This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40X635S, 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 SI40X635S
The AirTAC SI40 Standard Cylinder SI40X635S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 635mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40X635S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke635 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40X635S
- 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 SI40X635S
The AirTAC SI40X635S is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 635 mm stroke. Delivering 628 N push force at 0.5 MPa through a G1/4 port, it is replaced by the SAI40X635S. This direct upgrade shares the exact ISO 15552 mounting interface, bore, stroke, force and port, fitting existing fixtures perfectly.
The SAI upgrade features a refined piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. The SAI family also introduces SAIL, SAIF and BSAI lock variants absent in the SI line. The included magnet supports legacy CS1-B/DS1-B sensors, while a Viton H seal option raises operating temperature to 150 C.
Airtac SI40 Standard Cylinder SI40X635S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40X635S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40X635S |
| Bore size | Ø40 mm |
| Stroke | 635 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 SAI40X635S 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 SAI40X635S 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 SI40X635S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×635 | 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 SI40X635S Is Used
Long-Stroke Diversion
Pushes packages across transfer lines using the 635 mm stroke, relying on external guides to absorb side loads.
Actuated Guarding
Opens safety doors on automated cells, using the G1/4 port and ISO 15552 mounts for seamless fixture integration.
Replacing the Airtac SI40 Standard Cylinder SI40X635S with the SAI40X635S
To replace the discontinued SI40X635S, order the SAI40X635S. Verify the ISO 15552 mounting interface, 40 mm bore, 635 mm stroke, M12x1.25 rod thread and G1/4 port. Because the stroke is 635 mm, use external guides to prevent rod bending and side-load damage. If sizing up, a 50 mm bore yields 982 N push at 0.5 MPa; if sizing down, a 32 mm bore provides 402 N. The -S magnet works with CS1-B/DS1-B switches. A plain cylinder drifts on air loss; for load holding, use an external pilot check valve or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40X635S
- ✓ 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 SI40X635S FAQ
Yes, the SI40X635S is discontinued. The direct replacement is the SAI40X635S. It shares the same ISO 15552 mounting interface, 40 mm bore, 635 mm stroke, output force, G1/4 port and accessories, fitting your existing fixtures perfectly.
The G1/4 port is fixed by the 40 mm bore. It generates 628 N push and 528 N pull at 0.5 MPa, 879 N push at 0.7 MPa, 1130 N push at 0.9 MPa, and a theoretical max of 128 kgf at 1.0 MPa. The adjustable cushion is 27 mm.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40X635S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40X635S replacement — usually within 7-8 hours.