
The AirTAC SAIJ125 Adjustable Cylinder SAIJ125X280-20 is a genuine double-acting ISO 15552 profile-barrel air cylinder with a Ø125mm bore and 280mm stroke, G1/2 air ports and adjustable end cushioning. Its standardized mounting interface makes it interchangeable with other ISO 15552 cylinders at the mounting interface.
By turning the external stopper screw, you can shorten the effective travel, providing a 260-280mm usable window for fine-tuning the retract end position during commissioning. This eliminates the need to swap out the entire barrel when product sizes change on the line.
It features a robust 32mm carbon steel piston rod and M27x2 rod threading, paired with 40mm variable air cushions at both ends to manage deceleration. The extruded aluminum barrel includes sensor grooves on both sides for adding CMSE reed or DMSE electronic switches if needed later. The mounting set covers Basic, FA, LB, TC, FTC, TCM1, and TCM2 options, intentionally omitting FB, CA, CB, and CR mounts.
| Model | Airtac SAIJ125 Adjustable Cylinder SAIJ125X280-20 |
|---|---|
| Series | SAI ISO 15552 profile cylinder |
| Bore size | Ø125 mm |
| Stroke | 280 mm |
| Acting type | Double acting |
| Port size | G1/2 |
| Rod thread | M27×2 |
| 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 – 500 mm/s |
| Cushion | Adjustable, 40 mm |
| Max stroke | Up to 1500 mm |
Specifications follow the official AirTAC SAI series datasheet and ISO 15552 dimensions. Confirm against the product label before installation. Port options: G (BSPP) / NPT.
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 5734 N | 5734 N |
| 0.7 MPa | 8027 N | — |
| Max (@1.0 MPa) | 1169 kgf | |
Double-rod model: the rod passes through the rear cover, so both piston faces lose rod area and push is shown at the annular-area value. Actual usable force is lower than theoretical due to friction and back-pressure. Size with a safety margin.
| SAI | ISO 15552 profile-barrel cylinder series. |
|---|---|
| 125 | Bore size in mm. |
| ×280 | Stroke length in mm. |
| -S | Optional built-in magnet for sensor position sensing. |
Related SAI-family variants: SAID (double rod), SAIJ (adjustable stroke), SAIL (with lock), SAIF (with valve), BSAI (enclasp / clamp-lock), and SAI-S with built-in magnet. Rod material: carbon steel (blank) / SUS420J2 (A) / SUS304 (B); seals: TPU (blank) / Viton H / NBR N.
Dial in the 260-280mm retract position during product size transitions on packaging lines without swapping physical cylinder bodies.
Fine-tune the final resting position of heavy actuators at commissioning, using the rear screw to absorb mechanical tolerances.
Select this 125mm bore cylinder when your application requires heavy thrust in the 6000N range at standard 0.5 MPa working pressure, but demands a variable end-stop for quick machine changeovers. Because the 280mm stroke exceeds 300mm, ensure you use an external guide rail to support the load and prevent excessive side-load wear on the rod seals.
Choose this adjustable SAIJ model over a fixed-stroke SAI when you need to dial in the exact retract position without machining external stop blocks. Remember that the rear adjuster functions strictly as a travel stop and does not hold the load without live air pressure; for true load-holding, consider an external rod lock or the AirTAC SAIL or BSAI cylinder series. This unit uses a PT tapered port thread and has no standard magnet installed.
Quick checklist
The rear adjuster acts as an external stopper screw that lets you shorten the nominal 280mm stroke by up to 20mm, giving a usable travel window of 260-280mm. It sets the travel end and works with the 40mm air cushions to manage deceleration, but it does not function as a lock to hold the load without live air pressure.
It operates within a speed range of 30-500mm/s and uses a G1/2 port.
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