JPH0525812Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a dressing device for a grindstone of a grinding machine tool. More specifically, the present invention relates to a dressing device used for automatic dressing of a diamond grindstone used for processing difficult-to-cut materials such as ceramics.

[Prior Art] When a grinding wheel, which is a processing tool, becomes clogged or clogged, resulting in poor cutting quality, dressing is the process of renewing and restoring the cutting quality. Dressing is usually done by grinding a grinding wheel using a dressing wheel such as a point dresser, rotary dresser, or crushing roller made of single diamond. This dresser is used depending on conditions such as the type of grinding wheel, grinding conditions, and type of workpiece. When processing difficult-to-cut materials such as ceramics, a diamond grindstone is used as the grinding wheel because the workpiece is hard.

However, since the workpiece is hard, the diamond grindstone wears quickly and requires frequent dressing. In order to dress a diamond whetstone, it would be better to have a whetstone harder than diamond, but since there is none, the dresser must be softer than this. Generally, GC whetstones and WA whetstones are used.
These wheels use a relatively soft bonding agent to improve the sharpness of the dressing. In other words, when a soft binder is used, the abrasive grains involved in grinding are renewed one after another, and the sharpness is maintained. Therefore,
These dresser grindstones are several times to several tens of times more abrasive than diamond grindstones.

It is necessary to correct the relative position between the diamond grinding wheel and the dresser grinding wheel by the amount of wear using a numerical control device (NC device). As a result, since the dressing starting point changes, there are problems in that it is difficult to automate the dressing work and that dressing takes a long time. In particular, it was difficult to automate the dressing work of a diamond grinding wheel by assembling it into the machining center that makes up the FMS. Even with automation, it was difficult because there are many shapes and sizes of diamond grinding wheels.

Furthermore, as a result of dressing, the dimensions of the diamond grindstone for processing also change, which affects the processing dimensions. For this reason, measuring the dimensions of the workpiece and adjusting the depth of cut has to be done manually, making automation difficult.

In view of the above-mentioned problems, the present applicant has proposed an automated system for automating the dressing work of a diamond grinding wheel and for automating the correction of dressing wear.
(Japanese Patent Application No. 61-250767) The dressing device of the vertical machining center used in these applications requires two rotating dressing wheels that are perpendicular to each other. That is, it is used to dress the peripheral surface and end surface of a diamond grindstone.

[Problems to be solved by the invention] However, the amount of wear between the grindstone for dresser for end faces and the grindstone for dresser for circumference are different. Therefore, during dressing, it is necessary to memorize each amount of wear and to correct each amount during dressing. Furthermore, since two dresser grindstones are required on the pallet, it is difficult to mount them on the pallet in terms of space. Two drive motors are also required to drive the dresser grindstone. In order to solve these problems, the present invention provides one grindstone for dresser having mutually perpendicular surfaces.

[Means for Solving the Problems] The present invention adopts the following configuration in order to solve the above problems.

A dressing device for a machine tool, which is provided to face a main shaft on which a grinding wheel to be dressed is removably mounted, and has a table that moves relative to the main shaft and has pallet clamping means for clamping a pallet. For the grinding wheel having one or two grinding surfaces in two directions different by 90 degrees, a conical dresser surface with an apex angle of 90 degrees for dressing the grinding surface of the grinding wheel. and a dresser grindstone mounted rotatably at an angle of 45 degrees with respect to the axis of the main shaft, and a dresser drive means for driving the dresser grindstone provided on the pallet. This is a dressing device.

[Operation] An automatic tool changer takes out a rotationally driven grinding wheel from a tool storage magazine storing a plurality of tools, and places it on the main shaft of a machining center.
A pallet equipped with a dressing device is clamped to a machining center, and the grinding wheel is dressed with a dressing wheel that is loaded on the pallet and rotates.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the overall configuration when the present invention is applied to a vertical machining center 1. As shown in FIG. A column 3 is provided so that it can move back and forth on the bed 2. A main shaft housing 4 is provided on the column 3 so as to be movable up and down. This main shaft housing 4
is provided with a main shaft 5 rotatable in the vertical direction,
A diamond grindstone 6 is attached to the tip of the main shaft 5. The diamond grindstone 6 can be automatically replaced with another tool by an automatic tool changer (ATC) not shown. The spindle housing 4 that supports the spindle 5 is equipped with a detection ring 7 (described later) that detects contact between the diamond grindstone 6 and the dresser grindstone 10.

