This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX275S, 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 SI40BX275S
The AirTAC Airtac SI40 Standard Cylinder SI40BX275S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 275mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX275S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke275 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX275S
- 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 SI40BX275S
The AirTAC SI40BX275S is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 275 mm stroke. It features a SUS304 stainless steel rod, a built-in magnet for legacy CS1-B/DS1-B sensors, and delivers 628 N push force at 0.5 MPa through its G1/4 port. AirTAC replaced this legacy unit with the SAI40BX275S, a direct upgrade retaining the exact ISO 15552 mounting interface, stroke, and output force.
The SAI replacement introduces an upgraded piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life. Note that a plain cylinder drifts without live air; the cushion only decelerates, so use a pilot check valve or the SAIL lock variant for load holding.
Airtac SI40 Standard Cylinder SI40BX275S Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX275S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX275S |
| Bore size | Ø40 mm |
| Stroke | 275 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 SAI40BX275S 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 SAI40BX275S 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 SI40BX275S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×275 | 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 SI40BX275S Is Used
Stainless Rod Diverter
Ideal for diverting medium-weight packages on a washdown conveyor line, utilizing the 275 mm stroke and SUS304 rod for corrosion resistance.
Mid-Force Clamp Station
Provides reliable 628 N clamping force at 0.5 MPa for holding aluminum extrusions or light steel frames during machining operations.
Replacing the Airtac SI40 Standard Cylinder SI40BX275S with the SAI40BX275S
To replace the obsolete SI40BX275S, order the SAI40BX275S. Confirm your ISO 15552 mounting fixture, the 275 mm stroke, and the G1/4 port. This direct upgrade keeps the M12x1.25 rod thread and SUS304 stainless rod. Because the stroke is 275 mm, ensure your mechanics guide the load to prevent rod bending and side-load wear. The -S magnet works with legacy CS1-B/DS1-B switches, though the SAI family uses current AirTAC sensors. For sizing both ways: a 32 mm bore offers 402 N push at 0.5 MPa, while a 50 mm bore yields 982 N. If you need to hold a load securely without air, the standard cushion only decelerates; specify the SAIL air-released lock or BSAI clamp-lock variant, or use an external pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX275S
- ✓ 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 SI40BX275S FAQ
Yes, the SI40BX275S is discontinued. The direct replacement is the SAI40BX275S. It is dimensionally interchangeable per the ISO 15552 mounting interface, keeping the same 40 mm bore, 275 mm stroke, 628 N force, G1/4 port, and SUS304 rod.
The G1/4 port is fixed by the 40 mm bore. 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 max of 128 kgf at 1.0 MPa. Speed ranges from 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX275S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX275S replacement — usually within 7-8 hours.