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Machining Neodymium Magnets

Introduction to Neodymium Magnets

A neodymium magnet is a permanent magnet made from a NdFeb alloy. That is, an alloy made of neodymium, iron, and boron. Neodymium magnets are characterized by powerful magnetic fields, strong holding force, high coercivity, and resistance to demagnetization, which make them very useful in several applications. Neo magnets have been used in several industries, from manufacturing to medicine to space tech. They also have an essential role in future technology like electric cars, green energy, and levitation.

Neo magnets must be machined into different sizes and shapes when fabricated for their various applications. In this article, we discuss everything that goes into machining neodymium magnets.

What the Factory Will Pay Attention to When Machining Neodymium Magnets?

When we receive orders, we pay close attention to the manufacturing process. And when it comes to machining, here are

Slicing

Roughcast Dimensions

There are several methods of making neodymium magnets. They include polished cast, roughcast, and sintering. Polish cast and sintering involve making large blanks of neodymium magnets and then slicing them into smaller pieces as required. With roughcast, however, we use molds that will give the exact dimensions and tolerances we desire so the magnet will have a rough finish. Sometimes, the material may overflow during casting, resulting in an unusual shape. We slice off the extra parts in cases like these to get the desired shape and size.

Machining Difficulty

Nearly all neodymium magnets are sliced into the desired shape during production, and, generally, they are difficult to machine because they are hard and brittle. However, specific shapes are even more challenging to get. Some of the most straightforward shapes are block, ring, and disc, but engineers may request special features in their magnets for specific applications. These features include countersinks, threads, tapers, blind holes, special shapes, and many others.

Machining Method

There are several neo-magnets machining methods, all required in deriving different shapes; they also require different machines. We examine some of them below.

Routine Shape Neodymium Magnet

These shapes include blocks, discs, and cylinders. Depending on the shapes you want, we can cut them using Inner Circle Slicer, QP Slicer, or any Wire Electrical Discharge Machining equipment.

To make processing faster and increase output, we usually bond some neodymium magnet blanks together and put them in the machining equipment to be cut at once.

Irregular Neodymium Magnet (magnet with countersunk, arc, special-shaped)

Irregular neodymium magnets include rings, arcs, blocks, and tubes with countersunk holes and special shapes needed for unique applications. We usually use a laser cutter or other CNC machining equipment to cut these shapes.

Neodymium Magnet Laser Cutting Machine

When cutting neodymium magnets into unique and irregular shapes, the operator will follow the following process:

  • Design the shape you want your finished product to be in computer-aided design software (CAD), along with the dimensions.
  • Send the design to us, and we will load it into our laser cutter software.
  • Depending on the required shape and other patterns, we set the power and speed of the laser cutter.
  • Next, we put the neodymium magnet in the laser cutter and position the laser where we want the cutting to start.
  • We check the lens and position it appropriately to ensure it is focused.
  • We let the laser conduct a sample movement to ensure it is within our desired movement range. This way, we are sure it doesn’t go beyond the magnet.
  • We put on the fume extractor to channel smoke appropriately.
  • Begin the cut.

We use the laser cutting machine to cut, mark, engrave, and etch neodymium magnets according to the customer’s description.

Grade

We have different grades of neodymium magnets, all of which possess unique intrinsic characteristics. Generally, a giant magnet will generate a stronger magnetic field than a smaller one. So if you require a particular field strength, we will compare it to the size and grade of the magnet.

Tolerance

Tolerance is the acceptable difference between the requested magnets’ dimensions and the final product. When machining neodymium magnets, we ensure complete adherence to the dimensions and tolerances the customer gives us. If the magnets get any larger or smaller, they become useless.

Quantity

We also pay attention to the quantity of magnet we should slice. Few magnets take less time, thereby fewer resources, and more magnets take more time, thereby more resources. We have an automated counting process to ensure you get the number of neo magnets you ordered. Besides, before packing your goods, we double your orders to ensure everything complies.

Weight

In cases where the customer gives specific instructions concerning each magnet’s weight, we also consider it. The value of any product is to serve the purpose it’s meant for. If a product cannot serve its purpose of function in its application, it is useless. Hence we adhere to such instructions as provided by the patron.

Plating

Coating

The coating is the external layer we use to cover neodymium magnets to protect them from corrosion. Naturally, neodymium will corrode very quickly if exposed to the atmosphere or moisture. However, with our quality coating material and thorough testing in the Salt Spray Test Chamber, we can boast of the durability of our magnets. While the most commonly used coating comprises three layers of Nickel + Copper + Semi-bright Nickel, other options exist. To see the complete alternatives for neodymium magnet coating, visit our coating options page.

