This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X680S, 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 SI40X680S
The AirTAC SI40 Standard Cylinder SI40X680S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 680mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X680S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke680 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X680S
- 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 SI40X680S
The AirTAC SI40X680S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 680mm stroke. Generating 628N push force at 0.5MPa, it features a G1/4 air port, M12x1.25 rod thread, and 27mm adjustable air cushions. The direct replacement is the SAI40X680S, which maintains the exact ISO 15552 mounting interface, bore, and output force.
The SAI upgrade introduces a refined piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life. This -S model includes a piston magnet for legacy CS1-B/DS1-B sensors, while the SAI family also adds SAIL, SAIF, and BSAI lock variants previously unavailable.
Airtac SI40 Standard Cylinder SI40X680S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X680S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X680S |
| Bore size | Ø40 mm |
| Stroke | 680 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 SAI40X680S 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 SAI40X680S 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 SI40X680S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×680 | 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 SI40X680S Is Used
Long-Stroke Diversion
Pushes packages across a 680mm gap on a sorting line using the 628N push force, with the long stroke requiring external guides to prevent rod bending.
Vertical Lift Gate
Raises a lightweight access hatch using the 32kg safe vertical lift capacity, relying on a pilot check valve to hold the load securely when air is removed.
Component Ejection
Ejects machined parts from a fixture over a 680mm distance, utilizing the adjustable 27mm cushions to decelerate the payload smoothly at stroke end.
Replacing the Airtac SI40 Standard Cylinder SI40X680S with the SAI40X680S
To replace the SI40X680S, order the SAI40X680S. Verify your ISO 15552 mounting fixtures, G1/4 port, M12x1.25 rod thread, and the -S magnet requirement. The SAI accepts current AirTAC switches instead of the legacy CS1-B/DS1-B. For sizing, the 40mm bore yields 628N push at 0.5MPa; dropping to a 32mm bore gives 402N, while a 50mm bore provides 982N. Because this is a 680mm stroke, prevent rod bending by using an external guide to absorb side loads. A plain cylinder drifts without air and the cushion only decelerates; for load holding, use an external pilot check valve or explore the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X680S
- ✓ 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 SI40X680S FAQ
Yes, the SI40X680S is discontinued. The direct replacement is the SAI40X680S. It shares the identical ISO 15552 mounting interface, 40mm bore, 680mm stroke, G1/4 port, and output force, fitting directly into existing fixtures.
This 40mm bore double-acting cylinder has a G1/4 air port and provides 628N push / 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 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X680S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X680S replacement — usually within 7-8 hours.