This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X25S, 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 SI40X25S
The AirTAC Airtac SI40 Standard Cylinder SI40X25S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 25mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X25S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke25 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X25S
- 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 SI40X25S
The AirTAC SI40X25S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 25mm stroke. It delivers 628N push force at 0.5MPa via a G1/4 port. The direct replacement is the SAI40X25S, matching the exact interface, bore, stroke, force and mounting.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. The SAI family also adds SAIL, SAIF and BSAI lock variants the SI lacked. Your -S suffix means a magnet for CS1-B/DS1-B legacy switches; the SAI uses current AirTAC switches.
Airtac SI40 Standard Cylinder SI40X25S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X25S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X25S |
| Bore size | Ø40 mm |
| Stroke | 25 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 SAI40X25S 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 SAI40X25S 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 SI40X25S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×25 | 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 SI40X25S Is Used
Short-Stroke Clamping
Ideal for holding parts in machining fixtures where a 25mm travel provides rapid, repeatable clamping at 628N push force.
Ejector Mechanism
Suitable for ejecting small finished components from automated presses using a compact 40mm bore profile cylinder.
Gate Diversion
Powers short-stroke sorting gates on packaging lines, offering fast 30-800mm/s actuation and reliable sensor feedback.
Replacing the Airtac SI40 Standard Cylinder SI40X25S with the SAI40X25S
To replace this SI40X25S, order the SAI40X25S. Confirm the ISO 15552 mounting interface, 40mm bore, 25mm stroke, G1/4 port (PT/G/NPT thread) and your mounting accessory. The -S magnet equates to legacy CS1-B/DS1-B sensors, which swap to current AirTAC switches on the SAI. For sizing, neighbouring bores are 32mm (402N push) and 50mm (982N push) at 0.5MPa. A plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. The 25mm stroke is short, so side-load rod-bending risk is minimal.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X25S
- ✓ 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 SI40X25S FAQ
Yes, the AirTAC SI40X25S is discontinued. The direct replacement is the SAI40X25S. It is dimensionally interchangeable per ISO 15552, keeping the same 40mm bore, 25mm stroke, 628N force, G1/4 port and mounting interface.
The bore is 40mm with a G1/4 air port. At 0.5MPa it pushes 628N and pulls 528N. At 0.7MPa push is 879N, at 0.9MPa it is 1130N, and the theoretical max force is 128kgf at 1.0MPa. The rod is 16mm with an M12x1.25 thread.
Request a Quote for the SAI40X25S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X25S replacement — usually within 7-8 hours.