Home ::  Store News ::  Sunday 12 May, 2013

Powerful magnets is how to make out

by Administrator | post a comment

A drive motor for hybrid and electric vehicles, the Nd-Fe-B sintered magnet (neodymium - iron - boron) is an essential key member. Compared with the other magnet, neodymium magnet is not only a strong magnetic force, can achieve high power sufficient to drive the vehicle, but also, the motor can be reduced to a size suitable for a vehicle application.
Well, you know this NdFeB magnets is how to make out? It requires first containing the necessary material alloy is pulverized into fine particles, these particles together forming, and then sintered. Then cut to the desired size in order to complete. This process always feel like making a cake.
Of course, in the actual production of high quality NdFeB magnets is not so simple. Not only to the fine particle size of unified 3 ~ 5μm, but also pay attention to the uniformity in the shape, but also consider the sintering heating method, the need to spend a lot of effort to manufacture. By massive accumulation of small technology to reach today's practical level "(technical staff) in the development of neodymium magnets.
For example, the alloy is crushed to 3 to 5μm magnetic field forming process "is one of them. This step is to allow the orientation of a fine powder after pulverization (micro-magnets). The place orientation refers to the direction of magnetization of the micronized unified in a fixed direction, the higher the orientation, the greater the residual magnetic flux density (magnetic field strength indicator). The first embodiment this step micronized filled into a mold, applying a strong magnetic field on the micronized alignment, then the implementation of the pressure molding process. Which is unique in that the gentle pressure molding to the extent of the molded body does not collapse. Because the pressure is too large, then it will disrupt the hard-won unity of micronized orientation.
In order to achieve high alignment needed to create a uniform magnetic field space inside the mold, which is also very important. Due to the configuration of the electromagnet and the mold size, shape and material are the magnetic field is uneven, resulting in the deterioration of orientation, and therefore require the use of a magnetic field analysis by means of trimming, so that the magnetic field uniformity.

Rare earth magnets for fun and profit

by Administrator | post a comment

One can academically appreciate the fact that every electric motor in the world works because of magnetism. One can reflect on the fact that every transformer uses it, too. CRT monitors, TVs, brushless DC motors, power meters, modern welding gear and engine ignition timing systems, various vending machines and umpteen other gadgets use permanent magnets. And electromagnetism has a hand somewhere in making practically every other electronic device work.
To get a true, visceral appreciation for magnetism, though, you can't beat playing with magnets.

Really terrifyingly freakin 'strong magnets, by preference.

When I was a kid, I had a bag full of black ferrite magnets of various shapes and sizes. They were fine toys. I could not hurt myself with them.

I've grown up now. Well, physically at least. And so I've graduated to these.

"These", in this case, are neodymium iron boron (NIB) magnets. They're commonly just referred to as "neodymium" or "rare earth" magnets, and this composition is both more powerful and cheaper than the previous king of the permanent magnet world, samarium cobalt.

HOW strong?

Well, the smallest magnets in the above picture are little gold-plated cylinders only 6.4 by 2.3mm in size. The field extending from these magnets doesn't reach far with any strength, because the smaller a magnet of a given intrinsic strength is, the smaller will be the volume of space it can fill with a magnetic field of a given strength. Magnetic field strength drops off as the inverse cube of the distance from the magnet, too; get twice as far away and the field strength drops by a factor of about eight. So two of these little tackers barely notice each other over a distance of more than an inch.

But just tossing one of these tiny 'uns in the vague vicinity of another will cause them to click together end-to-end. And they do it strongly enough that I can hold the one on the end of a full stick of 12 of' em and twirl the rest around as fast as I can, without them letting go.

The strongest magnets in this collection, if you ignore the large-surface-area but thin and fragile hard drive magnets (of which more in a moment), are the 18.25mm-diameter spheres. Spherical magnets, mercifully, tend to push your fingers out of the way as they head for each other, so these ones aren't too prone to pinching people. But they can certainly do it, and playing with them without letting them smack together so hard that they damage themselves is easier said than done . These magnets are all covered with protective metal plating, but careless play will flake it off quite quickly, and the NIB material itself is quite fragile.

This collection of magnets is three "grab bags" worth, from ForceField, who seem to be pretty much the only really serious sellers of a proper range of cheap surplus rare earth magnets on the Internet at the moment.

News archive