This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X25STC, 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 SI40X25STC
The AirTAC Airtac SI40 Standard Cylinder SI40X25STC 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 SAI40X25STC, 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 → SAI40X25STC
- 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 SI40X25STC
The AirTAC SI40X25STC is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 25mm stroke. Delivering 628N push force at 0.5MPa via a G1/4 port, it is replaced by the SAI40X25STC. This direct upgrade keeps the exact ISO 15552 mounting interface, bore, and force ratings. The SAI features an upgraded piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life.
The original SI40X25STC includes a TC trunnion mount and a built-in piston magnet for legacy CS1-B/DS1-B sensors. The SAI replacement family uses current AirTAC switches and introduces variants the SI lacked, such as the SAIL air-released lock, SAIF integrated 4M valve, and BSAI clamp-lock. Note that a standard cylinder drifts on air loss; the air cushion only decelerates near stroke end. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI variants.
Airtac SI40 Standard Cylinder SI40X25STC Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X25STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X25STC |
| 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 SAI40X25STC 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 SAI40X25STC 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 SI40X25STC
| 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 SI40X25STC Is Used
Short-Stroke Clamping
Ideal for holding parts during machining, using the 25mm stroke to secure components with 628N of force at 0.5MPa.
Transfer Line Diversion
Provides compact actuation for routing small to medium products between conveyor belts without taking up excessive space.
Package Ejection
Delivers rapid, short bursts of force to push cartons off sorting lines, operating efficiently at 30-800 mm/s.
Replacing the Airtac SI40 Standard Cylinder SI40X25STC with the SAI40X25STC
To replace the SI40X25STC, order the SAI40X25STC. Confirm the ISO 15552 TC trunnion mounting interface, 40mm bore, 25mm stroke, G1/4 port, and the -S magnet for sensor compatibility. Sizing both ways: a neighbouring 32mm bore yields 402N push at 0.5MPa, while a 50mm bore yields 982N. This 40mm bore provides 628N push and 528N pull at 0.5MPa, with a theoretical max of 128kgf at 1.0MPa. Because a plain cylinder does not hold load without live air, install an external rod lock or pilot check valve for vertical loads, or specify the SAIL/BSAI lock variants. The 16mm rod and M12x1.25 thread remain unchanged.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X25STC
- ✓ 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 SI40X25STC FAQ
Yes, the AirTAC SI40X25STC is discontinued. The direct replacement is the SAI40X25STC, which shares the identical ISO 15552 mounting interface, 40mm bore, 25mm stroke, G1/4 port, and output force.
This 40mm bore double-acting cylinder features a G1/4 air port. It delivers 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a theoretical maximum of 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X25STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X25STC replacement — usually within 7-8 hours.