Magnetic grinding device and magnetic grinding control method

Patent metadata

Field	Value
Publication number	US-12115619-B2
Application number	US-202117602514-A
Country	US
Kind code	B2
Filing date	May 21, 2021
Priority date	May 28, 2020
Publication date	Oct 15, 2024
Grant date	Oct 15, 2024

Abstract

The present disclosure provides a magnetic grinding device and a magnetic grinding control method, and relates to the field of machining. According to the device, a magnet platform of a grinding piece fixing table is connected with an electromagnet; the grinding piece fixing table is used for fixing a to-be-ground workpiece; an output end of a programmable power supply is connected with a coil of the electromagnet; a permanent magnet grinding rod is located above the to-be-ground workpiece; and a magnetic grinding control system is connected with the programmable power supply and is used for acquiring grinding points, on the to-be-ground workpiece, of the permanent magnet grinding rod, and controlling an output voltage of the programmable power supply by utilizing a removal amount of a blank workpiece surface shape of the to-be-ground workpiece, the grinding points and a pulse width modulation (PWM) control method.

First claim

What is claimed is:

1. A magnetic grinding device, comprising: an electromagnet, a base, a grinding piece fixing table, a programmable power supply, a machine tool, a permanent magnet grinding rod, a controller and a grinding medium, wherein,
one end of the electromagnet is arranged on the base;
a magnet platform of the grinding piece fixing table is connected with the other end of the electromagnet; and the grinding piece fixing table is used for fixing a to-be-ground workpiece;
the grinding medium covers a to-be-ground workpiece;
the magnet platform is a plate pole which is used for gathering magnetic fields formed by the electromagnet after electrification on the upper surface of the plate pole, and distributing the magnetic fields uniformly;
an output end of the programmable power supply is connected with a coil of the electromagnet; and the programmable power supply is used for supplying power for the electromagnet;
the permanent magnet grinding rod is arranged on the machine tool and located above the to-be-ground workpiece;
the machine tool is used for controlling the permanent magnet grinding rod to magnetically grind the surface of the to-be-ground workpiece;
and the controller is connected with the programmable power supply and the machine tool, separately, and
the controller is used for acquiring grinding points, on the to-be-ground workpiece, of the permanent magnet grinding rod through the machine tool, and controlling an output voltage of the programmable power supply by utilizing a removal amount of a blank workpiece surface shape of the to-be-ground workpiece, the grinding points and a pulse width modulation (PWM) control method, so as to magnetically grind the to-be-ground workpiece,
specifically comprising:
establishing a Cartesian coordinate system by taking a projection point, on the surface of the to-be-ground workpiece, of a grinding head of the permanent magnet grinding rod as an origin 0, wherein a Z axis of the Cartesian coordinate system is parallel to the permanent magnet grinding rod, and an XOY plane formed by an X axis and a Y axis of the Cartesian coordinate system is parallel to the surface of the to-be-ground workpiece; and comparing the blank workpiece surface shape with a finished workpiece surface shape and determining a removal amount of each coordinate point on the surface of the to-be-ground workpiece by utilizing the Cartesian coordinate system;
computing a grinding pressure of the coordinate point by utilizing the removal amount of the coordinate point according to a formula

P
=

ϕ
Kvt

,

wherein p represents the grinding pressure; Φ represents the removal amount; K represents a constant coefficient; v represents a linear velocity of the grinding head; and t represents a grinding time
computing a magnetic field intensity of the coordinate point by utilizing the grinding pressure of the coordinate point according to a formula P=K1H, wherein P represents the grinding pressure; K1 represents a constant; and H represents the magnetic field intensity;
computing an electromagnet voltage of each point on the surface of the to-be-ground workpiece according to a formula

