This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X400SFTC, 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 SI40X400SFTC
The AirTAC SI40 Standard Cylinder SI40X400SFTC 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 SAI40X400SFTC, 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 → SAI40X400SFTC
- 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 SI40X400SFTC
The AirTAC SI40X400SFTC is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 400mm stroke. It delivers 628N push force at 0.5MPa via a G1/4 port. AirTAC replaced it with the SAI40X400SFTC, a direct upgrade sharing the exact same ISO 15552 mounting interface, bore, stroke, force, port, and FTC trunnion mount.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. The original SI -S magnet supports legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches. The SAI family also introduces SAIL, SAIF, and BSAI lock variants absent in the SI line.
Airtac SI40 Standard Cylinder SI40X400SFTC Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X400SFTC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X400SFTC |
| 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 SAI40X400SFTC 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 SAI40X400SFTC 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 SI40X400SFTC
| 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 SI40X400SFTC Is Used
Package Diversion
Actuates routing gates on packaging lines where the 628N push force easily deflects standard weight cartons over a 400mm travel distance.
Pneumatic Indexing
Drives a 400mm linear indexing table for step-by-step part feeding, relying on the adjustable 27mm air cushions for smooth end-of-stroke deceleration.
Replacing the Airtac SI40 Standard Cylinder SI40X400SFTC with the SAI40X400SFTC
To replace the SI40X400SFTC, order the SAI40X400SFTC keeping the 40mm bore, 400mm stroke, G1/4 port, and FTC trunnion mounting. Confirm your thread standard (PT/G/NPT) and magnet requirement. The 16mm rod uses an M12x1.25 thread. If you need more force, the 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 loads. A plain cylinder drifts on air loss—the cushion only decelerates—so use a pilot check valve, external rod lock, or the SAIL/BSAI lock variant for load holding.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X400SFTC
- ✓ 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 SI40X400SFTC FAQ
Yes, the SI40X400SFTC is discontinued. The direct replacement is the SAI40X400SFTC. It is dimensionally interchangeable per ISO 15552, matching the 40mm bore, 400mm stroke, G1/4 port, and FTC mounting interface for a seamless fixture swap.
The 40mm bore operates at 30-800 mm/s. Force ratings are: 628N push and 528N pull at 0.5 MPa; 879N push at 0.7 MPa; 1130N push at 0.9 MPa; with a theoretical max of 128 kgf at 1.0 MPa. It features a 16mm rod, M12x1.25 thread, and 27mm cushions.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X400SFTC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X400SFTC replacement — usually within 7-8 hours.