JPH04164570A - Electrolytic dressing method - Google Patents

Abstract

PURPOSE:To control the formation of a nonconductor film, and to maintain a good electrolytic dressing grinding state at all times even in case of whatever work section, by controlling the nonconductor film removal component quantity mixed in a grinding liquid in accordance with the work section of roughing, finishing, etc., and keeping the nonconductor film quantity formed on a grinding wheel face in a proper state at all times. CONSTITUTION:The dressing of a metal bond grinding wheel 2 is performed by using an electrolytic action. In this case, the mixing quantity into the grinding liquid of the nonconductor film remover in a tank 10 is controlled by the valve 11a of a nozzle 11 according to the work section of roughing, finishing, etc. Consequently, the nonconductor film quantity formed on the grinding wheel 2 face is kept in a proper state at all times.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an electrolytic dressing method used in an electrolytic dressing grinding device that applies an electrolytic action to a grinding wheel used for grinding to perform grinding. .

(Prior Art) In the grinding process, as the process progresses, phenomena such as an increase in grinding resistance or seizure with the workpiece occur due to crushing or clogging of the grindstone. Metal bonded whetstones are especially strong, so there is almost no self-sharpening effect on the cutting edge, and the above phenomenon is noticeable when processing hard materials such as ceramics. Dressing work is very important.

Recently, an electrolytic dredge grinding method has been developed as a dressing method for metal bonded grindstones, which allows constant dressing even during processing, and is being put into practical use in various fields.

Figure 3 shows an example of applying the electrolytic dressing grinding method to a surface grinder. As shown in FIG. 3, a metal bond grindstone 2 is fixed to a rotating shaft 1 of a grinding machine, and by bringing a power supply brush 3 into contact with the grindstone base metal, the entire surface of the metal bond grindstone 2 is used as an anode. On the other hand, the cathode 4 is disposed within the grindstone cover 5 so as to face the outer circumferential surface of the metal bond grindstone 2 and to be spaced apart from each other by a constant distance. Furthermore, a water-soluble grinding fluid containing an electrolyte is flowed between the two electrodes from a grinding fluid supply nozzle 6.7 provided on the top of the grinding wheel cover 5, etc., and then a separately provided electrolyte that outputs a direct current or pulse waveform current is added. An electrolytic action is caused between the two electrodes by the source 8, and only the metal bond of the metal bond grinding wheel 2, which is the anode, is selectively eluted.
The aim is to protrude the abrasive grains and remove chips. Note that 9 in the figure is a workpiece.

However, in electrolytic dressing grinding with the above configuration, when electrolytic dressing is performed using a conventional water-soluble grinding fluid, a nonconducting film such as metal oxide is generated on the surface of the metal bond grinding wheel 2 on the anode side, and the dressing The action will not proceed, leading to a decrease in dressing efficiency and processing efficiency.

On the other hand, the abrasive grain size for mirror polishing is 10μ.
When using a metal bonded grinding wheel 2 with a diameter of less than m, the amount of abrasive grain protrusion is very small, a few μm, and it is extremely difficult to control the roundness of the metal bonded whetstone 2 and the unevenness of the grinding wheel surface under the abrasive grain protrusion volume sales. If there is no cushioning material such as a metal oxide film on the surface of the grinding wheel, the bonding side of the grinding wheel and the workpiece will come into direct contact, resulting in roughened and burned surfaces.

As mentioned above, in electrolytic dressing grinding, it is better not to generate a nonconductive film on the grinding wheel surface during rough processing to semi-finishing, but it is better to cover the grinding wheel surface with a nonconductive film during mirror finishing processing. . It should be noted that the abrasive grain size of the metal bonded grindstone used for mirror finishing is small, and only a small amount of dressing is required, so that the reduction in dressing efficiency due to the nonconductor skin H is hardly a problem.

However, as a method for removing the generated nonconductor film,
As shown in Japanese Unexamined Patent Publication No. 60-20859, a method can be considered in which a grindstone for removing a coating such as WA having a low degree of bonding is separately provided and the coating is mechanically removed by this grindstone.

