This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX20, 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 SI40BX20
The AirTAC Airtac SI40 Standard Cylinder SI40BX20 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 SAI40BX20, 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 → SAI40BX20
- 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 SI40BX20
The AirTAC SI40BX20 is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 20mm stroke. It delivers 628N push force at 0.5MPa. The direct replacement is the SAI40BX20, sharing the same interface, port and force. This SI40BX20 variant features a SUS304 stainless steel rod and lacks a magnet, meaning it cannot accept a sensor.
The SAI upgrade utilizes two Y-shaped one-way piston seals for lower start-up pressure and longer life. Note the 20mm stroke is non-standard. The SAI family also adds SAIL, SAIF and BSAI lock variants absent in the SI line.
Airtac SI40 Standard Cylinder SI40BX20 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX20 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX20 |
| 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 SAI40BX20 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 SAI40BX20 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 SI40BX20
| 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 SI40BX20 Is Used
Stainless Rod Clamping
Ideal for short-stroke clamping in machining fixtures where the SUS304 rod resists corrosion from cutting fluids.
Compact Ejection
Provides a fast 20mm ejection stroke for small parts, delivering 628N push force at 0.5MPa operating pressure.
Holding Positioning
Used in light assembly stations to hold components, though an external check valve is needed to prevent drift.
Replacing the Airtac SI40 Standard Cylinder SI40BX20 with the SAI40BX20
To replace the discontinued SI40BX20, order the SAI40BX20. Confirm the ISO 15552 mounting interface, the G1/4 port, and the SUS304 stainless rod requirement. Because this SKU lacks a magnet, it cannot support sensing; if switches are needed, a different SAI version is required. For sizing, the 40mm bore yields 628N push at 0.5MPa; dropping to 32mm gives 402N, while 50mm gives 982N. A plain cylinder drifts on air loss, so for load holding consider an external pilot check valve or the SAIL lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX20
- ✓ 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 SI40BX20 FAQ
Yes, the SI40BX20 is discontinued. The direct replacement is the SAI40BX20, which maintains the same ISO 15552 mounting dimensions, 40mm bore, 20mm stroke, and G1/4 port for a seamless fixture swap.
This double-acting cylinder features a G1/4 air port and a 16mm piston rod. It delivers 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a maximum theoretical force of 128kgf at 1.0MPa.
Request a Quote for the SAI40BX20
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX20 replacement — usually within 7-8 hours.