This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX240, 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 SI40BX240
The AirTAC Airtac SI40 Standard Cylinder SI40BX240 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 240mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX240, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke240 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX240
- 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 SI40BX240
The AirTAC SI40BX240 is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore, 240 mm stroke, and a SUS304 stainless steel rod. Delivering 628 N push force at 0.5 MPa via a G1/4 port, it is replaced by the SAI40BX240 direct. This upgrade retains identical mounting, stroke, and force but uses an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life.
Because this SKU lacks a magnet, it cannot accept a CS1-B/DS1-B sensor. For high heat, Viton H seals raise the temperature limit to 150 C.
Airtac SI40 Standard Cylinder SI40BX240 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX240 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX240 |
| Bore size | Ø40 mm |
| Stroke | 240 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 SAI40BX240 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 SAI40BX240 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 SI40BX240
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×240 | 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 SI40BX240 Is Used
Stainless Rod Diverter
Ideal for washdown conveyor diverting where the SUS304 rod resists corrosion while pushing light packages with 628 N force.
Pallet Stop Gate
Acts as a pneumatic stop gate for low-inertia pallets, using adjustable end cushions to decelerate the 240 mm travel smoothly.
Light Press Ejector
Ejects small machined parts from a fixture, providing 528 N pull force to retract the 40 mm bore cylinder reliably.
Replacing the Airtac SI40 Standard Cylinder SI40BX240 with the SAI40BX240
To replace the SI40BX240, order the SAI40BX240. It drops into existing fixtures via the exact ISO 15552 mounting interface, matching the 40 mm bore, 240 mm stroke, G1/4 port, and M12x1.25 rod thread. Select the -B SUS304 rod for wet environments, or default to carbon steel. Since this SKU has no magnet, sensing is impossible; if position feedback is needed, order an SAI40 equivalent with an S suffix. At 240 mm stroke, side-load risks are moderate, so use guide rails to prevent rod bending. If dropping to a 32 mm bore reduces force too much, step up to a 50 mm bore. The air cushion only decelerates the piston; for load holding on air loss, use an external pilot check valve or the SAIL lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX240
- ✓ 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 SI40BX240 FAQ
Yes, the SI40BX240 is discontinued. The direct replacement is the SAI40BX240. It shares the exact ISO 15552 mounting interface, 40 mm bore, 240 mm stroke, G1/4 port, and output force, fitting existing fixtures perfectly while adding an upgraded piston seal.
This 40 mm bore cylinder features a G1/4 air port and M12x1.25 rod thread. It delivers 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 maximum of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX240
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX240 replacement — usually within 7-8 hours.