Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X250-20S
The AirTAC Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X250-20S is a genuine double acting, adjustable stroke ISO 21287 compact air cylinder with a Ø125mm bore and 250mm stroke, 1/4" air ports and a hard-anodized aluminium body. Its short compact envelope saves about 50% of the mounting length of an ISO 15552 profile cylinder.
- BoreØ125 mm
- Stroke250 mm
- Port size1/4"
- Acting typeDouble acting, adjustable stroke
- Rod threadM16×2.0
- CushionFixed TPU bumper (both ends)
- 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 ACEJ125 Adjustable Compact Cylinder ACEJ125X250-20S
The ACEJ125X250-20S is a double acting, adjustable-stroke compact cylinder built to ISO 21287: a 125 mm bore with a 250 mm stroke, a 25 mm hard-chrome S45C rod and a 1/4" PT port. At 0.5 MPa it pushes 6135.9 N and pulls 5890.5 N, rising to 8590.3 N push at 0.7 MPa, with a theoretical ceiling of 1251.4 kgf at 1.0 MPa. The -20 code adds an external stop screw that trims the extend stroke anywhere in a 20 mm window, so the usable extend range is 230-250 mm set on site without disassembly.
The hard-anodized aluminium body saves about 50% of the mounting length of an ISO 15552 profile cylinder, which matters when a 6 kN press or clamp must fit inside a tight weld cell or gantry. As a planning figure, budget roughly 3680 N of real work at 0.5 MPa (about 60% of the push rating), which is around 375 kg of vertical lift with a 2:1 margin. The -S magnet is fitted on this model, so CMSE / DMSE reed or solid-state switches can be clipped on for end-of-stroke signalling. Speed range is 30-500 mm/s over 0.15-1.0 MPa (22-145 psi).
Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X250-20S Technical Specifications
| Model | Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X250-20S |
|---|---|
| Series | ACEJ compact cylinder |
| Standard | ISO 21287 |
| Bore size | Ø125 mm |
| Stroke | 250 mm |
| Acting type | Double acting, adjustable stroke |
| Port size | 1/4" |
| Rod thread | M16×2.0 |
| 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 – 500 mm/s |
| Cushion | Fixed TPU bumper (both ends) |
| Max standard stroke | Up to 300 mm |
Specifications follow the official AirTAC ACE-series (ISO 21287) datasheet. Body: hard-anodized aluminium alloy; piston rod: S45C carbon steel with hard-chrome plating. Rod type: female thread (blank) or male thread (B). Thread options: PT (blank) / G. A built-in magnet is OPTIONAL — add the -S code to fit CMSE / DMSE position sensors.
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5890 N |
| 0.7 MPa | 8590 N | 8247 N |
| Max (@1.0 MPa) | 1251 kgf | |
Actual usable force is lower than theoretical due to friction and back-pressure. Size with a safety margin.
Model Code: Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X250-20S
| ACEJ | ISO 21287 compact cylinder (adjustable-stroke). |
|---|---|
| 125 | Bore size in mm. |
| ×250 | Stroke length in mm. |
| -20 | Adjustable stroke window (mm the extend stroke can be shortened on site). |
| S | Optional built-in magnet for CMSE / DMSE sensors (omit for no magnet). |
| B | Rod type: B = male thread; blank = female thread. |
ACE-family variants: ACE (double acting), ASE / ATE (single acting push / pull), ACED (double rod), ACEJ (adjustable stroke), TACE / TACED (non-rotating twin-guide yoke). Mounting accessories: FA / FB flange, LB foot, CA / CB clevis, CR, SDB pivot, FTC; plus I and Y knuckles. Thread PT (blank) / G.
Where the Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X250-20S Is Used
Heavy fixture clamping in machining cells
With 6135.9 N push at 0.5 MPa, the 125 mm bore clamps large castings or weldments in CNC fixtures, and the 20 mm adjustment window lets the setter dial the extend stroke between 230 and 250 mm to match part height.
Short-stroke press and forming stations
The compact body, roughly half the mounting length of an ISO 15552 profile cylinder, slots into stamping or marking heads where a 250 mm stroke and about 375 kg of practical vertical lift cover the part weight with margin.
Pallet and container ejection on packaging lines
Pull force of 5890.5 N at 0.5 MPa handles heavy tray or pallet push-off arms, while the fitted -S magnet with CMSE / DMSE switches confirms home and extended positions to the line PLC.
Is the Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X250-20S the Right Cylinder?
At this bore you are at the top of the ACEJ range: the next size down, the 100 mm bore, still delivers 3927.0 N push at 0.5 MPa and may suit lighter clamping, while there is no larger compact bore, so jobs needing more than about 6135.9 N at 0.5 MPa should move to a different cylinder family. Confirm exact envelope dimensions from the datasheet before laying out the fixture. The stop screw is a mechanical end stop for the extend stroke only; it does not lock the piston mid-stroke, and on air loss the rod will drift, so add a separate holding valve if the load must stay put. FA flange or LB foot mounts bolt to the ISO 21287 face, and the fitted -S magnet accepts CMSE / DMSE switches.
Quick checklist
- ✓ Required force at your working pressure
- ✓ Short stroke fits the compact body
- ✓ Port/thread type (PT / G)
- ✓ Add -S if you need the magnet for sensors
- ✓ Rod type (female / male B) & mount (FA/LB/CA)
Installation & Maintenance Notes
- check Use clean air filtered to 40µm or finer.
- check Keep within 0.15 – 1.0 MPa operating pressure.
- check Compact body: keep the stroke short and avoid side load on the rod.
- check Do not dismantle the threaded front/back covers.
- check Keep speed within the rated range; the TPU bumper absorbs stroke-end energy.
- check Installation by qualified personnel per AirTAC docs.
Airtac ACEJ125 Adjustable Compact Cylinder ACEJ125X250-20S FAQ
At 0.5 MPa the cylinder pushes 6135.9 N and pulls 5890.5 N; at 0.7 MPa those rise to 8590.3 N push and 8246.7 N pull, with a theoretical maximum of 1251.4 kgf at 1.0 MPa. The -20 code means an external stop screw shortens the 250 mm extend stroke by up to 20 mm, giving an on-site range of 230-250 mm. It is a double acting cylinder running on air filtered to 40 um at 0.15-1.0 MPa (22-145 psi), proof pressure 1.5 MPa (215 psi), speed 30-500 mm/s, temperature -20 to +70 C.
It is an ISO 21287 compact cylinder whose hard-anodized aluminium body saves about 50% of the mounting length of an ISO 15552 profile cylinder, with a fixed TPU bumper at each end absorbing end-of-stroke energy. Because the -S magnet is fitted on this model, CMSE / DMSE reed or solid-state switches can be mounted directly in the body slots for position feedback. FA flange and LB foot mounts attach to the standard ISO 21287 face, and the rod end carries a female M16x2.0 thread with a 1/4" PT port.
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