This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40AX25S, 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 SI40AX25S
The AirTAC Airtac SI40 Standard Cylinder SI40AX25S 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 SAI40AX25S, 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 → SAI40AX25S
- 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 SI40AX25S
The AirTAC SI40AX25S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 25mm stroke. Built with an extruded aluminum barrel and an SUS420J2 stainless piston rod, it delivers 628 N push force at 0.5 MPa. The direct replacement is the SAI40AX25S, matching the bore, stroke, G1/4 port, and ISO 15552 mounting interface.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The original -S magnet works with legacy CS1-B/DS1-B sensors, while the SAI family adds SAIL and BSAI lock variants the SI lacked.
Airtac SI40 Standard Cylinder SI40AX25S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40AX25S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40AX25S |
| 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 SAI40AX25S 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 SAI40AX25S 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 SI40AX25S
| 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 SI40AX25S Is Used
Short-Stroke Clamping
Ideal for compact 25mm clamping tasks in machining fixtures, utilizing the 628 N push force at 0.5 MPa to secure components firmly.
Package Diverting
Provides rapid 30-800 mm/s actuation for diverting small to mid-size packages on assembly lines, with the stainless rod resisting moisture.
Part Ejection
Delivers reliable ejection of machined parts from presses, with the 528 N pull force safely retracting the mechanism after the cycle.
Replacing the Airtac SI40 Standard Cylinder SI40AX25S with the SAI40AX25S
To replace this SI cylinder, order the SAI40AX25S. Confirm the ISO 15552 mounting interface, 40mm bore, 25mm stroke, G1/4 port (PT/G/NPT thread), and the SUS420J2 stainless rod option. The built-in magnet (-S) pairs with legacy CS1-B/DS1-B switches on the SI, but the SAI replacement uses current AirTAC switches. If you need more force, the neighboring 50mm bore yields 982 N push at 0.5 MPa; if less is needed, the 32mm bore yields 402 N. For load holding, note that a plain cylinder drifts on air loss—the cushion only decelerates. Use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants to hold loads securely.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40AX25S
- ✓ 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 SI40AX25S FAQ
Yes, the AirTAC SI40AX25S is discontinued. The direct replacement is the SAI40AX25S. It shares the exact same ISO 15552 mounting interface, 40mm bore, 25mm stroke, G1/4 port, and output force, fitting seamlessly into existing fixtures.
This 40mm bore cylinder features a G1/4 air port and M12x1.25 rod thread. The thrust ratings are: 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 maximum of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40AX25S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40AX25S replacement — usually within 7-8 hours.