This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40AX125S, 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 SI40AX125S
The AirTAC Airtac SI40 Standard Cylinder SI40AX125S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 125mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40AX125S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke125 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40AX125S
- 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 SI40AX125S
The AirTAC SI40AX125S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 125mm stroke. It delivers 628N push force at 0.5MPa, features a G1/4 port, and uses a SUS420J2 stainless piston rod for corrosion resistance. The built-in magnet supports legacy CS1-B/DS1-B switches.
AirTAC replaced this legacy unit with the SAI40AX125S, a direct replacement sharing the exact ISO 15552 mounting interface, force, and port size. The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life.
Airtac SI40 Standard Cylinder SI40AX125S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40AX125S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40AX125S |
| Bore size | Ø40 mm |
| Stroke | 125 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 SAI40AX125S 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 SAI40AX125S 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 SI40AX125S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×125 | 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 SI40AX125S Is Used
Corrosive Material Ejection
Utilizes the SUS420J2 stainless rod to push chemically treated or wet parts out of a machining center safely.
Vertical Package Diverting
Lifts or diverts light cartons on a sorting line where the 628N force and 125mm stroke are ideal.
Belt Tensioning Mechanism
Maintains dynamic tension on a transfer belt, using the magnetic piston for position feedback.
Replacing the Airtac SI40 Standard Cylinder SI40AX125S with the SAI40AX125S
To replace the SI40AX125S, order the SAI40AX125S keeping the same bore, stroke, G1/4 port, and ISO 15552 mounting. Confirm the -A stainless rod and -S magnet for current AirTAC switches. If you need more force, the 50mm bore offers 982N push at 0.5MPa; if less is needed, the 32mm bore provides 402N. Remember a plain cylinder drifts on air loss as the cushion only decelerates; for load holding use an external rod lock or the SAIL/BSAI lock variant. At 125mm stroke, side-load risks are low, but always guide the rod to prevent bending.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40AX125S
- ✓ 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 SI40AX125S FAQ
Yes, the SI40AX125S is discontinued. The direct replacement is the SAI40AX125S. It shares the same ISO 15552 mounting interface, 40mm bore, 125mm stroke, and G1/4 port, fitting existing fixtures perfectly while upgrading the piston seal.
It features a G1/4 air port. The force ratings are 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a theoretical maximum of 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40AX125S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40AX125S replacement — usually within 7-8 hours.