This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX350S, 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 SI40BX350S
The AirTAC Airtac SI40 Standard Cylinder SI40BX350S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 350mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX350S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke350 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX350S
- 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 SI40BX350S
The AirTAC SI40BX350S is a discontinued double-acting ISO 15552 profile cylinder featuring a 40mm bore, 350mm stroke, and a SUS304 stainless steel piston rod. Generating 628 N push force at 0.5 MPa, it is replaced by the SAI40BX350S. This direct upgrade keeps the same G1/4 port, M12x1.25 thread, and ISO 15552 mounting interface.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The SAI family also adds SAIL, SAIF, and BSAI lock variants the SI lacked. Your -S magnet works with legacy CS1-B/DS1-B sensors.
Airtac SI40 Standard Cylinder SI40BX350S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX350S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX350S |
| Bore size | Ø40 mm |
| Stroke | 350 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 SAI40BX350S 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 SAI40BX350S 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 SI40BX350S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×350 | 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 SI40BX350S Is Used
Stainless Rod Diverter
Ideal for pushing packages on a washdown conveyor line, utilizing the 350mm stroke and SUS304 rod for corrosion resistance.
Extended Reach Sorting
Actuates sorting arms over wider product lanes where the 40mm bore provides sufficient 628 N push force at 0.5 MPa.
Replacing the Airtac SI40 Standard Cylinder SI40BX350S with the SAI40BX350S
To replace the SI40BX350S, order the SAI40BX350S. It is a direct per the ISO 15552 mounting interface, retaining the 40mm bore, 350mm stroke, G1/4 port, and SUS304 rod. If you need more force, the 50mm bore offers 982 N push at 0.5 MPa; if less force is acceptable, the 32mm bore provides 402 N. Because this is a 350mm stroke, use external guides to prevent rod-bending side loads. A plain cylinder drifts on air loss—the cushion only decelerates—so use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant for load holding. The -S magnet supports legacy CS1-B/DS1-B switches.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX350S
- ✓ 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 SI40BX350S FAQ
Yes, the SI40BX350S is discontinued. The direct replacement is the SAI40BX350S. It features the same ISO 15552 mounting interface, 40mm bore, 350mm stroke, output force, G1/4 port, and SUS304 rod, fitting existing fixtures perfectly.
The bore is 40mm with 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. Speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX350S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX350S replacement — usually within 7-8 hours.