This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X785S, 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 SI40X785S
The AirTAC Airtac SI40 Standard Cylinder SI40X785S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 785mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X785S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke785 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X785S
- 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 SI40X785S
The AirTAC SI40X785S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 785mm stroke, delivering 628N push force at 0.5MPa through a G1/4 port. AirTAC replaced this legacy unit with the SAI40X785S, a direct sharing the exact interface, bore, stroke, force, and mounting. The SAI features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life.
The SAI family adds SAIL, SAIF, and BSAI lock variants absent in the SI line. Your SI40X785S includes a magnet for CS1-B/DS1-B switches, while the SAI uses current AirTAC sensors. Rod material options include carbon steel, SUS420J2, or SUS304.
Airtac SI40 Standard Cylinder SI40X785S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X785S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X785S |
| Bore size | Ø40 mm |
| Stroke | 785 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 SAI40X785S 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 SAI40X785S 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 SI40X785S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×785 | 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 SI40X785S Is Used
Long-Stroke Diversion
Pushes packages across transfer lines using the full 785mm travel, relying on external guides to prevent rod bending during lateral push.
Vertical Lift Gates
Raises lightweight access gates with a 32kg vertical lift capacity, requiring a pilot check valve to hold the load safely if air pressure drops.
Component Ejection
Ejects machined parts from a fixture using 628N of push force at 0.5MPa, cycling safely within the 30-800mm/s speed range.
Replacing the Airtac SI40 Standard Cylinder SI40X785S with the SAI40X785S
To replace the SI40X785S, order the SAI40X785S, confirming the ISO 15552 mounting interface, 40mm bore, 785mm stroke, G1/4 port, and magnet for position sensing. If you need more force, the 50mm bore offers 982N push at 0.5MPa; if less is required, the 32mm bore provides 402N. Because this is a 785mm stroke, use external guides to prevent rod bending and side-load damage. A plain cylinder drifts on air loss—the cushion only decelerates—so use an external rod lock or pilot check valve for load holding, or specify the SAIL or BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X785S
- ✓ 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 SI40X785S FAQ
Yes, the SI40X785S is discontinued. The direct replacement is the SAI40X785S. It shares the same ISO 15552 mounting interface, 40mm bore, 785mm stroke, output force, and G1/4 port, fitting existing fixtures perfectly.
This double-acting cylinder has a G1/4 port and M12x1.25 rod thread. It delivers 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a maximum theoretical force of 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X785S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X785S replacement — usually within 7-8 hours.