JP2846056B2 - Grinding device and grinding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to the grinding of hard and brittle materials such as ceramics, and is particularly used in large-scale computers and the like, and is a grinding device effective for grinding cooling components of LSIs. And a grinding method using the same.

[Conventional technology]

In conventional large-scale computers, aluminum cooling fins were mainly used as cooling components for LSIs.However, with the high performance of large-scale computers, the mounting density of LSIs has increased, and the amount of heat generated per LSI has also increased. High thermal conductivity is required.
Further, since metal powder causes an error due to miniaturization of wiring, use of a ceramic material, which is an electrically insulating material, as a cooling component of an LSI is being studied. In order to enhance the heat transfer effect, both the fin width and the pitch tend to be small and the accuracy tends to be severe.

Groove processing of ceramics is mainly performed using a diamond grindstone, and the thickness of the diamond grindstone used for the processing is reduced with the miniaturization of the fin width and pitch.

[Note] Metal-bonded diamond wheels and CBN wheels are effective for grinding hard and brittle materials, and these are collectively called superabrasive wheels.

If the grindstone is thin, the rigidity of the grindstone is reduced even when a metal bond diamond grindstone having excellent strength is used. If the grinding resistance increases due to clogging or crushing, the grindstone is deformed and the processing accuracy is reduced. Conventionally, grindstones have been dressed (sharpened) as a countermeasure to improve the sharpness of the grindstones. However, dressing of metal bond diamond grindstones is difficult, and discharge dressing and electrolytic dressing are mainly performed. However, since only one surface of the grindstone can be dressed in the discharge dress, an imbalance between the left and right of the dress effect easily occurs, and it is difficult to apply the in-process. Electrolytic dressing, Vol. 42, Machinery Research Institute (19
1988) As discussed on page 3, pages 97 to 106,
The entire surface of the grindstone is covered with an integral electrode (not on both sides), and the surface of the grindstone can be dressed uniformly (in-process electrolytic dressing method), but the sharpness on both sides of the grindstone due to the shape of the grindstone Could not correct the imbalance.

[Problems to be solved by the invention]

Although the above prior art is effective in reducing the grinding resistance, no consideration is given to the precision of the processed groove and the cut surface, and there is a problem that the undulation of the processed surface and the straightness are not improved. .

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide an apparatus and a method capable of processing or cutting a fine groove with high precision while controlling the sharpness of both sides of a grindstone.

[Means for solving the problem]

The configuration of the grinding apparatus according to the present invention for solving the above-described problems is such that a high-speed rotation is performed around a grindstone spindle, and a positive portion is formed on a flange portion of a metal-bonded superabrasive grindstone capable of grinding hard and brittle materials. Electrode, providing a negative electrode on the outer periphery of the whetstone,
In a grinding device that applies a voltage while supplying a processing liquid between both electrodes and grinds a workpiece while electrolytically dressing the grindstone, two electrode plates are provided to oppose respective surfaces on both side surfaces of the grindstone. In proportion to the warp of the grinding wheel or the force in the rotation axis direction of the grinding wheel, on the side surface having a large grinding resistance, an application unit for applying a larger voltage to the electrode plate, and a larger grinding resistance by an electrolytic dressing action. A control means for controlling the grinding wheel to reduce the warpage of the grinding wheel by reducing the grinding resistance of the applied surface.

In addition, the configuration of the grinding method according to the present invention for solving the above-described object, rotationally drives a super-abrasive grindstone of metal bond,
Providing a positive electrode on the grinding wheel flange portion, a negative electrode on the outer peripheral portion of the grinding wheel, supplying a working fluid between the two electrodes,
A greater voltage is applied to the side surface where the grinding resistance is large in proportion to the warp of the grinding wheel or the force in the rotation axis direction of the grinding wheel, and a larger voltage is applied, by the electrolytic dressing action, to reduce the grinding resistance of the surface to which a larger grinding resistance is applied, That is, the warpage of the grindstone is controlled to be small, and the grinding process is performed.

