It is clear that the procurement requirements of magnets are mainly divided into two parts, one is the basic requirements for magnets, and the other is the requirements for project delivery.
Basic requirements for magnets
When we want to clearly explain the procurement requirements of a magnet, there are several key points that need to be clarified: performance requirements, shape and size, magnetization direction, and surface treatment requirements. It is best for the buyer to provide a drawing of the magnet. Let’s take NdFeB permanent magnets as an example to explain in detail.
1. Performance requirements:
That is, the grade requirements of the magnet. There are many suppliers in the magnetic material industry, and each company has different definitions and performance ranges for the same brand. When communicating the brand, it is recommended that both the supplier and the buyer clarify the remanence Br and intrinsic coercive force Hcj of the corresponding brand, so that deviations are not easy to occur . (If the purchaser does not know the product grade, then it is necessary to provide some auxiliary judgment indicators, such as surface magnetism, pulling force, magnetic flux/magnetic moment, etc.)
In addition, according to factors such as the working environment of the magnet, indicators such as remanence and temperature coefficient of coercive force can be further clarified.
If there are clear requirements for indicators such as magnetic flux, the testing equipment and testing method should be agreed as the judgment standard.
2. Shape size and magnetization direction:
When describing procurement requirements, the basic shape and size requirements of the magnet must be clear, such as 6.0mm (+0.03/-0.03), for simple products, provide basic dimensions and tolerances of length, width and height; for magnets with complex shapes , profile and other angle requirements (similar to the red mark 30°±1° in the figure below) need to be provided more clearly, and it is recommended to provide clear drawings to the supplier.
In addition, the magnet also needs to mark the orientation direction of the product (NS pole), the magnetization method (single-pole charging or multi-pole charging), and the magnetization angle.
3. Surface treatment requirements:
The purchaser needs to specify the surface treatment method of the magnet, including the coating method (electroplating, electroless plating, electrophoresis, vapor deposition, etc.), coating material (zinc, nickel, copper, aluminum, epoxy resin, etc.), and coating thickness.
If there are requirements for salt spray or other tests, it is necessary to agree on the setting of test conditions, storage time and judgment criteria after the test.
4. Other requirements:
Such as: appearance requirements, other testing requirements (such as aging test, etc.), packaging requirements, transportation requirements, etc.
Product delivery
Most suppliers have magnet blanks in stock, and they have a certain amount of reserves for general performance. The shape of the magnet roughly determines the delivery time of the product.
Customized products generally require a special mold. If the manufacturer does not have a mold of a suitable size, there will be a time for mold making, and the product delivery time will be extended to a certain extent.
The overall construction period can be shortened, but it may not be fully delivered according to the buyer’s ideal time. For products with urgent delivery dates, orders must be placed in advance.
Correct procurement process
1. Sufficient preparation time If you want to buy arc motor magnets, you should start preparations as soon as possible. Because you need a sample before placing an order. Normally, it takes 14 days to 18 days for the factory to produce samples. If you want high-grade magnets, the factory needs to check whether there are ready-made raw materials in the market. Then the factory will send the samples to you, it will take extra 2-3 days. You need 1-2 days to check the quality. It takes 16-22 days to wait for real mass production. The premise of all the above calculations is that the product fully meets its own requirements without any problems. If the sample test fails, then the overall mass production time will be extended. So we need to reserve enough time. 2. Drawings are very important. If you want to save time and speed up the progress of the whole process, the most important thing is the drawings. The following information needs to be marked on the drawings: arc, arc length, height, width, thickness inner diameter, outer diameter, coating, grade, tolerance
2. Tolerance As you can see, the width is 3±0.05mm and the thickness is 2.2±0.05mm. But what does “±” mean? That’s a sign of tolerance. So if the width is 3.05mm or 2.95mm both are acceptable. If your product is high tech, your tolerances must be even tighter. And in this industry, tolerance tolerances are different. Different shapes, different tolerances. Like round magnets, the standard tolerance is ±0.05mm, while square magnets have a length and width of ±0.1mm and a thickness of ±0.05mm. If you have special requirements, the circular tolerance can be 0.02mm, the square, the length and width can be ±0.05mm, and the thickness can be ±0.03mm. Many factory tolerances can be ±0.01mm. But the tighter the tolerance, the higher the cost. For most people, standard tolerances will meet their requirements. 2. Temperature Regarding the drawing, as we can see, no temperature is written. But we all know that if the operating temperature is below 100 degrees, the magnet can work normally. Because the grade is N50M. M means the magnet works well if the temperature is 100 degrees Celsius or less.
3. indicates a number, such as N*M, which can be N35M, N38M, N40M, N42M, N45M, N48M, N50M, N52M. 3. Number of S and N poles This seems to be a very simple problem. But unfortunately, it’s easy to make mistakes. Most of the time, this happens when one of them (seller and buyer) is a newbie. Magnets are used in rotor devices. The number of magnets should be plural. Like 12, 24, 26. Because the same magnetic field will always push away things with similar magnetic fields. And these two different magnetic fields attract each other.
4. Magnetization direction
Magnetization direction is a very important factor. Magnets are also worthless if you get them wrong. However, since the arc is a special shape, there are four magnetization directions: diameter direction, width direction, and thickness direction.
Different directions of magnetization make different directions have greater power. So we should pay attention to this.
5.Choose the right performance.
NdFeB magnets have many performance grades depending on their magnetic properties and operating temperature. Choosing a magnet is not simply choosing a performance brand with stronger magnetic force and higher grade. Excess magnetism leads to waste of rare earths and increased cost. For example, you are using N52 performance magnets, but you may actually only need to use N35 performance magnets to meet product functional requirements. At this time, we need to study neodymium magnets of various sizes and properties, and find a balance between them.
6. Find a suitable magnet production factory.
When choosing a magnet manufacturer, please remember to choose the source factory. An experienced magnet supplier should not only provide support in terms of magnet price, but also provide a full set of support in magnet selection, proofing, transportation, after-sales service, etc. , Improve communication efficiency and save customer time. As the saying goes, time is money.
First of all, we need to understand the strength of this magnet manufacturer, including the scale of the factory, technical level and production capacity. Secondly, we need to understand the quality of this manufacturer’s magnet products, including magnetic properties, performance stability, etc. This is also one of the key indicators for evaluating a NdFeB magnet manufacturer. Finally, pay attention to the after-sales service of this manufacturer, which can help customers solve problems to the greatest extent. If you are looking for a good magnet manufacturer, I suggest you choose xiamen balin new materials co., ltd. It is a magnet manufacturer with rich experience
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