This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X350S, 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 SI40X350S
The AirTAC Airtac SI40 Standard Cylinder SI40X350S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 350mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X350S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke350 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X350S
- 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 SI40X350S
The AirTAC SI40X350S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 350mm stroke. Delivering 628N push force at 0.5MPa, it features a G1/4 air port and an integrated magnet for position sensing. AirTAC replaced this legacy unit with the SAI40X350S, a direct upgrade retaining the exact ISO 15552 mounting interface, bore, and output force.
The SAI replacement introduces an upgraded piston seal using two Y-shaped one-way elements for lower start-up pressure and extended life. The SAI family also adds SAIL, SAIF, and BSAI lock variants the original SI lacked. Your SI40X350S used CS1-B/DS1-B sensors, while the SAI takes current AirTAC switches.
Airtac SI40 Standard Cylinder SI40X350S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X350S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X350S |
| Bore size | Ø40 mm |
| Stroke | 350 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 SAI40X350S 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 SAI40X350S 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 SI40X350S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×350 | 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 SI40X350S Is Used
Package Diverting
Actuates routing gates on packaging lines where the 628N push force easily redirects standard weight cartons at speed.
Vertical Lowering
Lowers light fixtures or platens up to 32kg; pair with a pilot check valve to prevent uncontrolled drops on air loss.
Clamp Actuation
Drives medium-duty clamping mechanisms in machining cells, utilizing the 350mm stroke to clear the work area for loading.
Replacing the Airtac SI40 Standard Cylinder SI40X350S with the SAI40X350S
To replace the SI40X350S, order the SAI40X350S. Confirm the ISO 15552 mounting interface (LB, FA, TC, etc.), the G1/4 port thread (PT/G/NPT), and the magnet requirement. The SAI is a direct. If sizing up, the 50mm bore offers 982N push at 0.5MPa; sizing down, 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 rod lock or pilot check valve, or specify the SAIL/BSAI lock variant. For the 350mm stroke, use external guides to prevent rod bending and side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X350S
- ✓ 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 SI40X350S FAQ
Yes, the SI40X350S is discontinued. The direct replacement is the AirTAC SAI40X350S. It shares the exact same ISO 15552 mounting interface, 40mm bore, 350mm stroke, G1/4 port, and output force, fitting directly into existing fixtures.
The 40mm bore delivers 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. Operating speed is 30-800mm/s. It uses a 16mm rod, M12x1.25 thread, and 27mm adjustable cushions.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X350S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X350S replacement — usually within 7-8 hours.