This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX280S, 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 SI50 Standard Cylinder SI50BX280S
The AirTAC Airtac SI50 Standard Cylinder SI50BX280S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 280mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50BX280S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke280 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50BX280S
- 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 SI50 Standard Cylinder SI50BX280S
The AirTAC SI50BX280S is a discontinued double-acting ISO 15552 profile cylinder featuring a 50mm bore, 280mm stroke, and a SUS304 stainless piston rod. Delivering 982 N push force at 0.5 MPa, it is replaced by the SAI50BX280S. This direct upgrade retains the same G1/4 port, M16x1.5 thread, and ISO 15552 mounting interface.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The built-in magnet supports legacy CS1-B/DS1-B sensors, while the SAI family adds SAIL lock and BSAI clamp-lock variants absent from the SI line.
Airtac SI50 Standard Cylinder SI50BX280S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX280S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX280S |
| Bore size | Ø50 mm |
| Stroke | 280 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M16×1.5 |
| 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, 30 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI50BX280S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø50mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 982 N | 825 N |
| 0.7 MPa | 1374 N | — |
| Max (@1.0 MPa) | 200 kgf | |
The SAI50BX280S produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI50 Standard Cylinder SI50BX280S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×280 | 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 SI50 Standard Cylinder SI50BX280S Is Used
Diverting & Sorting
Drives diverter arms on packaging lines using the 982 N push force, with the SUS304 rod resisting washdown corrosion.
Clamp Actuation
Actuates mid-force clamping mechanisms on machining cells, relying on adjustable 30mm cushions for smooth end-of-stroke deceleration.
Replacing the Airtac SI50 Standard Cylinder SI50BX280S with the SAI50BX280S
To replace the discontinued SI50BX280S, order the SAI50BX280S. It drops into existing fixtures via the identical ISO 15552 mounting interface, matching the 50mm bore, 280mm stroke, G1/4 port, and M16x1.5 rod thread. Retain your mounting accessory and confirm the -S magnet for sensor compatibility. When sizing both ways, neighbouring bores are 40mm (628 N push @0.5 MPa) and 63mm (1559 N push @0.5 MPa). Note that a plain cylinder drifts on air loss; the air cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. At 280mm stroke, use guide rails to prevent rod bending under side loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX280S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI50 Standard Cylinder SI50BX280S FAQ
Yes, the SI50BX280S is discontinued. The direct replacement is the SAI50BX280S. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 280mm stroke, G1/4 port, and mounting interface.
The bore is 50mm with a G1/4 air port. Force output is 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa. Operating speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX280S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX280S replacement — usually within 7-8 hours.