This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X305SN, 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 SI40X305SN
The AirTAC Airtac SI40 Standard Cylinder SI40X305SN is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 305mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X305SN, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke305 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X305SN
- 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 SI40X305SN
The AirTAC SI40X305SN is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 305mm stroke. Delivering 628N push force at 0.5MPa via a G1/4 port, it is replaced by the direct replacement SAI40X305SN. This SAI upgrade retains the exact mounting interface, force, and stroke, but introduces an upgraded piston seal featuring two Y-shaped one-way elements for longer life and lower start-up pressure. The NBR seal supports -20 to +70C, while a Viton H option extends this to 150C.
The built-in magnet (-S) supports legacy CS1-B/DS1-B sensors, whereas the SAI family uses current AirTAC switches. The SAI line also adds SAIL, SAIF, and BSAI lock variants absent in the SI series.
Airtac SI40 Standard Cylinder SI40X305SN Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X305SN |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X305SN |
| Bore size | Ø40 mm |
| Stroke | 305 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 SAI40X305SN 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 SAI40X305SN 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 SI40X305SN
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×305 | 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 SI40X305SN Is Used
Package Diverting
Actuates diverter arms on packaging lines, utilizing the 305mm stroke to push cartons cleanly between adjacent conveyor belts.
Pneumatic Stopper
Deploys a physical stop block to halt pallets or workpieces in transit, relying on the 628N push force to absorb impact.
Replacing the Airtac SI40 Standard Cylinder SI40X305SN with the SAI40X305SN
To replace the SI40X305SN, order the SAI40X305SN direct equivalent, verifying the ISO 15552 mounting interface, 40mm bore, 305mm stroke, G1/4 port, and NBR seals. Because the 305mm stroke exceeds 300mm, use an external guide to prevent rod bending and premature seal wear from side loads. If you need more force, the neighboring 50mm bore yields 982N push at 0.5MPa; if less force is acceptable, the 32mm bore provides 402N. Note that a plain cylinder drifts on air loss—the cushion only decelerates—so for load holding use an external pilot check valve or the SAIL/BSAI lock variants. The -S magnet enables CS1-B/DS1-B sensors.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X305SN
- ✓ 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 SI40X305SN FAQ
Yes, the SI40X305SN is discontinued. The direct replacement is the SAI40X305SN. It is dimensionally interchangeable per ISO 15552, matching the 40mm bore, 305mm stroke, 628N force, G1/4 port, and mounting accessories, so it fits existing fixtures perfectly.
The 40mm bore features a G1/4 air port and a 16mm rod. The thrust ratings are: 628N push and 528N pull at 0.5 MPa, 879N push at 0.7 MPa, 1130N push at 0.9 MPa, and a theoretical maximum of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X305SN
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X305SN replacement — usually within 7-8 hours.