JP2568975B2 - Dry grinding method and equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry grinding method and a grinding apparatus that use an inert gas such as nitrogen gas as a processing atmosphere to realize a non-oxidizing effect, a cooling effect, and a low working resistance effect. .

[0002]

2. Description of the Related Art Grinding methods are classified into a wet grinding method using a grinding fluid and a dry grinding method performed directly in the atmosphere. Conventionally,
Since the dry grinding method does not use a grinding fluid, it is susceptible to grinding burns and grinding cracks due to the direct influence of grinding heat on the machined surface. In addition, the wet grinding method uses a cooling oil or water to obtain a lubricating effect, a cooling effect, and a cleaning effect. However, oxidation of the processed surface relating to the surface quality is inevitable. Also, in the processing of micro mechanical structural parts, the work is damaged only by the action of the hydraulic pressure of the grinding fluid, and is not always a satisfactory method. In addition, use of a grinding fluid in wet grinding causes contamination of the working environment due to scattering of mist and the like, but no suitable means for preventing this has been developed.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to realize a cooling effect, a non-oxidizing effect, a low working resistance effect , and a working work.
Purification of industrial environment, Lisa for processing atmosphere gas (inert gas)
An object of the present invention is to provide a dry grinding method and an apparatus capable of reducing costs by using a cycle . The above problem can be solved by the present invention having the following configuration. (1) In the dry grinding method of the workpiece, the grinding portion
In an airtight chamber filled with an inert gas at room temperature.
Grind the workpiece, and inert gas in the hermetic chamber
A circulating filtration device comprising a filter, a cooler and a blower for the body
Dry grinding method characterized by being filtered, cooled and recycled . (2) The dry grinding method according to (1), wherein an inert gas at room temperature is used as a medium for non-oxidizing, cooling, and low working resistance in the working atmosphere in the dry grinding method for the workpiece. Processing method. (3) In a dry grinding apparatus for a workpiece, an airtight chamber, which covers the grinding portion and is filled with an inert gas at normal temperature, and a device for circulating and filtering the inert gas in the airtight chamber, must be provided.
And the circulating filtration device includes a filter, a cooler, and a blower.
A dry grinding apparatus characterized by comprising:

[0004]

First, the operation of a dry grinding apparatus using an inert gas as an atmosphere for grinding a workpiece for carrying out the dry grinding method of the present invention will be described. This will be described with reference to FIG. The gas tight chamber 5 covering the grinding portion G on the surface grinder M is filled with an inert gas such as nitrogen gas by a gas tank 7, and a working atmosphere using the inert gas is generated. A grinding process is performed. The inert gas in the hermetic chamber 5 is constantly circulated and filtered by the circulating filtration device 8, and the filter 8a, the cooler 8b,
The inert gas that has been cleaned and cooled through the blower 8c is sent back to the grindstone cover 6 of the airtight chamber 5 again. In the airtight chamber 5, the workpiece is ground by the disk-shaped grinding wheel 4 under an inert atmosphere. Therefore, inactive in the airtight chamber 5
The volatile gas is generated by the filter 8a during the grinding process.
Fine grinding dust, abrasive dust, mist, etc. are filtered and removed for cleaning
The grinding machine heat and machine
The heat generated by the inert gas heated due to heat generation is collected and cooled.
And cleaned and cooled by the blower 8c.
The active gas is recycled into the hermetic chamber.

Next, in the dry grinding method of the present invention carried out in a working atmosphere using such an inert gas, the inert gas effectively acts as a medium for non-oxidation, cooling and low working resistance. The points are explained in comparison with the conventional dry grinding in the atmosphere. In the dry grinding method of the present invention, since the dry grinding in an atmosphere of air-tight chamber which is filled with inert gas can be performed, the deterioration of the oxidation reaction and the surface properties due to oxygen during grinding in air avoidance Is done. This fact is clear from the fact that in the experiments conducted by the inventor on grinding carbon steel in a processing atmosphere using nitrogen gas, the effect on non-oxidation was clearly observed, and oxide formation was observed on the processed surface. It was confirmed by the absence.

