JPS614665A - Cutting-off grinding method using current-carriable grinding wheel - Google Patents

Abstract

PURPOSE:To make high grinding capacity and continuance attainable as well as to aim at the prolongation of service life in a grinding wheel, by grinding a work continuously while dressing a peripheral surface of the conductive grinding wheel by means of mechanical, electrical and electrochemical actions. CONSTITUTION:While grinding work M, a dressing electrode 6 is made contact with a peripheral surface of the rotating wheel 1, and when a dressing power voltage is impressed on the wheel as feeding a contact part with the specified coolant, discharge, electrolytic and mechanical polishing actions are all produced between them, therefore chip dust of the work M sticking to on the peripheral surface of the wheel 1 is removed clean and thereby dressing takes place, so that the work M is ground under optimum conditions. Thus dressing takes place during operation, and a working surface of the wheel 1 is always kept in a state of no loading whereby highly efficient grinding is made performable and, what is more, a finished surface of the work M is very little in stain and defect and a characteristic inherent in the work M is in no case largely varied. In addition, becuase of a light polishing action, wear in the wheel is so little, that its service life is well prolongable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cutting and grinding method using an electrically conductive grindstone, in which a workpiece is processed using an electrically conductive grindstone, and at the same time, the grindstone is dressed.

Generally, if a whetstone is used continuously, some of the material will get mixed in between the abrasive grains, causing "clogging" and significantly reducing cutting efficiency. It is necessary to "retouch" it using a dresser, etc.

This situation applies not only to general insulating whetstones, but also to fully energized whetstones such as metal bond diamond whetstones, metal bond borazone whetstones, glass bond energized whetstones for electrolytic grinding, and electrolytic whetstones that have conductive points scattered on the circumference. Partially energized grinding wheels for electrical discharge grinding also become clogged, and as a result, especially when the workpiece is prone to clogging, machining efficiency is significantly reduced, and the life of the grinding wheel is also shortened. shellfish.

Under these circumstances, it is desired to propose a cutting and grinding method that can obtain high cutting efficiency of the grindstone without interrupting the processing of the workpiece due to dressing of the grindstone, and also has a long life of the grindstone.

The present invention has been made in view of the above points, and it is an object of the present invention to perform dressing with an excellent dressing effect without interrupting the processing of a workpiece for dressing a grindstone, while maintaining the original high processing ability. The purpose of the present invention is to provide a cutting and grinding method using an electrically conductive whetstone, which can increase the life of the whetstone.

V. That is, the present invention relates to a technical means for solving the above-mentioned problems by continuously processing a workpiece while dressing the circumferential surface of a conductive grindstone by mechanical, electrical, and electrochemical actions. It is something.

Next, an embodiment of the present invention will be described with reference to the drawings.

Ui1 whetstone The following grindstones can be used in the present invention.

(1) Fully energized grindstone <A> Metal bonded grindstone A grindstone for mechanical cutting manufactured by baking diamond particles or cubic boron nitride (CBN) particles as a binder on the periphery of a metallic disk or by electrodeposition.

<-B> Glass bond or resin bond whetstone s: C
, CBN, diamond, alumina, metal carbide, etc. abrasive grains bonded with glass or resin, a non-conductive grindstone is impregnated with, for example, silver, copper, Nilarkel, cobalt, etc. by a method such as electroless plating. A whetstone with conductivity applied to the entire surface of the whetstone.

Or, a fully electrically conductive whetstone in which the abrasive grains are combined with a powder of a conductive substance such as silver, copper, nickel, chromium, cobalt, graphite, or a mixture thereof, with glass or resin.

(2) Partially energized type grindstone (Fig. 1) Partially energized type grindstone 1 has a conductive band 2 formed by exposing a conductive material on the circumference of a disc made of non-conductive abrasive grains.
This is a grindstone for electrolytic discharge grinding, in which polishing bands 3 formed by leaving non-conductive abrasive grains between the conductive bands 2 are arranged alternately.

As an example of the abrasive grains, green carborundum, white alundum, pink alundum, silica, diamond, CBN, etc. can be used.

In addition, a current-carrying ring 4 is provided at the center of the grindstone 1, and this current-carrying ring 4
By embedding conductive paths 5 in a radial manner from the conductive strips 5 to electrically connect to each conductive band 2 on the circumferential surface.

As the conductive path 5, conductive materials such as silver or nickel hardened into rods or wires, carbon fibers, metals, or other known materials can be used.

