This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX55, 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 SI40BX55
The AirTAC Airtac SI40 Standard Cylinder SI40BX55 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 55mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX55, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke55 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX55
- 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 SI40BX55
The AirTAC SI40BX55 is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore and 55mm stroke, delivering 628 N push force at 0.5 MPa. This SKU features a SUS304 stainless piston rod for corrosion resistance and has no magnet, meaning it cannot accept a position sensor. It is replaced by the SAI40BX55.
The SAI40BX55 is a direct replacement retaining the exact ISO 15552 mounting interface, G1/4 port, and 128 kgf max force. The SAI upgrade utilizes two Y-shaped one-way piston seals for low start-up pressure and long life.
Airtac SI40 Standard Cylinder SI40BX55 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX55 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX55 |
| Bore size | Ø40 mm |
| Stroke | 55 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 SAI40BX55 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 SAI40BX55 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 SI40BX55
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×55 | 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 SI40BX55 Is Used
Stainless Rod Clamping
Ideal for medium-duty clamping tasks where the SUS304 rod prevents corrosion from occasional coolant splashes.
Transfer Line Diverters
Provides reliable 55mm stroke actuation to push packages on transfer lines, offering 628 N push at 0.5 MPa.
Compact Assembly Stations
Fits ISO 15552 fixtures perfectly, delivering an 879 N push at 0.7 MPa for pressing small components.
Replacing the Airtac SI40 Standard Cylinder SI40BX55 with the SAI40BX55
To replace the SI40BX55, order the SAI40BX55 to keep the identical ISO 15552 footprint, 40mm bore, 55mm stroke, and G1/4 port. Because this SKU lacks a magnet (-S), it cannot support sensing; if required, select a magnet-equipped SAI40B model and use current AirTAC switches instead of the legacy CS1-B/DS1-B. If downsizing, a 32mm bore yields 402 N push at 0.5 MPa; if upsizing, a 50mm bore provides 982 N. Note that a plain cylinder drifts on air loss—the cushion only decelerates. For load holding, use an external pilot check valve or explore the SAIL lock and SAIF integrated valve variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX55
- ✓ 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 SI40BX55 FAQ
Yes, the SI40BX55 is discontinued. The direct replacement is the SAI40BX55, which shares the same ISO 15552 mounting interface, 40mm bore, 55mm stroke, and G1/4 port.
The G1/4 port bore delivers a push of 628 N and pull of 528 N 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.
Request a Quote for the SAI40BX55
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX55 replacement — usually within 7-8 hours.