The dressing device 8 has a structure in which a dressing grindstone 10, a measuring block 11, etc. are mounted on a pallet 9. This dressing device 8 is
Like pallets 9 for other workpieces, they are pooled in a pallet pool line 13 and exchanged by a pallet changer 12. When a Dretsink command is received from the control device, machining center 1
It is clamped to the table and ready for dressing work.

Dressing Device (FIGS. 2 and 3) FIG. 2 shows an overview of the dressing device 8. As shown in FIG.
A dressing device 8 is mounted on the pallet 9. In the dressing device 8 mounted on the pallet 9, a grindstone shaft 21 is rotatably provided in a housing 20 via a bearing. A dresser grindstone 10 is fixed to the tip of the grindstone shaft 21, and an air motor 23 is directly connected to the other end. The compressed air is transferred from the compressor 30 to the solenoid valve 31, rotary valve 32, and shaft 3.
3. It enters the clamped pallet 9 through the table 34 and reference pad 35, and is connected to the air motor 2.
3 to rotate.

The dresser grindstone 10 used here is basically a general GC grindstone, but in order to have electrical conductivity,
It is divided into segments, and the segments are connected by metal layers 24. This metal layer 24 exists radially from the central hub portion to the outermost diameter of the grindstone. However, the grindstone portion is connected and is not separated from the connection portion between the grindstone portion and the metal layer portion.

Further, since the grindstone shaft 21 uses a normal rolling bearing, and the other parts are also made of metal, the metal layer 24 of the dresser grindstone 10, the grindstone shaft 21, the housing 20, the pallet 9, the table 34 of the machining center, etc. , bed 2, and other parts of the machine are electrically connected.

Although the measuring block 11 is not necessarily provided in the present invention, it automatically measures the contact points between the contacts 11a and 11b and the diamond grindstone 6 to measure the outer diameter and end face position of the diamond grindstone. The measurement block 11 has contacts 11a, 11
b, and these are made of conductors. When the diamond grindstone 6 is brought into contact with the contacts 11a and 11b, the wear of the dresser grindstone 10 can be measured using the position information of the NC device of the feed of the spindle 5 at that time or the feed of the table 34 that clamps the pallet 9. Measure by comparing with the dimensions of the grindstone 6.

In this embodiment, contact is simply detected, but a non-contact type air micrometer, electric micrometer, etc. may also be used. Furthermore, there is also a method of directly measuring the diameter of the dresser grindstone 10 using a measuring device such as a differential transformer or a magnetic scale.

A diamond grindstone 6 is attached to the main shaft 5 of the machining center 1 as a processing tool. The diamond grinding wheel 6 is roughly classified into two types, resin bond and metal bond, depending on the bonding material, but resin bond generally does not have electrical conductivity. However, since it has electrical conductivity by adding metal powder to the bonding material, there is no problem in using it in the dressing device of this embodiment.

Hereinafter, the present invention is based on the premise that a conductive diamond grindstone 6 is used. The spindle housing 4 of the machining center 1 is equipped with a detection ring 7, which detects when a tool mounted on the spindle 5 comes into contact with a metal part on the pallet 9 or contacts 11a, 11b of a measuring block. can be detected and a skip signal can be given to an NC device running a program created using a custom macro (a program created by the user).

The detection ring 7 (known to the public) has two cores built-in in this embodiment, and when the tip of the diamond grinding wheel 6 contacts the dresser grinding wheel 10 to form an RC closed circuit, the excited core of the two cores A circulating current flows, which is captured by the other pick-up core and sends a touch signal to the control section of the NC device.

Dressing operation We will consider the case where the end face portion of the diamond grinding wheel 6 is dressed and the case where the outer peripheral portion is dressed. In the case of dressing the end face portion, the dressing operation is started in the positional relationship shown at position O in FIG. 4.

