This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X50SFA, 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 SI40X50SFA
The AirTAC Airtac SI40 Standard Cylinder SI40X50SFA 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 SAI40X50SFA, 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 → SAI40X50SFA
- 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 SI40X50SFA
The AirTAC SI40X50SFA is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 50mm stroke. It delivers 628N push force at 0.5MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI40X50SFA, a direct replacement sharing the exact same ISO 15552 mounting interface, bore, stroke, output force, and FA flange mounting.
The SAI upgrade features a modernized piston seal using two Y-shaped one-way elements for low start-up pressure and extended life. The SAI family also introduces SAIL, SAIF, and BSAI lock variants unavailable in the SI line. Your existing CS1-B/DS1-B legacy sensors fit the -S magnet on this model, though the SAI uses current AirTAC switches.
Airtac SI40 Standard Cylinder SI40X50SFA Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X50SFA |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X50SFA |
| 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 SAI40X50SFA 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 SAI40X50SFA 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 SI40X50SFA
| 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 SI40X50SFA Is Used
Clamping Fixtures
Ideal for holding medium-duty workpieces during machining, delivering 628N of clamping force at 0.5MPa with precise 50mm travel.
Package Diverting
Short-stroke diverting arms on conveyor lines benefit from the 50mm stroke and robust FA flange mount under high cycling rates.
Stopper Gates
Acts as a reliable pneumatic stopper for cartons or totes on gravity rollers, with the magnet providing end-of-stroke confirmation.
Replacing the Airtac SI40 Standard Cylinder SI40X50SFA with the SAI40X50SFA
To replace the SI40X50SFA, order the SAI40X50SFA. Confirm the ISO 15552 interface, 40mm bore, 50mm stroke, G1/4 port (PT/G/NPT thread options), FA flange mounting, and the -S magnet for position sensing. For sizing, a 40mm bore yields 628N push at 0.5MPa; if you need less force, a 32mm bore provides 402N, while a 50mm bore offers 982N. Note that a plain cylinder does not hold load without live air—the cushion only decelerates. For load holding on air loss, use an external rod lock, a pilot check valve, or the SAIL/BSAI lock variant. Because the stroke is under 300mm, side-load rod-bending risks are minimal, but always ensure proper guide alignment.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X50SFA
- ✓ 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 SI40X50SFA FAQ
Yes, the SI40X50SFA is discontinued. The direct replacement is the SAI40X50SFA. It shares the same ISO 15552 mounting interface, 40mm bore, 50mm stroke, output force, G1/4 port, and FA flange, fitting directly into existing fixtures.
The 40mm bore features a G1/4 air port and M12x1.25 rod thread. It delivers 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a theoretical max force of 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X50SFA
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X50SFA replacement — usually within 7-8 hours.