E
=

H
*
Le
*
R

N

,

wherein E represents the electromagnet voltage; H represents the magnetic field intensity; Le represents an effective length of a magnetic path of the electromagnet; R represents the an impedance of the coil of the electromagnet; and N represents the turns of the coil of the electromagnet;
and starting the machine tool to acquire grinding points, at the blank workpiece surface shape, of the current permanent magnet grinding rod and electromagnet voltages of the grinding points, controlling an output voltage, at the grinding points, of the programmable power supply by utilizing the electromagnet voltages of the grinding points and the pulse width modulation (PWM) control method such that the electromagnet is electrified to form magnetic fields; and adsorbing, by the grinding points, magnetic grinding powder to form a magnetic grinding head so as to grind the surface of the to-be-ground workpiece.

2. The magnetic grinding device according to claim 1 , wherein the grinding piece fixing table specifically comprises: the magnet platform, a baffle and screws;
the magnetism of the magnetic platform is opposite to that of the grinding head of the permanent magnet grinding rod;
the baffle is fixed on the magnet platform such that a container is formed by the grinding piece fixing table;
and the screws run through the baffle and are used for fixing the to-be-ground workpiece.

3. The magnetic grinding device according to claim 1 , wherein the controller is configured to perform operations comprising:
acquiring the blank workpiece surface shape of the to-be-ground workpiece and the finished workpiece surface shape of the to-be-ground workpiece;
determining a removal amount of each point on the surface of the to-be-ground workpiece by utilizing the blank workpiece surface shape and the finished workpiece surface shape;
computing a grinding pressure of each point on the surface of the to-be-ground workpiece by utilizing the removal amount;
computing a magnetic field intensity of each point on the surface of the to-be-ground workpiece by utilizing the grinding pressure;
computing an electromagnet voltage of each point on the surface of the to-be-ground workpiece by utilizing the magnetic field intensity and turns of the coil of the electromagnet; and
controlling an output voltage of the programmable power supply by utilizing electromagnet voltages corresponding to the grinding points, on the to-be-ground workpiece, of the permanent magnet grinding rod and the pulse width modulation (PWM) method, so as to magnetically grind the to-be-ground workpiece.

4. A magnetic grinding control method applied to the magnetic grinding device according to claim 1 , comprising:
acquiring the blank workpiece surface shape of the to-be-ground workpiece and the finished workpiece surface shape of the to-be-ground workpiece; and
determining the removal amount of each point on the surface of the to-be-ground workpiece by utilizing the blank workpiece surface shape and the finished workpiece surface shape; wherein
the step of determining the removal amount of each point on the surface of the to-be-ground workpiece by utilizing the blank workpiece surface shape and the finished workpiece surface shape specifically comprising:
establishing the Cartesian coordinate system by taking the projection point, on the surface of the to-be-ground workpiece, of the grinding head of the permanent magnet grinding rod as the origin 0, wherein the Z axis of the Cartesian coordinate system is parallel to the permanent magnet grinding rod, and the XOY plane formed by the X axis and the Y axis of the Cartesian coordinate system is parallel to the surface of the to-be-ground workpiece;
comparing the blank workpiece surface shape with the finished workpiece surface shape, and determining the removal amount of each coordinate point on the surface of the to-be-ground workpiece by utilizing the Cartesian coordinate system;
computing the grinding pressure of each point on the surface of the to-be-ground workpiece by utilizing the

Assignees

• Univ Zhejiang Normal

Inventors

• E Shiju
• He Xinsheng
• Gao Chunfu
• Zhou Chongqiu
• Zheng Lanpeng
• Jiang Jiajie
• Zhang Huaiyi
• Wang Huadong
• Wang Chengwu

Classifications

• B23Q3/1546

  using permanent magnets · CPC title

• B23Q3/1543

  using electromagnets · CPC title

• B24B1/005

  using a magnetic polishing agent · CPC title

• B24B37/005 Primary

  Control means for lapping machines or devices · CPC title

• B24B37/00 Primary

  Lapping machines or devices; Accessories (B24B3/00 takes precedence) · CPC title