Airtac SEJ Adjustable Cylinder SEJ40X300-50
The AirTAC Airtac SEJ Adjustable Cylinder SEJ40X300-50 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 50mm window, so this Ø40mm unit covers an effective stroke of 250–300mm without changing cylinders. Force is equal in both directions.
- BoreØ40 mm
- Nominal stroke300 mm
- Adjust window50 mm
- Effective stroke250–300 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 SEJ40X300-50
The AirTAC SEJ40X300-50 is a double-acting, double-rod ISO 15552 profile cylinder featuring a 50 mm adjustable stroke window. A rod exits both ends, meaning the annulus area is identical in both directions. This yields an equal output force of 528 N each way at 0.5 MPa, preventing speed discrepancies between extend and retract motions.
You can dial the retract end-position up to 50 mm, setting an effective stroke range of 250 to 300 mm. A stop screw on the back rod lets you fine-tune the end position on the machine without changing hardware. The extruded aluminum barrel contains no external tie rods, and this unit ships without a magnet, so it will not support CMSE or DMSE position sensors.
Airtac SEJ Adjustable Cylinder SEJ40X300-50 Technical Specifications
| Model | Airtac SEJ Adjustable Cylinder SEJ40X300-50 |
|---|---|
| Series | SEJ ISO 15552 adjustable-stroke cylinder |
| Bore size | Ø40 mm |
| Nominal stroke | 300 mm |
| Adjustment window | 50 mm (250–300 mm) |
| Configuration | Double rod, double acting |
| Port size | PT1/4 |
| Rod thread | M12×1.25 |
|---|---|
| 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 50mm window. Port options: PT (standard) / G (BSPP).
Theoretical Output Force (Ø40mm)
| Pressure | Force (both directions) |
|---|---|
| 0.5 MPa | 528 N |
| 0.7 MPa | 739 N |
| Max (@1.0 MPa) | 108 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 SEJ40X300-50
| SEJ | ISO 15552 double-rod double-acting cylinder with adjustable stroke. |
|---|---|
| 40 | Bore size in mm. |
| ×300 | Nominal stroke length in mm. |
| -50 | 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 SEJ40X300-50 Is Used
Multi-Height Pallet Stops
Dial in the 250-300 mm stroke to stop pallets of varying heights on a conveyor, using the 528 N both-way force to halt loads consistently without speed mismatch.
Machine Commissioning
Fine-tune the exact end position during equipment setup; the 50 mm back-rod stop screw lets you find the perfect contact point without machining custom spacers.
Quick Part Changeover
Adjust the retract distance on the fly when switching a packaging line to a different box size, locking the screw once the new 250-300 mm position is set.
Is the Airtac SEJ Adjustable Cylinder SEJ40X300-50 the Right Cylinder?
This 50 mm adjustment window is ideal for commissioning a machine when the exact end stop is unknown, covering an effective 250-300 mm range. If you need less force, the adjacent 32 mm bore provides 345 N at 0.5 MPa both ways; if your load is heavier, step up to the 50 mm bore for 825 N both ways. If you do not need variable stops, a fixed-stroke SED cylinder is simpler.
Because the nominal stroke is 300 mm, use external guide rails to support the rod and prevent side-load damage. Remember that a plain SEJ does not hold position on air loss; the adjustable air cushion at both ends only decelerates near stroke end. For fail-safe holding, use an external rod lock. This ISO 15552 cylinder matches standard bore, port PT1/4, and mounting dimensions (Basic, FA, LB, TC, FTC, TCM1, TCM2) for direct interchangeability.
Quick checklist
- ✓ Need on-machine stroke fine-tuning?
- ✓ Adjustment window (50mm) 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 50mm 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 SEJ40X300-50 FAQ
A stop screw on the back rod mechanically shortens the retract stroke over a 50 mm window. You can dial the effective stroke anywhere from 250 mm up to the full 300 mm, then lock it in place.
Because the rod exits both ends, force is equal in both directions: 528 N at 0.5 MPa, 739 N at 0.7 MPa, and a maximum of 108 kgf at 1.0 MPa.
Authorized Export Seller
Genuine AirTAC parts produced by AirTAC factory.
1-Year Warranty
Covers non-human-caused product damage.
Fast Dispatch
Standard models are processed and dispatched in 3-5 business days.
Fast Reply
Most inquiries answered within 7-8 hours.
Related AirTAC SEJ Cylinders
Request a Quote for Airtac SEJ Adjustable Cylinder SEJ40X300-50
Send us the quantity and destination. We confirm price, stock and lead time — usually within 7-8 hours.