This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X350SN, 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 SI40X350SN
The AirTAC SI40 Standard Cylinder SI40X350SN 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 SAI40X350SN, 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 → SAI40X350SN
- 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 SI40X350SN
The AirTAC SI40X350SN is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 350mm stroke. Delivering 628N push force at 0.5MPa via a G1/4 port, it is replaced by the SAI40X350SN. This direct upgrade shares the same interface, force, and M12x1.25 rod thread, fitting existing fixtures perfectly.
The SAI features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure. The NBR seal handles -20 to +70C, with Viton H available for high heat. The -S magnet works with CS1-B/DS1-B sensors, while the SAI family adds SAIL lock, SAIF valve, and BSAI clamp variants.
Airtac SI40 Standard Cylinder SI40X350SN Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X350SN |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X350SN |
| 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 SAI40X350SN 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 SAI40X350SN 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 SI40X350SN
| 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 SI40X350SN Is Used
Package Diverting
Pushes light cartons off a sorting line using 628N thrust, with the 350mm reach clearing adjacent lanes.
Pallet Positioning
Indexes empty pallets into a staging area prior to filling, handling the 32kg vertical-lift equivalent safely.
Small Press Ejection
Ejects formed parts from a low-tonnage press, benefiting from the adjustable 27mm air cushions at cycle end.
Replacing the Airtac SI40 Standard Cylinder SI40X350SN with the SAI40X350SN
To replace the SI40X350SN, order the SAI40X350SN direct. Confirm the ISO 15552 mounting interface, 40mm bore, 350mm stroke, G1/4 port (PT/G/NPT threads), NBR seals, and the -S magnet for CS1-B/DS1-B switches. For sizing, a 32mm bore yields 402N push at 0.5MPa, while a 50mm bore yields 982N. At 350mm stroke, use external guides to prevent rod bending and side-load wear. A plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X350SN
- ✓ 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 SI40X350SN FAQ
Yes, the SI40X350SN is discontinued. The direct replacement is the SAI40X350SN. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 350mm stroke, 628N force, G1/4 port, and mounting interface.
The G1/4 port bore delivers a push force of 628N and pull of 528N at 0.5MPa, 879N push at 0.7MPa, 1130N at 0.9MPa, and a theoretical max of 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X350SN
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X350SN replacement — usually within 7-8 hours.