This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X300SFA, 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 SI40X300SFA
The AirTAC Airtac SI40 Standard Cylinder SI40X300SFA is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 300mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X300SFA, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke300 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X300SFA
- 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 SI40X300SFA
The AirTAC SI40X300SFA is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore, 300mm stroke, and an FA flange mounting interface. It delivers 628N push force at 0.5MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI40X300SFA, a direct upgrade sharing the exact same ISO 15552 mounting dimensions, bore, stroke, and output force.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. It also introduces SAIL, SAIF, and BSAI lock variants absent in the SI line. The built-in magnet supports CS1-B/DS1-B sensors, while a Viton H seal option raises the operating temperature to 150C.
Airtac SI40 Standard Cylinder SI40X300SFA Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X300SFA |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X300SFA |
| Bore size | Ø40 mm |
| Stroke | 300 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 SAI40X300SFA 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 SAI40X300SFA 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 SI40X300SFA
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×300 | 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 SI40X300SFA Is Used
Package Diversion
Actuates routing gates on 30-800mm/s packaging lines, using the 300mm stroke to clear standard totes.
Vertical Lift Stops
Raises and lowers pallet stops in low-force vertical lifts, safely handling loads near the 32kg limit.
Flange-Mounted Ejection
Utilizes the FA flange to securely eject formed components from press beds within compact fixture spaces.
Replacing the Airtac SI40 Standard Cylinder SI40X300SFA with the SAI40X300SFA
To replace the SI40X300SFA, order the SAI40X300SFA. Confirm the ISO 15552 interface, 40mm bore, 300mm stroke, G1/4 port, FA flange mount, and the -S magnet for legacy CS1-B/DS1-B sensors. When sizing, neighbouring bores are 32mm (402N push) and 50mm (982N push) at 0.5MPa. Because the 300mm stroke increases side-load and rod-bending risks, use an external guide to prevent premature wear. A plain cylinder drifts on air loss; the cushion only decelerates near stroke end. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. The SAIF variant adds a built-in valve for bores up to 100mm.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X300SFA
- ✓ 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 SI40X300SFA FAQ
Yes, the SI40X300SFA is discontinued. The direct replacement is the SAI40X300SFA. It shares the same ISO 15552 mounting interface, 40mm bore, 300mm stroke, output force, G1/4 port, and FA flange, fitting directly into existing fixtures.
The 40mm bore uses a G1/4 port and M12x1.25 rod thread. Force ratings are 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. Speed is 30-800mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X300SFA
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X300SFA replacement — usually within 7-8 hours.