This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X250N, 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 SI40X250N
The AirTAC Airtac SI40 Standard Cylinder SI40X250N is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 250mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X250N, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke250 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X250N
- 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 SI40X250N
The AirTAC SI40X250N is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 250mm stroke, delivering 628N push and 528N pull at 0.5 MPa. AirTAC replaced this EOL unit with the SAI40X250N. This direct successor matches the exact G1/4 port, M12x1.25 rod thread, and 27mm cushions, fitting existing ISO 15552 fixtures perfectly.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life. Because this specific SKU lacks a magnet (-S), it cannot accept a position sensor. For load holding, note that the air cushion only decelerates; use an external rod lock or pilot check valve.
Airtac SI40 Standard Cylinder SI40X250N Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X250N |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X250N |
| Bore size | Ø40 mm |
| Stroke | 250 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 SAI40X250N 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 SAI40X250N 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 SI40X250N
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×250 | 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 SI40X250N Is Used
Package Diverting
Drives diverting arms on packaging lines, utilizing the 250mm stroke to push cartons cleanly onto adjacent conveyor belts.
Material Ejection
Ejects completed goods from workstation fixtures, using the 628N push force at 0.5 MPa to clear light components reliably.
Replacing the Airtac SI40 Standard Cylinder SI40X250N with the SAI40X250N
To replace the SI40X250N, order the SAI40X250N and verify your ISO 15552 mounting interface, G1/4 port threads (PT/G/NPT), and 250mm stroke requirement. If you need position sensing, you must select an SAI variant with the magnet (-S), as this NBR-sealed SKU has none. For sizing, the 40mm bore yields 879N push at 0.7 MPa; if you need less force, a 32mm bore gives 563N, and a 50mm bore provides 1374N. Since the 250mm stroke is over 300mm, ensure adequate guide support to prevent rod bending and side loads. The cushion only decelerates the load; it will not hold position on air loss, so consider an external pilot check valve or the SAIL/BSAI lock variants for secure holding.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X250N
- ✓ 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 SI40X250N FAQ
Yes, the SI40X250N is discontinued. The direct replacement is the SAI40X250N. It shares the identical ISO 15552 mounting interface, 40mm bore, 250mm stroke, output force, and G1/4 port, so it fits directly into your existing fixtures.
This double-acting cylinder features a G1/4 air port and M12x1.25 rod thread. It delivers 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 force of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X250N
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X250N replacement — usually within 7-8 hours.