INOMAX ACS580 & ACS880 – Injection Molding Machine Solutions

High-Performance Variable Frequency Drives for Hydraulic, Hybrid & Electric Injection Molding Machines

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Overview

Injection molding is one of the most energy-intensive manufacturing processes in the plastics industry. Traditional hydraulic injection molding machines use fixed-speed pumps that run continuously at full speed – wasting enormous amounts of energy during idle time, cooling, and low-flow phases. With energy costs rising and sustainability becoming a competitive differentiator, machine builders and molders are turning to variable frequency drive (VFD) technology to cut energy consumption by 30-70% while improving precision, reducing noise, and extending equipment life.

At Inomax Technology, we supply ACS580 (general purpose) and ACS880 (high-performance) variable frequency drives to injection molding machine manufacturers, retrofitters, and end users worldwide. Our drives are engineered for demanding molding applications: fast dynamic response for instantaneous pressure buildup, high overload capacity for injection peaks, built‑in PID control for precise pressure and flow regulation, regenerative AFE options for energy recovery, and fieldbus integration for seamless connection to machine controllers.

We are also actively expanding our global partner network. If you are a distributor, system integrator, injection molding machine OEM, or retrofit specialist, we invite you to explore a partnership with INOMAX – factory‑direct pricing, technical support, market protection, and proven technology trusted by machine builders and molders worldwide.

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Why Injection Molding Machines Need High-Performance VFDs

The Energy Waste Problem

A conventional hydraulic injection molding machine uses a fixed-speed pump that runs continuously at full speed – regardless of whether the machine is injecting, holding, plasticizing, cooling, or idle. Studies show that a typical molding machine using a fixed-volume pump with a proportional valve wastes 50-70% of its total energy consumption.

Where the waste happens:

The result: A VFD-controlled variable-speed pump system typically saves 30-70% of the energy consumption of a conventional fixed-volume pump system.

Precision Requirements – Consistent Part Quality

Injection molding demands precise control of injection speed, holding pressure, back pressure, and screw speed. Traditional fixed-speed pumps use proportional valves to meter flow – an inherently wasteful and less precise method. VFDs with closed-loop control offer superior accuracy:

• Speed accuracy ±0.5% (ACS580) to ±0.01% (ACS880 with encoder) – Consistent screw speed for uniform melt quality

• Built‑in PID control – Maintains precise hydraulic pressure regardless of load variations

• Fast torque response (<5 ms on ACS880) – Instantaneous pressure buildup at the start of injection

Noise Reduction – A Better Workplace

A fixed-speed pump running at 100% speed continuously produces significant noise – often exceeding 85 dB(A). With VFD control, the pump runs at reduced speed during most of the cycle, dramatically reducing noise pollution. A VFD-controlled hydraulic system typically runs 10-15 dB(A) quieter – a 50-70% reduction in perceived loudness.

Extended Machine Life

Soft starting eliminates the electrical and mechanical shock of across-the-line motor starting. Reduced pump operating hours directly extend pump and valve life. Lower operating temperatures reduce seal degradation and hydraulic fluid oxidation. Eliminated pressure spikes reduce stress on hoses and cylinders.

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Key Technologies – Professional Solutions for Injection Molding Machines

1. Variable-Speed Pump Control – The Core Energy Saver

The primary function of a VFD in a hydraulic injection molding machine is to control the speed of the pump motor. Instead of the pump running at full speed continuously, the drive ramps motor speed up and down based on real-time demand from the machine controller.

How it works:

• Pressure feedback – A pressure transducer in the hydraulic manifold provides real-time feedback (4-20mA or 0-10V)

• Flow feedback – Optional flow meter or pump speed vs. pressure relationship

• PID control – The drive compares actual pressure to setpoint and adjusts motor speed to maintain target pressure

• Demand-based speed – During low-demand phases (cooling, idle), motor speed drops significantly – often to 10-30% of rated speed

• Energy savings – Power follows the affinity law: reducing speed by 50% reduces power consumption by approximately 87.5%

2. Fast Torque Response for Injection Peaks

The injection phase requires rapid pressure buildup – typically within 50-100 ms. Our ACS880 DTC technology delivers:

• Torque response <5 ms – Pressure rises almost instantly when the injection command is given

• Full torque at zero speed – No waiting for the pump to spin up from zero

• 200% starting torque – Handles high‑inertia screw motors and cold starts

For injection molding machine retrofits, this fast response directly translates to shorter cycle times and higher throughput.

