Festo EPRF-BS Stainless Steel Electric Cylinder: Sizing Guide for Washdown Areas
2026-11-11Washdown zones are hard on actuators. High-pressure water, caustic cleaning agents and constant humidity will find their way into an aluminium electric cylinder sooner or later. In October 2026 Festo launched a stainless steel motion series aimed squarely at these areas: the EPRF-BS stainless steel electric cylinder and the matching EMMH-AS stainless steel servo motor. This guide uses only what Festo has published in its press release (13 October 2026) and the EPRF catalogue datasheet (edition 2026/10), so you can decode the part number, pick a size and screw pitch, and avoid the installation details that are easy to miss.
The short answer
EPRF-BS is a ball screw electric cylinder with a 1.4404 / 316L stainless steel housing, IP69K protection, corrosion resistance class CRC 4, NSF-H1 grease and lifetime lubrication. It comes in five sizes (36, 45, 55, 75 and 86), with strokes up to 1,000 mm, feed force up to 12,500 N (size 86 with 5 mm pitch) and ±0.02 mm repeatability. If a washdown station needs multiple positions, accurate dosing or high force, it deserves a look. If the job is a simple end-to-end stroke, a stainless pneumatic cylinder is usually the simpler answer.
Reading the part number
Take the catalogue’s standard type EPRF-BS-55-200-10P-F-M1:
| Position | Code | Meaning |
|---|---|---|
| Series | EPRF | Electric cylinder |
| Drive system | BS | Ball screw |
| Size | 55 | 36, 45, 55, 75, 86 |
| Stroke | 200 | mm; standard steps 50 to 1,000, or any value from 25 to 1,000 mm within the size’s limits |
| Screw pitch | 10P | 5P, 8P, 10P, 15P, 16P, 25P, 32P (5 to 32 mm per revolution) |
| Rod thread | F | F = female thread; blank = male thread |
| Rod extension | (none) | …E = 1 to 200 mm |
| Mounting | M1 | M1 threaded flange; M2 through-hole flange; M3 foot; M4 rear trunnion; M5 threaded flange + rear foot; M6 through-hole flange + rear foot |
The standard types listed in the catalogue are all F + M1. Other combinations are ordered through the modular product system (size 55, for example, is part no. 8211891).
Key data by size
| Size | Pitches (mm/rev) | Stroke | Max. feed force Fx | Max. speed | Guide payload, horizontal / vertical |
|---|---|---|---|---|---|
| 36 | 8 | 25 to 250 mm | 380 N | 600 mm/s | 24 / 12 kg |
| 45 | 5, 10 | 25 to 800 mm | 1,000 N | 500 / 1,000 mm/s | 120 / 60 kg |
| 55 | 5, 10, 16 | 25 to 800 mm | 3,000 N (2,200 N with 16P) | 250 / 500 / 1,000 mm/s | 300 / 150 kg |
| 75 | 5, 10, 25 | 50 to 1,000 mm | 7,500 N (4,500 N with 25P) | 250 / 500 / 1,000 mm/s | 600 / 300 kg |
| 86 | 5, 15, 32 | 50 to 1,000 mm | 12,500 N (6,000 N with 32P) | 150 / 500 / 1,000 mm/s | 1,000 / 500 kg |
Speeds are listed in order of pitch, smallest first. Common to all sizes: ±0.02 mm repeatability, 100 µm reversing backlash (when new), plain-bearing guide, no built-in position sensing, any mounting position, −10 to 60 °C ambient and 0 to 95% relative humidity, non-condensing.
How to size it: pitch trades force for speed
- Start with force. Festo states that peak feed force within a motion cycle must not exceed the maximum feed force. The peak usually occurs while accelerating upwards on a vertical axis. The mean feed force (calculated to DIN 69051-4) then sets ball screw life.
- Then speed. Within one size, a finer pitch gives more force and less speed, a coarser pitch the opposite. Size 86 shows the spread: 12,500 N and 150 mm/s at 5P, 6,000 N and 1,000 mm/s at 32P.
- Check buckling on long strokes. Compressive force has to be limited according to rod length to avoid buckling; tensile force is not affected. Use the catalogue’s compressive force vs rod length curves for long pushing strokes.
