Rodless screw actuator
SMC LEFS rodless screw actuator
Ball screw slider-type electric actuator in sizes 16 to 40; series maximum 65 kg horizontal work load, 1,500 mm/s (AC servo) and 1,200 mm stroke, repeatability down to +/-0.01 mm.
Key specifications
| Stroke (max) | 1,200 mm |
|---|---|
| Linear speed (max) | 1,500 mm/s |
| Screw lead | 5 to 30 |
| Repeatability | 0.01 mm |
| Sizes | 16, 25, 32, 40 |
| Payload (max) | 65 kg |
| Motor | 24 V DC step motor, 24 V DC servo motor or AC servo motor |
| Cleanroom | 11-LEFS clean version to ISO Class 4 (ISO 14644-1) |
Summarised in our own words from SMC Corporation's published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1
Notes on this data
Repeatability +/-0.015 mm high-precision step type, +/-0.01 mm high-precision AC servo. LEFS-F high-performance variant reaches 75 kg.
Specify Motion is not affiliated with SMC Corporation. SMC and LEFS are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Typical applications
Alternatives that meet or exceed these figures
Engineers often come to us with a SMC part number and leave with an alternative that is easier to source, quicker to deliver or a better fit for the machine. These 3 series from our supply network are the closest match on published figures.
Screw-driven rodless actuator with recirculating ball-bearing guidance integral to the extrusion, so it carries loads up to 35.6 kN (with carrier options) without external guides.
| Published maximum | LEFS | B3S Screw-Drive Rodless |
|---|---|---|
| Force | — | 12,010 N |
| Stroke | 1,200 mm | 4,547 mm meets or exceeds |
| Speed | 1,500 mm/s | 1,524 mm/s meets or exceeds |
Ballscrew-driven linear module with built-in guide rail, supplied with or without an AC servo motor, for industrial positioning and multi-axis XY/XYZ systems.
| Published maximum | LEFS | LE Ballscrew Linear Actuator (semi-sea… |
|---|---|---|
| Force | — | 2,050 N |
| Stroke | 1,200 mm | 1,450 mm meets or exceeds |
| Speed | 1,500 mm/s | 1,600 mm/s meets or exceeds |
Compact C7 ballscrew linear module with built-in guide, matched to 100-400 W servo motors from the main Japanese and Taiwanese brands.
| Published maximum | LEFS | BLM Built-in Linear Module |
|---|---|---|
| Stroke | 1,200 mm | 1,250 mm meets or exceeds |
| Speed | 1,500 mm/s | 1,600 mm/s meets or exceeds |
Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.
What a rodless screw actuator is
A rodless screw actuator moves a carriage along the actuator body using a ball or lead screw inside a profile. The load mounts directly on the carriage, which runs on guides, either internal bearings or profile rails, so the actuator carries and guides the load as well as moving it. A sealing band typically closes the slot along the body. The motor mounts at one end, inline or folded, and stroke is set by the body length.
When engineers choose a rodless screw actuator
Choose a rodless screw actuator when the load needs carrying along a guided path with good positioning accuracy and stiffness, such as in pick-and-place, gantries and positioning axes. Screw drive gives high thrust and precision. The trade-offs are speed and length: long screws hit critical speed limits, so long strokes run slower. For long, fast strokes with lighter loads, a belt-driven rodless actuator is usually better.
How to specify the SMC LEFS
Send these with your enquiry and an engineer can confirm the right LEFS variant or an equivalent:
- Payload mass and position offset (kg, mm)
- Moment loads on the carriage (Nm)
- Stroke (mm), speed (mm/s) and acceleration (m/s²)
- Thrust force needed (N)
- Repeatability (mm)
- Orientation: horizontal, vertical or wall-mounted
- Environment and sealing (IP code)
Common mistakes to avoid
- Ignoring moment loads from offset payloads
- Choosing a long stroke at high speed and exceeding screw critical speed
- Not adding a brake for vertical axes
- Assuming the sealing band keeps out fine dust or liquids
SMC LEFS: frequently asked questions
What is the SMC LEFS?
Ball screw slider-type electric actuator in sizes 16 to 40; series maximum 65 kg horizontal work load, 1,500 mm/s (AC servo) and 1,200 mm stroke, repeatability down to +/-0.01 mm. Published series figures include stroke 1,200 mm, linear speed 1,500 mm/s, repeatability 0.01 mm, payload 65 kg. It is made by SMC Corporation; Specify Motion can help source it or propose an equivalent.
Who makes the SMC LEFS?
The SMC LEFS is made by SMC (SMC Corporation) and is listed here for engineers comparing options. Specify Motion is not affiliated with SMC Corporation; brand names are used only to identify the product.
What is the stroke of the SMC LEFS?
The published series maximum stroke is 1,200 mm. Individual models and sizes in the LEFS range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
Is there an alternative to the SMC LEFS?
Yes. On published figures, Tolomatic B3S Screw-Drive Rodless and LE Ballscrew Linear Actuator (semi-sealed) are the closest match from our supply network. An engineer confirms the fit against your application before recommending anything.
Is a belt or screw rodless actuator better?
A screw rodless actuator gives more thrust, stiffness and positioning accuracy, which suits pressing, vertical axes and precise positioning. A belt actuator is faster and handles longer strokes, which suits transfer and pick-and-place over distance. Many machines use both: belts for long horizontal moves and screws for shorter, precise or vertical axes.
What limits the speed of a screw-driven actuator?
Speed is limited by the screw's critical speed, the rotation at which it starts to whip. Critical speed falls sharply as unsupported length increases, so long strokes have lower maximum speeds. Screw supports, larger diameters or a coarser lead raise usable speed. Manufacturers publish speed against stroke curves that should be checked.
Further reading: Rodless belt vs screw actuators · How to size a linear actuator · Linear actuators
Other rodless screw actuator series
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