Magnetic Declination Measuring Instrument

Currently, it is not strict to require the accuracy and consistency of material magnetization direction in most magnetic material production processes. However, with the increasing application of magnetic materials, the requirements to the accuracy of permanent magnets is also becoming higher. Compared with the requirements of traditional magnetic materials, new application technologies have more special requirements for the magnetic properties of permanent magnets. Due to the extremely important impact of the final magnetization vector direction (magnetic declination) of permanent magnets on the performance of precision magnetic components, the magnetic declination angle of permanent magnets is an important indicator to measure the performance of permanent magnets. The DX-2012AM permanent magnet magnetic declination measurement instrument provides an effective measurement solution for enterprises to solve high-end magnetic material production.

The DX-2012AM permanent magnet magnetic declination measuring system consists of a three-dimensional Helmholtz coil connected to an independent three-component fluxmeter, forming a hardware testing part. By converting the test data of the three components using a microcomputer, a complete permanent magnet material quality testing system is formed. Place the magnet on the sample stage, test the magnetic flux component using the pull-up method, and calculate the magnetic moment and the magnetic field deviation angle value in the main axis direction. Can display total magnetic moment M and spindle magnetic declination angle α, Ø x, Ø y, Ø z, and the corresponding coil constants of the test coil.

2.1. DX-2012AM magnetic declination test host : Three-channel fluxmeter

Fluxmeter range: 1mWb/10mWb/100mWb/1000mWb, four gears, accuracy: 0.5%;

Fuxmeter resolution: 0.01%, 0.1uWb min.;

Input impedance corresponding range: 1kΩ/10kΩ/100kΩ/1MΩ;

Drift: 1uWb/min (corresponding to 10mWb test range after adjusting stably)

Host function

Directly display the flux of a three-channel fluxmeter;

Directly display magnetic declination θz of the tested sample;

Comparison between θz and the setting value, easy to judge qualified or unqualified and classify high-precision products;

Stand-alone test or connect to PC with RS232 interface and automatically record test data ;

Repeatability and reproducibility of magnetic moment M and magnetic declination θz is less than 10%.

2.2 DXHC150 3-aixal helmholtz coils (round-shape)

XY coil constant designed as: 0.015 Wb*cm/V*s, calibration accuracy: better than 0.5%;

Z coil constant designed as: 0.05 Wb*cm/V*s, calibration accuracy: better than 0.5%;

Coil orthogonal angle: better than ±0.2°;

Main axial coil (Z coil places up and down, easy to improve the test accuracy of magnetic declination);

Test sample range:
a. 30mm3～150mm3 (homogeneous area: 0.3%);
b. 30mm3～30mm3 (homogeneous area: 1.0%).

2.3. DX-2012AM magnetic declination testing software

Automatically record the serial no. of the tested sample;

Automatically record θz, total magnetic moment M and flux Øx,Øy,Øz.

Coil resistance is Ohm, directly input, test software auto-corrects fluxmeter amplification coefficient to ensure the test accuracy.

● Direct display of three-flux meter flux;

● Directly display the magnetic declination of the tested sample & theta;Z;

● Can compare magnetic declination & theta;Z with the set value, judge whether the product is qualified or not, or classify high-precision products;

● can stand-alone online detection, can also be connected with the computer, the test data for testing and saving;

● Magnetic moment M test uncertainty: 0.5%, repeatability: ± 0.1%;

● Magnetic declination & theta;Z uncertainty: 0.2 ° (relative position of fixed sample and coil);

● Test repeatability: ± 0.1 °;

● Software intelligent correction: solve the problem of flux meter drift, initial zero point and the influence of coil resistance on integral

Put the magnet on the sample table, test the magnetic flux component by the pulling method, and obtain the magnetic moment and the deviation angle of the magnetic field in the direction of the main axis by calculation. It can display the total magnetic moment M, spindle magnetic declination α, Øx, Øy, Øz, and the coil constant of the corresponding test coil.

The hardware composition is high-speed 32 digitals M4 single-chip system, 3 sets of built-in fluxmeter, 7 inches 800*480 resolution LCD.

4.1 The front panel is shown as follows:

4.2 The back panel is shown as follows:

A single Helmholtz coil can be used to measure the magnetic moment M produced by the permanent magnet in the magnetization direction. The magnetic moment M can be obtained through the relational expression M=KH×Φ, in which KH is the Helmholtz coil constant, while the Φ is the magnetic flux of the magnetic induction to the coil. As for the quality inspection of the permanent material samples after being magnetized, the Helmholtz coil is adopted and it is getting quite popular and universal. It is extremely important for the designed one-dimensional and three-dimensional Helmholtz coil to participate in the mutual parameter transmission with its international peers.

Through the efforts of the company's collective wisdom, DX-2012AM magnetic declination measuring device was completed and can be put on the market as a new product. Compared with the original prototype, this equipment improved the design of the machine body, add a pneumatic push sample structure for the separation of large rare earth permanent magnet samples, and coil constants K of XY axis coils are designed to be under 0.015cm. All of these meet the needs of customers at home and abroad. As the equipment does not involve the use of graphic records, we change the computer configuration to laptops, mainly used as the record of the test samples, and all the recorded parameters can be directly printed out.

4.3 Software Screenshot