Magnet-free linear motor
MMF4 / MMD Magnet-free Track Linear Motor Modules
Linear motor and stage modules with the magnets in the moving forcer and a passive steel track, giving low EMI, low attraction and cheap long travel.
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- 1Products
- 2Performance
- 3Environment
- 4Volumes
- 5Your spec
What are you specifying?
Select everything you need. A motor, drive and gearbox can be specified together as one axis.
Key specifications
| Peak force (max) | 1,124 N |
|---|---|
| Continuous force (max) | 456 N |
| Stroke (max) | 3,000 mm |
Series ranges as published; individual models vary. The full datasheet, drawings and CAD models are available on request.
Options
- Stand-alone motor or module
- Base widths 90/130/140/175/210 mm
- Repeatability grades +/-3, +/-2, +/-1 um
- Integrated high-resolution encoders
Typical applications
What a magnet-free linear motor is
A magnet-free linear motor places its magnets and coils in the moving forcer and runs over a passive toothed steel track with no magnets in it. The forcer switches flux through the steel teeth to produce thrust, similar to flux-switching or reluctance principles. Because the track is just shaped steel, it is cheap per metre, does not attract ferrous debris the way a magnet track does and produces little stray field along the stroke. Feedback comes from an encoder.
When engineers choose a magnet-free linear motor
Choose a magnet-free design for long strokes where magnet track cost would dominate, and for areas where an exposed magnet track would be a problem, such as metal swarf, medical or electronics environments. The trade-offs are force density and attraction: performance per size is typically lower than a conventional iron-core motor, and an attraction force still acts between forcer and steel track. Check that cost savings on track outweigh any larger forcer.
How to specify the MMF4 / MMD Magnet-free Track Linear Motor Modules
Send these with your enquiry and an engineer can confirm the right MMF4 / MMD Magnet-free Track Linear Motor Modules variant:
- Stroke (m) and number of forcers
- Peak and continuous force (N)
- Speed and acceleration (m/s, m/s²)
- Attraction force and guide capacity (N)
- Positioning accuracy (µm)
- Environment: swarf, cleanliness, EMI limits
- Drive and encoder compatibility
Common mistakes to avoid
- Assuming no magnets in the track means no attraction force
- Not checking drive compatibility with this motor type
- Comparing on force alone without cost per metre of stroke
- Ignoring encoder choice on very long strokes
MMF4 / MMD Magnet-free Track Linear Motor Modules: frequently asked questions
Can you help replace MMF4 / MMD Magnet-free Track Linear Motor Modules or source the original?
Send the full model code, quantity and required date. Our engineers can check original-part availability and assess suitable alternatives, including supply-network options where appropriate. We confirm compatibility and any changes needed before recommending a replacement.
What is the MMF4 / MMD Magnet-free Track Linear Motor Modules?
Linear motor and stage modules with the magnets in the moving forcer and a passive steel track, giving low EMI, low attraction and cheap long travel. Published series figures include peak force 1,124 N, continuous force 456 N, stroke 3,000 mm. It is available through our supply network, and our engineers can confirm the right variant for your application.
Who makes the MMF4 / MMD Magnet-free Track Linear Motor Modules?
The MMF4 / MMD Magnet-free Track Linear Motor Modules is part of a range available through our supply network. Send us your requirement for pricing, lead time, datasheets and CAD.
What is the peak force of the MMF4 / MMD Magnet-free Track Linear Motor Modules?
The published series maximum peak force is 1,124 N. Individual models and sizes in the MMF4 / MMD Magnet-free Track Linear Motor Modules range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
How does a magnet-free linear motor work?
The forcer carries both coils and magnets, and the track is a passive toothed steel bar. Switching current in the forcer coils changes how flux flows through the teeth, producing thrust along the track. Because the track contains no magnets, it is cheaper for long strokes and does not hold onto magnetic debris.
What are the advantages of a passive steel track?
A passive steel track costs less per metre than a magnet track, so long strokes become more economical. It also does not attract ferrous swarf or create strong stray fields along the axis, which helps in machining, medical and electronics environments. The track still needs keeping clean and straight.
Further reading: How to select a linear motor · Linear actuators
Often compared with
Engineers specifying this series often compare it with:
Engineer support
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How it works
From enquiry to delivery
Send a part number or describe the application. Our engineers take it from there: the right product, a clear quotation, and delivery and support arranged.
- 01Tell us what you needSend a part number, or configure the application, quantities and timing.
- 02An engineer reviews itWe check the specification and find the original part, a checked equivalent or a complete axis.
- 03Receive your quotationProducts, pricing, lead time and compatibility notes in one reply.
- 04Order and deliveryWhen you are happy, the order is placed and delivery and after-sales support are arranged.