hydraulic) was conducted.

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Key Advantages of 120-Ton Injection Molding Machines

The 120-ton injection molding machine class presents distinct technical and operational advantages, positioning it as the preferred equipment for manufacturers requiring balanced performance, resource optimization, and high product diversity in mid-volume environments.

Operational Versatility and Adaptability

Various plastic parts produced by a 120-ton injection molding machine

The 120-ton capacity is the optimal nexus for production versatility, proficiently handling a broad spectrum of technical requirements.

  • Part and Tooling Range: The machine comfortably manages multi-cavity tools for smaller parts while still accommodating medium-sized components up to its 350 cm² projected area limit.
  • Material Flexibility: Its standard plasticizing unit is configured to process common commodity resins (PP, PE) as well as demanding engineering thermoplastics (PC, PEEK), minimizing the need for specialized equipment changes.
  • Production Agility: The mid-range size facilitates faster mold changeovers and shorter setup times than larger machinery, supporting efficient manufacturing of diverse Stock Keeping Units (SKUs).

Cost-Effectiveness

Comparative Study of Machine Tonnage Metrics

This machine segment provides a maximized utilization of capital resources relative to production output.

  • Capacity Alignment: The 120-ton class delivers substantial production capability necessary for medium-volume runs, effectively minimizing capital overhead that would be required for acquiring underutilized, higher-tonnage equipment.
  • Sustained Throughput: It ensures consistent, high-rate throughput for the majority of precision parts without over-investing in unused clamping force, directly supporting long-term production stability.

Space Efficiency

Factory floor layout showing space requirements for a 120-ton injection molding machine

Efficient use of production floor space is a defining advantage of the 120-ton class.

  • Space Consolidation: With typical operational dimensions around 5.0 × 1.4 × 1.7 meters, the machine provides a substantial tonnage-per-square-meter ratio, allowing
  • Layout Flexibility: The compact operational footprint simplifies factory floor planning, enabling more flexible and efficient cell manufacturing layouts.

Precision and Power Efficiency

Leveraging modern drive technologies, the 120-ton machine enhances part quality and operational metrics.

  • Enhanced Repeatability: The prevalence of all-electric and servo-hydraulic systems in this class ensures superior motion control, directly translating to dimensional repeatability below 0.01 mm—critical for automotive and medical parts.
  • Optimized Power Draw: The installed power (typically 11–16 kW during operation) is directly managed by servo technology, ensuring that power is consumed proportional to the force demanded, rather than continuously, maximizing long-term operational sustainability.
4.2
Overall Rating
Versatility
4.5
Cost-Effectiveness
4.3
Energy Efficiency
4.0
Maintenance Requirements
3.8
Production Speed
4.2

Selection Criteria and Applications

Selecting the right injection molding machine requires careful consideration of multiple factors. Professionals evaluating 120-ton machines must follow a structured technical evaluation to ensure the machine’s constraints are optimally aligned with production requirements.

Key Factors for Selection

Production Requirements

  • Part projected area and volume; Required material viscosity and melt temperature.
  • Cycle time targets and cooling demands.
  • Dimensional tolerance and surface finish specifications.
  • Directly determines necessary Clamping Force (tonnage) and Shot Volume.
  • Influences the choice between all-electric (speed) and servo-hydraulic systems.
  • Dictates the required machine Repeatability (e.g., all-electric systems for <0.01 mm precision).

Physical Constraints

  • Machine footprint and Tonnage-to-Area Ratio.
  • Platen dimensions and Tie Bar Clearance.
  • Minimum/Maximum Mold Shut Height.
  • Essential for plant layout planning and space utilization.
  • Determines the maximum physical size of the mold base.
  • Ensures the mold tool fits securely between the platen surfaces.

Operational Efficiency Metrics

  • Power consumption (kW) and energy source type (Servo vs. All-Electric).
  • Labor complexity and automation integration requirements.
  • Planned maintenance schedule and spare parts logistics.
  • Impacts long-term utility usage and operational sustainability.
  • Affects staffing models and auxiliary equipment placement.
  • Determines equipment uptime predictability.

Suitable Industries and Applications

The 120-ton machine excels in applications demanding precision in mid-sized components and high-cavitation runs for smaller parts, making it a critical asset across several high-specification industries:

Automotive Sub-Assemblies

  • Medium-sized, highly cosmetic interior trim components.
  • Electrical connector housings.
  • Non-structural under-the-hood fasteners and brackets.

Electronics Enclosures

  • Precision device housings and structural chassis components.
  • Intricate switch and terminal block assemblies requiring tight dimensional tolerances.

Medical and Laboratory Consumables

  • High-volume sample containers and diagnostic equipment casings.
  • Detailed non-implantable device components that demand high material purity and repeatability.

Specialty Packaging

  • Multi-cavity tools for high-volume thin-walled caps and closures.
  • Medium-sized food storage containers requiring precise sealing surfaces.
Various industry applications for parts made with 120-ton injection molding machines

Comparison with Other Tonnage Machines

Understanding how 120-ton machines compare to lower and higher tonnage alternatives helps manufacturers select the optimal equipment for their specific requirements.

Specification 80-100 Ton Machines 120 Ton Machines 150-200 Ton Machines
Typical Projected Area Max Small (up to 155 cm² / 24  in²) Medium (up to 350 cm² / 54 in²) Medium-Large (up to 600 cm² / 93 in²)
Shot Volume Range (Theoretical) 100 – 150 cm³ 163 – 265 cm³ 300 – 450 cm³
Platen Size (Nominal) 500 × 450 mm 610 × 560 mm 750 × 700 mm
Floor Space (Approximate) 8-10 m² 10-12 m² 15-20 m²
Energy Consumption (Operating) 8-12 kW 11-16 kW 18-25 kW
Typical Part Weight Max Under 150 grams Under 250 grams Under 400 grams
Typical Applications Precision electrical connectors, small vials/caps, medical luer fittings, small gear components. Automotive interior trim, electronic device enclosures, multi-cavity closures, medical diagnostic components. Mid-size housing/panels, large kitchenware (bowls), automotive instrument panels (small), thicker-walled containers.

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Conclusion

The 120-ton injection molding machine represents an optimal balance of capabilities for medium-scale manufacturing operations. Its specific clamping force and injection capacity establish a versatile and powerful platform for medium-volume, high-precision component manufacturing.

For professionals evaluating equipment, the core principle remains technical matching: ensuring the projected area and material characteristics are precisely aligned with the machine’s capacity. The 120  ton class offers a robust operating envelope that maintains production efficiency and component quality across diverse application requirements.

Furthermore, the integration of advanced technologies—specifically all-electric motion control and Industry 4.0 connectivity—will continuously expand the operational boundaries of this machine size. By embracing these advancements, the 120 ton machine secures its long-term viability as a reliable, high-throughput asset for future-oriented production facilities.

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