Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20S
The AirTAC Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20S is a genuine double acting, adjustable stroke JIS-standard round-body mini air cylinder with a Ø40mm bore and 80mm stroke, 1/4" air ports and a SUS304 stainless-steel barrel for mildly corrosive environments. For the same bore and stroke it is shorter than an ISO 6432 cylinder, saving mounting space.
- BoreØ40 mm
- Stroke80 mm
- Port size1/4"
- Acting typeDouble acting, adjustable stroke
- Rod threadM14×1.5
- CushionFixed TPU bumper pads
About the Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20S
Trimming the extend stroke by up to 20 mm on site, the AirTAC MFJ40X80-20S lets you dial in the exact end position without buying a new cylinder or adding external stops. This JIS-standard round-body mini cylinder features a SUS304 stainless steel barrel and riveted aluminium covers, giving you a shorter mounting envelope than an ISO 6432 unit for the same 40 mm bore and 80 mm stroke. The integrated -S magnet enables CMSG, DMSG or EMSG switches for position sensing.
In the 40 mm bore class, this double-acting actuator delivers a robust 628.3 N push force at 0.5 MPa, making it suitable for moderate load moving. Derived from that 0.5 MPa push figure, it handles a safe working load of roughly 377 N, or lifts about 32 kg vertically with a 2:1 safety margin. It uses a 1/4" port, a 16 mm piston rod with an M14x1.5 male thread, and fixed TPU bumper pads to decelerate the stroke ends.
Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20S Technical Specifications
| Model | Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20S |
|---|---|
| Series | MFJ JIS mini cylinder |
| Bore size | Ø40 mm |
| Stroke | 80 mm |
| Acting type | Double acting, adjustable stroke |
| Port size | 1/4" |
| Rod thread | M14×1.5 |
| 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 – 800 mm/s |
| Cushion | Fixed TPU bumper pads |
| Max standard stroke | Up to 500 mm |
Specifications follow the official AirTAC MF/MFC (JIS-standard) datasheet. Barrel: SUS304 stainless steel; covers: aluminum alloy (round-body, riveted rolling-packed construction). Thread options: PT (blank) / G / NPT.
Theoretical Output Force (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | 739 N |
| Max (@1.0 MPa) | 128 kgf | |
Actual usable force is lower than theoretical due to friction and back-pressure. Size with a safety margin.
Model Code: Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20S
| MFJ | JIS-standard round-body mini cylinder (adjustable-stroke). |
|---|---|
| 40 | Bore size in mm. |
| ×80 | Stroke length in mm. |
| -S | Optional built-in magnet for CMSG / DMSG / EMSG sensors. |
MF-family variants: MF / MFC (double acting ±cushion), MSF / MTF (single acting push / pull), MFD / MFCD (double rod ±cushion), MFJ / MFCJ (adjustable stroke ±cushion). Back covers CA / U / CM. Mounting LB / FA / SDB / TC.
Where the Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20S Is Used
Changeover Stations
Fine-tune the extend position during product line changeovers by turning the external adjuster, saving setup time without swapping hardware.
Trial Fit Rigs
Dial in the exact end stop on prototype assembly rigs where the final kinematic position is unknown, using the 20 mm adjustment window.
Variable Position Stops
Act as an adjustable physical stop for medium-weight items, leveraging the 628.3 N push force to push parts accurately.
Is the Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20S the Right Cylinder?
When sizing these JIS-standard cylinders, compare the real thrust: the MFJ40 hits 628.3 N push and 527.8 N pull at 0.5 MPa, whereas the smaller MFJ32 provides 402.2 N push. Choose the 40 mm bore if your trial fits or changeover stations need that extra force. The external adjuster is perfect for line changeovers where the exact extend position is not final, letting you shorten the 80 mm stroke within its 60-80 mm usable window.
For mounting, select LB foot, FA flange or TC trunnion brackets (SDB and back-cover options are not available on this build). Remember that the bumper pads only decelerate the stroke end; they do not lock the piston. If your application must hold a load on air loss, add an external rod lock or pilot check valve.
Quick checklist
- ✓ Required force at your working pressure
- ✓ Stroke and mounting space
- ✓ Port/thread type (PT / G / NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Back cover (CA/U/CM) & mount (LB/FA/SDB/TC)
Installation & Maintenance Notes
- check Use clean air filtered to 40µm or finer.
- check Keep within 0.15 – 1.0 MPa operating pressure.
- check Avoid side load on the piston rod.
- check Do not dismantle the riveted front/back covers.
- check Use correct back cover (CA/U/CM) & mount (LB/FA/SDB/TC).
- check Installation by qualified personnel per AirTAC docs.
Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20S FAQ
This 40 mm bore, double-acting cylinder uses a 1/4" port and a 16 mm rod with an M14x1.5 thread. It generates 628.3 N push and 527.8 N pull at 0.5 MPa, or 879.6 N push and 738.9 N pull at 0.7 MPa. The theoretical maximum force is 128.1 kgf at 1.0 MPa, with an operating speed of 30-800 mm/s.
The external adjuster shortens the extend stroke by up to 20 mm on site, giving a usable extend range of 60-80 mm, while retract remains full stroke. The -S suffix means a piston magnet is built in for CMSG, DMSG or EMSG switches. Fixed TPU bumpers decelerate the stroke ends but do not function as a locking brake.
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