This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40AX20, 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 SI40AX20
The AirTAC Airtac SI40 Standard Cylinder SI40AX20 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 SAI40AX20, 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 → SAI40AX20
- 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 SI40AX20
The AirTAC SI40AX20 is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 20mm stroke, delivering 628N push force at 0.5MPa. The direct replacement is the SAI40AX20, featuring the same G1/4 port, M12x1.25 thread, and mounting interface. This SKU has an SUS420J2 stainless rod but lacks a magnet, so it cannot accept a sensor switch.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. The SAI family also adds SAIL, SAIF, and BSAI lock variants the SI lacked.
Airtac SI40 Standard Cylinder SI40AX20 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40AX20 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40AX20 |
| 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 SAI40AX20 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 SAI40AX20 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 SI40AX20
| 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 SI40AX20 Is Used
Short-Stroke Clamping
Ideal for holding parts in machining fixtures where a compact 20mm stroke and 628N force secure the workpiece.
Gate Diversion
Actuates sorting gates on packaging lines, with the SUS420J2 stainless rod offering corrosion resistance.
Replacing the Airtac SI40 Standard Cylinder SI40AX20 with the SAI40AX20
To replace the SI40AX20, order the SAI40AX20 to retain the exact ISO 15552 mounting interface, 40mm bore, 20mm stroke, and G1/4 port. Because this specific SKU has no magnet (-S), it cannot support legacy CS1-B/DS1-B sensors; order an SAI variant with a magnet if position sensing is required. For sizing, a 32mm bore offers 402N push at 0.5MPa, while a 50mm bore provides 982N. Note that a plain cylinder drifts on air loss; the 27mm air cushion only decelerates the load. For secure holding, use an external pilot check valve or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40AX20
- ✓ 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 SI40AX20 FAQ
Yes, the SI40AX20 is discontinued. The direct replacement is the SAI40AX20, which maintains the same ISO 15552 mounting interface, 40mm bore, 20mm stroke, 628N force, and G1/4 port.
The bore is 40mm with a G1/4 air port. Force output is 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N at 0.9MPa, and a theoretical max of 128kgf at 1.0MPa.
Request a Quote for the SAI40AX20
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40AX20 replacement — usually within 7-8 hours.