This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X250SLB, with the same bore, stroke, output force, port and mounting, so it fits the same application. The SAI replacement keeps the same ISO 15552 mounting interface, bore, stroke, output force and accessories, so it drops straight into existing fixtures. It is the current-production version of this cylinder with an upgraded piston seal.
Airtac SI40 Standard Cylinder SI40X250SLB
The AirTAC Airtac SI40 Standard Cylinder SI40X250SLB is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 250mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X250SLB, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke250 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X250SLB
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac SI40 Standard Cylinder SI40X250SLB
The AirTAC SI40X250SLB is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 250mm stroke. It delivers 628N push and 528N pull at 0.5MPa through a G1/4 port. The direct replacement is the SAI40X250SLB, matching the exact ISO 15552 mounting interface, LB foot mount, force, and stroke.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. For applications needing load holding, the SAI family adds SAIL lock and BSAI clamp-lock variants the SI lacked. This -S SKU includes a magnet for CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches.
Airtac SI40 Standard Cylinder SI40X250SLB Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X250SLB |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X250SLB |
| Bore size | Ø40 mm |
| Stroke | 250 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M12×1.25 |
| Fluid | Air (filtered by 40µm element) |
|---|---|
| Operating pressure | 0.15 – 1.0 MPa |
| Proof pressure | 1.5 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 800 mm/s |
| Cushion | Adjustable, 27 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI40X250SLB carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 kgf | |
The SAI40X250SLB produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI40 Standard Cylinder SI40X250SLB
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×250 | Stroke length in mm. |
| -S | Optional built-in magnet for sensor position sensing. |
Legacy SI-family variants: SID (double rod), SIJ (adjustable stroke) — each maps to its SAI equivalent (SID→SAID, SIJ→SAIJ). Rod material: carbon steel (blank) / SUS420J2 (A) / SUS304 (B).
Where the Airtac SI40 Standard Cylinder SI40X250SLB Is Used
Package Diversion
Pushes medium-weight cartons off a main conveyor line using the 628N push force and 250mm travel distance.
Pallet Positioning
Aligns empty pallets at a strapping station, utilizing the LB foot mount to stabilize the 250mm stroke against side loads.
Clamp Actuation
Drives a secondary clamping arm on an assembly fixture, safely holding workpieces with a 377N working load.
Replacing the Airtac SI40 Standard Cylinder SI40X250SLB with the SAI40X250SLB
To replace the SI40X250SLB, order the SAI40X250SLB. Confirm the ISO 15552 interface, 40mm bore, 250mm stroke, G1/4 port, LB foot mounting, and the -S magnet. When sizing, the 40mm bore yields 628N push at 0.5MPa; stepping down to a 32mm bore drops force to 402N, while a 50mm bore increases it to 982N. For this 250mm stroke, ensure guide support to prevent rod bending and side-load wear. A plain cylinder does not hold load without live air; the cushion only decelerates. For secure holding, use an external pilot check valve or the SAIL lock variant. Rod material options include carbon steel, SUS420J2, and SUS304.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X250SLB
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI40 Standard Cylinder SI40X250SLB FAQ
Yes, the AirTAC SI40X250SLB is discontinued. The direct replacement is the SAI40X250SLB. It features the same ISO 15552 mounting interface, 40mm bore, 250mm stroke, G1/4 port, and LB foot mount, fitting existing fixtures perfectly.
The 40mm bore uses a G1/4 port and provides 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, and a theoretical maximum of 128kgf at 1.0MPa. It operates at 30-800mm/s with a 27mm adjustable air cushion at both ends.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X250SLB
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X250SLB replacement — usually within 7-8 hours.