This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX400S, 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 SI40BX400S
The AirTAC Airtac SI40 Standard Cylinder SI40BX400S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 400mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX400S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke400 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX400S
- 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 SI40BX400S
The AirTAC SI40BX400S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore, 400mm stroke, and a SUS304 stainless steel rod. Delivering 628 N push force at 0.5 MPa via a G1/4 port, it is replaced by the SAI40BX400S. This direct upgrade shares the exact ISO 15552 mounting interface, bore, and stroke.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The original -S magnet supports legacy CS1-B/DS1-B sensors, while the SAI family introduces SAIL, SAIF, and BSAI lock variants the SI lacked.
Airtac SI40 Standard Cylinder SI40BX400S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX400S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX400S |
| Bore size | Ø40 mm |
| Stroke | 400 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 SAI40BX400S 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 SAI40BX400S 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 SI40BX400S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×400 | 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 SI40BX400S Is Used
Stainless Rod Lowering
Ideal for pushing or lowering 32 kg vertical loads in washdown environments using the SUS304 rod, relying on the 628 N thrust at 0.5 MPa.
400mm Transfer Stroke
Handles 400mm linear product diversion on packaging lines, requiring external guides to mitigate side-load on the extended rod.
Pneumatic Clamping
Securely clamps mid-weight workpieces, utilizing the adjustable 27mm air cushions at both ends to decelerate the 16mm rod smoothly.
Replacing the Airtac SI40 Standard Cylinder SI40BX400S with the SAI40BX400S
To replace the SI40BX400S, order the SAI40BX400S, confirming the ISO 15552 interface, 40mm bore, 400mm stroke, G1/4 port, and SUS304 rod. For sizing down, a 32mm bore yields 402 N push at 0.5 MPa; sizing up to 50mm provides 982 N. If you need to hold the load without live air, note that a plain cylinder drifts—the cushion only decelerates—so use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. Because the 400mm stroke exceeds 300mm, use an external guide to prevent rod bending and side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX400S
- ✓ 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 SI40BX400S FAQ
Yes, the SI40BX400S is discontinued. The direct replacement is the SAI40BX400S. It shares the same ISO 15552 mounting interface, 40mm bore, 400mm stroke, force, G1/4 port, and SUS304 rod, fitting existing fixtures perfectly.
It features 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 SAI40BX400S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX400S replacement — usually within 7-8 hours.