How much energy does an all-electric injection moulding machine save?

It depends heavily on the hydraulic machine it replaces. One measured case by Efficiency Vermont found a new all-electric machine used 26% of the energy per kilogram of a 1971 hydraulic machine. Vendors often quote 50–70% savings, while Husky argues the gain over modern variable-pump hydraulics is nearer 15%. Measure your own machines before building a business case.

Which actuator suits an injection moulding ejector or core-pull?

An electric rod actuator with a ball or roller screw and a servo motor, sized for the ejection force, stroke and speed. Ejection forces are usually far below clamp and injection forces, so a ball screw often suffices; roller screws suit heavy, high-cycle duties. Check temperature at the mould, side load from the ejector plate and whether a food-grade lubricant is required.

Can electric actuators replace hydraulics on a thermoformer?

Yes, and published results are encouraging: Curtiss-Wright Exlar reports a thermoforming retrofit with roller-screw actuators that nearly doubled output from 20 to 37 cycles per minute with more consistent parts. The key is sizing for both the fast platen move and the high forming or trim force at the end of stroke, which may need a toggle or a large motor.

What slip ring does a rotary blow moulding machine need?

A through-bore slip ring carrying heater power, thermocouple and sensor signals and often a fieldbus, sometimes combined with pneumatic channels for blowing air. Check the heater current per circuit, the noise sensitivity of thermocouple signals, the wheel speed and the temperature near the moulds. Ethernet-rated rings are needed if EtherCAT or PROFINET crosses the wheel.

Which safety standards apply to plastics machinery?

The machine-specific type C standards are EN ISO 20430 for injection moulding machines, EN 422 for blow moulding, EN 1114-1 for extruders and EN 12409 for thermoformers, alongside ISO 13849-1 for control safety. In the EU, Regulation (EU) 2023/1230 replaces the Machinery Directive from 20 January 2027. Your notified body or safety consultant will confirm which editions to cite.

What should I send for a plastics machinery enquiry?

Send machine type and axis, force and speed at each step of the cycle, stroke, cycle rate, hold times, moving mass and orientation, ambient temperature at the mounting point, cleanliness or food-contact requirements, controller and fieldbus, safety functions, and for conversions the existing hydraulic cylinder bore, rod and pressure. For slip rings add circuits, heater power and air channels.

Actuators and servo motors for plastics machinery

Specify Motion technical library · Updated 30 October 2026 · How we prepare our content

In short:Plastics and rubber machines are moving from hydraulics to servo-electric drive: roller-screw actuators and servo motors on injection, clamp, ejector and thermoforming axes, high-torque gearboxes on extruder and winder drives, and slip rings on rotating blow-moulding wheels and winders. Size each axis at the two corners of its cycle, maximum force at low speed and maximum speed at low force, then check heat near barrels and moulds.

Typical requirements

Energy, all-electric vs old hydraulic moulder (one measured case)	0.16 vs 0.61 kWh/kg, about 26% of the energy (Efficiency Vermont, 2005)
Energy saving claims, all-electric moulding	50–70% vs hydraulic (vendor); about 15% vs modern variable-pump hydraulics (Husky)
Thermoforming retrofit (published case)	20 to 37 cycles per minute after an electric roller-screw retrofit (Exlar)
Actuator efficiency (vendor figure)	About 90% electric roller screw vs about 50% hydraulic
Roller-screw actuator force (published ranges)	About 18 kN (RSA-ST) to 294 kN (RSX) per catalogue
UK plastics industry	About 5,700 companies and 160,000 direct jobs (BPF)

Machinery we specify motion for

Electric and hybrid injection moulding machines
Blow moulding machines (extrusion and stretch)
Extrusion lines, haul-offs and winders
Thermoforming machines
Plastic film and bag making
Part ejection, mould positioning and sprue pickers
Tyre building and green tyre transfer
Rubber cutting and calendering
Ultrasonic welding presses

What plastics and rubber machinery demands from motion

Plastics and rubber processing combines heat, high force and relentless cycling. An injection moulding machine may close, inject, hold and eject several times a minute, every minute, for years, with molten polymer at a few hundred degrees a short distance from the actuators. Extrusion and film lines run continuously for weeks. Tyre and rubber machinery adds heavy loads, sticky compounds and tight synchronisation.

