This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40AX25SN, 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 SI40AX25SN
The AirTAC SI40 Standard Cylinder SI40AX25SN 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 SAI40AX25SN, 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 → SAI40AX25SN
- 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 SI40AX25SN
The AirTAC SI40AX25SN is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 25mm stroke. It delivers 628N push and 528N pull at 0.5MPa through a G1/4 port. The direct replacement is the SAI40AX25SN, matching the exact bore, stroke, force, port and ISO 15552 mounting interface for existing fixtures.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. This -A variant uses a SUS420J2 stainless piston rod for corrosion resistance, and the -SN config adds an NBR seal (-20 to +70C) with a piston magnet for CS1-B/DS1-B switches.
Airtac SI40 Standard Cylinder SI40AX25SN Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40AX25SN |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40AX25SN |
| 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 SAI40AX25SN 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 SAI40AX25SN 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 SI40AX25SN
| 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 SI40AX25SN Is Used
Short-Stroke Clamping
Ideal for holding light machining fixtures or workpieces securely in automated CNC cells using the 25mm stroke.
Component Ejection
Provides reliable 628N push force at 0.5MPa to eject small molded parts or stamped electronics from production tooling.
Diverting Mechanisms
Powers low-profile sorting gates and diverter arms on packaging lines where a compact 40mm bore is required.
Replacing the Airtac SI40 Standard Cylinder SI40AX25SN with the SAI40AX25SN
To replace the SI40AX25SN, order the SAI40AX25SN direct. Verify the ISO 15552 mounting interface, 40mm bore, 25mm stroke, G1/4 port, and your specific mounting accessory. The -A rod is SUS420J2 stainless steel, the -S magnet works with legacy CS1-B/DS1-B sensors (the SAI uses current AirTAC switches), and -N is the NBR seal. When sizing both ways, a 32mm bore neighbor offers 402N push at 0.5MPa, while a 50mm bore provides 982N. Note that a plain cylinder drifts on air loss as the cushion only decelerates; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. The SAIF variant adds a built-in valve for bores 32-100.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40AX25SN
- ✓ 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 SI40AX25SN FAQ
Yes, the SI40AX25SN is discontinued. The direct replacement is the SAI40AX25SN. It shares the same ISO 15552 mounting interface, 40mm bore, 25mm stroke, output force, G1/4 port, and mounting accessories, fitting directly into existing fixtures.
The G1/4 port bore delivers a push force of 628N and a pull force of 528N at 0.5MPa. At 0.7MPa push is 879N, at 0.9MPa it is 1130N, and the theoretical max is 128kgf at 1.0MPa. Operating speed is 30-800mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40AX25SN
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40AX25SN replacement — usually within 7-8 hours.