Printing & Packaging VFD Solutions

High-Performance Variable Frequency Drives for Printing Presses, Converters, and Packaging Machinery

Overview

The printing and packaging industry demands precision, synchronization, and reliability. From high-speed gravure and flexographic printing presses to bag-making machines, slitter rewinders, laminators, and carton folders – every machine relies on precise speed control, accurate tension management, and minimal downtime.

At Inomax Technology, we provide dedicated variable frequency drives (VFDs) engineered for the unique requirements of printing and packaging applications. Our VFDs deliver microsecond-level speed regulation, closed-loop tension control, multi-motor synchronization, and energy savings – all in compact, rugged packages designed for dusty, high-temperature production environments.

Whether you are building a new printing line, retrofitting an aging press, or optimizing a packaging converter, our engineering team delivers customized VFD solutions that improve print register, reduce waste, and increase throughput.

Key Applications in Printing & Packaging

Application	VFD Role
Gravure printing press	Main drive synchronization, unwind/rewind tension control, register correction
Flexographic printing press	Plate cylinder independent drive, web tension regulation, anilox roll speed matching
Offset printing press	Feeder and delivery control, ink roller speed profiling, dampening system regulation
Laminating machine	Dual unwind tension matching, nip roller speed synchronization, rewind taper tension
Slitter rewinder	Unwind tension control, knife speed synchronization, rewind torque profiling
Bag making machine	Intermittent or continuous motion sealing, servo-driven cross cutter, film pull roller control
Pouch making machine	Indexing accuracy, heat seal temperature compensation, multi-axis electronic gearing
Blown film extruder	Haul-off speed regulation, winding tension control, bubble stability via air ring VFD
Carton folding/gluing machine	Belt conveyor speed matching, compression section profiling, counter/ejector timing
Paper converting (tissue, board)	Embossing drum synchronization, log saw feed control, core winding taper tension

Industry Challenges & Our Solutions

Challenge 1: Tension Fluctuations

Uneven tension causes web breaks, misregistration, wrinkles, and waste.

Our Solution
Our VFDs feature closed-loop tension control using load cell or dancer roller feedback. Built-in PID adjusts motor torque continuously to maintain setpoint tension – even during acceleration, deceleration, or roll diameter changes. For taper tension winding, we provide diameter calculation via speed ratio or ultrasonic sensor, automatically reducing tension as roll builds.

Challenge 2: Multi-Motor Synchronization

Printing presses often have 5–20 motors (unwind, infeed, print stations, outfeed, rewind) that must run at precisely matched speeds.

Our Solution
Electronic line shaft (ELS) technology using high-speed communication (Profinet IRT, EtherCAT). One VFD acts as master, sending speed and position references to all slaves with <1μs skew. Our drives also support gear ratio emulation – set a master/slave ratio (e.g., 2.345:1) for perfect registration without mechanical gearing.

Challenge 3: Register Accuracy

Gravure and flexo presses require micron-level circumferential and lateral register.

Our Solution
Our VFDs accept encoder feedback from print cylinders and provide dynamic register correction. When a register sensor detects a deviation, the VFD can advance or retard the individual motor shaft in real-time (down to 0.01-degree resolution) without stopping the press.

Challenge 4: Frequent Start/Stop & Jogging

Packaging machines like bag makers and pouch sealers cycle hundreds of times per minute.

Our Solution
High-duty cycle rating (up to 600 starts/hour). Our VFDs feature advanced IGBT thermal management and DC braking with automatic release for rapid indexing. Jog mode with adjustable acceleration (0–10 Hz) allows safe manual positioning.

Challenge 5: Dust, Humidity, and Washdown

Printing plants often have paper dust, ink mist, and high humidity; food packaging requires washdown capability.

Our Solution
IP54, IP65, and IP66 enclosures with conformal-coated circuit boards. Stainless steel versions available for food-grade packaging. Cooling via heat sink with no fan (for low-power models) or externally mounted fans with filter protection.

