CN106938410A - The burnishing device and its method of big L/D ratio internal surface of elongated tube - Google Patents

Abstract

The invention belongs to the technical field of magnetic grinding, and in particular relates to a polishing device and a method thereof for the inner surface of a slender tube with a large aspect ratio. The workpiece clamping mechanism on the machine bed, the grinding mechanism arranged on the machine bed, the grinding mechanism includes an ultrasonic generator, a magnetic grinding device, and the magnetic grinding device includes an external grinding device and an internal grinding device. The invention adds ultrasonic vibration to the traditional magnetic grinding process, so that the magnetic abrasive particles have a high-frequency impact on the inner surface of the slender tube, and adds auxiliary magnetic poles in the inner cavity of the slender tube. The auxiliary magnetic poles can form a magnetic circuit with the external magnetic poles, increasing the When the magnetic induction intensity per unit space is increased, the magnetic induction intensity per unit space increases, and the grinding pressure also increases accordingly, and the material removal amount is about 1.5 times that of traditional magnetic grinding.

Description

Polishing device and method for inner surface of slender tube with large aspect ratio

technical field

The invention belongs to the technical field of magnetic grinding, and in particular relates to a polishing device and a method for polishing the inner surface of a slender tube with a large aspect ratio.

Background technique

The piping system composed of various alloy pipes is the lifeline of equipment and is widely used in aerospace, petrochemical and machinery manufacturing and other fields. The quality of the inner surface of the pipe will directly affect the service life of the equipment. Restricted by the use environment, many pipes are thin-walled and slender pipes with relatively large length and diameter (inner diameter is 2mm-6mm). It is difficult for ordinary tools to enter during processing and cannot be observed with the naked eye. Traditional polishing methods are difficult to complete. Using the magnetic grinding method can overcome the limitations brought by the traditional method, and can perform ultra-precision polishing on the inner surface of the pipe.

Chinese Patent Publication (Announcement) No. CN103624634B discloses a method and device for magnetic grinding and polishing of the inner surface of a thick-walled ceramic tube. Grinding and polishing is achieved by the relative movement between the grinding particles and the inner surface of the ceramic tube workpiece. Because the method is only limited to grinding and polishing the inner surface of the large-diameter ceramic tube workpiece, and because the movement form of the magnetic abrasive particles is single, it is easy to cause scratches on the surface of the workpiece.

Chinese Patent Publication (Notice) No. CN202137643U proposes a polishing machine for the inner wall of a slender tube. The device drives the workpiece to rotate through a motor, and an iron core wound with a coil is arranged on the side of the tube, and an alternating current is passed through the coil, and the iron core will generate The linear reciprocating alternating magnetic field drives the magnetic abrasive particles inside the lumen to perform linear reciprocating motion along the axial direction of the tube. Since there is no auxiliary polishing device in the lumen of this device, the actual number of magnetic abrasive particles involved in the processing is low, and the grinding efficiency is not high. Moreover, after the coil is energized, the heat is severe, and a corresponding heat dissipation device must be equipped, otherwise there will be safety hazards.

Contents of the invention

The purpose of the present invention is to provide a polishing device and method for the inner surface of a slender tube with a large aspect ratio, which has a simple structure, is convenient to operate, has high grinding efficiency, and can effectively perform ultra-precision machining on the inner surface of the slender tube.

The purpose of the present invention is achieved through the following technical solutions:

The polishing device of the inner surface of the elongated tube with large aspect ratio of the present invention is characterized in that it comprises a machine tool body, a moving mechanism arranged on the machine tool body, and a workpiece clamping mechanism arranged on the machine tool body, which is arranged on The grinding mechanism on the machine bed,

The moving mechanism includes a screw guide rail arranged on the machine bed body, a screw drive motor connected to the screw guide rail, slide plate I and slide plate II arranged on the screw guide rail, and The photoelectric switch I and the photoelectric switch II on the machine bed and separated by a certain distance,

The workpiece clamping mechanism includes a chuck arranged on the machine bed body, a bearing seat assembly arranged on the slide I and opposite to the chuck,

The grinding mechanism includes an ultrasonic generator connected to the chuck, a magnetic grinding device arranged on the slide II, and the magnetic grinding device includes an external grinding device and an internal grinding device. The external grinding device includes a base, a magnetic yoke arranged on the base, an external magnetic pole connected to the magnetic yoke, and a magnetic gathering device connected to the external magnetic pole. The internal grinding device is a Auxiliary pole.