Further, the cooling effect of the inert gas (nitrogen gas) will be described based on the results of experiments of grinding carbon steel (S45C) by the inventors. The inventors prototyped an infrared sensor radiation temperature measurement system using an optical fiber, and measured the infrared intensity during dry grinding of carbon steel. The measurement was successful. FIG. 5 is an explanatory view of a main part of the grinding temperature measurement in the above-mentioned measuring system.
The optical fiber 13 is inserted into the
2 was fixed at a position 100 μm from the bottom 12a. A dry one-pass plane plunge grinding with a depth of cut of 20 μm was performed, and the optical fiber 13 was placed on the bottom 12 of the small hole 12 of the workpiece 3.
Workpiece 3 that receives infrared rays emitted from a
The transient temperature of the ground surface 3a was measured. When the total cutting depth is 160 μm, the fine hole 12 penetrates the ground surface 3a. The measured value of the air atmosphere when the grinding surface 3a reaches a position 80 μm from the bottom 12a is almost equal to the measured value of the same inert gas atmosphere, but the measured values near the surface thereafter are those of the air atmosphere. It was hot. When the voltage difference between the two is converted into a temperature, there is a temperature difference of 100 ° C. between the measured value in the air atmosphere and the measured value in the inert atmosphere when the ground surface 3a reaches a position 40 μm from the bottom 12a.
In the air atmosphere, a temperature rise due to the oxidative combustion reaction was observed. From these measurements and other related experiments, the following was found. (1) In the grinding processing of S45C material in an air atmosphere, the measurement output takes into account the heat generated by the processing and the heat generated by the oxidation combustion reaction of the chips. (2) Quantitatively, the heat generated by oxidation other than the heat generated by processing generates a much larger amount of heat immediately after processing than the heat generated by processing. (3) The measurement output of the grinding wheel surface by this measurement system is output according to the surface without being affected by the atmosphere when the grinding wheel grinding point is located directly above the optical fiber. (4) From the above, the cooling effect by the inert gas atmosphere that does not cause the oxidation reaction is confirmed. No grinding burns or grinding cracks were observed on the machined surface due to the grinding heat.

[0007] Also, a stainless steel (S
US304) The effect of reducing the grinding resistance of an inert gas (nitrogen gas) will be described based on the results of grinding experiments. FIG. 2 is a measured output waveform diagram of the main grinding component force resistance in an inert gas atmosphere, and FIG. 3 is a measured output waveform diagram in an air atmosphere. These measurement data are based on a main component force resistance measuring device (Kistler dynamometer) using a piezoelectric element sensor (Kistler, Switzerland)
Was used for the measurement. Workpiece (SUS
304), when the dry plane plunge grinding with a cutting depth of 10 μm per pass was performed in a large number of passes, the main component resistance of the grinding (the tangential direction in the workpiece tangential direction) at the 8th pass by the “Kistler dynamometer” (Grinding resistance). The output waveforms in FIGS. 2 and 3 are measured values of the stainless steel workpiece (length 22 to 24 mm, width 10 mm) in the eighth pass. A transient abnormal value that is not present in the measured value in the inert atmosphere in FIG. 2 appears in the grinding main component force resistance value in the air atmosphere in FIG. 3 (indicated by a dotted line S). this is,
It is considered that the grinding resistance at the 8th pass caused the disc grinding wheel to lose weight, and the strength of the grinding wheel in contact with the workpiece was directly expressed in the grinding main component resistance value. On the other hand, in the grinding process in an inert gas atmosphere, no reduction is observed in the disc-shaped grindstone, so that the effect of reducing the grinding resistance in the same atmosphere can be confirmed. As described above, in the dry grinding method of the present invention in which an inert gas such as nitrogen gas is used as the processing atmosphere in the hermetic chamber, the inert gas is used as a medium for non-oxidation, cooling, and low processing resistance in the grinding method. Act as
It can be seen that there is no flow of the inert gas and effective utilization is achieved . In dry grinding in an ordinary air atmosphere, an oxidation coloring film may be formed on the surface of a workpiece due to an oxidation reaction. However, according to the present invention, such coloring is not generated.
It turns out that oxidation has not progressed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a dry grinding apparatus using an inert gas as an atmosphere for grinding a workpiece according to the present invention in a surface grinder will be described with reference to the drawings. FIG. 1 is a diagram illustrating the configuration of a dry grinding apparatus 1 according to the present invention. In the figure,
M is a surface grinder, and 2 is a table of the surface grinder M. Reference numeral 3 denotes a workpiece mounted on the table 2, which reciprocates with the table 2 in the horizontal direction on the drawing. Reference numeral 4 denotes a disk-shaped grinding wheel attached to a horizontal grinding wheel shaft in the front direction, which rotates the grinding wheel 4 at high speed to grind a plane of the workpiece 3 reciprocating. On the grinding machine M, a table 2 and a workpiece 3 reciprocating and a grinding wheel 4 rotating toward the front are arranged.
A box-shaped hermetic chamber 5 is hermetically covered so as to air-tightly cover the grinding portion G including the following. A grinding wheel cover 6 is protrudingly provided at a protruding portion of the central grinding wheel 4. The air supply hole 5 of the airtight chamber 5
a and an inert gas tank 7 are connected by a pipe via an on-off valve 7a, and an inert gas such as nitrogen gas is supplied and filled into the airtight chamber 5 from the gas tank 7; A processing atmosphere filled with an inert gas is generated.

