This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX355S, 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 SI40BX355S
The AirTAC Airtac SI40 Standard Cylinder SI40BX355S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 355mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX355S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke355 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX355S
- 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 SI40BX355S
The AirTAC SI40BX355S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 355mm stroke. Featuring a SUS304 stainless piston rod (-B) and a built-in magnet (-S) for CS1-B/DS1-B legacy sensors, it delivers 628 N push force at 0.5 MPa. AirTAC replaced this EOL unit with the SAI40BX355S, a direct replacement sharing the exact ISO 15552 mounting interface, G1/4 port, and 128 kgf maximum force.
The SAI upgrade introduces an advanced piston seal with two Y-shaped one-way elements for lower start-up pressure and extended life. Note that plain SI/SAI cylinders require live air to hold a load; for fail-safe holding, consider the SAIL or BSAI lock variants.
Airtac SI40 Standard Cylinder SI40BX355S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX355S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX355S |
| Bore size | Ø40 mm |
| Stroke | 355 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 SAI40BX355S 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 SAI40BX355S 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 SI40BX355S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×355 | 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 SI40BX355S Is Used
Diverting Gate Actuation
Drives routing flaps on packaging lines where the 32 kg vertical lift capacity and 355mm travel smoothly reposition products.
Stainless Rod Washdown
The SUS304 piston rod (-B) suits food-grade or moist environments, pushing 628 N at 0.5 MPa to operate hygienic doors.
Vertical Lowering
Handles controlled descent of light fixtures; note that an external pilot check valve is required to hold the load if air pressure drops.
Replacing the Airtac SI40 Standard Cylinder SI40BX355S with the SAI40BX355S
To replace the SI40BX355S, order the SAI40BX355S. Verify your ISO 15552 mounting accessories (LB, FA, TC, etc.), the G1/4 air port, and the M12x1.25 rod thread. The -S magnet enables current AirTAC switches, while the -B SUS304 rod suits corrosive environments. Sizing both ways: this 40mm bore yields 628 N push at 0.5 MPa; if undersized, a 50mm bore provides 982 N. Because the 355mm stroke is long, prevent rod bending by using external guides to absorb side loads. A plain cylinder drifts on air loss; for load holding, use an external pilot check valve or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX355S
- ✓ 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 SI40BX355S FAQ
Yes, the SI40BX355S is discontinued. The direct replacement is the SAI40BX355S. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 355mm stroke, G1/4 port, and mounting interface.
It features a G1/4 air port. The 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 maximum of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX355S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX355S replacement — usually within 7-8 hours.