Key Technical Features for Printing & Packaging

Feature	Benefit
Speed regulation accuracy	±0.01% of max speed with encoder feedback; ±0.5% without encoder
Speed range	0–500 Hz standard; up to 1,500 Hz for high-speed slitting
Tension control	Built-in PID with dancer, load cell, or torque reference input; taper tension algorithm
Multi-motor sync	Electronic line shaft, master-follower, electronic gearing, cam profiling
Register control	Dynamic correction via encoder or proximity sensor; programmable advance/retard
I/O for packaging	6 digital inputs (including registration sensor, cut command), 2 analog inputs (tension sensor, speed reference), 2 relay outputs (blade trigger, alarm), 2 transistor outputs (pulse train up to 100 kHz)
Communication	Modbus RTU, Profibus, Profinet IRT, EtherCAT, Ethernet/IP, CANopen for servo-like integration
Protection	Overvoltage, overcurrent, short-circuit, phase loss, overtemp, motor thermal (PTC)
Environmental	-10°C to +50°C operating, IP20/IP54/IP65, conformal coating

Product Series Overview

Series	Power Range	Key Features	Ideal For
ACS880	1.5 kW – 160 kW	Built-in tension PID, electronic line shaft, register correction, pulse train input	Printing presses (gravure, flexo), laminators
ACS580	1.5 kW – 250 kW	Compact design, high starting torque (200% for 2s), rapid cycling (600 starts/hr)	Bag makers, pouch machines, slitter rewinders
ACS880 AFE	15 kW – 5000 kW	High power for main press drives, AFE option for regenerative braking, <5% THDi	Large gravure presses, high-speed extruders
ACS580 Servo-like	1.5 kW – 22 kW	2 kHz current loop, 16 kHz switching, absolute encoder support	Electronic cam applications, cross cutter

Why Choose Inomax Technology for Printing & Packaging?

Industry-specific algorithms – Pre-programmed macros for tension control, register correction, and electronic gearing.
Fast commissioning – Our free software includes a “Printing Press Wizard” and “Bag Machine Wizard” that sets up parameters in under 10 minutes.
Global service – On-site support and remote diagnostics for production-critical lines.
Retrofit expertise – Drop-in replacements for Siemens, ABB, Mitsubishi, Delta, and Yaskawa drives with same footprint and I/O mapping.

Frequently Asked Questions

Q1: How do I select a VFD for tension control on a gravure printing press unwind stand?

A: Selecting a VFD for unwind tension control requires three decisions: control method, power rating, and braking capability.

Control method: For most gravure unwinds, we recommend closed-loop torque control using a load cell or dancer roller. Our ACS880 series has a built-in tension PID that takes a 0–10V or 4–20mA signal from the sensor. The VFD automatically reduces motor torque as the roll diameter decreases (using either a diameter calculator via speed ratio or an ultrasonic sensor). Alternatively, for simple applications, open-loop torque control using the VFD’s torque limit can work if you have a constant friction brake.
Power rating: The VFD should be sized for the unwind motor’s peak torque (including roll inertia at maximum diameter). As a rule, add 20% to the motor’s rated current to account for regenerative braking during acceleration of heavy rolls.
Braking capability: Unwind VFDs spend significant time in regenerative mode (the motor is being pulled by the web). You need either a braking resistor or an Active Front End (AFE) to dissipate or return energy. For presses with frequent stops, a braking resistor is cost-effective. For continuous regenerative operation (e.g., rewinder with taper tension), an AFE drive (ACS880-AFE) returns >95% of energy to the line.

We provide a free sizing worksheet – just tell us your roll weight, maximum diameter, core diameter, web tension (N/m or PLI), and line speed.

Q2: Can I use one VFD to synchronize multiple print stations on a flexographic press?

A: Yes – this is the primary application for electronic line shaft (ELS) technology. Our ACS880 VFDs support three synchronization methods:

Master/follower over communication (recommended): One VFD (master) runs at the speed reference. All other VFDs (followers) receive the master’s speed via Profinet IRT or EtherCAT with <1μs skew. You can set individual gear ratios per station (e.g., master: 1000 RPM, station 2: 0.985× for plate stretch compensation).
Encoder follower: Each follower VFD has an encoder input that tracks the master’s actual speed (via a master encoder signal splitter). This works without fieldbus but requires wiring.
Pulse train synchronization: For servo-like positioning, our VFDs accept a high-speed pulse train (up to 100 kHz) from a master controller.

For flexo presses with 6–10 color stations, we typically configure a Profinet IRT network with one master VFD (the main impression drum) and all other stations as followers. The result is perfect registration even during acceleration and deceleration – no more “banding” or misregister. We also provide an auto-registration option: each follower VFD can accept a registration sensor input and automatically advance/retard its shaft position in real-time (down to 0.01° resolution).

