DE2700713A1 - Contact free measurement for ground work - uses surface reflected laser light converted into electrical signal and fed to comparator - Google Patents

Abstract

The contact-free measurement is for grinding edges and grinding angle of materials which are worked on grinding machines. The machined materials are measured optically by observing the tight reflected from the material surface, which is reflected in different directions according to the inclination of the ground or unground surface. The measurement can take place continuously during the grinding process. The measurement can be carried out on moving material. The reflected light is picked up by an optical detector and is converted into an electrical signal. The electrical signal, as a parameter of the measured valve, is compared with a given valve and the comparison valve is fed to an evaluation device.

Description

Application for a patent for a:

Method for the non-contact measurement of grinding edges and grinding angles of materials that are processed with grinding machines.

If materials are processed with grinding machines, the Dimensional accuracy of the cut two sizes of interest.

1. The distance from a reference edge of the transition between the ground and the unprocessed Material - the grinding edge.

2. The angle between a grinding surface and a reference surface - the so-called grinding angle.

The invention relates to a method for non-contact measurement of Grinding edges and angles, even with moving materials, as well as a device to carry out the procedure.

This method enables automatic control of grinding machines, especially in mass production, through control of ongoing production and automatic Adjustment of the grinding disks.

In the previously known processes, the machined materials were after finishing the grinding process measured with gauges. These Method is time-consuming and only allows control on the finished part.

The object of this invention is the non-contact measurement of the Material during or immediately after the grinding process and receipt of a signal for readjusting the grinding wheels. It thus becomes an automation in grinding processes for mass productions achieved with no scrap quota through continuous control produced grinding for dimensional accuracy.

The unprocessed surface of the material and the ground The surface of the material forms an angle at the grinding edge. A parallel one A light beam of sufficient intensity is generated when it hits the unprocessed Surface of the material, especially in the case of glass or metal, reflected back. Will this part of the surface ground at a certain angle (for example the edge of a knife) so the light beam is no longer reflected back in itself, but rather deflected according to the angle between the ground and the unmachined surface.

The change in direction of the reflected beam at the transition of the processed - Unprocessed surface can be used as a measure for the position of the grinding edge.

The device for measuring grinding edge and angle is a laser 1 is used as the light source.

The laser has the advantages of sufficient intensity and emitting one parallel light beam of a certain wavelength of light. The ray of light is split into 2 parallel light beams with a beam splitter 2 (Figure 1.) In A semitransparent mirror 3 is attached to each of these light beams. These 2 light beams are adjusted so that they are above and below as shown in FIG the grinding edge 4 hits the workpiece 5.

This adjustment can be done by mirrors 6 and inclined plane-parallel glass panes 7, according to FIG. 3.

The distance between the two light beams above and below the grinding edge 4 depends on the tolerances of the desired distance of the grinding edge from a reference edge 8. Both light beams are detected by microscope optics 9 the surface of the workpiece is focused. This reduces the beam diameter and higher measurement accuracy achieved. The workpiece must be at a fixed reference 8 in order to measure the distance between the reference edge and the grinding edge precisely guarantee. Part of the amount of light of the reflected beam is from the semitransparent mirror 3 deflected in the direction of a photodiode 11.

In order to switch off influences of the ambient light, the diode is placed in front of it an interference filter 12 is set, which only light of the wavelength of the laser light lets through.

The beam that hits the machined, ground surface 13, becomes the unmachined surface corresponding to twice the angle of this machined surface 10 Surface 13 deflected from the direction of incidence.

A photodiode, also in the back-reflection direction, as above is described, adjusted, accordingly no light signal is received in this case. Depending on whether both, one or no photodiode 11 emits a signal, one can Differentiation can be made according to the following procedure (Figure 4).

Signal Signal Results below * above * a. yes no cut fine b. yes yes bevel edge too high * c. no no bevel edge too far down * * according to the Figure 4 In case b. and c. can this signal of the photodiodes in a known manner be evaluated electronically and a tracking of the grinding wheels by means of Servomotors are made.

The laser beam can be directed to a beam diameter using microscope optics 9 of the order of Am. In the experiments carried out, it was possible the position of the grinding edge of a razor blade measured with an accuracy of + 5 Sm will.

The measurement of the grinding angle can be done in a similar way (Fig 5). The structure is easier here. The laser beam is off the ground surface 13 reflected at a certain angle according to the surface inclination. Locally the target angle of the reflected beam is a row of 3 photodiodes 11 with Diaphragms 14 and an interference filter 12 are arranged. The middle diode is input Signal if the angle of the reflective surface corresponds to the required dimension.

If the angle is larger or smaller than the target angle, appears Signal from upper or lower diode, which is evaluated electronically in a corresponding way, adjustment of the grinding wheels by means of servomotors is possible.

The accuracy of the arrangement can be achieved by the corresponding distance Photodiode can be set, or by lengthening the light path from the surface to be increased to the photodiode.

It was mentioned at the beginning that the advantages of the invention therein to measure continuously optically without contact. The measurement can also take place during a movement of the workpiece when the workpiece is on along the reference edge. For example, when grinding metal belts which are pulled through under the grinding wheel, the measurement of the grinding edge and Grinding angles can be made directly on the running belt. For grinding wheels, that are moved over a held workpiece can be synchronized with the grinding wheels the workpiece is measured and the grinding process when the specified dimensions are reached being stopped. Since the measurement is carried out with parallel laser light, the measuring arrangement can away from the object to be measured, which in confined spaces of Advantage is.

Through continuous measurement and evaluation of the measurement results with The described arrangement can automate the grinding machines in industrial Mass production can be achieved.

Claims (5)

Patent claims method for contactless measurement of grinding edges and grinding angles of materials that are machined with grinding machines, thereby characterized in that the machined materials optically through perception of the light reflected from the surface of the material can be measured, which depending on the inclination of the sanded or unsanded surface according to different Directions is reflected that the measurement is continuous during the grinding process can take place that the measurement can be made on moving material that the light reflected from the material is perceived by an optical detector, is converted into an electrical signal, the electrical signal as the magnitude of the Measured value is compared with a predetermined value and the comparison value is a Evaluation device is supplied. 2. The method according to claim 1, characterized in that for measurement Laser light is used. 3. The method according to claim 1 and 2, characterized in that before an interference filter is attached to the optical detector, which only covers wavelengths of the laser light used lets through. 4. The method according to claims 1 and 2, characterized in that that the diameter of the light beam to increase the measurement accuracy by a Optics is focused on the measuring point. 5. Process according to claims 1 to 4, characterized in that that measurements are taken at several points on the material, but only as a light source a laser is used and the light beam is split by beam splitters.