[Action]

When a voltage is applied between the diamond grindstone and the electrode via the working fluid, an electrolytic action occurs according to the potential difference between the diamond grindstone and the electrode, and the binder (metal bond material) of the grindstone is eluted, so that the sharpness is improved. If the electrolysis voltage on both sides of the whetstone is different, the sharpness on both sides of the whetstone also differs, causing a difference in the resistance to receive the whetstone side, and the whetstone is bent to the lower resistance side and processed along the groove or cut surface. You. The amount of warpage at this time is proportional to the amount of change in the resistance value applied to the side surface of the grindstone, and the amount of change in the resistance value is proportional to the product of the unit difference between the two electrodes and the application time. By controlling the sharpness on both sides and changing the force applied to the side of the whetstone, correcting the bending direction of the whetstone,
A high-precision machined surface without warpage can be obtained.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 is a first embodiment of the present invention, and is a perspective view of a grinding apparatus according to the present invention.

The configuration of FIG. 1 is such that 1 is a grindstone spindle, 2 is a diamond grindstone, 2a is a grindstone layer, 2b is a base metal, 2c is abrasive grains,
(3a, 3b) is a negative electrode, 5 is a working fluid supply nozzle, 6
Is a working fluid, 7 is a grindstone flange, 8 is a spring,
9 is a positive electrode, 10 is a feeder wire, 11 (11a, 11b)
Is a voltage supply device, 12 is a workpiece, 13 is a dynamometer, 14
Is a microscope.

In FIG. 1, reference numeral 2 denotes a diamond grindstone attached to a main shaft 1 of a grinding machine. A base metal 2b made of metal, and abrasive grains 2c made of a hard material such as diamond on the outer periphery of the base metal 2b are made of copper. Abrasive layer fixed in metal such as nickel
2c, the grinding wheel 2 is rotated in the direction of the arrow. Electrodes 3 made of metal such as copper having excellent conductivity are arranged on both sides of the grinding stone 2 so as to face the grinding stone 2. The electrode 3 is composed of electrodes 3a and 3b for controlling the sharpness of the side surface of the grindstone. Each electrode is independent and the processing liquid 6 is supplied from the processing liquid supply nozzle 5 to the gap between the grinding stone 2 and the electrode 3 (negative electrode). Is done.

[Note] The working fluid in this case has cooling, lubricating and electrolytic properties.

Grinding wheel flange 7 fixing the grinding wheel 2 to the grinding machine spindle 1
A carbon plate 9 strongly pressed by a spring 8 is connected to a positive electrode side of a voltage supply device 11 via a feeder wire 10. The electrode 3 is also connected to the negative electrode of each voltage supply device 11 by a feeder line 12.

With the processing device configured in this way, the diamond grinding stone 2
A description will now be given of the operation of forming a groove with high precision.

First, when the grindstone 2 is rotated and a predetermined voltage is applied between the grindstone 2 and the electrodes 3a and 3b by the voltage supply devices 11a and 11b while supplying the machining fluid 6, the grindstone 2 and the electrode 3 are supplied via the machining fluid 6.
A current flows between a and 3b. Assuming that the voltage by 11a is Ea and the voltage by 11b is Eb, when Ea> Eb, the potential difference from the grindstone 2 is larger on the electrode 3a side, the electrode 3a side of the grindstone 2 is more strongly electrolyzed, and Since the amount of metal eluted is large and the dressing effect is large, the sharpness of the whetstone 2 is reduced by the electrode 3a.
Since the side is improved and the force applied to the side surface of the grindstone is smaller on the electrode 3a side and larger on the electrode 3b side, the processing proceeds with the grindstone 2 pressed against the electrode 3a side, and the groove is bent toward the electrode 3a side.

Conversely, when Ea> Eb, the sharpness of the electrode 3b is improved, and the grindstone 2 is bent toward the electrode 3b.

Now, when a workpiece is placed on a grinding machine and a grinding operation is performed using the apparatus of this embodiment, the force applied in the axial direction of the grinding wheel (the thickness direction of the grinding wheel) is ΔF, Assuming that the amount of warpage is δ, the relationship between ΔF and δ can be expressed by δ = C ₁ ΔF + C ₀ (1). (C ₁ : proportionality constant) FIG. 3 is a diagram showing the relationship between ΔF and δ described above.

Microscope 14 for observing the upper part of groove during grinding
A result, the read warping δ groove, the dynamometer 13 which is arranged at the bottom of the workpiece 12, reads the force ΔF acting in the axial direction of the grinding wheel 2 during processing, (1) from the relationship equation, a C ₁ Find C ₀ .