FIG. 4b shows the subsequent operation until the dressing is completed. The O position represents the edge of the diamond grinding wheel 6 at the approach point, and represents the sequential movement of the point with numbers assigned in that order. In other words, it moves at a fast rate from the approach point, then moves in the X direction, and returns (same as).

Next, make a cut in the Y-axis direction by a certain amount, for example, 10 μm, move from the position to V in the X direction, and return to (the same position). As this process is repeated, it will come into contact with the dresser grindstone 0 several times. In the figure, it is assumed that the contact was made at point a on the way to the empty space. Since both the diamond grindstone 6 and the dresser grindstone 0 are electrically conductive, their contact can be detected by the detection ring 7 in FIG. 1 and can be obtained as a skip signal.

Measurement operation Perform at position A in Figure 2. Such position selection is possible using the table 34 of the vertical machining center 1.
This is done using the X, Y, and Z axis movement functions.

After selecting the position, the end face of the diamond whetstone 6 is pressed against the end face of the contactor 11b, and the wear of the diamond whetstone 6 is measured based on the contact position. The entire operation and correction is done using a program created using a custom macro for the NC device.
Make the call in the following program.

G65 P The direction length, H is the tool offset number, and A is the type of bond, for example, 1: resin bond, 2: metal bond.

The contact between the diamond grindstone 6 and the dresser grindstone 10 is detected by the detection ring 6 shown in FIG. 1, and is given as a skip signal. At this time, the actual dimensions of the diamond grindstone 6 are calculated from the machine position at the point where the skip signal was obtained and the coordinates of the contact 11b. The tool correction is rewritten using the difference between the planned dimensions, the actual dimensions, and the actual dimensions of the diamond grindstone 5 as the correction amount. Furthermore, the diameter of the dresser grindstone 10 is calculated from the machine position at the final stage of dressing and the measured grindstone dimensions, and the corresponding tool correction memory is rewritten.

[Other Examples] A dressing device 40 shown in FIG. 6 has a dressing device main body fixed to a tombstone 41. The tombstone 41 is fixed on the pallet 9. It essentially performs the same function as the previous embodiment, but with the tombstone 41 removed,
If the dressing device 40 is directly fixed to the pallet 9 and the dresser grindstone 10 is replaced, there is an advantage that it can also be used as a horizontal shaft type dressing device.

Although the dresser grindstone 10 of the embodiment described above is driven using an air motor operated by air pressure supplied from below the table, the present invention is not limited to this. Electrical contacts may be provided on the table, bed, etc., and brought into contact with contacts provided on the dressing device to be driven by an electric motor. Furthermore, there is also a method of mounting a battery on the pallet and using it as a power source.
No need for codes etc.

[Effects of the invention] As detailed above, the dressing device of the present invention is mounted on a pallet and has two dressing surfaces that are orthogonal to each other. It has the advantage of being done.

[Brief explanation of the drawing]

Fig. 1 is an overall view of the present invention applied to a vertical machining center, Fig. 2 is an overview of the dressing device of the present invention, Fig. 3 is a side view of the dressing device of Fig. 2, and Fig. 4 FIG. 4a is a diagram showing the starting point when dressing the end face of the diamond grinding wheel, FIG. 4b is a diagram showing the locus of dressing the end face, and FIG. FIG. 5b is a diagram showing the trajectory of circumferential dressing, and FIG. 6 is a diagram showing another embodiment of the dressing device using a tombstone. 1... Vertical machining center, 6... Diamond grindstone, 8, 40, 50... Dressing device, 10... Grindstone for dresser, 9... Pallet,
11...Measurement block.

Claims (1)

[Claims for Utility Model Registration] A table that is provided so as to face a main shaft on which a grinding wheel to be dressed is removably mounted, and that has pallet clamping means that moves relative to the main shaft and clamps a pallet. The dressing device for a machine tool is equipped with an apex angle for dressing the grinding surface of the grinding wheel having one or two grinding surfaces in two directions different by 90 degrees. A dresser grindstone that forms a 90-degree conical dresser surface and is rotatably mounted at an angle of 45 degrees with respect to the axis of the main shaft; and a dresser drive means for driving the dresser grindstone are mounted on the pallet. A dressing device characterized by being provided with.