This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40AX55S, 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 SI40AX55S
The AirTAC Airtac SI40 Standard Cylinder SI40AX55S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 55mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40AX55S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke55 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40AX55S
- 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 SI40AX55S
The AirTAC SI40AX55S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore, 55mm stroke, and SUS420J2 stainless steel rod. Delivering 628 N push force at 0.5 MPa via a G1/4 port, it is directly replaced by the SAI40AX55S. This direct upgrade shares the exact ISO 15552 mounting interface, bore, stroke, force, and port size. The SAI features an upgraded piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life. It also includes a piston magnet for legacy CS1-B/DS1-B switches.
The SAI family introduces variants the SI line lacked, such as the SAIL air-released lock and SAIF built-in 4M valve for bores 32-100. Note that a plain cylinder drifts on air loss; the air cushion only decelerates near stroke end, so use a lock variant or pilot check valve for load holding.
Airtac SI40 Standard Cylinder SI40AX55S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40AX55S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40AX55S |
| Bore size | Ø40 mm |
| Stroke | 55 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 SAI40AX55S 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 SAI40AX55S 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 SI40AX55S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×55 | 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 SI40AX55S Is Used
Short-Stroke Diverting
The 55mm stroke provides precise actuation for diverting light to medium products along material handling lines without occupying excess space.
Fixture Positioning
Drops directly into existing ISO 15552 fixtures to move 32 kg vertical loads, benefiting from the upgraded SAI Y-shaped piston seals for low friction.
Replacing the Airtac SI40 Standard Cylinder SI40AX55S with the SAI40AX55S
To replace the discontinued SI40AX55S, order the SAI40AX55S. Verify your ISO 15552 mounting interface, 40mm bore, 55mm stroke, G1/4 port (PT/G/NPT thread), and mounting accessory. The -A suffix specifies the SUS420J2 stainless rod, and -S indicates the magnet for CS1-B/DS1-B switches (the SAI uses current AirTAC switches). If you need more force, the 50mm bore offers 982 N push at 0.5 MPa; if less is required, the 32mm bore provides 402 N. For load holding on air loss, remember the cushion only decelerates and cannot hold position—select the SAIL or BSAI lock variant, or use an external rod lock.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40AX55S
- ✓ 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 SI40AX55S FAQ
Yes, the SI40AX55S is discontinued. The direct replacement is the SAI40AX55S. It shares the same ISO 15552 mounting interface, 40mm bore, 55mm stroke, force, and G1/4 port, fitting existing fixtures perfectly while adding an upgraded piston seal.
This 40mm bore cylinder uses a G1/4 air port. It delivers 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 maximum force of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40AX55S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40AX55S replacement — usually within 7-8 hours.