Airtac SEJ Adjustable Cylinder SEJ50BX125-30S
The AirTAC SEJ Adjustable Cylinder SEJ50BX125-30S 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 30mm window, so this Ø50mm unit covers an effective stroke of 95–125mm without changing cylinders. Force is equal in both directions.
- BoreØ50 mm
- Nominal stroke125 mm
- Adjust window30 mm
- Effective stroke95–125 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 SEJ50BX125-30S
The AirTAC SEJ50BX125-30S is a double-acting, double-rod ISO 15552 profile cylinder featuring a SUS304 stainless steel rod on both ends for corrosion resistance. A stop screw on the back rod lets you dial the retract stroke over a 30mm window, giving an effective working range of 95-125mm. This mechanical adjustability is ideal for fine-tuning end positions directly on the machine during commissioning.
Because the rod exits both ends, the annulus area is symmetrical, delivering equal force and speed in both directions at 825N each way at 0.5MPa. The extruded aluminum barrel contains no external tie rods, and adjustable air cushions at both ends decelerate the load near stroke end.
Airtac SEJ Adjustable Cylinder SEJ50BX125-30S Technical Specifications
| Model | Airtac SEJ Adjustable Cylinder SEJ50BX125-30S |
|---|---|
| Series | SEJ ISO 15552 adjustable-stroke cylinder |
| Bore size | Ø50 mm |
| Nominal stroke | 125 mm |
| Adjustment window | 30 mm (95–125 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 30mm 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 SEJ50BX125-30S
| SEJ | ISO 15552 double-rod double-acting cylinder with adjustable stroke. |
|---|---|
| 50 | Bore size in mm. |
| ×125 | Nominal stroke length in mm. |
| -30 | 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 SEJ50BX125-30S Is Used
Packaging Machine Changeover
Dial in the 95-125mm retract stroke to match varying carton depths on a packaging line, using the 825N both-way force to securely push folding flaps without re-engineering the mounting block.
CNC Load-and-Unload Trial
Fine-tune the extraction distance of stainless steel parts from a machining cell, using the 30mm stop screw window to perfect the hand-off position during initial robot commissioning.
Is the Airtac SEJ Adjustable Cylinder SEJ50BX125-30S the Right Cylinder?
Verify the 30mm adjustment window covers your required positioning range. If 825N at 0.5MPa is excessive, stepping down to the 40mm bore drops output to 528N both ways; if you need more push, the 63mm bore raises it to 1402N. A fixed-stroke SED is sufficient if you never need to alter the end position after setup. For position holding on air loss, note this cylinder does not lock; use an external rod lock or BSED. To match this ISO 15552 replacement, confirm the 50mm bore, 125mm nominal stroke, PT1/4 port, and your required mounting (Basic, FA, LB, TC, FTC, TCM1, or TCM2). The built-in -S magnet supports CMSE reed and DMSE electronic sensors.
Quick checklist
- ✓ Need on-machine stroke fine-tuning?
- ✓ Adjustment window (30mm) 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 30mm 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 SEJ50BX125-30S FAQ
A mechanical stop screw on the rear rod lets you shorten the retract stroke by up to 30mm. This gives an effective stroke range of 95-125mm. You set the exact end position on the machine, then lock the screw in place.
Because it is a double-rod cylinder, force is identical in both directions: 825N at 0.5MPa, 1154N at 0.7MPa, and a maximum of 168kgf at 1.0MPa. It is dimensionally interchangeable per ISO 15552 and uses a PT1/4 port.
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