The number of said external magnetic poles is two and they are arranged at 90 degrees, and the arrangements are respectively N-S poles and S-N poles.

The auxiliary magnetic pole is a radially magnetized cylindrical magnetic pole, and the cross-sectional diameter of the cylindrical magnetic pole is 2mm-4mm.

The external magnetic poles and auxiliary magnetic poles are both NdFeB permanent magnet materials.

A method for polishing the inner surface of a slender tube using a polishing device for the inner surface of a slender tube with a large aspect ratio, characterized in that it comprises the following steps:

a. There is a processing gap of 1 mm between the inner surface of the elongated tube workpiece and the auxiliary magnetic pole, and the magnetic abrasive particles with an average particle size of 180 μm-250 μm are mixed with water-based abrasive liquid at a volume ratio of 1:3, and then filled evenly In the processing gap;

b. clamp the slender tube workpiece on the ultrasonic generator, turn on the ultrasonic generator to make the slender tube workpiece perform axial ultrasonic vibration, the vibration frequency is 0-19KHZ, and the amplitude is 0-20 μm;

c. The chuck drives the ultrasonic generator to rotate at a constant speed, and the rotating speed is 500r/min-2000r/min;

d. The external grinding device on the slide box I moves along the screw guide rail driven by the slide box I, and repeatedly moves at a constant speed between the photoelectric switch I and the photoelectric switch II. The speed is 50mm/min-100mm/min.

Advantages of the present invention:

The polishing device and method for the inner surface of the slender tube with a large aspect ratio of the present invention add ultrasonic vibration to the traditional magnetic grinding process, so that the magnetic abrasive particles have a high-frequency impact on the inner surface of the slender tube, and the inner surface of the slender tube Adding auxiliary magnetic poles, the auxiliary magnetic poles can form a magnetic circuit with the external magnetic poles, the magnetic induction intensity in the unit space increases, and the grinding pressure also increases, and the material removal is about 1.5 times that of traditional magnetic grinding; in addition, the external magnetic poles are arranged at 90 degrees, The arrangements are N-S poles and S-N poles, which can form a magnetic circuit with the auxiliary magnetic poles in the inner cavity of the slender tube, which increases the magnetic induction intensity per unit space and improves the grinding efficiency.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is a schematic diagram of the structure of the processing area of the present invention.

Fig. 3 is a schematic structural diagram of the processing principle of the present invention.

Fig. 4 is a schematic diagram of the trajectory of a single magnetic abrasive particle.

Figure 5 is a comparison diagram before and after grinding of the surface roughness value measured by a roughness measuring instrument.

detailed description

The specific implementation manner of the present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figures 1, 2, 3, 4 and 5, the polishing device of the inner surface of the elongated tube with large aspect ratio of the present invention is characterized in that it comprises a machine bed, a moving mechanism arranged on the machine bed, arranged on the workpiece clamping mechanism on the machine bed, the grinding mechanism arranged on the machine bed,

Described moving mechanism comprises the lead screw guide rail 13 that is arranged on the described machine tool bed, the lead screw drive motor 15 that is connected with this lead screw guide rail 13, the slide plate I11 that is arranged on the described lead screw guide rail 13 and slide Plate II12, a photoelectric switch I14 and a photoelectric switch II16 arranged on the bed of the machine tool and separated by a certain distance,

The workpiece clamping mechanism includes a chuck 1 arranged on the machine bed, a bearing seat assembly 9 arranged on the slide I11 and opposite to the chuck 1,

The grinding mechanism includes an ultrasonic generator 2 connected to the chuck 1, a magnetic grinding device arranged on the slide II 12, and the magnetic grinding device includes an external grinding device and an internal grinding device. Described external grinding device comprises base, is arranged on the yoke 4 on this base, the external magnetic pole 5 that is connected with this magnetic yoke 4, and the magnetic gathering device 6 that is connected with this external magnetic pole 5, and described internal grinding device is The auxiliary magnetic pole 7 is arranged inside the elongated tube 3 .

