This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX425S, 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 SI40BX425S
The AirTAC Airtac SI40 Standard Cylinder SI40BX425S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 425mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX425S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke425 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX425S
- 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 SI40BX425S
The AirTAC SI40BX425S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 425mm stroke. Featuring a SUS304 stainless piston rod (-B) and a built-in magnet (-S) for CS1-B/DS1-B switches, it delivers 628 N push force at 0.5 MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI40BX425S.
The SAI40BX425S is a direct replacement retaining the exact ISO 15552 mounting interface, bore, stroke, and port. The upgrade introduces a two Y-shaped one-way piston seal for lower start-up pressure and longer life.
Airtac SI40 Standard Cylinder SI40BX425S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX425S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX425S |
| Bore size | Ø40 mm |
| Stroke | 425 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 SAI40BX425S 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 SAI40BX425S 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 SI40BX425S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×425 | 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 SI40BX425S Is Used
Diverting Gate Actuation
Drives routing flaps on packaging lines where the 628 N push force at 0.5 MPa easily overcomes flap inertia and the SUS304 rod resists washdown moisture.
Carton Push-off
Pushes corrugated cartons off accumulation rollers, utilizing the built-in magnet and CS1-B/DS1-B sensors to confirm full extension at 425mm.
Replacing the Airtac SI40 Standard Cylinder SI40BX425S with the SAI40BX425S
To replace the SI40BX425S, order the SAI40BX425S. Verify the ISO 15552 mounting accessory (LB, FA, TC, etc.), the G1/4 port thread (PT/G/NPT), the -S magnet for current AirTAC switches, and the -B SUS304 rod. For sizing both ways: a neighbouring 32mm bore yields 402 N push at 0.5 MPa, while a 50mm bore yields 982 N. Note that a 425mm stroke requires external guides to prevent rod-bending under side loads. A plain cylinder drifts on air loss—the cushion only decelerates—so use a pilot check valve or the SAIL/BSAI lock variant for load holding.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX425S
- ✓ 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 SI40BX425S FAQ
Yes, the SI40BX425S is discontinued. The direct replacement is the SAI40BX425S. It shares the identical ISO 15552 mounting interface, 40mm bore, 425mm stroke, G1/4 port, and output force, fitting existing fixtures perfectly while adding an upgraded piston seal.
The 40mm bore uses a G1/4 air port and a 16mm rod. Force output is 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, with a theoretical maximum of 128 kgf at 1.0 MPa. Speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX425S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX425S replacement — usually within 7-8 hours.