(Problem to be Solved by the Invention) However, the above method is not very effective in that it causes scratches on the finished surface of the workpiece due to the abrasive grains falling off from the film removal grindstone, and also requires a separate grindstone feeding mechanism and rotating shaft. There are issues such as no.

The present invention has been proposed in view of the above points, and its purpose is to control the generation of a nonconducting film depending on the processing section and to realize stable electrolytic dressing grinding regardless of the processing section. An object of the present invention is to provide an electrolytic dressing method that obtains the desired results.

(Means for Solving the Problems) The present invention is directed to the electrolytic dressing grinding process in which a metal bond grinding wheel is dressed using electrolytic action, and the present invention is directed to the use of impurities that are mixed into the grinding fluid depending on the machining classification such as rough machining and finishing machining. The above object is achieved by controlling the amount of components removed from the conductive film and maintaining the amount of the non-conducting film formed on the grinding wheel surface in an appropriate state at all times.

In addition, in the electrolytic dressing grinding process that uses electrolytic action to dress the metal bond grinding wheel, rough machining,
The amount of nonconductor film removal components mixed into the grinding fluid is controlled according to the processing category such as finishing, and the amount of nonconductor film generated on the grinding wheel surface is always kept in an appropriate state. The removal component forms a complex compound with the metal ions eluted by electrolytic action, which has the effect of preventing the formation of a nonconductor film, and the structure is such that only the nonconductor film removal component is recovered from the recovered grinding fluid, and the above purpose is achieved. Achieved.

(Embodiment) FIG. 1 shows an embodiment of the present invention, which is applied to a surface grinder.

That is, the present invention is similar to the conventional example shown in FIG.
In addition to providing an electrolytic power source 8, a tank 10 containing a nonconducting film removing agent, which is a nonconducting film removing component, is provided above the grinding wheel cover 5, and a liquid supply nozzle 11 is supplied from the tank 10 into the grinding wheel cover 5. It is arranged in

Therefore, in this example, an EDTA (ethylenediaminetetraacetic acid) solution is used as a nonconductor film removing agent that forms a complex compound with the eluted metal ions through electrolytic action and prevents the formation of a nonconductor film.

This EDTA coordinates with the eluted metal ions to form stable complex ions, which has the function of preventing passivation, and is less corrosive than sodium chloride, sodium nitrate, etc. used in electrolytic processing fluids. It is quite small and there is no need to worry about mechanical corrosion.

In addition, as a nonconductor film removing agent, it generates metal ions and stable ions, and l! Other materials may be used as long as they are not corrosive to machinery or toxic to humans.

The present nonconductive film removing agent is supplied to the electrolytic dressing section by a valve 11 provided in the liquid supply nozzle 11 whose flow rate can be controlled.
The amount of metal ions to be electrolytically eluted is predicted and adjusted in advance using a.

Since EDTA reacts with metal ions at a molar ratio of 1:1, the concentration of the EDTA solution and the diameter of the grinding wheel used.

The required amount of liquid can be roughly calculated from known values such as width, abrasive grain size, electrochemical equivalent of eluted metal, specific gravity, electrolysis current value, electrolysis time, and electrolysis efficiency.

FIG. 2 shows an example of flow rate control.

After being supplied to the electrolytic dressing section, this nonconductive film removing agent flows over the machine table and flows into the grinding fluid recovery tank 12 provided below. This grinding fluid recovery tank 12
Now, with the sedimentation tank 12a, filter, centrifuge, etc.
After the chips in the liquid are removed, only the nonconductive film removing agent is sucked up by the first pump P1 and collected in the nonconductive film removal sub-processing device 13 equipped with a submicron filter capable of automatic cleaning. The nonconductive film removing agent may be recovered by treatment with an anion exchange resin, treatment using a semipermeable membrane and electrophoresis, or the like.