3. Built‑in PID Control for Pressure and Flow

Both ACS580 and ACS880 include powerful built‑in PID controllers specifically configured for hydraulic pressure and flow control.

Key PID features for injection molding:

• Pressure setpoint via analog input – Direct connection to machine PLC or dedicated controller

• Pressure feedback via pressure transducer – Real-time feedback from manifold or cylinder

• Flow setpoint via speed reference – Pump speed directly correlates to flow

• Auto-tuning – Drive automatically calculates optimal P, I, D gains

• Two independent PID sets – Switch between injection, holding, and plasticizing profiles

• Sleep/wake-up mode – Stops pump during extended cooling cycles; restarts automatically when cycle resumes

4. Regenerative AFE (Active Front End) – Energy Recovery

During deceleration of high-inertia loads (screw motor braking, fast traverse deceleration), the motor regenerates energy. Traditional systems waste this energy as heat in braking resistors. Our ACS880 AFE option captures this regenerated energy and returns >95% to the grid.

Key AFE benefits for injection molding:

• THDi <5% at 80-100% load – Eliminates harmonic interference with machine controls and sensors

• Unity power factor (>0.99) – Reduces utility penalties; maximizes transformer utilization

• Regenerative energy recovery – Returns braking energy to the grid; typical savings of an additional 5-10%

• Constant DC bus voltage – Immune to grid fluctuations common in industrial environments

For hybrid molding machines with servo-driven pumps, the AFE is essential for capturing energy during the regenerative braking of the servo motor.

5. Multi-Pump Control for Large Machines

Large injection molding machines (≥800 tons) often use multiple pumps in parallel – one for main injection, one for plasticizing, and additional pumps for core pull, ejector, and carriage movement. Our drives support:

• Multi-pump cascade control – One VFD controls one pump at variable speed; auxiliary pumps start/stop across the line

• Master-slave torque control – Multiple VFDs controlling multiple pumps with perfect load sharing

• Common DC bus – Energy sharing between pumps; reduced input power

6. Fieldbus Integration for Machine Controllers

Injection molding machines use dedicated controllers from manufacturers like Engel, Husky, Krauss‑Maffei, Sumitomo (Demag), Arburg, Haitian, and others. Our drives support all major industrial protocols for seamless integration:

• Profinet IO – For Siemens-based controllers and many European machines

• EtherNet/IP – For Rockwell-based controllers and many American machines

• EtherCAT – For Beckhoff-based controllers and high‑speed synchronization

• Profibus DP – For legacy controllers

• CANopen – For many European and Asian controllers

• Modbus RTU/TCP – For universal compatibility

We provide complete GSDML, ESI, and EDS files, plus sample code for common injection molding controllers.

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Injection Molding Machine Cycle – Where VFDs Save Energy

Typical cycle-weighted energy savings: 30-70% depending on cooling time and part complexity.

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Product Series Overview

Selection guide:

• Choose ACS580 for standard hydraulic injection molding machine pump drives where cost-effectiveness is the primary driver

• Choose ACS880 for large machines, high-cycle applications, machines requiring fast dynamic response, or applications with regenerative energy recovery

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Technical Specifications – Professional Grade

ACS580 Series (Cost‑Effective for Standard Machines)

ACS880 Series (High‑Performance for Large & Fast-Cycle Machines)

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Real Projects – Proof of Performance

Our drives are used by injection molding machine manufacturers, retrofitters, and molders worldwide.

Measured results from these installations:

• Energy savings: 35-65% (validated by power meters before/after retrofit)

• Cycle time reduction: 5-12% (faster pressure buildup)

• Noise reduction: 10-15 dB(A)

• Hydraulic oil temperature reduction: 10-20°C (reduced cooling requirement)

• Pump life extension: estimated 2-3× (reduced operating hours)

• Payback period: 6-18 months depending on duty cycle

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For Distributors, System Integrators & Injection Molding Retrofit Specialists

Why Partner with INOMAX?

Partnership Models

Distributor Support Program

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Frequently Asked Questions

For End Users (Technical)

Q1: How much energy can I save by adding a VFD to my hydraulic injection molding machine?

