Airtac SAIJ125 Adjustable Cylinder SAIJ125AX40-20S
The AirTAC Airtac SAIJ125 Adjustable Cylinder SAIJ125AX40-20S is a genuine double-acting ISO 15552 profile-barrel air cylinder with a Ø125mm bore and 40mm 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
- Stroke40 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2
- CushionAdjustable, 40 mm
About the Airtac SAIJ125 Adjustable Cylinder SAIJ125AX40-20S
The AirTAC SAIJ125X40-20-S is a double-acting ISO 15552 profile cylinder featuring a rear-mounted stroke adjuster. With a 40 mm nominal stroke and a 20 mm adjustment range, it provides a usable travel window of 20 to 40 mm. This allows precise end-position tuning at commissioning without swapping the cylinder or adding external stops. It delivers a robust 6136 N push force at 0.5 MPa, making it suitable for heavy-duty positioning tasks.
This variant includes a SUS420J2 stainless steel rod (code A) for enhanced corrosion resistance and is equipped with a magnet (-S) for use with AirTAC CMSE reed and DMSE electronic sensors. The extruded aluminum barrel features sensor grooves on both sides, and the rear adjuster acts strictly as a travel stop to decelerate the load, not as a lock. For holding loads without live air, consider the SAIL or BSAI series.
Airtac SAIJ125 Adjustable Cylinder SAIJ125AX40-20S Technical Specifications
| Model | Airtac SAIJ125 Adjustable Cylinder SAIJ125AX40-20S |
|---|---|
| Series | SAI ISO 15552 profile cylinder |
| Bore size | Ø125 mm |
| Stroke | 40 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 SAIJ125AX40-20S
| SAI | ISO 15552 profile-barrel cylinder series. |
|---|---|
| 125 | Bore size in mm. |
| ×40 | 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 SAIJ125AX40-20S Is Used
Machine Changeover
Dial in the 20-40 mm travel window during product size transitions without swapping cylinders or bolting on external stops.
Heavy Duty Clamping
Leverage 6136 N of push force at 0.5 MPa to secure heavy workpieces, using the rear adjuster to set the exact clamp position.
Variable End Stops
Fine-tune the retract end-position on automated assembly lines, using the rear screw to trim the 40 mm stroke by up to 20 mm.
Is the Airtac SAIJ125 Adjustable Cylinder SAIJ125AX40-20S the Right Cylinder?
Choose this 125 mm bore when you need substantial thrust—6136 N push at 0.5 MPa or 8590 N at 0.7 MPa. If your application requires less force, stepping down to a 100 mm bore yields 3927 N push at 0.5 MPa, whereas a 160 mm bore offers 10053 N for heavier loads. The adjustable stroke is selected over a fixed SAI model when machine setups require variable end-stops or product-size changeovers. The rear screw fine-tunes the travel end without external hardware.
When replacing an ISO 15552 cylinder, match the 125 mm bore, 40 mm stroke, 20 mm adjustment, PT tapered port thread, and the -S magnet. The SAIJ mounting set includes Basic, FA, LB, TC, FTC, TCM1, and TCM2, omitting FB, CA, CB, and CR. Because the nominal stroke is under 300 mm, side-load risks are lower, but external guides are still recommended for heavy radial loads.
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 SAIJ125AX40-20S FAQ
At 0.5 MPa operating pressure, this 125 mm bore cylinder provides 6136 N of push force and 5734 N of pull force. At 0.7 MPa, the push force increases to 8590 N.
The rear adjuster acts as a travel stop that lets you trim the 40 mm nominal stroke back by up to 20 mm, creating a 20 to 40 mm usable travel window. It sets the end position but does not lock the load without live air pressure.
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