This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X400SFA, 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 SI40X400SFA
The AirTAC Airtac SI40 Standard Cylinder SI40X400SFA is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 400mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X400SFA, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke400 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X400SFA
- 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 SI40X400SFA
The AirTAC SI40X400SFA is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 400mm stroke. It delivers 628N push and 528N pull at 0.5MPa, utilizing a G1/4 port and M12x1.25 rod thread. AirTAC replaced this legacy unit with the SAI40X400SFA, a direct upgrade sharing the exact same ISO 15552 mounting interface, force output, and FA flange accessories.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. The SAI family also introduces lock variants like the SAIL and BSAI that the original SI line lacked. Your -S suffix indicates a piston magnet for legacy CS1-B/DS1-B sensors.
Airtac SI40 Standard Cylinder SI40X400SFA Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X400SFA |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X400SFA |
| Bore size | Ø40 mm |
| Stroke | 400 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 SAI40X400SFA 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 SAI40X400SFA 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 SI40X400SFA
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×400 | 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 SI40X400SFA Is Used
Carton Diverting
Drives a 400mm diverting arm on a packaging line, utilizing the 628N push force at 0.5MPa to push heavy cardboard cartons reliably onto parallel conveyors.
Component Ejection
Ejects machined parts from a fixture with a 16mm rod, requiring the magnetic -S option and CS1-B/DS1-B switches to confirm full retraction before the next cycle.
Replacing the Airtac SI40 Standard Cylinder SI40X400SFA with the SAI40X400SFA
To replace the SI40X400SFA, order the SAI40X400SFA. Verify your ISO 15552 FA flange mount, 400mm stroke, G1/4 port thread (PT/G/NPT), and the -S magnet requirement. If you need more force, the neighboring 50mm bore yields 982N push at 0.5MPa; if less is acceptable, the 32mm bore provides 402N. Because this is a 400mm stroke, use an external guide to prevent rod bending and side-load damage. A plain cylinder drifts on air loss—the cushion only decelerates—so for load holding use an external pilot check valve, or select the SAIL/BSAI lock variant. The SAIF variant with a built-in 4M valve is also available for bores 32-100mm.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X400SFA
- ✓ 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 SI40X400SFA FAQ
Yes, the SI40X400SFA is discontinued. The direct replacement is the SAI40X400SFA. It shares the identical ISO 15552 mounting interface, 40mm bore, 400mm stroke, G1/4 port, and FA flange, fitting your existing fixtures perfectly while upgrading the piston seal.
At 0.5MPa it provides 628N push and 528N pull. Push force is 879N at 0.7MPa and 1130N at 0.9MPa. The theoretical max is 128kgf at 1.0MPa. Operating speed is 30-800mm/s, with a 27mm adjustable air cushion at both ends.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X400SFA
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X400SFA replacement — usually within 7-8 hours.