Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20
The AirTAC Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20 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 MFJ40X80-20
Trimming the extend end by up to 20 mm on-site, the MFJ40X80-20 lets you set an exact 60 to 80 mm forward travel without buying a new cylinder or adding external stops. This JIS-standard round-body mini cylinder features a SUS304 stainless barrel and riveted aluminium covers, giving you a shorter overall mounting length than a comparable ISO 6432 unit while resisting mild washdown.
Built for double-acting air service at 0.15 to 1.0 MPa, the 40 mm bore uses a 1/4 inch port and a 16 mm rod to deliver 628.3 N of push force at 0.5 MPa. For sizing moving masses, expect a safe working load around 377 N, lifting about 32 kg vertically with a 2:1 margin. Note this SKU lacks the -S magnet, so it cannot host CMSG or DMSG sensors, and the fixed TPU bumpers only decelerate the stroke end.
Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20 Technical Specifications
| Model | Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20 |
|---|---|
| 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 MFJ40X80-20
| 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 MFJ40X80-20 Is Used
Changeover Stations
Dial in the 60 to 80 mm extend stroke during product changeovers to accommodate different part heights without machining new hard stops.
Trial Fit Rigs
Leverage the 628.3 N push force to seat components while trimming the forward travel by up to 20 mm to find the exact kinematic position.
Variable Position Stops
Use the external adjuster to set precise lower endpoints for pressing or locating tasks, relying on the fixed TPU bumpers for end deceleration.
Is the Airtac MFJ Adjustable Mini Cylinder MFJ40X80-20 the Right Cylinder?
When choosing between the two available bores, the MFJ40 delivers 628.3 N push at 0.5 MPa against the MFJ32 at 402.2 N, making this 40 mm version the right pick when you need to shift heavier jigs. The 20 mm adjustable window is ideal for trial fits and line changeovers where the exact end position is not yet finalised. You can fine-tune the extend stroke directly at the cylinder.
Mount this unit using LB foot, FA flange, or TC trunnion brackets, as there is no SDB or back-cover option. Remember that the external adjuster sets the end position but does not lock mid-stroke; if air pressure drops, the piston drifts, so fit an external rod lock or pilot check valve to hold a suspended load. To add sensing later, switch to the -S magnet variant.
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 MFJ40X80-20 FAQ
This 40 mm bore double-acting cylinder uses a 1/4 inch port and a 16 mm rod with an M14x1.5 male thread. It generates 628.3 N push and 527.8 N pull at 0.5 MPa, 879.6 N push and 738.9 N pull at 0.7 MPa, with a theoretical maximum of 128.1 kgf at 1.0 MPa.
The external adjuster shortens the extend stroke by up to 20 mm on-site, giving a usable 60 to 80 mm forward travel while retract remains full. It uses fixed TPU bumper pads to decelerate the stroke end, not an adjustable air cushion. This SKU has no -S magnet, so it cannot accept CMSG or DMSG sensors.
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