Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-50S
The AirTAC Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-50S is a genuine double-acting ISO 15552 profile-barrel air cylinder with a Ø125mm bore and 400mm stroke, G1/2 air ports and adjustable end cushioning. Its standardized mounting interface makes it a drop-in replacement for other ISO 15552 cylinders in automation lines.
- BoreØ125 mm
- Stroke400 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2
- CushionAdjustable, 40 mm
About the Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-50S
The AirTAC SAIJ125X400-50-S is a double-acting, single-rod ISO 15552 profile cylinder equipped with a rear stroke adjuster. It delivers 6136N of push force at 0.5 MPa and features a 400mm nominal stroke that can be dialed back by up to 50mm, providing a usable travel window of 350-400mm. This built-in adjustability allows you to fine-tune the retract end-position at commissioning without swapping out the entire cylinder or adding external stops.
Fitted with a carbon steel rod and a PT tapered G1/2 port, this unit includes a magnetic piston (-S) for electronic DMSE solid-state or reed CMSE position sensing. The extruded aluminum barrel incorporates sensor grooves on both sides for flexible switch mounting. The rear adjuster acts strictly as a travel stop to set the end-position, not a lock, and cannot hold a load without live air pressure.
Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-50S Technical Specifications
| Model | Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-50S |
|---|---|
| Series | SAI ISO 15552 profile cylinder |
| Bore size | Ø125 mm |
| Stroke | 400 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.
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 kgf | |
Actual usable force is lower than theoretical due to friction and back-pressure. Size with a safety margin.
Model Code: Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-50S
| SAI | ISO 15552 profile-barrel cylinder series. |
|---|---|
| 125 | Bore size in mm. |
| ×400 | 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.
Where the Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-50S Is Used
Variable End-Stop Machining
Dial in the 350-400mm travel window during machine setup to accommodate different part lengths without physically replacing the actuator.
Product Changeover Diverter
Quickly adjust the retract stroke by up to 50mm on a packaging line to handle varying package dimensions on the fly.
Heavy Assembly Press
Leverage the 6136N push force at 0.5MPa for pressing components, using the rear stop to fine-tune the final pressing depth accurately.
Is the Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-50S the Right Cylinder?
Choose this 125mm bore when your application requires heavy thrust—stepping down to a 100mm bore yields only 3927N at 0.5MPa, whereas this model provides 6136N. The 50mm adjustment range is ideal for production lines handling varying product sizes, allowing rapid changeover of the end-stop without hardware modifications. If your process requires the cylinder to hold a load mechanically during an air-pressure loss, consider the SAIL or BSAI series instead, as the SAIJ adjuster is a stop, not a clamp-lock.
When replacing an ISO 15552 cylinder, verify the 125mm bore, 400mm stroke, 50mm adjustment, PT G1/2 port, and the -S magnet requirement. Supported mounts include Basic, FA, LB, TC, FTC, TCM1, and TCM2 (omitting FB, CA, CB, CR). Because the 400mm stroke is relatively long, an external guide is recommended to prevent excessive rod side-loading and premature wear.
Quick checklist
- ✓ Required force at your working pressure
- ✓ Stroke and mounting space
- ✓ Port/thread type (PT/NPT/G)
- ✓ Magnet (-S) for sensors?
- ✓ Side load — consider a guided cylinder
Installation & Maintenance Notes
- check Use clean air filtered to 40µm or finer.
- check Keep within 0.15 – 1.0 MPa operating pressure.
- check Avoid side load on the piston rod.
- check Adjust end cushion screws for smooth stops.
- check Use correct mounting accessory (FA/FB/CA/CB/LB/TC).
- check Installation by qualified personnel per AirTAC docs.
Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-50S FAQ
At 0.5 MPa operating pressure, this 125mm bore cylinder provides 6136N of push force and 5734N of pull force. It can deliver up to 1251 kgf at its maximum 1.0 MPa pressure.
The rear adjuster screw acts as a mechanical stop that shortens the effective stroke. For this 400mm stroke model, you can trim the travel back by up to 50mm, creating a usable 350-400mm window. It functions as an end-position stop, not a load-holding lock.
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