Q3: What VFD features are important for a high-speed slitter rewinder?
A: For slitter rewinders, the most critical VFD features are:

Taper tension algorithm: As the roll diameter increases, tension must decrease linearly or parabolically to prevent “telescoping” and roll crush. Our VFDs have a programmable taper tension function: you set starting tension (at core diameter) and ending tension (at full roll), and the drive automatically calculates tension reference based on actual diameter (computed via line speed / roll RPM).
Dual motor control (unwind + rewind): The unwind VFD runs in regenerative torque control (pulling back tension), while the rewind VFD runs in torque control (winding). Both must share a common line speed reference. Our drives can be linked via a simple analog signal (0–10V torque reference) or over fieldbus.
Inertia compensation: For large diameter changes (e.g., 100mm core to 800mm full roll), the rotational inertia changes dramatically. Our VFDs include an inertia compensation parameter that automatically adjusts acceleration torque based on diameter.
Oscillation damping: Slitter rewinders can experience tension oscillations at certain speeds. Our VFD has an anti-oscillation filter (adjustable from 0.1 to 10 Hz) that stabilizes the loop.

For surface wind (drum-driven) rewinders, a standard VFD with speed control and torque limit works. For center wind (shaft-driven), you must use closed-loop torque control. Provide your slitter’s mechanical configuration, and we will pre-configure the drive before shipping.

Q4: How do I improve register accuracy on a gravure printing press using VFDs?
A: Register errors come from mechanical backlash, thermal expansion of cylinders, and speed variations. Our VFDs attack this problem in three layers:

Precise speed regulation: With an encoder on the main press line shaft, our VFD achieves ±0.01% speed regulation. That means at 300 m/min, the speed error is less than ±30 mm/min – negligible over a 1m repeat length.
Individual station register correction: Each print station VFD accepts a register sensor input (proximity or photoelectric). When the sensor detects a mark deviation, the VFD can:
- Advance the motor by a programmed angle (e.g., +0.5°)
- Retard the motor by a programmed angle
- Apply a speed offset for a short time (e.g., +1% for 100ms)
This correction happens on-the-fly without stopping the press. Our ACS580 allows you to map the register correction to a digital input – for example, a PLC sends a 100ms pulse to advance the station by 0.2°.
Electronic line shaft with position following: For presses with servo-like requirements, we can configure our VFD as an electronic cam. The master position (via encoder) is used to generate a slave position profile. For example, the printing cylinder may need to dwell at a certain angle for ink transfer. Our VFD can follow a cam table stored in its memory.

For a typical 8-color gravure press, adding encoder feedback and register correction reduces waste from 5% to under 1.5% – a massive saving on expensive film or paper.

Q5: Can a VFD be used on a bag making machine with intermittent motion (stop-go cycling)?

A: Absolutely – but you need a VFD designed for high dynamic performance and frequent start/stop. Standard industrial VFDs overheat when cycled more than 20 times per minute. Our ACS880 series is specifically rated for 600 starts per hour (10 per minute) continuous, with peak capability of 1,200 starts per hour for short periods.

Key features for intermittent bag machines:

DC braking with auto-release: When the machine stops, the VFD injects DC current to hold the motor stationary (preventing film creep). At the next start command, DC braking releases automatically before acceleration.
S-curve acceleration: To prevent film snapping, our VFD offers S-curve profiles (adjustable from 0 to 5 seconds). The film accelerates smoothly, reducing tension spikes.
Indexing accuracy: For bag makers with a cut-off knife, we support pulse train positioning. A PLC sends a number of pulses (e.g., 10,000 pulses = one bag length), and the VFD moves the motor precisely that distance. Positioning accuracy is ±1 encoder count.
Regenerative energy handling: Frequent stopping regenerates energy into the DC bus. Our VFDs have a built-in braking transistor and can accept an external braking resistor. For very high cycle rates (e.g., 120 bags/minute), we recommend a dynamic braking resistor sized to absorb the full stopping energy without overheating.

We have successfully retrofitted hundreds of bag makers (including blown film baggers, T-shirt bag machines, and zipper pouch sealers) with our VFDs. The result: faster cycle times, less film waste, and quieter operation compared to clutch/brake systems.

Q6: How does a VFD help with tension control on a laminating machine with two unwinds?
A: Laminating machines bond two or more webs together using adhesive, heat, or pressure. The challenge is maintaining equal tension on both unwinds so that the laminated product does not curl or wrinkle.

Our solution uses two VFDs in master-follower torque mode:

Master VFD runs the main nip roller (laminating station) in speed control. Its actual speed is broadcast over fieldbus (or a 0–10V analog signal) to both unwind VFDs.
Unwind A VFD receives the master speed and also a tension reference from its own load cell or dancer. It runs in torque control, automatically adjusting motor torque to maintain the setpoint tension (e.g., 200 N). As the roll diameter decreases, the torque needed for the same tension drops – the VFD calculates diameter via line speed / roll RPM and scales torque accordingly.
Unwind B VFD does the same independently.

