This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X50STC, 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 SI40X50STC
The AirTAC Airtac SI40 Standard Cylinder SI40X50STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 50mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X50STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke50 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X50STC
- 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 SI40X50STC
The AirTAC SI40X50STC is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 50mm stroke. It delivers 628N push force at 0.5MPa through a G1/4 port. AirTAC replaced this legacy unit with the SAI40X50STC, a direct upgrade sharing the exact same ISO 15552 mounting interface, M12x1.25 rod thread, and 27mm cushions.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life. The original -S magnet supports legacy CS1-B/DS1-B sensors, while the SAI family introduces SAIL, SAIF, and BSAI lock variants the SI lacked.
Airtac SI40 Standard Cylinder SI40X50STC Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X50STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X50STC |
| Bore size | Ø40 mm |
| Stroke | 50 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 SAI40X50STC 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 SAI40X50STC 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 SI40X50STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×50 | 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 SI40X50STC Is Used
Package Diverting
Pushes lightweight cartons off a sorting line using a 50mm stroke, relying on the 628N push force to overcome box friction at high cycle rates.
Small Part Ejection
Ejects machined plastic components from a fixture, where the 528N pull force safely retracts the tooling without stressing the TC trunnion mount.
Gate Actuation
Opens and closes a lightweight pneumatic flow diverter, using the 27mm adjustable cushions to soften the impact at the 50mm stroke ends.
Replacing the Airtac SI40 Standard Cylinder SI40X50STC with the SAI40X50STC
To replace this SI40X50STC, order the SAI40X50STC and confirm the ISO 15552 TC trunnion mounting, 50mm stroke, G1/4 port, and -S magnet. If you need more force, the neighbouring 50mm bore yields 982N push at 0.5MPa; if less is acceptable, the 32mm bore provides 402N. Remember a plain cylinder drifts on air loss—the cushion only decelerates—so for load holding specify an external pilot check valve or the SAIL/BSAI lock variant. The TC mount requires a precision clevis pin to avoid side-loading.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X50STC
- ✓ 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 SI40X50STC FAQ
Yes, the AirTAC SI40X50STC is discontinued. The direct replacement is the SAI40X50STC. It shares the identical ISO 15552 mounting interface, 40mm bore, 50mm stroke, G1/4 port, and output force, fitting directly into your existing TC trunnion fixtures.
At 0.5MPa it provides 628N push and 528N pull force. At 0.7MPa push is 879N, and at 0.9MPa it is 1130N. The theoretical maximum force is 128kgf at 1.0MPa. Operating speed ranges from 30-800mm/s, operating pressure is 0.15-1.0MPa, and it uses a G1/4 port.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X50STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X50STC replacement — usually within 7-8 hours.