This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX185S, 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 SI40BX185S
The AirTAC Airtac SI40 Standard Cylinder SI40BX185S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 185mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX185S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke185 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX185S
- 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 SI40BX185S
The AirTAC SI40BX185S is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore, 185mm stroke, and SUS304 stainless steel rod. It delivers 628N push force at 0.5MPa via a G1/4 port. The direct replacement is the SAI40BX185S, matching the interface, force, and stroke.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. The -S magnet works with legacy CS1-B/DS1-B sensors, while a Viton H seal option raises heat resistance to 150C.
Airtac SI40 Standard Cylinder SI40BX185S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX185S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX185S |
| Bore size | Ø40 mm |
| Stroke | 185 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 SAI40BX185S 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 SAI40BX185S 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 SI40BX185S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×185 | 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 SI40BX185S Is Used
Stainless Rod Clamping
Ideal for washdown or corrosive fixture clamping using the SUS304 rod, providing a reliable 528N pull force at 0.5MPa.
185mm Package Diverting
The 185mm stroke pushes light packages between conveyor lanes, safely handling loads near the 377N working limit.
Replacing the Airtac SI40 Standard Cylinder SI40BX185S with the SAI40BX185S
To replace the SI40BX185S, order the SAI40BX185S. Confirm the ISO 15552 mounting interface, the 40mm bore, 185mm stroke, G1/4 port, and your specific mounting accessory. The -B code denotes the SUS304 rod for corrosion resistance, and -S indicates the magnet for CS1-B/DS1-B switches (the SAI uses current AirTAC switches). If you need more force, the neighbouring 50mm bore offers 982N push at 0.5MPa; if less is required, the 32mm bore provides 402N. Note that a plain cylinder drifts on air loss as the cushion only decelerates; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. The SAIF variant adds a built-in valve for bores 32-100.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX185S
- ✓ 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 SI40BX185S FAQ
Yes, the SI40BX185S is discontinued. The direct replacement is the SAI40BX185S. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 185mm stroke, G1/4 port, and mounting interface.
This 40mm bore cylinder uses a G1/4 air port and provides 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a theoretical maximum of 128kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX185S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX185S replacement — usually within 7-8 hours.