LT6782B - Polished workpiece holder with ultrasound actuator - Google Patents

Abstract

The invention belongs to the field of technologies for metal and ceramic surface treatment, and in particular- it is a holder for a workpiece with an ultrasonic actuator, which ensures better than usual quality during polishing. A new polishing workpiece holder with an ultrasonic actuator, present in a cylindrical piezoelectric element, is provided, in which high-frequency oscillations are excited, operating in the second-mode oscillation resonance mode, i.e., at the upper edge of the periphery of the cylindrical piezoelectric element. Depending on the shape of the cylinder, the frequency of the high-frequency second-mode oscillations, excited by the piezoelectric element, standing wave deformations with several nodes and blisters (at least two) are formed in the upper peripheral part of the cylinder, where the treated parts are fixed. In this way, several parts are treated simultaneously. Due to the selected cylinder shape, the frequency of the high frequency second mode oscillations, excited in the piezoelectric element, is twice as high as the frequency of the main resonant piezoelectric element, i.e. it reaches (~ 85 kHz), improves the surface quality of the treated parts, reduces surface cracks, reduces surface roughness.

Description

TECHNICAL FIELD

The invention belongs to the field of metal and ceramic surface treatment technologies, and more particularly to a holder for an abrasive workpiece with an ultrasonic actuator, which ensures better than usual quality during grinding.

BACKGROUND OF THE INVENTION

There is a known grinding device for forming microstructural surfaces in silicon carbide and tungsten carbide samples, which consists of a frame fitted with a feedpiece feed with high frequency oscillating piezoelectric transducers that provide oscillations along the tangential vector of the grinding disk, see Bing Gu, assisted grinding of hard and brittle linear micro-structured surfaces, Precision Engineering, 48, 2017, 98-106, ISSN 0141-6359).

There is a known vibratory machining device and method (US7508116 B2, published March 24, 2009) which uses piezoelectric transducers to provide high frequency (up to 50 kHz) oscillations to the workpiece and tool in the normal direction of the workpiece surface and in the tangential direction of the workpiece feed.

In the specified devices, one machined part is attached to the feed, the surface of which is subjected to high-frequency vibrations, which allow to reduce the amount of micro-cracks in the surface of the machined part. High frequency oscillations are excited by piezoelectric transducers operating in first mode oscillation resonance mode, i. the maximum oscillation amplitude in the central part of the piezoelectric transducer is transmitted to the workpiece. It is important to mention that due to the chosen direction of oscillations, as well as low frequency (~ 35 kHz), the reduction of grinding forces due to vibroacoustic lubrication, which would be observed when the vibrations are applied perpendicular to the disk grinding vector, is eliminated. Also, applying the proposed excitation scheme to rod grinding tools risks causing the tool to auto-vibrate, which can drastically affect the quality of the final product.

SUMMARY OF THE INVENTION

The aim of the invention is to increase the efficiency of the device by enabling simultaneous processing of a larger number of parts, at the same time improving the quality of the surface of the workpiece to be machined, reducing surface cracks, and reducing surface roughness.

This object is achieved by installing a new grinding workpiece holder with an ultrasonic actuator in the feed of the device, in which high-frequency oscillations operating in the second-mode oscillation resonance mode are excited in the cylindrical piezoelectric element. Depending on the cylindrical shape, the frequency of the high-frequency second-mode oscillations excited by the piezoelectric element, standing wave deformations are formed at its upper edge of the periphery, with several nodes and blisters (at least two) in place of the machined parts. In this way, several parts are machined simultaneously. Due to the selected cylindrical shape, the frequency of the high frequency second mode oscillations excited in the piezoelectric element is twice as different from the basic resonant frequency in the piezoelectric element, i. reaches (~ 85 kHz), improves the surface quality of machined parts, reduces surface cracks, reduces surface roughness.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a general view of a workpiece holder with an ultrasonic actuator;

Fig. Fig. 2 shows a top view (2a) of an abrasive workpiece holder with an ultrasonic actuator, and Fig. 2b shows a deformation of a wave standing in the upper edge of the periphery in a cylindrical piezoelectric element excited in section A-A, with several nodes and blisters in place. In paragraph 2a, the number of approximate locations of vibration wave nodes and bubbles is indicated by numbers without arrows.

