This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X320, 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 SI40X320
The AirTAC SI40 Standard Cylinder SI40X320 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 320mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X320, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke320 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X320
- 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 SI40X320
The AirTAC SI40X320 is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 320 mm stroke. Delivering 628 N push force at 0.5 MPa via a G1/4 port, it is replaced by the SAI40X320. This direct upgrade matches the exact ISO 15552 mounting interface, bore, stroke, force and accessories, fitting existing fixtures perfectly. Because this specific SKU lacks the -S magnet, it cannot accept a position sensor.
The SAI40X320 introduces an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The SAI family also adds lock and valve variants the SI lacked, such as the SAIL, SAIF and BSAI models.
Airtac SI40 Standard Cylinder SI40X320 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X320 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X320 |
| Bore size | Ø40 mm |
| Stroke | 320 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 SAI40X320 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 SAI40X320 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 SI40X320
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×320 | 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 SI40X320 Is Used
Material Diversion
Actuates routing gates on packaging lines, using the 628 N push force at 0.5 MPa to shift moderate product loads smoothly.
Clamp Actuation
Drives mid-force clamping fixtures on machining cells, relying on the 320 mm stroke to clear the work area for robotic loading.
Replacing the Airtac SI40 Standard Cylinder SI40X320 with the SAI40X320
To replace the SI40X320, order the SAI40X320 and verify the ISO 15552 mounting interface, 320 mm stroke, G1/4 port (PT/G/NPT thread) and mounting accessories. Since this SKU has no -S magnet, it cannot support legacy CS1-B/DS1-B sensors; order a magnet-equipped SAI if sensing is required. For load holding, note that 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. At 320 mm stroke, prevent rod bending by using external guides to manage side loads. If sizing alternatives, a 32 mm bore yields 402 N push at 0.5 MPa, while a 50 mm bore provides 982 N.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X320
- ✓ 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 SI40X320 FAQ
Yes, the SI40X320 is discontinued. The direct replacement is the SAI40X320. It is dimensionally interchangeable per ISO 15552, retaining the same 40 mm bore, 320 mm stroke, output force, G1/4 port and mounting interface.
The G1/4 port feeds a 40 mm bore that generates 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. It operates at 30-800 mm/s with a 27 mm adjustable air cushion at each end.
Request a Quote for the SAI40X320
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X320 replacement — usually within 7-8 hours.