Magnetization Direction

Neodymium magnets often have a preferred direction of magnetization. This direction could be axial or diametrical. When making neo magnets using the sintering process, we pressed them in the presence of a magnetic field to order their magnetic dipoles in a single direction. Once it is done, it cannot be changed. In round-shaped magnets, axial magnetization means that one of the poles is at the top with the other pole under it. In contrast, radial magnetization means the poles are along the sides of the magnet, opposite one another.

Outward Appearance

The outward appearance of magnets also matters, and we consider them in our machining process. We ensure our magnets have the smoothest finish achievable to minimize air gaps that rough surfaces may cause.

Concentricity

Concentricity is among the least popular terms in machining that many factories don’t discuss. It refers to the tolerance of spherical and cylindrical parts such that the tube wall is consistent. In some machined magnets, the tube wall may be thick on one end but thinner on the other. This inconsistency in machining may cause the magnet to malfunction in its application, starting a chain reaction that may compromise the functioning of an assembly. When we machine neodymium magnets, we give special care to concentricity to ensure that it functions perfectly in its application.

Parallelism

Parallelism is a type of orientation tolerance that focuses on the flatness of surfaces. When dealing with parallelism, the surface in question is compared to a datum plane to fabricate the tolerance zone. The parallelism tolerance in neo magnets is established with two parallel planes set at a distance apart. The space between the two planes controls the parallelism tolerance. We also use a surface plate and a height gauge to inspect our magnets before approval.

Perpendicularity

Perpendicularity is the dimensional tolerance that dictates how much a workpiece can deviate from a 90-degree angle when placed against a datum or surface. A 90-degree angle is formed when one horizontal line comes in contact with a vertical line. Like parallelism, this tolerance is checked by two parallel lines perpendicular to the datum. The edge of the workpiece must then lie within these lines to make it fit for its application.

Other

Dimensional Inspection

Dimensional inspection is the industry term that describes the process of assessing the geometric qualities of machined products to see how much they comply with the specifications provided by the customer. In other words, it compares what a product is to what it is supposed to be. If a product differs from the desired specification, it is discarded. Below are the tools we use for dimensional inspection

  • Vernier Caliper: the vernier caliper is a precise measuring tool that can accurately measure square, rectangular, and round-shaped objects, inside and outside, as required. It has one mobile and one immobile tooth, which the user is required to clasp around the object to be measured.
  • Outside micrometer: outside micrometers are incredibly accurate, which is why they are industry standard measuring tools. We use them to measure our neodymium magnet’s outer diameter, i.e., the thickness, to ensure compliance with the specifications. Outside micrometers are very accurate and come in various shapes for unique applications. They can be used to measure both flat and cylinder-shaped magnets, and, like the caliper, the user will clasp the object being measured between the two teeth–the anvil and spindle.
  • Inside micrometer: the inside micrometer accurately measures the inside diameter of a cylindrical magnet. Although the vernier caliper can take measurements of inside diameter, the inside micrometer takes more reliable measurements because it is adjusted such that its whole length fits into the diameter of the hole to be measured.
  • Fluxmeter: unlike the other tools mentioned above, the flux meter does not measure geometric dimensions. Instead, it measures the strength of the magnetic flux of permanent magnets. In production, we use flux meters for quality control and sorting. In cases where the customer orders different neo magnet grades, we sort them such that one grade forms one group. And in quality control, we use them to ensure the magnetic fields generated in the magnets meet the requirements.

Delivery Time

The delivery time is another thing we keep at the back of mind when machining or producing neodymium magnets for customers. Customers don’t have the same delivery time, but we strive to consistently deliver our goods on time while at the same time rendering excellent service. When you place an order with us, we can complete them within one to two weeks.

Where to Buy Neodymium Magnets?

ROBO magnetic is an industry leader in the manufacturing and fabrication of neodymium magnets, serving Asia, Europe, America, and other parts of the world. We have professional engineers working in our industries and using state-of-the-art equipment to ensure we deliver the best products. If you want to purchase quality neodymium magnets in bulk, contact our team or request a FOB price to get started.

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Article by

ROBO Magnetic Product Team

We are the manufacturer with 16 years of experience in custom neodymium magnets.

Need A Quote? Get in touch with us directly.

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