Airtac SEJ Adjustable Cylinder SEJ125X90-40S
The AirTAC Airtac SEJ Adjustable Cylinder SEJ125X90-40S 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 40mm window, so this Ø125mm unit covers an effective stroke of 50–90mm without changing cylinders. Force is equal in both directions.
- BoreØ125 mm
- Nominal stroke90 mm
- Adjust window40 mm
- Effective stroke50–90 mm
- Port sizePT1/2
- CushionAdjustable, 40 mm
About the Airtac SEJ Adjustable Cylinder SEJ125X90-40S
The AirTAC SEJ125X90-40S is a double-acting, double-rod ISO 15552 profile cylinder. A rod exits both ends, yielding identical extend and retract forces of 5734 N each way at 0.5 MPa. The retract stroke is mechanically adjustable via a stop screw on the back rod over a 40 mm window, giving an effective stroke range of 50 to 90 mm.
This 125 mm bore pneumatic cylinder features a PT1/2 port, a 32 mm rod with an M27x2 thread, and a built-in magnet for CMSE or DMSE sensors. Field-adjustable air cushions at both ends decelerate the heavy 1169 kgf max load near stroke end without acting as a mechanical lock.
Airtac SEJ Adjustable Cylinder SEJ125X90-40S Technical Specifications
| Model | Airtac SEJ Adjustable Cylinder SEJ125X90-40S |
|---|---|
| Series | SEJ ISO 15552 adjustable-stroke cylinder |
| Bore size | Ø125 mm |
| Nominal stroke | 90 mm |
| Adjustment window | 40 mm (50–90 mm) |
| Configuration | Double rod, double acting |
| Port size | PT1/2 |
| Rod thread | M27×2 |
|---|---|
| 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 – 500 mm/s |
| Cushion | Adjustable, 40 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 40mm window. Port options: PT (standard) / G (BSPP).
Theoretical Output Force (Ø125mm)
| Pressure | Force (both directions) |
|---|---|
| 0.5 MPa | 5734 N |
| 0.7 MPa | 8027 N |
| Max (@1.0 MPa) | 1169 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 SEJ125X90-40S
| SEJ | ISO 15552 double-rod double-acting cylinder with adjustable stroke. |
|---|---|
| 125 | Bore size in mm. |
| ×90 | Nominal stroke length in mm. |
| -40 | 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 SEJ125X90-40S Is Used
Press Tonnage Calibration
Dial in the 50-90 mm retract stop to precisely set forming depth on heavy stamping presses, utilizing the 8028 N both-way force at 0.7 MPa for consistent high-tonnage actuation.
Pallet Size Changeover
Adjust the mechanical end position on the fly when switching between different pallet heights in automated material handling, leveraging the equal push/pull force to maintain stability.
Heavy Fixture Clamping
Fine-tune clamping reach during machine commissioning on large machining centers, using the 40 mm window to match the stop precisely without swapping out the 125 mm bore hardware.
Is the Airtac SEJ Adjustable Cylinder SEJ125X90-40S the Right Cylinder?
Verify the 40 mm adjustment window covers your required end-position range. If 5734 N at 0.5 MPa is excessive, step down to the 80 mm bore which provides 2268 N both ways; if you need more, note 125 mm is the largest in this series. If the exact end position is fixed and never changes, a standard SED double-rod cylinder suffices. For variable stops during changeover, this SEJ is ideal.
A plain SEJ does not hold position on air loss; the stop screw and cushion only set the mechanical end and decelerate. For fail-safe holding, use an external rod lock. When replacing an ISO 15552 unit, match the 90 mm stroke, 40 mm window, PT1/2 port, and mounting choice (Basic, FA, LB, TC, FTC, TCM1, or TCM2).
Quick checklist
- ✓ Need on-machine stroke fine-tuning?
- ✓ Adjustment window (40mm) 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 40mm 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 SEJ125X90-40S FAQ
A stop screw on the rear rod mechanically shortens the retract stroke over a 40 mm window. You can dial the effective stroke anywhere from 50 mm up to the nominal 90 mm. Once set, you lock the screw in place for precise end-position control.
Because it is a double-rod cylinder, the force is identical in both directions: 5734 N at 0.5 MPa, 8028 N at 0.7 MPa, and a maximum of 1169 kgf at 1.0 MPa. The 125 mm bore operates at speeds of 30-500 mm/s.
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