This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X381SN, 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 SI40X381SN
The AirTAC Airtac SI40 Standard Cylinder SI40X381SN is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 381mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X381SN, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke381 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X381SN
- 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 SI40X381SN
The AirTAC SI40X381SN is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 381mm stroke. It delivers 628N push force at 0.5MPa and uses a G1/4 air port. AirTAC replaced this legacy unit with the SAI40X381SN, a direct replacement sharing the exact same ISO 15552 mounting interface, bore, output force, and porting.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. The NBR seals handle -20 to +70C, while the magnet-equipped piston supports legacy CS1-B/DS1-B switches.
Airtac SI40 Standard Cylinder SI40X381SN Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X381SN |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X381SN |
| Bore size | Ø40 mm |
| Stroke | 381 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 SAI40X381SN 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 SAI40X381SN 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 SI40X381SN
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×381 | 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 SI40X381SN Is Used
Package Diversion
Drives sorting pop-up arms on packaging lines, utilizing the 381mm stroke to push cartons cleanly onto adjacent conveyors.
Pallet Handling
Actuates pallet stops and positioning gates in automated storage systems where a 32kg safe vertical lift margin is sufficient.
Light Pressing
Applies downward clamping pressure for light assembly fixtures, relying on adjustable air cushions to decelerate at stroke end.
Replacing the Airtac SI40 Standard Cylinder SI40X381SN with the SAI40X381SN
To replace the SI40X381SN, order the SAI40X381SN. Confirm the ISO 15552 mounting interface, G1/4 port, M12x1.25 rod thread, and the -S magnet for CS1-B/DS1-B sensors. The 381mm stroke is nonstandard; at this length, prevent rod bending by using external guides to absorb side loads. If sizing up or down, adjacent bores are 32mm (402N push @0.5MPa) and 50mm (982N push @0.5MPa). This plain cylinder will drift on air loss; for load holding, use an external pilot check valve, rod lock, or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X381SN
- ✓ 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 SI40X381SN FAQ
Yes, the SI40X381SN is discontinued. The direct replacement is the SAI40X381SN. It is dimensionally interchangeable per ISO 15552, matching the 40mm bore, 381mm stroke, G1/4 port, and mounting fixtures.
The G1/4 port bore delivers 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a theoretical max of 128kgf at 1.0MPa. It operates at 30-800mm/s with a 27mm adjustable cushion.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X381SN
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X381SN replacement — usually within 7-8 hours.