This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X400S, 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 SI40X400S
The AirTAC Airtac SI40 Standard Cylinder SI40X400S 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 SAI40X400S, 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 → SAI40X400S
- 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 SI40X400S
The AirTAC SI40X400S 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. The direct replacement is the SAI40X400S, which matches the exact ISO 15552 mounting interface, bore, stroke, output force and porting. The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. The SAI family also adds lock and valve variants (SAIL, SAIF, BSAI) absent in the SI line.
The -S suffix indicates a piston magnet for legacy CS1-B/DS1-B switches; the SAI replacement uses current AirTAC switches. Rod material options include carbon steel, SUS420J2 (A) or SUS304 (B), and Viton H seals raise the operating temperature to 0-150 C.
Airtac SI40 Standard Cylinder SI40X400S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X400S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X400S |
| 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 SAI40X400S 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 SAI40X400S 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 SI40X400S
| 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 SI40X400S Is Used
Material Diversion
Actuates diverter arms on packaging lines, using the 400mm stroke to shift products between adjacent belt lanes smoothly.
Component Ejection
Pushes machined parts out of a CNC enclosure, relying on the adjustable air cushions to decelerate the 400mm travel without slamming.
Replacing the Airtac SI40 Standard Cylinder SI40X400S with the SAI40X400S
To replace the SI40X400S, order the SAI40X400S and confirm the ISO 15552 mounting interface, 40mm bore, 400mm stroke, G1/4 port (PT/G/NPT thread options) and mounting accessory (LB, FA, TC, etc.). The magnet (-S) is preserved. Sizing both ways: if you need more force, the 50mm bore offers 982N push at 0.5MPa; if you can accept less, the 32mm bore provides 402N. Note that a plain cylinder drifts on air loss—the cushion only decelerates at stroke end. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. Because the 400mm stroke is long, prevent rod bending by using an external guide to absorb side loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X400S
- ✓ 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 SI40X400S FAQ
Yes, the SI40X400S is discontinued. The direct replacement is the SAI40X400S. It is dimensionally interchangeable per ISO 15552, matching the 40mm bore, 400mm stroke, 628N force, G1/4 port and mounting fixtures.
The bore is 40mm with a G1/4 air port and M12x1.25 rod thread. At 0.5MPa it pushes 628N and pulls 528N. At 0.7MPa push is 879N, at 0.9MPa it is 1130N, and the theoretical max is 128kgf at 1.0MPa. Speed is 30-800mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X400S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X400S replacement — usually within 7-8 hours.