This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X55S, 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 SI40X55S
The AirTAC Airtac SI40 Standard Cylinder SI40X55S 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 SAI40X55S, 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 → SAI40X55S
- 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 SI40X55S
The AirTAC SI40X55S is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 55 mm stroke. It delivers 628 N push force at 0.5 MPa through a G1/4 port. The direct replacement is the SAI40X55S, matching the exact bore, stroke, output force, port and mounting interface.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. The SAI family also adds SAIL, SAIF and BSAI lock variants the SI lacked, while this -S model retains its magnet for CS1-B/DS1-B switches.
Airtac SI40 Standard Cylinder SI40X55S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X55S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X55S |
| 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 SAI40X55S 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 SAI40X55S 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 SI40X55S
| 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 SI40X55S Is Used
Component Clamping
Secures mid-weight machined parts during milling or drilling, using the 628 N push force to hold fixtures firmly without deflection.
Package Diverting
Actuates a 55 mm stroke diverting arm to push small to medium cartons off a main production line at speeds up to 800 mm/s.
Replacing the Airtac SI40 Standard Cylinder SI40X55S with the SAI40X55S
To replace the SI40X55S, order the SAI40X55S. Verify the ISO 15552 mounting interface, 55 mm stroke, G1/4 port (PT/G/NPT thread) and the -S magnet for legacy CS1-B/DS1-B sensors. For sizing, the 40 mm bore yields 628 N push at 0.5 MPa; dropping to a 32 mm bore gives 402 N, while a 50 mm bore provides 982 N. A plain cylinder drifts without live air, so for load holding use an external rod lock, pilot check valve, or the SAIL/BSAI variant. The 55 mm stroke avoids side-load rod-bending risks seen in longer travels.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X55S
- ✓ 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 SI40X55S FAQ
Yes, the SI40X55S is discontinued. The direct replacement is the SAI40X55S. It shares the identical ISO 15552 mounting interface, 40 mm bore, 55 mm stroke, force, and G1/4 port, fitting existing fixtures perfectly.
This 40 mm bore cylinder features a G1/4 air port and a 16 mm rod. 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 maximum theoretical force of 128 kgf at 1.0 MPa.
Request a Quote for the SAI40X55S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X55S replacement — usually within 7-8 hours.