ring / tube magnet radially oriented

[ballaouey]

I'm looking for a supplier (or manufacturer) with magnet ring / tubes radially oriented,
that would have this kind of item in current dimensions in they catalog or at least in some usual dimensions.
it does not bother me to adapt my design.
I first need to make some prototypes and validation tests.
I do not have amounts at the moment, and I do not want to buy a specific mold.

 

[MagMike]

Isotropic materials such as Ceramic 1 or Alnico 2 can easily be magnetized radially.
Bonded NdFeB materials can also be magnetized radially, but the magnetizing fixturing is more complicated.

This isn't a sales website. Can you describe more about your application or at least provide rough dimensions and/or performance requirements (please do not say 'as strong as possible')? Then it would be possible to evaluate feasibility.

 

[EdStainless]

Even some oriented grades of Ferrite and Alnico can be made with radial orientation, however these tend to be custom configurations.
The tradeoff is strength vs cost.
If you need high strength you can build rings out of RE segments, but these are very expensive.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[ballaouey]

The application is to do a voice coil linear actuator to move a total mass ( without the mobile actuator mass) of 60g , for a total stoke af 1.2mm going 0.5ms from 0 to 1.2mm position and 0.5ms reversing .

The application is to do a voice coil linear actuator to move a total mass ( without the mobile actuator mass) of 60g , for a total stroke of 1.2mm going during 0.5ms from 0 to 1.2mm position and the same time 0.5ms reversing .

I've calculated that for a total mass of 104g ( adding just a copper coil of 44.2g to the mobile mass ) I need 500N for a mouvement with constant accélaration during 0.5ms to go from 0 to 1.2mm.
I look the BEI Kimco LA16-16-000A but even with overvoltage for driving it,it's difficult to expect more than 200N.
so I thought to have a better Force/cooper mass ratio with a radial magnetic field longest with a biggest number of turn winding on it, to have a strongest Laplace-Lorentz's force resultant.

NeFeB seems to be good , but I can't find pieces for prototyping and make more spécific calculation.
I don't want more than the N48 for NeFeB because is very difficult to produce , so I don't expect more than that
but even N31 is difficult to found
I've estimated for me a inner diameter of 35mm and 20mm high is already interestinge, outer diameter depending of the demagnetisation of the material
so it's not a criteria

the problem is to have some parts with approximatively this dimensions

regards

 

[EdStainless]

If you can afford a bit larger assembly and more fixed weight then look at building magnetic circuit using an axially oriented magnet.
A cup with the magnet in the center and a pole piece on the magnet will create a very high field in the air gap between the edges of the cut and the pole piece.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[ballaouey]

Thank you EdStainless
I thought to this version, as the magnetic circuit speakers are made, it is not optimal for the outside diameter, it's biggest than that for the solution of the radial magnet magnetized.

In fact, my load must be under the linear motor voice coil , ( this one is moving horizontaly ), so biggest is the diameter footprint , more the offset of the inertial center have to be studied with the guidance means (and more fragile the mechanical parts are ), bigger must be the mobile mass, ans so on ..

this is my ultimate solution if I can't do otherwise
I thought to put some magnetics cup circuit like that serially , with an shaft in the center of the pole piece , joining coils on the cups, to minimize the outer diameter with approx. the same dynamic than a big 'pancake'.

build rings with magnetics segments worries me for repeatability disparity and the radial field leakage between the segment, it seems difficult to have something that I can trust
In the end I need 200 voice coil actuator per year if it's work well, so the magnet must have the same caracteristic more or less for each one.

So my first step is to see the 'state of the art' if I can afford a radially magnetised tube or not.

 

[sreid]

Take a look at linear shaft motors such as

http://www.nipponpulse.com/products/overview/linear-shaft-servomotors