This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X20S, 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 SI40X20S
The AirTAC Airtac SI40 Standard Cylinder SI40X20S 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 SAI40X20S, 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 → SAI40X20S
- 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 SI40X20S
The AirTAC SI40X20S is a discontinued double-acting ISO 15552 profile cylinder. Delivering 628 N push force at 0.5 MPa through a 40 mm bore, it features a 16 mm rod, M12x1.25 thread, and a G1/4 port. The direct replacement is the SAI40X20S, matching the exact stroke, force, and ISO 15552 mounting interface.
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 variants the SI lacked. Your -S magnet works with legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches.
Airtac SI40 Standard Cylinder SI40X20S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X20S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X20S |
| 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 SAI40X20S 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 SAI40X20S 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 SI40X20S
| 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 SI40X20S Is Used
Short-Stroke Clamping
Ideal for holding light workpieces in machining fixtures where a 20 mm stroke provides rapid, precise actuation.
Ejector Mechanisms
Provides fast ejection of small parts from automated assembly chutes using the 628 N push force at 0.5 MPa.
Package Diverting
Suitable for actuating small diverters or gates on conveyor lines, handling loads safely within the 377 N working range.
Replacing the Airtac SI40 Standard Cylinder SI40X20S with the SAI40X20S
To replace the SI40X20S, order the SAI40X20S keeping the same ISO 15552 mounting interface, 40 mm bore, 20 mm stroke, G1/4 port, and magnet. If you need more force, the 50 mm bore offers 982 N push at 0.5 MPa; if less is acceptable, the 32 mm bore provides 402 N. A plain cylinder drifts on air loss as the cushion only decelerates, so for load holding consider the SAIL lock, BSAI clamp-lock, or an external pilot check valve. The SAIF variant integrates a 4M valve for compact setups.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X20S
- ✓ 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 SI40X20S FAQ
Yes, the SI40X20S is discontinued. The direct replacement is the SAI40X20S. It is dimensionally interchangeable per ISO 15552, matching the 40 mm bore, 20 mm stroke, 628 N force, G1/4 port, and mounting accessories.
The G1/4 port bore delivers a push force of 628 N and a pull force of 528 N at 0.5 MPa. At 0.7 MPa push is 879 N, at 0.9 MPa it is 1130 N, and the theoretical maximum is 128 kgf at 1.0 MPa.
Request a Quote for the SAI40X20S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X20S replacement — usually within 7-8 hours.