Additionally, our VFDs can handle taper tension for each unwind if the final roll requires less tension at the core (e.g., for stretchy films). For machines with a rewind station, we provide a third VFD that runs in torque-controlled winding with diameter-based taper.

We also offer an anti-wrinkle algorithm: if either tension deviates by more than 15% from setpoint for more than 0.5 seconds, the VFD triggers an alarm and can automatically reduce line speed to prevent scrap.

Q7: What communication protocols are best for integrating VFDs into a printing press control system (PLC/HMI)?
A: For printing and packaging, the best protocol depends on your control platform and synchronization requirements:

Protocol	Best for	Sync accuracy	Our support
Profinet	Siemens-based presses with multi-axis synchronization	<1us	Yes (ACS880)
EtherCAT	Beckhoff, Omron, or high-speed packaging machines	<100ns	Yes (ACS880)
EtherNet/IP	Rockwell (Allen-Bradley) PLCs, moderate speed requirements	1-5ms	Yes (standard for ACS880)
Modbus TCP	Simple monitoring, non-critical sync	10-50ms	Yes (standard for ACS880)
Profibus DP	Legacy Siemens systems	1-10ms	Yes (optional for ACS580 ACS880 MAX500)
CANopen	Smaller packaging machines, low cost	1-5ms	Yes (standard on ACS580,ACS880)

For gravure and flexo presses with 6+ color stations, we strongly recommend Profinet IRT or EtherCAT because they provide deterministic, isochronous communication. This ensures all follower drives receive the master speed reference at exactly the same time, eliminating speed skew that causes register errors.

We provide complete GSDML files (for Profinet), ESI files (for EtherCAT), and EDS files (for EtherNet/IP). Our free configuration software includes example projects for Siemens TIA Portal, Rockwell Studio 5000, and CODESYS.

Q8: Can a VFD replace a servo motor on a pouch making machine cross cutter?

A: For many pouch and bag making applications, yes – a high-performance VFD with encoder feedback can replace a servo motor, saving 40–60% on drive cost. However, there are trade-offs:

When a VFD works well:

Cutting length >200mm
Cycle rate <150 cuts/minute
Accuracy requirement ±1mm
Inertia ratio (load/motor) <10:1

When you still need a servo:

Very short cut lengths (<50mm) requiring rapid acceleration/deceleration
Cycle rates >200 cuts/minute
Accuracy <±0.2mm
Complex cam profiles (e.g., flying knife with nonlinear motion)

Our ACS580-Servo-like series bridges the gap: it has a 2 kHz current loop (vs 0.5 kHz for standard VFDs), 16 kHz switching frequency (quieter, smoother torque), and supports absolute encoders (EnDat, BiSS). It can handle indexing moves with positioning accuracy of ±1 encoder count.

For a typical pouch machine with 300mm cut length at 120 cuts/min, our VFD + 3-phase induction motor solution costs about half of a comparable servo system. We offer a free comparison tool – just provide your cut length, cycle rate, and desired accuracy, and we will recommend the most cost-effective solution.

Q9: How do I set up a VFD for taper tension winding on a rewinder?

A: Taper tension reduces tension as the roll diameter increases to prevent “starring” (wrinkles from the core outward) and telescoping. Our VFDs have a dedicated taper tension function that requires three parameters:

Starting tension (T_start) – tension at core diameter (e.g., 300 N)
Ending tension (T_end) – tension at full roll (e.g., 150 N)
Taper curve type – linear (most common), parabolic, or custom via 10-point table

The VFD automatically calculates the actual roll diameter using line speed / roll RPM (no additional sensor needed). At any diameter D, the tension reference is:
T_ref = T_start - (T_start - T_end) × (D - D_core) / (D_full - D_core) for linear taper.

You can also enable inertia compensation: when accelerating, the VFD adds extra torque to overcome roll inertia; when decelerating, it reduces torque. Without this, the web tension spikes during speed changes.

Step-by-step setup using our keypad or software:

Set control mode to “Torque control with diameter input”
Enter core diameter and maximum roll diameter
Enter T_start and T_end
Set taper type to “Linear”
Enable inertia compensation (adjustable from 0 to 200%)
Perform a test wind and adjust T_end until the roll is firm but not crushed.

For dual-station turret winders, we also provide automatic roll transfer – when one roll reaches full diameter, the VFD can signal the PLC to switch to the empty core and resume winding with minimal speed dip.

Q10: What maintenance does a printing press VFD require in a dusty paper environment?

