This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X325S, 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 SI40X325S
The AirTAC SI40 Standard Cylinder SI40X325S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 325mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X325S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke325 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X325S
- 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 SI40X325S
The AirTAC SI40X325S is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 325 mm stroke. Delivering 628 N push force at 0.5 MPa through a G1/4 port, it is replaced by the SAI40X325S. This direct successor matches the exact ISO 15552 mounting interface, bore, stroke, force and port size.
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 denotes a piston magnet for legacy CS1-B/DS1-B sensors.
Airtac SI40 Standard Cylinder SI40X325S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X325S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X325S |
| Bore size | Ø40 mm |
| Stroke | 325 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 SAI40X325S 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 SAI40X325S 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 SI40X325S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×325 | 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 SI40X325S Is Used
Package Diversion
Pushes medium-weight cartons off a main conveyor belt using the 628 N push force at 0.5 MPa over a 325 mm travel distance.
Pallet Stopper Gate
Acts as a pneumatic stop gate for incoming warehouse pallets, requiring external guides to handle the long 325 mm stroke side-loads.
Component Ejection
Ejects machined parts from a fixture, utilizing the integrated magnet and CS1-B/DS1-B sensors to confirm full ejection position.
Replacing the Airtac SI40 Standard Cylinder SI40X325S with the SAI40X325S
To replace the SI40X325S, order the SAI40X325S. Verify the ISO 15552 mounting interface, the 325 mm stroke, the M12x1.25 rod thread, and the G1/4 port. Because this is a 325 mm stroke, use external guides to prevent rod bending and side-load damage. If sizing down, a 32 mm bore yields 402 N push at 0.5 MPa; if sizing up, a 50 mm bore yields 982 N. The standard cylinder does not hold load without live air—the cushion only decelerates—so add an external rod lock or pilot check valve, or specify an SAIL or BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X325S
- ✓ 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 SI40X325S FAQ
Yes, the AirTAC SI40X325S is discontinued. The direct replacement is the SAI40X325S. It shares the same ISO 15552 mounting interface, 40 mm bore, 325 mm stroke, output force and G1/4 port, fitting existing fixtures perfectly.
This double-acting cylinder has a 16 mm rod, M12x1.25 thread, 27 mm cushion, G1/4 port, and operates at 30-800 mm/s. Force 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 maximum theoretical force of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X325S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X325S replacement — usually within 7-8 hours.