This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX20S, 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 SI40BX20S
The AirTAC Airtac SI40 Standard Cylinder SI40BX20S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 20mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX20S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke20 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX20S
- 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 SI40BX20S
The AirTAC SI40BX20S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 20mm stroke. Delivering 628N push force at 0.5MPa via a G1/4 port, it is directly replaced by the SAI40BX20S. This direct upgrade shares identical ISO 15552 mounting dimensions, bore, stroke, output force and accessories, fitting existing fixtures perfectly.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. This specific SI40BX20S variant includes a SUS304 stainless piston rod for corrosion resistance and a magnetic piston for legacy CS1-B/DS1-B sensors.
Airtac SI40 Standard Cylinder SI40BX20S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX20S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX20S |
| Bore size | Ø40 mm |
| Stroke | 20 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 SAI40BX20S 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 SAI40BX20S 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 SI40BX20S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×20 | 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 SI40BX20S Is Used
Corrosive Clamping
Ideal for short-stroke clamping in washdown or chemical environments using the SUS304 rod, providing 628N of secure holding force at 0.5MPa.
Compact Ejection
Fits tight machinery footprints for part ejection tasks, utilizing the 20mm stroke and magnetic piston for precise end-of-stroke position confirmation.
Replacing the Airtac SI40 Standard Cylinder SI40BX20S with the SAI40BX20S
To replace the SI40BX20S, order the SAI40BX20S ensuring the ISO 15552 mounting interface, 40mm bore, 20mm stroke, G1/4 port (PT/G/NPT thread), and mounting accessory match. Retain the -S magnet for current AirTAC switches and the -B SUS304 stainless rod. If downsizing, a 32mm bore yields 402N push at 0.5MPa; if upsizing, a 50mm bore provides 982N. Note that a plain cylinder drifts on air loss as the cushion only decelerates. For load holding, use an external pilot check valve or the SAIL/BSAI lock variants. The SAIF variant offers a built-in 4M valve for bores 32-100.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX20S
- ✓ 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 SI40BX20S FAQ
Yes, the AirTAC SI40BX20S is discontinued and end-of-life. The direct replacement is the SAI40BX20S. It shares the same ISO 15552 mounting interface, 40mm bore, 20mm stroke, output force, G1/4 port, and mounting accessories, fitting directly into existing fixtures.
The 40mm bore features a G1/4 air port and M12x1.25 rod thread. It delivers 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a theoretical maximum force of 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX20S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX20S replacement — usually within 7-8 hours.