Airtac SAIJ125 Adjustable Cylinder SAIJ125AX850-20S
The AirTAC Airtac SAIJ125 Adjustable Cylinder SAIJ125AX850-20S is a genuine double-acting ISO 15552 profile-barrel air cylinder with a Ø125mm bore and 850mm 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
- Stroke850 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2
- CushionAdjustable, 40 mm
About the Airtac SAIJ125 Adjustable Cylinder SAIJ125AX850-20S
The AirTAC SAIJ125X850-20-S is a double-acting, single-rod ISO 15552 profile cylinder equipped with a rear stroke adjuster. It delivers 6136N of push force and 5734N of pull force at 0.5 MPa, making it suitable for heavy-duty handling. The integrated rear stopper screw allows you to trim the nominal 850 mm stroke back by up to 20 mm, creating a precise 830-850 mm usable travel window for fine-tuning end positions during commissioning.
This variant features a SUS420J2 stainless steel rod (code A) for improved corrosion resistance and includes a magnet (-S) for use with AirTAC CMSE reed and DMSE electronic sensors. The extruded aluminum barrel includes sensor grooves on both sides, and the unit operates at speeds of 30-500 mm/s with PT tapered G1/2 ports.
Airtac SAIJ125 Adjustable Cylinder SAIJ125AX850-20S Technical Specifications
| Model | Airtac SAIJ125 Adjustable Cylinder SAIJ125AX850-20S |
|---|---|
| Series | SAI ISO 15552 profile cylinder |
| Bore size | Ø125 mm |
| Stroke | 850 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 SAIJ125AX850-20S
| SAI | ISO 15552 profile-barrel cylinder series. |
|---|---|
| 125 | Bore size in mm. |
| ×850 | 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 SAIJ125AX850-20S Is Used
Variable End-Stop Positioning
Dial in the exact 830 to 850 mm retract distance during machine setup to accommodate different product lengths without adding external physical stops.
Heavy-Duty Changeover
Leverage 6136N of thrust at 0.5 MPa to push heavy pallets or assemblies, adjusting the rear stopper screw quickly when switching production runs.
Corrosion-Resistant Actuation
Utilize the SUS420J2 stainless steel rod in humid manufacturing environments where standard carbon steel rods might degrade over time.
Is the Airtac SAIJ125 Adjustable Cylinder SAIJ125AX850-20S the Right Cylinder?
Choose this 125 mm bore when 80 mm falls short (the 80 mm bore yields 2513N push at 0.5 MPa) or when 100 mm is insufficient (providing 3927N). An adjustable stroke is preferred over a fixed SAI cylinder when you need variable end-stops to accommodate product-size changes on a line without physically swapping components. For any stroke of 850 mm, the long unsupported piston rod demands an external guide to prevent excessive side-loading and premature seal wear.
When matching this for an ISO 15552 replacement, verify the 850 mm stroke, 20 mm adjustment range, PT G1/2 port thread, and the -S magnet requirement. The rear adjuster acts strictly as a travel stop and does not hold the load without live air pressure; for true fail-safe load holding, select the SAIL or BSAI series instead. The SAIJ mounting set includes Basic, FA, LB, TC, FTC, TCM1, and TCM2, deliberately omitting FB, CA, CB, and CR.
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 SAIJ125AX850-20S FAQ
At 0.5 MPa operating pressure, this 125 mm bore cylinder provides 6136N of push force and 5734N of pull force. It can reach a maximum thrust of 1251 kgf at 1.0 MPa.
The rear stopper screw lets you shorten the 850 mm nominal stroke by up to 20 mm, providing an adjustable travel window between 830 mm and 850 mm to fine-tune the end position without replacing the cylinder.
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