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Our Technologies
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Our Technologies

Materials, discoveries and basic principles of our present technologies discover more
 

Permanent Magnets

A permanent magnetic chuck is simply activated and deactivated mechanically.
The magnets are always active inside the chuck. However the magnetic flux stays locked inside the chuck when it is deactivated.

When activated, the magnetic flux
is locked into the part that is worked.
The hold is then secure :

When deactivated, the Magnetic Flux
is locked inside the chuck.
The part is now free, for removal :


Electromagnets

When applying a continuous electrical current to a steel conductor, a magnetic field is created :

We can reverse the magnetic field by switching the polarity on the coil :


The magnetic field is generated by the activated coil. By sending continuous current, the inductor (the part that is being coiled) wraps itself in a magnetic field.

No current goes through the coil,
So there is no magnetic field and the part is free :

When sending a continuous current to the coil,
We create a magnetic field and the part is held :


Electro-permanent

Full demagnetization system
The ALNICO magnet is inactive.
It is not at all magnetized :

By sending a continuous electrical pulse
to the coil.
The part is then magnetized and held firmly :



Compensated System
The magnetic flux locks itself inside the chuck
And the part is released and free :

By sending an electrical pulse to the coil. We change the magnetic direction of the ALNICO magnet. This allows the magnetic flux to go through the part itself. The part is then held.
To release the part, we send an inverted electrical pulse
To the coil that enables the polar direction to change :
 
Matériaux, découvertes et principes fondamentaux de nos technologies actuelles
Eres   Discovery
Magnets used
for navigation

Discovery of new continents
- 1000
 
 
 0
 
1000
• Natural magnetic rocks (Fe3O4)
  Discovered in Minor Asia in the town of
  MAGNESIE a rock named magnétite.
• Discovery of Iron
• Iron is magnetized with of the magnétite
• Compass with floating needle
Navigation 1200 • First compasses
Study of electrostatics and magnetostatics 1600
 


1800
• 1st scientific study on magnets conducted by GILBERT
• 1st magnetic circuit (rock + steel) for experiences.
• Electrostatic studies
• Iron magnets
• VOLTA invents the battery
 
Dynamic electricity
 
1820
 
 
1850
• Relation between magnetism and electricity by OERSTED
  (the scientist that observed the deviation of the compass)
• The laws of electromagnetism. AMPERE (the genius that in 1 month will establish these laws)
• Motors and dynamos with magnets
Electrical Machines 1900 • Powerful Electro magnets
• Dynamo machines
• Industrialization of motors
All of these are found in electrical meters, telephones, ignition magnetos …
Development
of magnetic materials
1930
1938
 
1941
1970
1983
 
• Mishima (Japan) isotopic Molded alloys 58%fe – 30% Ni – 12% al : ALNICO
• England -Anisotropic molded alloys (Field treated- oriented magnets)
  50%fe – 24%co - 14%Ni – 8% Al
• Néel (France) Ferrite – Magnetic powder Industrialization by Philips (1955)
• Japan : Rare earth magnetic powder Samarium Cobalt (SmCo) very expensive
• Japan + USA –  Rare earth magnetic powder (without cobalt) high powered magnets
  Néodyme+fer+bore+praseodymium (NdFeB)
  Three types of magnets are used today

ALNICO

Iron – Cobalt – Nickel – Titanium – Aluminum
Silicon - Copper


Metallurgy process :
- Fusion of the components
- Shell molding
- Thermal homogenizing
- Thermal under field
- Stabilization revenue
- Machining - control - magnetization
Density : 7,5
Max temp : 550° C
Max induction: 12.800 G
Maximum coercivity: 650 Oe

 
ALNICO magnets have a high resistance to corrosion and to shocks. They can be used at high temperatures (up to 550°C) all while conserving an excellent stability. A high induction value and a low coercivity field make it especially great for applications that do not require a temporary magnetization/demagnetization (it is the only magnet that we can use for the fabrication of electro permanent lifters when we have demagnetize the magnet to release the part).


FERRITE

Iron oxide - Strontium carbonate - Binder

Metallurgy process :
- Mixing of powders
- Calcination at 130°
- Grinding in dry and humid temperatures
- Compression under field
- Sintering at 1300°
- Machining - control - magnetization
Density : 4,7
Max temp use : 250° C
Max induction : 4.000 G
Max coercivity field : 3.000 Oe


FERRITE magnets have an elevated resistance to corrosion and to the majority of chemical agents. It however is still sensitive to chocks. A low induction value and an elevated coercivity field. The magnets were used to fabricate the second generation of lifting magnets so that the magnetic force is the same throughout time. The down side to using this type of magnet comes from its weak induction value. To get strong lifting force, we must use more magnets so the lifting magnet is much larger and heavier. For example, a lifting magnet of 400kg weighs 54kg! (compared to only 32kg when using Alnico magnets).


NEODYMIUM

Neodymium – Iron - Boron

Metallurgy process :
- Fusion of constituents
- Grinding
- Compression under field
- Sintering at 1100°
- Thermal treatment
- Machining - Control – Magnetization   
Density : 7,3
Max temp use: 100° C
Max induction : 13.000 G
Max coercivity field : 12.000 Oe

 
This Magnet discovered in the 80’s will revolutionize the magnet world, due to it’s extremely high magnetic performances. It’s ratio of induction (force) to volume is amazing.
It’s resistance to corrosion is pretty weak so most applications will require a surface protection, a Nickel protection is applied to certain lifting magnets. These magnets are used to fabricate the last generation of permanent lifting magnets so that the magnetic force stays the same through time (high coercivity field) with the same lifting capacity with a ratio of force to volume can be divided by 3. For example, a lifting magnet of 400kg that weighs 54kg with ferrite magnets only weighs 10kg with neodymium magnets !
 A few magnetic principals

The magnetic flux always goes from the north pole to the south pole
The magnets with the same polarity are repelled by each other, and attract each other if they are opposite.
Ferromagnetic parts are the ones that conduct magnetic flux the best. The greatest resistance for the magnetic flux is air.
The magnetic flux lines must never cross each other.
Every flux line is closed, they have no beginning or end.

Knowing that the magnetic saturation of standard steel is at 16,000 Gauss, our job is to aim to get the max flux in the maximum surface to get as close as possible to 16,000 Gauss.   

We use several different terms when speaking of magnetic fields :
  • Gauss (G), multiples or submultiples
  • Tesla (T), multiples or submultiples
  • Amper per Meter (A/m), multiples or submultiples

You can easily go from one format to another using the conversion principals in this chart.
  Gauss Tesla Amper per Meter
  1G 0,1 mT 80 A/m
  1 mG 0,1 µT 0,08 A/m
  10 000 G 1 T 800 000 A/m
  1 mG 100 nT 80 m A/m
  10 mG 1 µT 0,8 A/m
  12,5 mG 1,25 µT 1 A/m
  1 Gauss = 1.000 milligauss (mG)
1 Tesla = 1.000 millitesla (mT)  = 1.000.000 microtesla (µT)  = 109 nanotesla (nT)
1 A/m = 1.000 milliamper/m (mA/m)