- Apply an operating coefficient. Festo gives fb values of 1.0 to 1.2 for measuring machines, 1.2 to 1.4 for handling and robotics and 1.4 to 1.6 for press-fitting, to translate catalogue life into real life.
- Confirm in software. Festo’s Electric Motion Sizing tool calculates the axis, motor and drive combination; Festo Automation Suite handles commissioning.
Four details that catch people out
- The piston rod takes no torque. Max. torque Mx is 0 Nm, and the rod can rotate by up to ±0.7° (sizes 36 to 55) or ±0.5° (sizes 75 and 86) when new. If the load is offset or must not turn, add external guidance.
- Route the pressure compensation tube out of the food zone. A pressure compensation hole in the motor mounting kit stops vacuum or overpressure building up inside the cylinder. Festo says to connect plastic tubing and run it to a non-food area such as the control cabinet, leave it open, and never connect it to pressure or vacuum. Festo recommends NPQR stainless push-in fittings.
- Home slowly. Homing against a fixed stop is limited to 0.01 m/s, with end-position impact energy capped per size (8 mJ for size 36 up to 250 mJ for size 86).
- The motor is a separate choice. Motors mount axially or in parallel via the matching kit; permitted motor combinations are listed on Festo’s EAMM-A and EAMM-U pages.
The matching motor: EMMH-AS
According to the press release, the EMMH-AS stainless steel servo motor comes in four sizes from 195 W to 1.52 kW and is also rated IP69K and CRC4. It uses a single-cable connection with integrated pressure compensation tubing and a battery-free absolute encoder, with an optional holding brake for vertical axes. Festo servo drives connect it to PROFINET, EtherCAT, EtherNet/IP and Modbus.
Electric cylinder or stainless pneumatic cylinder?
| Situation | Better fit |
|---|---|
| Simple end-to-end stroke | Stainless pneumatic cylinder (for example CRDNG) |
| Several intermediate or programmable positions | Electric cylinder |
| Filling or dosing that relies on repeatability | Electric cylinder (±0.02 mm for EPRF) |
| No clean compressed air, or a goal to cut air use | Electric cylinder |
| Controlled speed and force profiles | Electric cylinder with servo drive |
For a broader comparison, see our pneumatic vs hydraulic vs electric cylinder selection guide. On the pneumatic side, our overviews of the Festo CRDNG stainless steel standard cylinder and the Festo CRHD stainless steel round cylinder cover the stainless alternatives.
Selection checklist
| Check | What to confirm |
|---|---|
| Load and orientation | Payload mass, horizontal or vertical, any offset |
| Force | Peak and mean feed force against the limit for each pitch |
| Speed and cycle | Max. speed, acceleration, cycle time |
| Stroke | Within the size’s range; buckling curve for pushing loads |
| Environment | Cleaning method and agents, temperature within −10 to 60 °C |
| Mounting | M1 to M6, male or female rod thread, rod extension |
| Motor and drive | Axial or parallel kit, motor type, fieldbus |
| Pressure compensation | Tube route ends outside the food zone |
Talk to us
Send us your load, stroke, cycle time, mounting orientation and cleaning regime at doskee@dustry.ltd. We will help you put together the points to confirm with Festo. You can also browse our Festo product category.
FAQ
What is the maximum force of EPRF-BS?
12,500 N feed force, for size 86 with 5 mm pitch. See the table above for other sizes and pitches.
Can EPRF-BS be used in direct food contact?
Festo describes it as suitable for food contact, and the datasheet refers to the declaration of conformity. Ask Festo for that declaration before you finalise the design.
Does it need regreasing?
No. The datasheet lists lifetime lubrication, and Festo uses NSF-H1 grease.
Does the cylinder have position sensing?
The datasheet lists position sensing as “none”. Position feedback comes from the encoder of the motor you pair it with.
Is it a drop-in replacement for a stainless pneumatic cylinder?
No. It needs a motor, a drive and a control program, and the mounting dimensions differ, so plan it as a redesign.
Sources: Festo press release: Festo introduces new stainless steel motion series (13 Oct 2026); Festo EPRF electric cylinder datasheet (PDF, edition 2026/10); Festo EPRF product page.