This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X250H, 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 SI40X250H
The AirTAC Airtac SI40 Standard Cylinder SI40X250H 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 SAI40X250H, 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 → SAI40X250H
- 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 SI40X250H
The AirTAC SI40X250H is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore, 250mm stroke, and Viton H high-temperature seals (0 to 150 C). It delivers 628 N push force at 0.5 MPa through a G1/4 port. AirTAC replaced this EOL unit with the SAI40X250H, a direct sharing the same interface, force, and mounting.
The SAI upgrade features two Y-shaped one-way piston seals for low start-up pressure. Because this specific SKU lacks a magnet (-S), it cannot accept a position switch.
Airtac SI40 Standard Cylinder SI40X250H Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X250H |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X250H |
| 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 SAI40X250H 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 SAI40X250H 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 SI40X250H
| 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 SI40X250H Is Used
Hot End Ejection
Ejecting molded parts near heat zones using the Viton H seal rated for 0-150 C, providing reliable 628 N push force.
Diverting Arm
Actuating a 250mm stroke diverting arm on a packaging line, safely handling a 377 N working load at 0.5 MPa.
Vertical Lift Stop
Raising a 32 kg pallet stopper gate vertically, requiring an external pilot check valve since the cushion only decelerates.
Replacing the Airtac SI40 Standard Cylinder SI40X250H with the SAI40X250H
To replace the SI40X250H, order the SAI40X250H and confirm the ISO 15552 mounting interface, 40mm bore, 250mm stroke, G1/4 port, and Viton H seal. This non-magnetic SKU cannot take a sensor; if sensing is needed, specify an SAI40X250HS and use current AirTAC switches. For load holding, note that a plain cylinder drifts on air loss—the cushion only decelerates—so use an external pilot check valve or the SAIL/BSAI lock variant. At 250mm stroke, guide external rods to prevent side-load bending. If downsizing to a 32mm bore yields 402 N (insufficient), step up to a 50mm bore for 982 N.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X250H
- ✓ 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 SI40X250H FAQ
Yes, the SI40X250H is discontinued. The direct replacement is the SAI40X250H. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 250mm stroke, G1/4 port, and mounting fixtures.
The bore is 40mm with a G1/4 port. Force output is 628 N push and 528 N pull at 0.5 MPa, 879 N push at 0.7 MPa, 1130 N push at 0.9 MPa, and a theoretical max of 128 kgf at 1.0 MPa. Speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X250H
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X250H replacement — usually within 7-8 hours.