The grinding fluid that has collected the nonconductive film remover flows into the clear fluid tank 12b via the grinding tube 13a, is sucked up by the second pump P2, and is sent to the grinding point via the vibrator 14 connected to the grinding fluid nozzle 6.7. and supplied again to the electrolytic dressing section.

In addition, when recovering a nonconductor film removal agent by filters, it is necessary that the nonconductor film removal agent has the largest molecule among the components contained in the grinding fluid.

After installing each device as described above, during rough to semi-finishing, the amount of nonconductor film removal agent is controlled to an appropriate amount and supplied to the electrolytic dressing section together with the grinding fluid, and a nonconductor film is generated on the grinding wheel surface. Controls the amount to an appropriate level, does not generate a nonconductive film, and maintains a highly efficient dressing state.

On the other hand, during mirror finishing processing, the non-conducting film remover used during the previous processing is recovered and the non-conducting film removing agent is not allowed to flow into the electrolytic dressing section, thereby creating a non-conducting film on the grinding wheel surface. This prevents contact between the grindstone base and the workpiece, resulting in a good mirror finish.

In addition, it is necessary to avoid unnecessary consumption of the metal bond grinding wheel 2 due to metal bond electrolysis during rough to semi-finishing processing, so the electrical conditions of the electrolysis power source 8 or the flow rate of the nonconductive film removing agent must be adjusted appropriately. It is necessary to am.

(Effects of the Invention) As described above, according to the present invention, in the electrolytic dressing grinding process in which a metal bond grinding wheel is dressed using electrolytic action, particles are mixed into the grinding fluid depending on the processing classification such as rough processing and finishing processing. Control the amount of components removed from the nonconducting film,
The amount of nonconducting film formed on the grinding wheel surface is always kept at an appropriate level, or in addition, the above-mentioned nonconducting film removing component generates a complex compound with the metal ions eluted by electrolytic action to form a nonconducting film. In addition to having the effect of preventing However, a good electrolytic dressing grinding condition can always be maintained in any processing section.

(2) Since the generated nonconductive film is not removed using a separate grindstone, there is no need to worry about scratches on the finished surface of the workpiece due to falling abrasive grains, and there is no need to provide a separate grindstone feeding mechanism.

(3) Special technology for dressing the grindstone! This makes it possible to easily maintain sharpness.

There are other effects.

[Brief explanation of the drawing]

The first rM is an example in which the present invention is applied to a surface grinder, and the second rM is an example in which the present invention is applied to a surface grinder.
The figure shows an example of controlling the flow rate and electrolytic dressing current value for removing a nonconducting film according to the present invention, and FIG. 3 shows a conventional example in which electrolytic dressing is applied to a surface grinder. I... Rotating shaft 2... Metal bond grinding wheel 3... Power supply plano 4... Cathode 5... Grinding wheel cover 6.7... Grinding fluid nozzle 8 ... ・Electrolysis power source 9...Workpiece 10...Tank 11・Liquid supply nozzle 12-...Grinding fluid recovery tank 13...-Nonconductor film removal side processing device (baka 1 Figure 1 Figure 2 Time (min)

Claims (2)

[Claims] (1) In the electrolytic dressing grinding process that uses electrolytic action to dress the metal bond grinding wheel, the amount of components removed from the nonconducting film mixed in the grinding fluid is controlled according to the processing classification such as roughing and finishing, and An electrolytic dressing method characterized in that the amount of nonconducting film formed on the surface is always maintained in an appropriate state. (2) In the electrolytic dressing grinding process that uses electrolytic action to dress the metal bond grinding wheel, the amount of components removed from the nonconducting film mixed in the grinding fluid is controlled according to the processing classification such as roughing and finishing, and The amount of nonconductor film formed on the surface is always maintained in an appropriate state, and furthermore, the above-mentioned nonconductor film removal component forms a complex compound with the metal ions eluted by electrolytic action, and has the effect of preventing the formation of a nonconductor film. An electrolytic dressing method characterized in that only nonconductor film removal components are recovered from the recovered grinding fluid.