This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40AX425S, 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 SI40AX425S
The AirTAC Airtac SI40 Standard Cylinder SI40AX425S 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 SAI40AX425S, 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 → SAI40AX425S
- 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 SI40AX425S
The AirTAC SI40AX425S is a discontinued double-acting ISO 15552 profile cylinder featuring a 40mm bore, 425mm stroke, and a SUS420J2 stainless steel rod. Delivering 628 N push force at 0.5 MPa, it is replaced by the SAI40AX425S. This direct successor shares the exact interface, G1/4 port, and M12x1.25 thread.
The SAI upgrade introduces a two-piece Y-shaped piston seal for lower start-up pressure and longer life. The SAI family also adds SAIL, SAIF, and BSAI lock variants absent from the SI line.
Airtac SI40 Standard Cylinder SI40AX425S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40AX425S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40AX425S |
| 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 SAI40AX425S 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 SAI40AX425S 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 SI40AX425S
| 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 SI40AX425S Is Used
Package Diversion
Actuates routing gates on packaging lines where the 528 N pull force at 0.5 MPa easily deflects standard cartons.
Lab Test Fixtures
The SUS420J2 stainless rod provides corrosion resistance for damp environmental chambers and fluid test rigs.
Replacing the Airtac SI40 Standard Cylinder SI40AX425S with the SAI40AX425S
To replace the SI40AX425S, order the SAI40AX425S, matching the 40mm bore, 425mm stroke, G1/4 port, and ISO 15552 mounting. The -S magnet supports CS1-B/DS1-B sensors (the SAI uses current AirTAC switches), and the -A rod specifies SUS420J2 stainless steel. For sizing, a 32mm bore offers 402 N push at 0.5 MPa, while a 50mm bore provides 982 N. At 425mm, this long stroke risks rod bending under side loads, so use external guides. Note that plain cylinders drift on air loss; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40AX425S
- ✓ 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 SI40AX425S FAQ
Yes, the SI40AX425S is discontinued. The direct replacement is the SAI40AX425S. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 425mm stroke, G1/4 port, and mounting interface.
The G1/4 port bore delivers 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. Operating speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40AX425S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40AX425S replacement — usually within 7-8 hours.