Further, the processing apparatus 1 circulates an inert gas used for grinding in the airtight chamber 5 and circulates and filters the filter 8a, the cooler 8b, and the blower 8c for clean and cooling. 8 are installed. The exhaust hole 5b of the hermetic chamber 5 and the circulating filter 8 are connected via a feed pipe 9a, and feeds the inert gas in the hermetic chamber 5 into the circulating filter 8. In the device 8, the supplied inert gas circulates in the order of the filter 8a, the cooler 8b, and the blower 8c. First, in the filter 8a, fine grinding dust generated during the grinding process is removed.
Abrasive dust and the like are collected to purify the inert gas. The next cooler 8b recovers and cools the heat generated by the inert gas heated by the grinding heat, mechanical heat, and the like. In the next blower 8c, the clean and cooled inert gas is sent back to the grindstone cover 6 in the airtight chamber 5. The return pipe 9b is connected to the air supply hole 6a on the side surface of the grinding wheel cover 6.

On the other hand, in the grinding wheel cover 6, the disk-shaped grinding wheel 4 is rotating at a high speed (FIG. 4). Thus, at the grinding point of the grinding wheel 4, the inert gas filled in the airtight chamber 5 is processed. An atmosphere is generated, and the inert gas that has been cleaned and cooled by the circulation filtration device 8 is discharged again to the grinding point, and the processing using the fresh inert gas is performed so that the dry grinding method of the present invention can always be performed. Generate and hold the atmosphere.

[0011] Then, was carried out dry grinding method of the present invention in the processing atmosphere using such an inert gas, the above-mentioned [work
As described in the section for “
As a medium for low machining resistance , and with a flow of inert gas
Without, it was confirmed that they are working effectively.

[0012]

As described in detail above, the dry grinding method and the apparatus of the present invention using an inert gas as the grinding atmosphere for the workpiece are different from the conventional dry grinding method in the atmosphere, and are different from the conventional dry grinding method. Effect, non-oxidizing effect, low working resistance effect , clean working environment, working atmosphere gas (inactive)
Cost can be reduced by recycling
In addition, grinding burns, grinding cracks, and generation of oxides as in the prior art can be eliminated very efficiently . In particular, the present invention is suitable for the grinding of parts that do not like oxidation. In addition, if the present invention is applied to the field of grinding small mechanical structure components that are easily damaged by the hydraulic pressure of the grinding fluid that employs wet grinding, such damage will not occur, making a great contribution to the field. It is what makes. Furthermore, according to the apparatus of the present invention, contamination of the working environment due to scattering of the mist of the grinding fluid in the conventional wet grinding does not occur. Further, the grinding ability for the workpiece can be improved by the low machining resistance effect according to the present invention.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory side view of a processing apparatus of the present invention.

FIG. 2 is a measurement output waveform diagram of a main component resistance of grinding in an inert gas atmosphere.

FIG. 3 is a measurement output waveform diagram of a main component resistance of grinding in an air atmosphere.

FIG. 4 is a side view of the grinding wheel.

FIG. 5 is an explanatory diagram of a main part of grinding temperature measurement.

[Explanation of symbols]

1 Dry grinding machine 2 Table
Reference Signs List 3 Workpiece 4 Grinding stone 5 Airtight chamber 5a Air supply hole 5c Exhaust hole 6 Grinding stone cover 6a Air supply hole 7 Inert gas tank 7a Open / close valve 8 Circulation filter 8a Filter 8b Cooler 8c Blower 9a Send pipe 9b Return pipe 11 Grinding wheel shaft 12 Fine hole 13 Optical fiber M Surface grinder G Grinding part

Continuation of the front page (56) References JP-A-5-220665 (JP, A) JP-A-57-211460 (JP, A) JP-A-55-112761 (JP, A) JP-A-55-96249 (JP, A) , A)

Claims (3)

(57) [Claims] In a dry grinding method for a workpiece , grinding is performed.
An airtight chamber filled with room temperature inert gas that covers the processing section
Grinding the workpiece in the airtight chamber
Circulation filtration of active gas with filter, cooler and blower
A dry grinding method characterized by filtering, cooling and circulating through a filtration device . 2. The dry grinding method according to claim 1 , wherein an inert gas at room temperature is used as a medium for non-oxidizing, cooling, and low working resistance in the working atmosphere in the dry grinding method for the workpiece. Processing method. 3. A dry grinding apparatus for a workpiece, comprising: an airtight chamber, which covers the grinding portion and is filled with an inert gas at normal temperature; and a device for circulating and filtering the inert gas in the airtight chamber. And the circulating filtration device includes a filter, a cooler,
Dry grinding machine characterized by comprising a grinding machine.