This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X350STC, 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 SI40X350STC
The AirTAC Airtac SI40 Standard Cylinder SI40X350STC 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 SAI40X350STC, 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 → SAI40X350STC
- 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 SI40X350STC
The AirTAC SI40X350STC is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 350mm stroke. It delivers 628N push force at 0.5MPa through a G1/4 port. AirTAC replaced this legacy unit with the SAI40X350STC, a direct upgrade retaining the exact ISO 15552 mounting interface, bore, stroke, force, and TC trunnion mount.
The SAI replacement introduces an upgraded piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life. It also adds SAIL, SAIF, and BSAI lock variants the SI line lacked. The built-in magnet supports CS1-B/DS1-B sensors, while a Viton H seal option extends operating temperature to 150 C.
Airtac SI40 Standard Cylinder SI40X350STC Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X350STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X350STC |
| 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 SAI40X350STC 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 SAI40X350STC 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 SI40X350STC
| 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 SI40X350STC Is Used
Material Diversion
Drives 350mm stroke diverters on packaging lines, using the TC trunnion to handle pivoting loads within the 377N safe working limit.
Vertical Lift Gates
Raises lightweight access gates up to 32kg, benefiting from the adjustable 27mm air cushions to soften end-of-stroke impacts.
Component Ejection
Pushes machined parts out of fixtures, relying on the 628N thrust at 0.5MPa and the G1/4 air port for rapid cycling.
Replacing the Airtac SI40 Standard Cylinder SI40X350STC with the SAI40X350STC
To replace the SI40X350STC, order the SAI40X350STC. Confirm the ISO 15552 TC trunnion interface, 40mm bore, 350mm stroke, G1/4 port, and the -S magnet for CS1-B/DS1-B switches. Because the 350mm stroke exceeds 300mm, use an external guide to prevent rod bending and side-load wear. If sizing up or down, a 32mm bore yields 402N push at 0.5MPa, while a 50mm bore yields 982N. A plain cylinder drifts on air loss; for load holding, use an external pilot check valve or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X350STC
- ✓ 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 SI40X350STC FAQ
Yes, the AirTAC SI40X350STC is discontinued. The direct replacement is the SAI40X350STC. It is dimensionally interchangeable per ISO 15552, matching the 40mm bore, 350mm stroke, 628N force, G1/4 port, and TC mounting interface.
This double-acting cylinder uses a G1/4 port. It provides 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a theoretical max force of 128kgf at 1.0MPa. The 16mm rod uses an M12x1.25 thread.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X350STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X350STC replacement — usually within 7-8 hours.