Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-20S
The AirTAC Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-20S 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 SAIJ125X400-20S
The AirTAC SAIJ125X400-20-S is a double-acting ISO 15552 profile cylinder featuring a rear-mounted stroke adjuster. With a 400 mm nominal stroke and a 20 mm adjustment range, it provides a usable travel window of 380 to 400 mm. This built-in adjustability allows you to fine-tune the retract end-position at commissioning without adding external stops or swapping the cylinder. It delivers substantial thrust, generating 6136 N of push force and 5734 N of pull force at 0.5 MPa.
Equipped with a -S magnet, this model integrates seamlessly with AirTAC CMSE reed and DMSE electronic solid-state sensors housed in the dual-side sensor grooves. The extruded aluminum barrel design omits tie-rods, and the mounting set is limited to Basic, FA, LB, TC, FTC, TCM1, and TCM2. The 32 mm carbon steel rod and M27x2 thread provide robust load-bearing capability, while the PT tapered ports ensure a reliable pneumatic seal.
Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-20S Technical Specifications
| Model | Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-20S |
|---|---|
| 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 SAIJ125X400-20S
| 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 SAIJ125X400-20S Is Used
Machine Changeover
Dial in the exact retract position within the 380-400 mm window during product size changes without physically swapping cylinders or repositioning external stop blocks.
Variable End-Stop Positioning
Fine-tune the end-of-stroke location on diverter mechanisms by up to 20 mm at commissioning to perfectly synchronize with downstream conveyor feeds.
Heavy Assembly Pressing
Leverage the 6136 N push force at 0.5 MPa to seat heavy components, using the rear adjuster to set precise pressing depth limits for varying batch dimensions.
Is the Airtac SAIJ125 Adjustable Cylinder SAIJ125X400-20S the Right Cylinder?
Choose this 125 mm bore cylinder when a 100 mm bore (offering 3927 N push at 0.5 MPa) lacks the necessary force, but a 160 mm bore (10053 N push at 0.5 MPa) would be excessive. The adjustable stroke is ideal for product changeovers on a line, allowing the retract end-stop to be dialed back by up to 20 mm without mechanical modifications. When replacing an ISO 15552 cylinder, match the 125 mm bore, 400 mm stroke, 20 mm adjustment, PT port thread, and the -S magnet requirement.
Because the total stroke is 400 mm, the long unsupported rod is susceptible to side-loading; an external guide rail should be used to prevent premature seal wear. Note that the rear adjuster acts only as a travel stop and does not hold the load without live air. For dead-load holding, consider the SAIL (air-released lock) or BSAI (clamp-lock) variants.
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 SAIJ125X400-20S FAQ
At a 0.5 MPa operating pressure, this 125 mm bore cylinder generates 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 screw allows you to shorten the effective travel by up to 20 mm. This creates a 380 to 400 mm usable stroke window, enabling fine-tuning of the end position without changing the cylinder.
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