The number of said external magnetic poles is two and they are arranged at 90 degrees, and the arrangements are respectively N-S poles and S-N poles.

The auxiliary magnetic pole 7 is a radially magnetized cylindrical magnetic pole, and the cross-sectional diameter of the cylindrical magnetic pole is 2mm-4mm.

Both the external magnetic pole and the auxiliary magnetic pole 7 are NdFeB permanent magnet materials.

A method for polishing the inner surface of a slender tube using a polishing device for the inner surface of a slender tube with a large aspect ratio, characterized in that it comprises the following steps:

a. There is a processing gap of 1 mm between the inner surface of the elongated tube 3 and the auxiliary magnetic pole 7, and the magnetic abrasive particles 8 with an average particle size of 180 μm-250 μm are mixed with the water-based abrasive liquid at a volume ratio of 1:3, Evenly filled in the processing gap;

b. clamp the slender tube 3 on the ultrasonic generator 2, turn on the ultrasonic generator 2 to make the slender tube 3 perform axial ultrasonic vibration, the vibration frequency is 0-19KHZ, and the amplitude is 0-20 μm;

c. The chuck 1 drives the ultrasonic generator 2 to rotate at a constant speed, and the rotating speed is 500r/min-2000r/min;

d. The external grinding device on the slide box I11 moves along the screw guide rail 13 driven by the slide box I11, and repeatedly moves at a constant speed between the photoelectric switch I14 and the photoelectric switch II16, The moving speed is 50mm/min-100mm/min.

The slender tube 3 is clamped by the ultrasonic generator 2, and rotates under the drive of the chuck 1; movement; the auxiliary magnetic pole 7 maintains its synchronous axial movement under the adsorption of the external magnetic pole 5; the auxiliary magnetic pole 7 is placed inside the elongated tube 3, and a processing gap of 1 mm is left between the inner surface of the elongated tube 3 After mixing the magnetic abrasive particles 8 with an average particle size of 200 μm and the water-based abrasive liquid, they are evenly filled in the processing gap; when the slide box I11 touches the photoelectric switch I14, the screw drive motor 15 will change the direction to make the slide The crate Ⅰ11 moves in the opposite direction until it touches the photoelectric switch Ⅱ16 at the other end, and the lead screw drive motor 15 will change the direction again, so that the cycle moves; It is 0-19KHZ, and the amplitude is 0-20μm; the chuck 1 drives the ultrasonic generator 2 to rotate at a constant speed, and the speed is 500r/min-2000r/min. The introduction of vibration makes the magnetic abrasive particles 8 move in a "Z" shape (as shown in Figure 5), and the grinding distance increases; the processing position of the magnetic abrasive particles 8 changes frequently, which improves the cutting ability and grinding efficiency of the magnetic abrasive particles 8.

The bearing block assembly 9 is positioned and installed on the slide box II12, and is used to prevent the eccentricity of the elongated tube 3 during rotation.

Example 1, the elongated tube 3 with a surface roughness value of about 2.2 μm is ground with the device and method of the present invention. Before grinding, the inner surface of the elongated tube 3 has obvious pits, protrusions and obvious processing texture, and the peaks and troughs of the surface roughness profile are relatively large (as described in a in Figure 5). On the surface, this process is similar to mechanical shot peening, and the addition of vibration enhances the rolling and renewal of the magnetic abrasive particles 8. The magnetic abrasive particles 8 fully participate in the grinding, and the surface morphology of the processed workpiece is more fine and uniform. At this time The surface roughness value can reach 0.15 μm (as shown in b in Figure 5); the original peaks and valleys of the inner surface of the slender tube 3 processed by the method of the present invention have been removed, and the processed surface profile tends to be smooth.