BEST MODES FOR IMPLEMENTATION

This description provides a new grinding workpiece holder with an ultrasonic actuator in which high-frequency oscillations operating in a second-mode oscillation resonance mode, i.e., are excited in a cylindrical piezoelectric element. at the upper edge of the periphery of the cylindrical piezoelectric element. The said second-mode resonant mode occurs only in the cylindrical piezoelectric element. Depending on the shape of the cylinder, the frequency of the high frequency second mode oscillations excited in the piezoelectric, standing wave deformations are formed at its upper edge of the periphery, with several nodes and bubbles (at least two) whose position on the cylinder surface depends on the selected piezoelectric element, i. piezocylinder parameters. The workpieces are fastened in place of the formed blisters. In this way, several parts are machined simultaneously.

As described in this description, the new grinding workpiece holder with ultrasonic actuator increases the efficiency of the machine due to the possibility to machine a larger number of parts simultaneously.

It is important to note that due to the selected cylindrical shape, the frequency of the high frequency second mode oscillations excited in the piezoelectric element is twice as high as the frequency of the main resonant piezoelectric element, i. reaches (~ 85 kHz), increases the surface quality of machined parts, reduces surface cracks, reduces surface roughness.

Fig. Figure 1 shows an abrasive workpiece holder with an ultrasonic actuator. The actuator comprises a cylindrical piezoelectric element (1), which is fastened rigidly to the feed (6) by means of a clamp (2) with holes for fastening the workpieces (3). The actuator also has a high frequency generator (4).

Fig. 2 shows a top view (2a) of an abrasive workpiece holder with an ultrasonic actuator, comprising a clamp (2) with holes for workpieces (3), which is fixed in a feed (6) by a screw (5) together with a cylindrical piezoelectric element (1).

Fig. 2b, section A-A shows the stationary wave deformations (7) excited by several cylindrical piezoelectric elements in the upper edge of the periphery with several nodes (8) and blows (9) (at least two), in which the machined parts (3) are fixed in place.

During operation of the workpiece processing machine, the holder of the workpiece with an ultrasonic actuator and the workpieces (3) mounted therein are placed at the locations of the standing wave deformation (7) bubbles (9) formed on the cylindrical piezoelectric element (1) and pressed firmly (2). with holes in the screw (5) at the feed (6).

When the high-frequency generator (4) is connected to the cylindrical piezoelectric element (1), it generates high-frequency oscillations operating in the second mode oscillation resonance mode and forms stationary wave deformations (7) with several nodes (8) and blows at the upper edge of the cylinder. 9). The cylindrical piezoelectric element (1) is embedded in the tufts (9) of deformations (7) at the upper edge of the periphery by a clamp (2) with holes, the machined parts (3) are subjected to high-frequency microvibration, which improves the processing of several parts simultaneously and improves quality, reduced surface cracks, reduced surface roughness.

Compared to the nearest analogue, this new grinding workpiece holder with ultrasonic actuator not only increases the efficiency of the device by simultaneously machining a larger number of parts, but also improves the surface quality of machined parts, reduces surface cracks and reduces surface roughness.

Claims (3)

DEFINITION OF THE INVENTION 1. A grinding workpiece holder with an ultrasonic actuator comprising a feed for attaching a workpiece, a high frequency piezoelectric transducer, characterized in that the piezoelectric transducer is cylindrical in excitation of high frequency oscillations in the upper edge of the cylinder operating in a second mode oscillation mode. An abrasive workpiece holder with an ultrasonic actuator according to claim 1, characterized in that at least two machined parts can be mounted in the feed, which are subjected to high-frequency oscillations at the same time. A holder for an abrasive workpiece with an ultrasonic actuator according to claim 1, characterized in that the piezoelectric converter is fixed to the base at the locations of the deformation nodes of the wave formed on the cylindrical piezoelectric element.