This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX625S, 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 SI40BX625S
The AirTAC Airtac SI40 Standard Cylinder SI40BX625S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 625mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX625S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke625 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX625S
- 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 SI40BX625S
The AirTAC SI40BX625S is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore, 625 mm stroke, and a SUS304 stainless steel rod. Delivering 628 N push force at 0.5 MPa, it is replaced by the SAI40BX625S. This direct upgrade shares the exact ISO 15552 mounting interface, G1/4 port, and M12x1.25 rod thread. The SAI features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life.
Because this unit includes the -S magnet, it supports legacy CS1-B/DS1-B sensors, whereas the SAI replacement uses current AirTAC switches. The -B rod option provides corrosion resistance over standard carbon steel. Note that a 625 mm stroke increases side-load risks; external guides are recommended. Also, standard cylinders drift on air loss—the cushion only decelerates, so use a pilot check valve or SAIL lock variant to hold loads.
Airtac SI40 Standard Cylinder SI40BX625S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX625S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX625S |
| Bore size | Ø40 mm |
| Stroke | 625 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 SAI40BX625S 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 SAI40BX625S 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 SI40BX625S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×625 | 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 SI40BX625S Is Used
Divert Gate Actuation
Drives routing flaps on packaging lines, using the 625 mm stroke to clear wide product lanes while the 628 N push force handles flap inertia.
Sample Ejection
Ejects processed test samples from wash stations, where the SUS304 stainless rod provides necessary corrosion resistance against moisture.
Replacing the Airtac SI40 Standard Cylinder SI40BX625S with the SAI40BX625S
To replace the discontinued SI40BX625S, order the SAI40BX625S. Verify your ISO 15552 mounting fixtures, G1/4 port, and M12x1.25 rod thread. The -S magnet and -B SUS304 rod are retained. If you need less force, a 32 mm bore yields 402 N push at 0.5 MPa; for more force, a 50 mm bore yields 982 N. With a 625 mm stroke, prevent rod bending by using external guides to manage side loads. A plain cylinder does not hold load without live air—the cushion only decelerates. For load holding, use an external rod lock, a pilot check valve, or the SAIL/BSAI lock variant. The SAIF variant offers a built-in valve if needed.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX625S
- ✓ 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 SI40BX625S FAQ
Yes, the SI40BX625S is discontinued. The direct replacement is the SAI40BX625S. It shares the same ISO 15552 mounting interface, 40 mm bore, 625 mm stroke, G1/4 port, and output force, fitting directly into existing fixtures.
The bore is 40 mm with a G1/4 air port. Force ratings are: 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. Speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX625S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX625S replacement — usually within 7-8 hours.