This type of grindstone 1 has a structure in which conductive bands 2 and abrasive bands 3 are alternately formed on the circumferential surface.
Examples include those shown in the figure.

[B] Dressing conditions When dressing both types of grindstones 1 described above, the present invention does not simply dress by mechanical action with a dresser as in the past, but independently from the processing of the workpiece M.
One of the features is that by generating an energized state between the grinding wheel 10 and the circumferential surface, two actions of electrolysis and discharge, or two actions of electrolysis, discharge, and mechanical grinding are repeated at high speed for dressing.

To explain the dressing method specifically, the dressing electrode 6 is placed on the peripheral end surface of the grindstone 1 away from the contact portion with the workpiece M so as to be in contact with or close to it.

Terminals 9 and 10 of the power supply device 7 are connected to the dressing electrode 6 and the grinding wheel 1, respectively, so that current is generated between the dressing electrode 6 and the peripheral end surface of the grinding wheel 1.

(Fig. 1) In order to generate an energized state between the tracing electrode 6 and the processing surface of the grinding wheel 1, one or more pairs of dressing electrodes 6 are placed on the circumferential surface of the grinding wheel 1, and the distance between the pairs is narrowed. Place the power supply device 7
Another possible method is to connect to. (FIG. 6) Further, a liquid supply nozzle 8 is arranged to supply a predetermined machining liquid to the gap or contact portion between the dressing electrode 6 and the grindstone 1.

Various types of power supplies can be used as the power supply for dressing processing, and for example, an AC power supply or a DC power supply of 1 to 1000V (10 to 1oOOOH2) can be used.

Furthermore, the dressing current is adjusted in the average current range of 0.05 to 10 OA depending on the contact area of the grindstone and the type of workpiece.

The voltage (or current) waveform for dressing can be smooth (Figure 7), sine wave (Figure 8), square wave (Figure 9.10), sawtooth wave (Figure 11), or distorted wave (Figure 11). It is possible to use an alternating current (AC containing harmonics) or a waveform that is a combination of the above, but in either case, it is desirable that the average voltage is positive on the grinding wheel side.

[Ha1 How to dress Next, the functions and effects of the dress will be explained in detail.

While machining the workpiece M, the dressing electrode 6 is brought into contact with the circumferential surface of the rotating grindstone 1, and when the dressing power source is applied while supplying a predetermined machining fluid to this contact portion, the rain gap An electric discharge action, an electrolytic action, and a mechanical polishing action occur between the wheels, and as a result, the cutting powder of the workpiece M that had adhered to the circumferential surface of the grinding wheel 1 is completely removed, and the grinding wheel 1 is refinished to achieve the best results. The workpiece M is machined under these conditions.

Further, when the dressing electrode 6 is placed close to the circumferential surface of the grindstone 1 without contacting it, the dressing is performed by electrolytic action and discharge action.

In either case, the clogged matter is electrically removed, and the falling off of the abrasive grains of Nagi'ci1 is kept to a minimum.

Incidentally, the dressing effect is influenced by the material of the dressing electrode 6 as well as electrical conditions such as voltage, current, and voltage waveform.

The material for the dressing electrode 6 must have conductivity and abrasiveness, but it is also required to have ease of generation of discharge arc, resistance to arc abrasion, resistance to corrosion, etc., and any material with these characteristics is required. Can be used.

For example, various electrically conductive grindstone materials including resin, glass, metal, or a mixture thereof as a binder, various electrode alloys such as silver-tungsten alloy, copper-tungsten alloy, etc. can be used.

``Second'' Machining Method Conventionally, in cutting and grinding using electrolytic action and electrical discharge action, such as electrolytic grinding and electrolytic discharge grinding, or mechanical cutting and grinding using a conductive grindstone, the dress of the grindstone is not covered. This was done separately from the processing of the workpiece.

The present inventor discovered that when processing a workpiece M using a conductive grindstone, if the grindstone is dressed using the above-mentioned dressing method and the workpiece M is processed at the same time, the workpiece M can be processed with extremely high precision. 111f I acknowledge that cutting and grinding work can be done without damaging the material properties of object M.

In other words, when dressing is performed using the above-mentioned dressing method, the electrolytic action and the electrical discharge action, or when the dressing electrode 6 is brought into contact with the grinding wheel 1, the mechanical polishing action acts synergistically with these actions, so it is extremely Effective refinishing is performed during machining, and the machining surface of the grindstone 1 is always kept free of clogging.

