Airtac SEJ Adjustable Cylinder SEJ50X75-20FA
The AirTAC Airtac SEJ Adjustable Cylinder SEJ50X75-20FA is a genuine double-acting ISO 15552 double-rod cylinder with a mechanically ADJUSTABLE stroke: a back-rod stop screw lets you fine-tune the retract end over a 20mm window, so this Ø50mm unit covers an effective stroke of 55–75mm without changing cylinders. Force is equal in both directions.
- BoreØ50 mm
- Nominal stroke75 mm
- Adjust window20 mm
- Effective stroke55–75 mm
- Port sizePT1/4
- CushionAdjustable, 30 mm
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac SEJ Adjustable Cylinder SEJ50X75-20FA
The AirTAC SEJ50X75-20FA is a double-acting, double-rod ISO 15552 profile cylinder featuring a 20mm adjustable stroke window. A rod exits both ends, meaning the annulus area is identical in both directions. This delivers equal force and speed extending and retracting, providing 825 N each way at 0.5 MPa. You can dial the retract end from 55mm up to 75mm to perfectly match a mechanical stop.
A stop screw on the back rod mechanically shortens the retract stroke over that fixed 20mm window, which you lock after setting. The FA front-foot mounting bracket is included. This extruded aluminum barrel design omits external tie rods entirely, and the field-adjustable air cushions at both ends decelerate the load near stroke end without acting as a fail-safe lock.
Airtac SEJ Adjustable Cylinder SEJ50X75-20FA Technical Specifications
| Model | Airtac SEJ Adjustable Cylinder SEJ50X75-20FA |
|---|---|
| Series | SEJ ISO 15552 adjustable-stroke cylinder |
| Bore size | Ø50 mm |
| Nominal stroke | 75 mm |
| Adjustment window | 20 mm (55–75 mm) |
| Configuration | Double rod, double acting |
| Port size | PT1/4 |
| Rod thread | M16×1.5 |
|---|---|
| Operating pressure | 0.15 – 1.0 MPa |
| Proof pressure | 1.5 MPa |
| Temperature | -20 to +70 °C (0–150 °C with FKM seals) |
| Speed range | 30 – 800 mm/s |
| Cushion | Adjustable, 30 mm |
Specifications follow the official AirTAC SEJ datasheet and ISO 15552 / VDMA 24562 dimensions. The adjustment screw shortens the retract end only; do not exceed the 20mm window. Port options: PT (standard) / G (BSPP).
Theoretical Output Force (Ø50mm)
| Pressure | Force (both directions) |
|---|---|
| 0.5 MPa | 825 N |
| 0.7 MPa | 1155 N |
| Max (@1.0 MPa) | 168 kgf |
A rod exits both ends, so extend and retract force are identical. Actual usable force is lower than theoretical; size with a safety margin.
Model Code: Airtac SEJ Adjustable Cylinder SEJ50X75-20FA
| SEJ | ISO 15552 double-rod double-acting cylinder with adjustable stroke. |
|---|---|
| 50 | Bore size in mm. |
| ×75 | Nominal stroke length in mm. |
| -20 | Adjustment stroke window in mm (options: 10/20/30/40/50/75/100). |
| -S | Optional built-in magnet for CMSE / DMSE sensor sensing. |
Rod material: carbon steel (blank) / SUS420J2 (A) / SUS304 (B). Seals: TPU (blank) / FKM high-temp (H) / NBR (N). Thread: PT (blank) / G. Mounting (SEJ): Basic, LB, FA, TC, FTC, TCM1, TCM2. Related: SED (double rod, fixed stroke), SE (single rod).
Where the Airtac SEJ Adjustable Cylinder SEJ50X75-20FA Is Used
Packaging Flap Folding
Dial the 55-75mm retract stroke to fine-tune carton flap folding arms on the machine, using the equal 825N both-way force to positively push and pull the mechanism.
Quick Part Changeover
Adjust the back-rod stop screw to shift the end position when switching a conveyor line to a different product height, locking the 20mm window precisely without changing hardware.
Trial Spot Welding
Set the exact electrode touch position during commissioning of a 50mm bore welding fixture, relying on the adjustable stroke to find the optimal 55-75mm contact distance.
Is the Airtac SEJ Adjustable Cylinder SEJ50X75-20FA the Right Cylinder?
Verify the 20mm adjustment window covers your required end-position range; this FA-mounted unit dials the retract stroke from 55 to 75mm. If 825 N at 0.5 MPa is insufficient, stepping up to the 63mm bore yields 1402 N both ways, while dropping to the 32mm bore provides 345 N. If your machine never requires position changes, a fixed-stroke SED cylinder is enough. For fail-safe holding on air loss, use an external rod lock, as the cushion and stop screw only set the mechanical end.
When replacing an ISO 15552 cylinder, match the 50mm bore, 75mm nominal stroke, PT1/4 port, and FA mount. This SKU lacks a magnet, so it cannot carry CMSE or DMSE sensors without adding an -S option. Since the stroke is under 300mm, side-load stress is minimal, but external guides are still recommended for heavy lateral loads.
Quick checklist
- ✓ Need on-machine stroke fine-tuning?
- ✓ Adjustment window (20mm) covers your range
- ✓ Equal force both directions OK
- ✓ Port/thread type (PT/G)
- ✓ Magnet (-S) for CMSE/DMSE sensors?
Installation & Maintenance Notes
- check Use clean air filtered to 40µm or finer.
- check Keep within 0.15 – 1.0 MPa operating pressure.
- check Set the stop screw within the 20mm window; lock it after adjusting.
- check Adjust end cushion screws for smooth stops.
- check Use correct mounting accessory (LB/FA/TC/FTC/TCM1/TCM2).
- check Installation by qualified personnel per AirTAC docs.
Airtac SEJ Adjustable Cylinder SEJ50X75-20FA FAQ
A stop screw on the rear rod mechanically shortens the retract stroke over a 20mm window. You can dial the effective retract stroke from 55mm up to 75mm, then lock the screw in place to hold that exact end position.
Because the rod exits both ends, the force is equal in both directions. It generates 825 N at 0.5 MPa, 1154 N at 0.7 MPa, and a maximum of 168 kgf at 1.0 MPa.
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