This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X270S, 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 SI40X270S
The AirTAC Airtac SI40 Standard Cylinder SI40X270S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 270mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X270S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke270 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X270S
- 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 SI40X270S
The AirTAC SI40X270S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 270mm stroke. Delivering 628N push force at 0.5MPa via a G1/4 port, it is replaced by the SAI40X270S. This direct upgrade matches the exact interface, bore, stroke, force, port and mounting, fitting existing fixtures perfectly.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The SI40X270S includes a magnet for CS1-B/DS1-B sensors, while the SAI family adds SAIL, SAIF and BSAI lock variants previously unavailable.
Airtac SI40 Standard Cylinder SI40X270S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X270S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X270S |
| Bore size | Ø40 mm |
| Stroke | 270 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 SAI40X270S 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 SAI40X270S 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 SI40X270S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×270 | 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 SI40X270S Is Used
Package Diversion
Actuates routing gates on packaging lines where 628N push force at 0.5MPa easily deflects standard totes.
Clamp Actuation
Provides 270mm travel to position and clamp medium workpieces inside CNC machining fixtures.
Replacing the Airtac SI40 Standard Cylinder SI40X270S with the SAI40X270S
To replace the SI40X270S, order the SAI40X270S: it is dimensionally interchangeable per ISO 15552, keeping the 40mm bore, 270mm stroke, G1/4 port and M12x1.25 rod thread. Confirm your mounting accessory (LB, FA, CA, TC) and thread option (PT, G, NPT). Because the -S suffix indicates a magnet, ensure you order the SAI with a magnet and use current AirTAC switches (the legacy SI used CS1-B/DS1-B). For sizing, a 50mm bore offers 982N push at 0.5MPa if you need more force, while a 32mm bore provides 402N. At 270mm stroke, use a guide to prevent rod bending and side-load damage. A plain cylinder drifts on air loss—the cushion only decelerates—so for load holding use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X270S
- ✓ 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 SI40X270S FAQ
Yes, the AirTAC SI40X270S is discontinued. The direct replacement is the SAI40X270S. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 270mm stroke, 628N force, G1/4 port and mounting interface.
The 40mm bore uses a G1/4 air port. Force outputs 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.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X270S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X270S replacement — usually within 7-8 hours.