Therefore, higher efficiency machining is possible compared to conventional machining in which such dressing is not applied, and the machined surface of the workpiece M has extremely few distortions and defects, which improves the characteristics of the workpiece M. It doesn't change much.

In addition, due to the electrolytic and discharge effects, the special feature is that the mechanical polishing effect is much lighter than that of conventional mechanical dressings, or even there is no mechanical polishing effect at all, allowing for sufficient refinishing. As a result, the wear of the grinding wheel is minimal compared to conventional methods.

In addition, there are several ways to dress the workpiece M during processing, such as continuous dressing in parallel with processing and intermittent dressing. Select the most suitable processing method after considering the following.

[Book] Processing device The device for carrying out the processing method of the present invention consists of a part for processing the workpiece M and a part for dressing the grindstone 1, and either has an independent power supply for dressing or a part for dressing the workpiece M. Workpiece M
They are roughly divided into the following three types depending on whether they have a power source for electrical processing.

(1) A type that has a power source exclusively for dressing but does not have a power source for machining the workpiece Figure 12 shows an example of the basic fishing configuration of a device that has a power source exclusively for dressing.

Although this type uses a conductive grindstone, the workpiece M
The processing is only by mechanical grinding and cutting action.

(2> Type with two power supplies: one for dressing and one for workpiece processing. Figure 13 shows the power supply for dressing 7 and the processing power supply for workpiece M)
An example of a basic 4R configuration of a device with 1 separately leaked is shown.

In this type, the machining of the workpiece M is performed by a combination of electrolytic action and mechanical grinding action, or electrolytic discharge action and mechanical grinding action, but the tracing power supply 7 is the machining power supply for the workpiece M. Since it is independent from 11, it is possible to freely select when to dress during processing.

(3) 1 - Type in which the power supply for dressing and the power supply for machining the workpiece are the same Figures 14 to 16 show the basic configuration of a device equipped with a single power supply that can perform the same functions of dressing and machining the workpiece M at the same time. An example is shown below.

In the case of this type of device with the wiring shown in Box 14.16, dressing is always carried out in parallel with the processing of workpiece M.
In the case of the apparatus shown in FIG. 15, the timing of dressing the workpiece M during processing can be freely selected.

Since the present invention is as explained above, the following effects can be expected.

By arranging dressing electrodes close to or in contact with each other on the peripheral end surface of the grinding wheel, and by generating an energized state between the two, melting and electrolytic dissolution by electric discharge and electrolysis can be performed independently of the machining operation of the workpiece. Since the three mechanical grinding actions act synergistically on the peripheral end surface of the grindstone, extremely good dressing is achieved.

As a result, processing efficiency is much higher than that of the conventional method, and processing can be performed without leaving distortions or minute defects on the workpiece.

In particular, when the workpiece is machined by electrolytic action and electrical discharge action, dressing is particularly effective because it maintains the best electrical discharge electrolytic conditions during processing.

Previously, mechanical dressing was relied upon, but as in the present invention, even if the mechanical dressing action is weak or absent, electrolytic action and discharge action provide sufficient palate cleansing.

As a result, the wear of the grinding wheel is minimal compared to conventional dressing, and the life of the grinding wheel is extended.

(c) Sufficient palate cleansing is achieved through a weak abrasive action, so instead of using expensive whetstones made with expensive diamond particles or cubic boron butite, use a whetstone made of inexpensive commercially available abrasive grains. I can do that.

[Brief explanation of drawings]

Figure 1: An explanatory diagram of the machining state of the workpiece. Figures 2-5: An explanatory diagram of other grindstones. Figure 6: An explanatory diagram of the method of arranging the needle electrodes. Figures 7-11: An explanatory diagram of the applied power supply. Figures 12 to 16: Explanation of processing equipment by type Diagram 1: Disc grindstone 2: Conductive band 3: Polishing band 4: Current-carrying ring 5
: Current path 6: Dressing electrode M: Workpiece

Claims (1)

[Claims] An electrode is placed on the peripheral end surface of a rotating electrically conductive disc grindstone, and while machining liquid is supplied between the electrode and the grindstone, a dressing power source that generates electrolysis and discharge is applied between the electrode and the grindstone. A cutting and grinding method using an electrically conductive grinding wheel, which is characterized by dressing the grinding wheel and simultaneously processing the workpiece.