Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-20
The AirTAC Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-20 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 SAIJ125X400-20
The AirTAC SAIJ125X400-20 is a double-acting ISO 15552 profile cylinder featuring a rear-mounted stroke adjuster. It provides a 380-400 mm usable travel window, allowing you to dial back the 400 mm nominal stroke by up to 20 mm during machine commissioning without adding external stops. Delivering 6136 N of push force at 0.5 MPa, it is built for heavy-duty positioning.
This bore size uses a robust 32 mm carbon steel rod and M27x2 threads to handle high side loads, though the 400 mm stroke still requires an external guide to prevent rod bending. The extruded aluminum barrel includes sensor grooves on both sides, and pneumatic cushioning at both ends decelerates the moving load. The rear stopper sets the retract end position but does not hold the load without live air pressure.
Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-20 Technical Specifications
| Model | Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-20 |
|---|---|
| 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 SAIJ125X400-20
| 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 SAIJ125X400-20 Is Used
Product Changeover
Dial in the exact 380-400 mm retract position during format changes on heavy machinery without swapping out the entire actuator.
End-Stop Tuning
Fine-tune the final end-of-stroke position at commissioning using the 20 mm rear adjuster to compensate for mechanical tolerances.
Heavy-Duty Forming
Leverage the 6136 N push force at 0.5 MPa for high-thrust pressing and clamping operations requiring precise stroke limits.
Is the Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-20 the Right Cylinder?
Choose this 125 mm bore when you need high force (6136 N push at 0.5 MPa) with fine end-position tuning. Stepping down to a 100 mm bore drops the force to 3927 N, while a 160 mm bore increases it to 10053 N. The adjustable rear screw is ideal for product changeovers where exact end-stops vary, replacing the need to swap a fixed-stroke SAI cylinder.
For dimensionally interchangeable ISO 15552 replacements, match the 125 mm bore, 400 mm stroke, 20 mm adjustment, PT tapered port threads, and standard carbon steel rod. This model uses the reduced SAIJ mounting set (Basic, FA, LB, TC, FTC, TCM1, TCM2) and omits FB, CA, CB, and CR mounts. Because the 400 mm stroke exceeds 300 mm, an external guide is mandatory to manage side loading. If the machine requires the load to stay held without continuous air, select an SAIL or BSAI cylinder, as the SAIJ adjuster is a stop, not a lock.
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 SAIJ125X400-20 FAQ
At 0.5 MPa operating pressure, this 125 mm bore cylinder provides 6136 N of push force and 5734 N of pull force. It can deliver up to 1251 kgf at its maximum 1.0 MPa pressure.
The rear adjuster screw allows you to shorten the effective stroke by up to 20 mm, creating a 380-400 mm usable travel window. This stopper sets the retract end position but does not hold the load without live air pressure.
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