Based on our case studies and industry data, typical energy savings range from 30% to 70% depending on your cycle characteristics:

• Thin-wall parts with long cooling times – 60-70% savings (pump off during long cooling)

• Large parts with long hold times – 50-60% savings (pump runs at low speed during hold)

• Fast cycles with minimal cooling – 30-40% savings (pump still runs at high speed for injection)

• Multiple machines on same hydraulic power unit – 40-50% savings (load sharing)

A typical 500-ton machine operating 6,000 hours/year with $0.12/kWh electricity can save $15,000-$25,000 annually.

Q2: Will adding a VFD affect my cycle time?

Properly tuned, a VFD should not increase cycle time – and may actually reduce it. The fast torque response of DTC (<5 ms) ensures pressure builds up instantly at the start of injection. For machines with long cooling times, the VFD can stop the pump entirely during cooling and restart instantly when the cycle continues – no cycle time penalty.

Q3: Can I retrofit my existing fixed-speed injection molding machine with a VFD?

Yes – and this is one of the most cost-effective energy efficiency upgrades available for injection molding. The retrofit typically includes:

• Installing the VFD between the main disconnect and the pump motor

• Adding a pressure transducer to the hydraulic manifold (if not already present)

• Configuring the drive for pressure PID control

• Tuning the PID parameters for your specific machine and cycle

• Minor modifications to the machine controller (start/stop signals, pressure setpoint)

Most retrofits can be completed in 1-2 days. Payback is typically 6-18 months.

Q4: How does the VFD communicate with my injection molding machine controller?

Our drives support all major protocols: analog signals (0-10V pressure setpoint, 4-20mA pressure feedback), discrete I/O (start/stop, run/fault), and digital fieldbus (Profinet, EtherNet/IP, EtherCAT, Profibus DP, CANopen, Modbus). We provide GSDML, ESI, and EDS files for seamless integration with controllers from Engel, Husky, Krauss‑Maffei, Sumitomo, Arburg, Haitian, and others.

Q5: What is the difference between ACS580 and ACS880 for injection molding?

Q6: What is the expected service life of INOMAX drives in injection molding applications?

With proper maintenance, 20+ years. Key factors: operating environment (clean vs. dusty), maintenance practices (regular cleaning, fan replacement), and duty cycle. We recommend quarterly inspection and cleaning, annual cooling fan replacement (or 40,000 operating hours), and 5-7 year DC bus capacitor replacement.

For Distributors & Partners (Commercial)

Q7: What is the minimum order quantity (MOQ) for distributors?

No strict MOQ for initial orders. Volume discounts apply from 10 units per order. For OEM/private label, MOQ is negotiated.

Q8: What is the standard warranty period?

2 years from date of manufacture or 12 months from commissioning, whichever comes first. Extended warranty up to 5 years available.

Q9: What is your typical lead time?

Popular models (≤250 kW) – 3-5 working days from our China factory + shipping. Larger units (250-6,000 kW) – 2-4 weeks.

Q10: Do you offer market protection?

Yes. Exclusive territory agreements (subject to minimum commitment) and project registration. Registered projects are protected – we will not quote directly or work with other distributors on that project.

Q11: Can you customize drives for my OEM requirements?

Yes: private labeling, custom parameter presets for specific injection molding machine models, special enclosures, modified firmware, custom voltage/frequency ranges.

Q12: What technical support can I expect for my customers?

Free pre-sales support: drive sizing, harmonic analysis, configuration recommendations. Post-sales: remote diagnostics (free), on-site commissioning (fee-based). Product training for your technical staff.

Q13: How does INOMAX compare to ABB, Siemens or Danfoss for injection molding?

We are legitimate competitors. Our ACS880 uses the same Direct Torque Control (DTC) technology as ABB ACS880. Performance specifications match or exceed competition. Price is 20-30% lower. Lead times are shorter. Customization is more flexible. Our retrofit kits are specifically designed for injection molding applications.

Q14: Do you offer retrofit kits specifically for injection molding machines?

Yes. We offer pre‑engineered retrofit packages including:

• Drive sized for your pump motor

• Pressure transducer (if needed)

• Pre‑configured parameters for your machine type

• Wiring diagram and installation guide

• Commissioning checklist

Contact us with your machine specifications for a quote.

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Ready to Partner with INOMAX?

Join a growing network of distributors, retrofit specialists, and injection molding machine builders who have discovered that INOMAX delivers premium performance at a competitive price – with real factory support.

Apply for distributorship today:

• Fill out the form below with your company information and market focus

• We will contact you within 24 hours to discuss partnership terms

• Receive distributor pricing, marketing materials, and technical documentation