SU1458173A1 - Method of investigating resistance of optical part glass to attrition in polishing - Google Patents

Abstract

The invention relates to the field of processing optical parts and can be used in the automated shaping of high-precision large-sized optical surfaces. The purpose of the invention is to improve the accuracy and productivity of determining the technological constant and obtaining its absolute value in a linear measure, independent of the machine settings and tool sizes, and ultimately an increase in the productivity of automated shaping. To do this, the surface of the workpiece is processed locally with a tool, making a plane-parallel movement. A glass removal chart is constructed, the average removal rate is determined, and the technological constant is determined by mathematical dependence and used for automated fine-tuning of large-sized optical components. 1 il. (L

Description

I

The invention relates to the study of the resistance of glass to abrasion and can be used to determine the technological constant for the automated shaping of optical surfaces.

The purpose of the invention is to improve the accuracy and productivity of determining the technological constant, to obtain its absolute value, independent of machine settings and tool sizes, in a linear measure and ultimately increase the productivity of automated shaping by reducing the number of processing sessions by predicting them more accurately. .

The drawing shows a graph of glass spinning.

The method is implemented as follows.

A blank of the required glass grade of spherical or flat shape with an accuracy of N 1,, 3 is processed locally with a tool whose size is less than the diameter of the part. The tool is given a plane-parallel circular motion, by displacing its axis from the tool's spindle axis by the amount — the eccentricity of the plane-parallel motion. All tool points at the same time describe the same circle with a radius, equal to

00

with

ny

6, with the same speed, equal to V

Where

CO angle spindle speed

tool.

Before processing, apply the applied load to the tool. After processing for the required time, the part is controlled by the interference method by means of a test glass or an interferometer. Record the interference pattern on the film. The microscopic measurement of the curvature of the interference band passing through the middle of the treated circular zone at several points. Build a graph for polishing glass. The drawing shows a graph: polishing, glass with an instrument f 70 mm at 5 mm, Yakhod on the graph is the average polishing value. The technological constant is determined by the formula

TO

rh () - 26) 2 1 oHz vt

where h is the average value of glass polishing in the treated local zone;

P Qj-j - the total pressure of the tool on the surface of the workpiece; V - processing speed; , t is the processing time.

The method was implemented as follows. In determining the technological constant, machines for the automated adjustment of the AD-700 and AD-1000 were used, allowing the implementation of plane-parallel tool twisting. The magnitude of the eccentricity of the plane-parallel movement, the processing speed and the pressure of the tool on the surface being machined on these machines are set by the reprocessing and can vary over a wide range. Technological constant was determined on different brands of glass, in particular on the cellar CO 115m. As a blank, a spherical mirror of 0412 mm was taken, which was processed in several places with tools with a diameter of 40-100 mm at a specific pressure of 40-100 g / cm and a speed of 60-100 Im / s. The value of the technological constant turned out to be 0.00035 microns.

with Ria 10 G / CM, V 10 mm / s And

t J min

. A certain technological constant was used in the automated adjustment of large-sized optical components with a diameter of 400–1200 mm with instruments of 030–300 mm. As a result of processing in 5-6 sessions, optical surfaces with mean square deviation of L / 40–71/70 (–A 0.6328 μm) were obtained.

A feature of this method is its independence from the kinematics of the machine and the diameter of the tool.

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This method can also be used to determine the technological constant during grinding, but in this case it is necessary to use contact measurement methods, rather than interference, for determining the value of grinding, for example, a spherometer tuned to O on the raw areas of the optical surface.

Claims (1)

Invention Formula The method of studying the resistance of glass to optical parts by attrition during polishing, which consists in processing the glass preform with tool C with selected polishing material and suspension at given pressures, speeds and processing times, determines the amount of polishing of the workpiece material and characterized in that, in order to increase the accuracy and productivity of the process by determining the absolute value of the technological value, does not depend it from the machine settings and instru sizes ment, in a linear measure, the surface treatment of the workpiece is carried out with an instrument making a plane-parallel circular motion in a local zone, the size of which is determined from the condition: D, the amount of glass polishing is determined at several points of the diametral section of the treated circular zone, a graph is plotted and the average glass polishing value is found on it, and the technological constant is determined by the formula TO  irh (i 2) 2 RSBC t 51458173 in diameter tool; R. - eccentricity of plane-parallel circular motion; h is the average value of glass polishing in the treated local zone; O total tool pressure on the workpiece surface. processing speed; processing time.