The polishing device and method for the inner surface of the slender tube with a large aspect ratio of the present invention add ultrasonic vibration to the traditional magnetic grinding process, so that the magnetic abrasive particles 8 have a high-frequency impact on the inner surface of the slender tube 3, and in the fine An auxiliary magnetic pole 7 is added to the inner cavity of the long tube 3. The auxiliary magnetic pole 7 can form a magnetic circuit with the external magnetic pole 5. The magnetic induction intensity in a unit space increases, and the grinding pressure also increases accordingly. The material removal amount is about 1.5 times that of traditional magnetic grinding; In addition, the external magnetic poles 5 are arranged at 90 degrees in N-S poles and S-N poles, which can form a magnetic circuit with the auxiliary magnetic poles 7 in the inner cavity of the elongated tube 3, increasing the magnetic induction intensity per unit space and improving the grinding efficiency.

Claims (5)

1. a kind of burnishing device of big L/D ratio internal surface of elongated tube, it is characterised in that including machine tool body, set in this lathe Travel mechanism in bed body, is arranged on the workpiece grip mechanism on the machine tool body, is arranged on grinding on the machine tool body Grinding machine structure,

Described travel mechanism includes the lead screw guide rails being arranged on the machine tool body, the leading screw being connected with this lead screw guide rails Motor, is arranged on slide carriage I and slide carriage II in the lead screw guide rails, be arranged on the machine tool body and be spaced one section away from From optoelectronic switch I and optoelectronic switch II,

Described workpiece grip mechanism includes being arranged on chuck on the machine tool body, be arranged on the slide carriage I and with institute The relative bearing block assembly of chuck is stated,

Described grinding mechanism includes the supersonic generator being connected with described chuck, is arranged on the magnetic on the slide carriage II Power lapping device, described magnetic grinder includes outer abrasive device and internal lapping device, described outer abrasive dress Put including base, the yoke on this base is set, the external magnetic poles being connected with this yoke are connected with this external magnetic poles Poly- magnetic device, described inside lapping device is to be arranged on the auxiliary magnetic pole inside elongated tubular.

2. the burnishing device of big L/D ratio internal surface of elongated tube according to claim 1, it is characterised in that described outside Number of magnetic poles is two and arranged in 90 degree that arrangement mode is respectively N-S poles and S-N poles.

3. the burnishing device of big L/D ratio internal surface of elongated tube according to claim 1, it is characterised in that described auxiliary Magnetic pole is the cylinder magnetic pole of radial magnetizing, and the cross-sectional diameter of this cylinder magnetic pole is 2mm-4mm.

4. the burnishing device of the big L/D ratio internal surface of elongated tube according to claim 1,2 or 3, it is characterised in that described External magnetic poles and auxiliary magnetic pole are Nd-Fe-B permanent magnetic iron material.

5. a kind of internal surface of elongated tube polishing method of the burnishing device of utilization big L/D ratio internal surface of elongated tube, it is characterised in that Comprise the following steps：

A. 1mm processing gap is left between the inner surface and auxiliary magnetic pole of the elongated tube workpiece, by average grain diameter be 180 μm- 250 μm of magnetically grinding particle and water base lapping liquid by volume 1：After 3 mixing, it is uniformly filled in processing gap；

B. by the elongated tubular piece-holder on supersonic generator, opening supersonic generator makes elongated tube workpiece do axial direction Ultrasonic vibration, vibration frequency is 0-19KHZ, and amplitude is 0-20 μm；

C. described chuck drives supersonic generator to be uniform speed rotation, and rotating speed is 500 r/min -2000r/min；

D. the outer abrasive device on the slip crate I, the lead screw guide rails movement described in the drive lower edge in slip crate I, and At the uniform velocity moved repeatedly between described optoelectronic switch I and optoelectronic switch II, translational speed is 50 mm/min -100mm/min.