The UK industry is substantial: the British Plastics Federation puts it at about 5,700 companies and around 160,000 people directly employed. Much of that capacity runs injection moulding, extrusion and thermoforming machines that are steadily being replaced or retrofitted, and every replacement is a chance to rethink the drive system.

Electric vs hydraulic: what the evidence says

The case for electric drives rests on energy, repeatability, cleanliness and noise. The energy figures vary widely, so treat them carefully:

Source	Comparison	Result
Efficiency Vermont case study (measured, one week)	New 390-ton all-electric vs 1971 hydraulic machine	0.16 vs 0.61 kWh/kg, about 26% of the energy
FANUC (vendor claim)	All-electric vs hydraulic	50–70% less energy
Husky, quoted by PlasticsToday	Electric vs modern variable-displacement hydraulics	About 15% more efficient
Curtiss-Wright Exlar (vendor figure)	Roller-screw actuator vs hydraulics	About 90% vs about 50% efficiency

The honest conclusion: replacing an old fixed-pump hydraulic machine saves a lot; replacing a modern servo-pump hydraulic machine saves less. The other benefits, shot-to-shot repeatability, no oil near the mould, lower noise and less cooling, often decide the case on their own. Our hydraulic to electric actuator guide walks through a conversion.

Where motion components sit on plastics machinery

Machine	Axes	Main components
Injection moulding	Clamp, injection, screw rotation, ejector, core-pull, nozzle	Servo motors with roller screws or toggles, ejector actuators, drives, linear encoders
Blow moulding	Parison, mould clamp, carriage, blow pin, wheel rotation	Servo motors and actuators, slip rings on rotary wheels
Extrusion	Screw drive, haul-off, cutter, winder, traverse	Main motor and gearbox, servo haul-off and flying cutter, slip rings on winders
Thermoforming	Forming and trim platens, chain index, plug assist	Roller-screw actuators or servo toggles, servo index drives
Film and bag making	Seal bars, cut, fold, unwind tension	Servo motors, linear actuators, encoders
Tyre building	Drum rotation, transfer rings, ply servers	Servo motors, gearboxes, direct-drive motors, slip rings
Ultrasonic welding	Horn stroke and force	Electric servo press actuators

Servotecnica’s slip ring catalogue lists blow moulding, plastic bag making and extrusion as plastics uses, and Exlar reports Dukane chose its GSX actuators for an ultrasonic welding press line.

How to size a thermoforming platen actuator: a worked example

Take a vertical forming platen with 120 kg moving mass, a 200 mm stroke completed in 0.35 s and a 15 kN forming force at the top of stroke, at 30 cycles per minute.

Motion. A triangular profile gives peak speed v = 2 × 0.2 ÷ 0.35 ≈ 1.14 m/s and acceleration a = 4 × 0.2 ÷ 0.35² ≈ 6.5 m/s².
Acceleration force. Lifting: 120 × (9.81 + 6.5) ≈ 1,960 N.
Lead choice. For 1.14 m/s a 25 mm lead screw turns at 45.6 rev/s, about 2,740 rpm. A 10 mm lead would need about 6,840 rpm, too fast for most screws and motors.
Torque at forming force. With the 25 mm lead and an assumed efficiency of 0.85: 15,000 × 0.025 ÷ (2π × 0.85) ≈ 70 Nm. During acceleration: 1,960 × 0.025 ÷ 5.34 ≈ 9 Nm plus rotor inertia.
The two corners. The axis needs high speed at low force and high force at nearly zero speed. Check both points against the motor’s torque-speed curve. A large servo motor with about 120 Nm peak could do it directly, or a servo-driven toggle can give force multiplication near the end of stroke so a smaller motor runs faster.
Heat. If the forming force is held for 0.5 s of each 2 s cycle, that alone gives an RMS torque of about 35 Nm. Size the motor’s continuous rating with derating for the hot machine environment.