In the equation (1), δ = 0, that is, ΔF = −C ₀ / C
_It is necessary to control the potential difference ΔE = Ea−Eb between the electrodes 3a and 3b so that the value of ₁ is maintained as a constant standard value. (The voltages Ea and Eb of the voltage supply devices 11a and 11b are controlled.) This makes it possible to control the sharpness of both sides of the grinding wheel and reduce the force acting on the side surfaces of the grinding wheel. The groove of the workpiece can be precisely ground.

Since C ₁ and C ₀ change successively throughout the processing period, ΔC is determined by microscopic observation in accordance with a change in the value of the warpage amount δ.
Control the value of F. In addition, automatic control can be performed.

FIG. 2 is a perspective view of a grinding device according to a second embodiment of the present invention.

In the apparatus shown in FIG. 2, an electrode 15 for controlling the sharpness of the grinding wheel end face is added to the electrode 3 in addition to the apparatus shown in FIG.
It is provided between a and 3b. Each electrode is an insulator 4
In isolation. The electrode 15 is connected to the voltage supply device 11c by a feeder line. Other symbols are the first
It is the same as the figure.

When the apparatus of the second embodiment is used, the effect of electrolytic dressing for reducing the grinding resistance in the normal direction (the outer peripheral end face of the grinding wheel) during the grinding process is added.

According to the second embodiment, high-precision machining can be expected by controlling the amount of warpage of the ground surface, and furthermore, higher performance and higher quality products can be obtained by electrolytic dressing at the tip of the grinding wheel. Further, the service life of the grindstone itself can be extended, and the economy is improved.

〔The invention's effect〕

According to the present invention, dressing of a grinding wheel surface can be performed while performing good grinding of a processing surface of a workpiece requiring precision in process, (1) saving time and labor saving required for grinding; 2) High-precision processing of hard and brittle materials, and (3) the effect of extending the life of the grindstone is achieved, which contributes to the improvement of economic efficiency.

[Brief description of the drawings]

FIG. 1 is a perspective view of an apparatus according to a first embodiment of the present invention, FIG. 2 is a perspective view of an apparatus according to a second embodiment of the present invention, and FIG. It is a relation diagram with quantity. DESCRIPTION OF SYMBOLS 1 ... Whetstone spindle 2 ... Diamond whetstone 2a ... Whetstone layer 2b ... Base metal 2c ... Abrasive grain 3 (3a, 3b) ... Negative electrode 4 ... Insulator 5 ... Processing fluid supply nozzle 6 ... Processing Liquid 7 Grindstone flange 8 Spring 9 Positive electrode 10 Feeder wire 11 (11a, 11b, 11c) Voltage supply device 12 Workpiece 13 Dynamometer 14 Microscope 15 Negative electrode

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B24B 53/00 B23H 5/00 B24B 53/007

Claims (2)

(57) [Claims] A positive electrode is provided on a flange portion of a metal-bonded superabrasive grindstone capable of grinding hard and brittle material at a high speed around a spindle of a grindstone, and a negative electrode is provided on an outer peripheral portion of the grindstone. And applying a voltage while supplying a machining fluid between the two electrodes,
In a grinding apparatus for grinding a workpiece while electrolytically dressing the grindstone, two electrode plates are provided to oppose respective surfaces on both side surfaces of the grindstone, and are proportional to a warp of the grindstone or a force in a rotation axis direction of the grindstone. do it,
Applying means for applying a larger voltage to the electrode plate on a side surface having a large grinding resistance, and reducing the grinding resistance of a surface to which a larger grinding resistance is applied by an electrolytic dressing action, thereby reducing the warpage of the grinding wheel. And a control means for performing the control as described above. 2. A super-abrasive grindstone of metal bond is driven to rotate, a positive electrode is provided on a flange portion of the grindstone, a negative electrode is provided on an outer peripheral portion of the grindstone, and processing is performed between the two electrodes. The liquid is supplied, and a greater voltage is applied to a side having a greater grinding resistance in proportion to the warp of the grinding wheel or the force in the direction of the rotation axis of the grinding wheel, and the grinding resistance of the surface to which a greater grinding resistance is applied by an electrolytic dressing action. Characterized in that the grinding wheel is controlled so as to reduce the warpage thereof.