Airtac SAIJ40 Adjustable Cylinder SAIJ40BX55-20S
The AirTAC Airtac SAIJ40 Adjustable Cylinder SAIJ40BX55-20S is a genuine double-acting ISO 15552 profile-barrel air cylinder with a Ø40mm bore and 55mm stroke, G1/4 air ports and adjustable end cushioning. Its standardized mounting interface makes it a drop-in replacement for other ISO 15552 cylinders in automation lines.
- BoreØ40 mm
- Stroke55 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- CushionAdjustable, 30 mm
About the Airtac SAIJ40 Adjustable Cylinder SAIJ40BX55-20S
The AirTAC SAIJ40X55-20-S is a double-acting ISO 15552 profile cylinder equipped with a rear stroke adjuster, allowing you to dial back the nominal 55 mm travel by up to 20 mm for a precise 35-55 mm usable window. Built with a SUS304 stainless steel rod and a PT tapered port, it delivers 628 N of push force at 0.5 MPa. The integrated magnet supports position sensing via CMSE reed or DMSE electronic switches.
Because the external stopper acts solely as a travel end-limit and relies on the air cushion for deceleration, it does not hold the load without live air pressure. For secure load-holding without continuous air, an external rod lock or related SAIL pneumatic lock cylinder is required. This extruded aluminum profile unit omits FB and CA mounts, utilizing a reduced SAIJ mounting set of Basic, FA, LB, TC, FTC, TCM1, and TCM2.
Airtac SAIJ40 Adjustable Cylinder SAIJ40BX55-20S Technical Specifications
| Model | Airtac SAIJ40 Adjustable Cylinder SAIJ40BX55-20S |
|---|---|
| Series | SAI ISO 15552 profile cylinder |
| Bore size | Ø40 mm |
| Stroke | 55 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M12×1.25 |
| 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 – 800 mm/s |
| Cushion | Adjustable, 30 mm |
| Max stroke | Up to 1200 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 (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 kgf | |
Actual usable force is lower than theoretical due to friction and back-pressure. Size with a safety margin.
Model Code: Airtac SAIJ40 Adjustable Cylinder SAIJ40BX55-20S
| SAI | ISO 15552 profile-barrel cylinder series. |
|---|---|
| 40 | Bore size in mm. |
| ×55 | 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 SAIJ40 Adjustable Cylinder SAIJ40BX55-20S Is Used
Product Changeovers
Dial in the exact end-position from 35 to 55 mm during format size changes on a packaging line without changing the cylinder hardware.
Machine Setup
Fine-tune the retract distance during commissioning to perfectly seat parts, using the rear screw to avoid costly mechanical shimming.
Variable End Stops
Accommodate multiple product lengths on a single conveyor by adjusting the stroke window on the fly to meet varying process requirements.
Is the Airtac SAIJ40 Adjustable Cylinder SAIJ40BX55-20S the Right Cylinder?
Select this 40 mm bore when an application requires less thrust than the 50 mm variant (982 N push at 0.5 MPa) but more than the 32 mm bore (402 N). The adjustable 35-55 mm stroke is optimal for machine setups requiring frequent product-size changeovers, eliminating the need to physically swap cylinders or bolt on external stops. Ensure your setup specifies a 40 mm bore, 55 mm stroke, 20 mm adjustment, PT port thread, and the -S magnet.
If your process demands absolute position holding during a pressure loss, remember that this rear adjuster functions only as a stop, not a brake. You must integrate a pilot-operated check valve or explore the BSAI clamp-lock series for true mechanical holding power.
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 SAIJ40 Adjustable Cylinder SAIJ40BX55-20S FAQ
At 0.5 MPa operating pressure, this 40 mm bore cylinder provides 628 N of push force and 528 N of pull force. At a maximum 1.0 MPa, it can deliver up to 128 kgf.
The rear adjuster screw allows you to shorten the 55 mm nominal stroke by up to 20 mm, creating a usable travel window of 35-55 mm. This stopper only limits the travel end and does not lock the load without live air pressure.
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