This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X240S, 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 SI40X240S
The AirTAC Airtac SI40 Standard Cylinder SI40X240S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 240mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X240S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke240 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X240S
- 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 SI40X240S
The AirTAC SI40X240S is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 240 mm stroke. Delivering 628 N push force at 0.5 MPa, it is replaced by the direct replacement SAI40X240S, which shares the exact interface, port and mounting. The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. The SI -S magnet supports CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches.
The G1/4 port and M12x1.25 rod thread remain unchanged. If high heat is expected, Viton H seals raise the temperature limit to 150 C. For load holding on air loss, the cushion only decelerates; use an external rod lock or the SAIL/BSAI lock variants.
Airtac SI40 Standard Cylinder SI40X240S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X240S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X240S |
| Bore size | Ø40 mm |
| Stroke | 240 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 SAI40X240S 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 SAI40X240S 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 SI40X240S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×240 | 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 SI40X240S Is Used
Package Diverting
Actuates diverting arms on packaging lines to route boxes using the 628 N push force.
Clamp Actuation
Provides reliable clamping pressure for lightweight machining fixtures at 0.5 MPa.
Gate Control
Operates sorting gates in distribution centers with a 240 mm stroke length.
Replacing the Airtac SI40 Standard Cylinder SI40X240S with the SAI40X240S
To replace the SI40X240S, order the SAI40X240S. Confirm the ISO 15552 mounting interface, the G1/4 port, and your mounting accessory (LB, FA, TC). The -S suffix means a magnet is present for CS1-B/DS1-B switches. Sizing both ways: a 32 mm bore yields 402 N push at 0.5 MPa, while a 50 mm bore yields 982 N. At 240 mm stroke, guide rods are advised to prevent rod bending under side loads. A plain cylinder drifts on air loss; for held loads use a pilot check valve or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X240S
- ✓ 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 SI40X240S FAQ
Yes, the SI40X240S is discontinued. The direct replacement is the SAI40X240S. It is dimensionally interchangeable per ISO 15552, retaining the same 40 mm bore, 240 mm stroke, force, G1/4 port and mounting fixtures.
The 40 mm bore cylinder has a G1/4 air port. Force ratings are: 628 N push and 528 N pull at 0.5 MPa, 879 N push at 0.7 MPa, 1130 N push at 0.9 MPa, and a theoretical max of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X240S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X240S replacement — usually within 7-8 hours.