A: Paper dust and ink mist are the main enemies of VFDs in printing environments. Follow this schedule:

Interval	Action
Weekly	Check cooling fan operation (listen for unusual noise). Use a soft brush to clean external air intake grilles.
Monthly	If installed in IP20 enclosure, vacuum the interior using a ESD-safe vacuum (do not blow compressed air into the drive – it can lodge dust in heatsink fins). For IP54 units, clean the external fan and filter.
Quarterly	Measure heatsink temperature via VFD parameter (should be <80°C). If higher, clean more frequently. Tighten power terminals (paper dust + vibration loosens connections).
Every 6 months	Replace air filters (if IP54). Inspect conformal coating for any scratches that expose copper tracks.
Annually	Replace cooling fans (expected life 40,000 hours, but in dusty printing plants, reduce to 20,000 hours ~ 2.5 years). Replace DC bus capacitors if ripple voltage exceeds 5% of nominal.

Preventive upgrades:

Install a pre-filter box with washable foam ahead of the VFD enclosure
Use IP65 stainless steel VFDs for washdown areas (e.g., food packaging printing)
Add a temperature switch that alarms when internal enclosure temperature exceeds 45°C

We offer a remote monitoring module that tracks VFD operating hours, fan runtime, and heatsink temperature, sending alerts before failures occur. For critical printing lines, consider our extended warranty with annual on-site preventive maintenance.

Q11: Can I retrofit an older printing press (with DC drives) to AC VFDs?

A: Yes – retrofitting DC drives to AC VFDs is one of our most common projects. The benefits are substantial: lower energy consumption (AC motors are 3–5% more efficient), reduced maintenance (no brushes/commutators), better speed regulation, and modern communication.

Typical retrofit steps:

Motor replacement: Replace DC motors with standard AC induction motors (or permanent magnet motors for higher efficiency). Ensure the motor mounting footprint matches or use adapter plates.
VFD selection: Size the VFD for the AC motor’s nameplate current (not the DC motor’s armature current – AC motors draw less current for the same torque). For example, a 50 HP DC motor might be replaced with a 37 kW AC motor + 45 kW VFD.
Control integration: Most old presses have analog speed references (0–10V) and relay logic. Our VFDs accept the same analog signals, so you can keep the existing potentiometer and PLC. For more advanced retrofits, we replace the control panel with an HMI + VFD network.
Fieldbus mapping: If your press uses a master line shaft with resolvers, we can replace the resolver feedback with an encoder connected to the VFD.
Braking: DC drives often regenerated into a resistor bank. Our VFDs can reuse the existing braking resistor if its resistance and power rating are compatible (we check this for you).

We provide a retrofit kit that includes the VFD, AC motor, encoder, and pre-configured parameters – typically reducing installation time to 2–3 days. One of our customers retrofitted a 6-color gravure press and saw a 22% reduction in electrical consumption and a 40% reduction in spare parts inventory (no more DC drive cards).

Q12: How do I tune the PID for dancer-controlled unwind on a laminator?

A: Dancer position control is a classic PID application. Incorrect tuning causes hunting (oscillation) or sluggish response. Here is a step-by-step tuning method using our VFD’s built-in autotune plus manual refinement:

Initial setup:

Set dancer potentiometer to mid-position (0–10V = 0–100% travel)
Configure VFD analog input as “PID feedback” (dancer position)
Set PID setpoint to 50% (mid-travel)
Disable integral (I=0) and derivative (D=0) initially

Manual tuning steps:

Proportional gain (P): Increase P until the dancer begins to oscillate (you’ll hear the unwind motor speed cycling). Then reduce P by half. For most laminators, P between 0.5 and 2.0 works.
Integral time (I): Decrease I (increase integral action) until the dancer returns to setpoint within 2 seconds after a disturbance (e.g., tapping the dancer roll). If it overshoots and oscillates, increase I slightly. Start with I=0.5 seconds.
Derivative (D): Add a small D (0.05–0.2 seconds) to reduce overshoot. Too much D makes the system noisy.

Quick autotune:
Our VFD includes a one-touch PID autotune – put the machine in “tune mode,” and the drive will inject step changes and calculate optimal P, I, D. We still recommend a final manual check.

Pro tip: For unwinds with large inertia (heavy rolls), enable feed-forward – the VFD adds a torque offset proportional to acceleration, reducing dancer movement during speed changes.

If you share your dancer roll weight, spring rate (if any), and line speed range, we can provide recommended PID starting values by email.

Ready to Optimize Your Printing or Packaging Line?

Every printing press and packaging machine has unique requirements. Our engineers are ready to help you select, size, and integrate the right VFD solution – whether you are building new equipment, retrofitting old lines, or improving tension control.

Contact us today to: