This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X250SN, 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 SI40X250SN
The AirTAC SI40 Standard Cylinder SI40X250SN 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 SAI40X250SN, 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 → SAI40X250SN
- 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 SI40X250SN
The AirTAC SI40X250SN is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 250mm stroke. Delivering 628 N push force at 0.5 MPa via a G1/4 port, it is directly replaced by the SAI40X250SN. This direct upgrade matches the exact ISO 15552 mounting interface, bore, stroke, force, and port size.
The SAI successor features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. It also introduces SAIL, SAIF, and BSAI lock/valve variants absent from the SI line. The original NBR seals operate from -20 to +70 C, while a Viton H option extends this to 150 C.
Airtac SI40 Standard Cylinder SI40X250SN Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X250SN |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X250SN |
| 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 SAI40X250SN 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 SAI40X250SN 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 SI40X250SN
| 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 SI40X250SN Is Used
Package Diverting
Pushes light to medium cartons at 30-800 mm/s on packaging lines, utilising the 628 N thrust to redirect goods efficiently without overshooting.
Clamping Fixtures
Secures workpieces during machining operations, where the 250mm stroke provides ample clearance for loading and unloading parts safely.
Replacing the Airtac SI40 Standard Cylinder SI40X250SN with the SAI40X250SN
To replace the discontinued SI40X250SN, order the SAI40X250SN. Verify the ISO 15552 mounting interface, 40mm bore, 250mm stroke, G1/4 port (PT/G/NPT thread options), and your specific mounting accessory (LB, FA, TC, etc.). The -S magnet works with legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches. The -N denotes NBR seals. Sizing both ways: a neighbouring 32mm bore yields 402 N push @0.5 MPa, whereas a 50mm bore yields 982 N. At 250mm stroke, use guide rails to prevent rod bending and side-load damage. Note that a plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external pilot check valve or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X250SN
- ✓ 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 SI40X250SN FAQ
Yes, the AirTAC SI40X250SN is discontinued. The direct replacement is the SAI40X250SN. It shares the identical ISO 15552 mounting interface, 40mm bore, 250mm stroke, output force, and G1/4 port, fitting existing fixtures perfectly.
This double-acting cylinder features a G1/4 port. It delivers a push force of 628 N and a pull force of 528 N at 0.5 MPa. At 0.7 MPa push is 879 N, at 0.9 MPa it is 1130 N, and the theoretical maximum is 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X250SN
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X250SN replacement — usually within 7-8 hours.