The same two-corner check applies to injection units (fast fill, then high hold pressure) and clamp units (fast close, then full tonnage). See how to size a linear actuator and ball screw vs roller screw.

Injection moulding axes in detail

An all-electric injection moulding machine typically has four main servo axes: clamp (often through a toggle that multiplies force near lock-up), injection (a screw driving the plasticising screw forward), screw rotation for plasticising, and ejection. Some add nozzle touch and core-pull axes. Each has a different duty:

Clamp. Fast open and close at low force, then full clamp tonnage held during injection and cooling. The toggle does most of the force multiplication; the motor sizes on speed and the brief lock-up peak.
Injection. A fast fill at high speed, then pack and hold at high force and nearly zero speed. This is the most demanding two-corner axis on the machine.
Screw rotation. Continuous torque during plasticising against back pressure. Size on RMS torque.
Ejection. Short, fast moves with moderate force. A ball screw actuator usually suffices.

Hybrid machines keep hydraulics for the clamp and use servo drives elsewhere, or drive a hydraulic pump with a servo motor so it only runs when needed. When choosing between them, list each axis with its force, speed and duty, then decide axis by axis: the linear actuators, servo motors, gearboxes and servo drives hubs cover the options for each.

Extrusion, film and winding lines

Extrusion lines are continuous, so the motion problem is synchronisation and tension rather than force. Haul-offs set the pull speed, flying cutters match line speed for each cut, and winders control tension as the roll diameter grows. Servo motors with gearheads or direct-drive motors run these axes; encoders on measuring wheels set cut length. Winders with turret spindles need through-bore slip rings for power and signals. Heated rolls need a slip ring rated for the roll temperature, such as the High & Low Temperature Slip Ring range, published from -55 °C to 250 °C.

Rubber and tyre manufacturing

Tyre building machines rotate building drums, transfer the green tyre between stations and apply plies and treads in synchronised steps. The loads are heavy and the compounds sticky, so axes need high torque at low speed, stiff gearing and protection from contamination. Rotating drums carrying sensors or segment actuators need slip rings, and transfer rings use servo or electric linear axes. Specify drum inertia, index and acceleration times, and the synchronisation needed between drum and servers.

Things that catch engineers out

Sizing only at peak force or only at peak speed. Check both corners of the torque-speed curve.
Ignoring heat from barrels, moulds and heaters. Motors, encoders, lubricants and cables near the tool need derating or relocation.
Hold time. Holding pressure or forming force heats motors as much as moving does.
Thermocouple signals through slip rings. Low-level signals need clean contacts, shielding and separation from heater circuits.
Lubricant contamination. Food, medical and optical mouldings may need food-grade or sealed actuators.
Regenerative energy. Fast clamp and platen decelerations return energy; plan for it.

What to send an engineer

Machine type, axis, and the force and speed at each step of the cycle.
Stroke, cycle rate, hold times and moving mass.
Ambient temperature at the mounting point and any heat sources nearby.
Cleanliness, food-contact or medical requirements.
Controller, fieldbus, encoder interface and safety functions.
For conversions: hydraulic cylinder bore, rod, pressure and stroke.

Our engineers can propose matched actuators, motors and drives; start in the spec builder.

Electric actuators for injection moulding and thermoforming

Roller-screw and ball-screw rod actuators drive injection, clamp, ejector, core-pull, platen and trim-press axes. Electric axes give repeatable position and force from shot to shot without hydraulic oil near the mould. Specify peak force and when it occurs, stroke, peak speed and when it occurs, cycle rate, hold time, mounting and temperature at the actuator. Roller screws carry the high loads of clamp and injection axes for longer; ball screws suit lighter, faster ejector and handling moves. Check screw life at the equivalent load and keep lubrication away from food and medical mouldings.

Injection moulding: injection and clamp axes
Injection moulding: ejector and core-pull
Thermoforming: forming and trim platens
Ultrasonic welding presses: horn stroke and force
Blow moulding: mould clamp and blow pin