This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X425S, 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 SI40X425S
The AirTAC Airtac SI40 Standard Cylinder SI40X425S 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 SAI40X425S, 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 → SAI40X425S
- 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 SI40X425S
The AirTAC SI40X425S is a discontinued double-acting ISO 15552 profile cylinder featuring a 40mm bore and 425mm stroke. It delivers 628 N push and 528 N pull at 0.5 MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI40X425S, a direct sharing the exact interface, bore, stroke, force and mounting.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. The -S suffix indicates a piston magnet for CS1-B/DS1-B sensors, while the SAI family also adds SAIL lock, SAIF valve and BSAI clamp variants.
Airtac SI40 Standard Cylinder SI40X425S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X425S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X425S |
| 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 SAI40X425S 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 SAI40X425S 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 SI40X425S
| 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 SI40X425S Is Used
Material Diversion
Drives sorting flappers on packaging lines, utilizing the 628 N push force to deflect cartons at high cycling speeds.
Vertical Lowering
Lowers light fixtures or gates up to 425mm, requiring external guides to prevent rod bending during the descent.
Pallet Handling
Actuates stops and lifts in pallet flow tracks, where the 32 kg vertical lift capacity handles empty pallets safely.
Replacing the Airtac SI40 Standard Cylinder SI40X425S with the SAI40X425S
To replace the SI40X425S, order the SAI40X425S, confirming the ISO 15552 mounting interface, 40mm bore, 425mm stroke, G1/4 port (PT/G/NPT thread options) and your specific mounting accessory. Because this is a 425mm stroke, add external guides to prevent rod bending and side-load wear. For higher force, the neighbouring 50mm bore yields 982 N push at 0.5 MPa; for less, the 32mm bore gives 402 N. 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 to hold loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X425S
- ✓ 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 SI40X425S FAQ
Yes, the SI40X425S is discontinued. The direct replacement is the SAI40X425S. It is dimensionally interchangeable per ISO 15552, matching the 40mm bore, 425mm stroke, 628 N force, G1/4 port and mounting fixtures.
The 40mm bore uses a G1/4 port. Force outputs 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 maximum of 128 kgf at 1.0 MPa. Speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X425S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X425S replacement — usually within 7-8 hours.