JPS5890452A - Grinding method and grinder using whetstone wheel - Google Patents

Abstract

PURPOSE:To improve the efficiency of grinding processing by performing it by prescribed times at the 1/3-1/2 cutting speed of a usual one without performing dressing a CBN whetstone after truing it and thereafter grinding a workpiece under a normal condition. CONSTITUTION:When a CBN whetstone grinds a workpiece under a normal condition without dressing the whetstone after tooling it, the surface of the whetstone welds resulting in the deterioration of processing quality, but when performing grinding reducing the cutting speed to 1/3-1/2, no deterioration of the quality is produced. In case workpieces of high-carbon chrome steel are subjected to infield grinding with the CBN whetstone, two workpieces are ground by reducing the cutting speed from 1.1 to 0.6mm./min in 3x and from 0.3 to 0.16mm. in 4x. From the third workpiece the cutting quality of the whetstone is also recovered, enabling processing with a normal cutting speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for grinding a workpiece made of hardened and tempered steel material using a ×××× grinding wheel, and a grinding machine for the same. It is an object of the present invention to provide an efficient grinding method for continuous and large-volume infeed grinding work, and a grinder for the same.

XXXX grinding wheels with cubic boron nitride as abrasive grains bonded by resin, vitrified or metal bond have a high grinding ratio and are very effective for difficult-to-cut materials, but when high-precision truing is performed, the grinding wheel surface becomes smooth. The sharpness of the whetstone deteriorates, and additional dressing is required to restore the sharpness. If the grinding process is applied, the grinding wheel surface will be welded and the processing quality will deteriorate. This problem has delayed the expansion of the use of stones in mass-produced precision grinding work, which requires the stable production of high-quality products with high efficiency.

However, the sharpness decreased by truing tends to recover as the grinding progresses and is maintained for a long time thereafter.In other words, the above problem of decreased sharpness is a temporary phenomenon immediately after truing. Conventionally, the workpieces during this period were disposed of as negative stock.

In order to avoid this negative stock, conventionally, in addition to the truing device, a dressing device was installed next to the grinding machine.
With this dressing device, alumina sticks etc. can be used alternately during true ink or after true ink.
They had no dressing. Therefore, the configuration of the grinding machine is complicated, and there are also problems in improving work efficiency and stabilizing quality.

This invention solves the above problems, and XXX
The X-grinding wheel is used to grind at the speed of the diamond true ink method, thereby eliminating the occurrence of negative stock immediately after the truing. The present invention will be explained in detail below based on the drawings. Figures 1 and 3 are diagrams showing the grinding cycle, and the inner cylinder 1 shows the conventional one, and Figure 2 shows the grinding cycle according to the present invention. Fig. 3 shows a method in which the reduced cutting speed is one stage and the number of pieces to be ground is two, and Fig. 3 shows the same method in which the reduced cutting speed of the present invention is two stages, and the first stage is one, and the second stage is one. An example in the case of two pieces is shown.(・In both cases, the horizontal axis is time and the vertical axis is the depth of cut.

In the conventional grinding wheel k shown in Fig. 1, the XXXX grinding wheel on the grinding machine is first trued, then dressed, and then table-ined to face the workpiece.
Start grinding. ■ indicates rapid advance, ■ indicates rough depth of cut, ■ indicates finished depth of cut, ■ indicates spark out, ■ indicates rapid retraction, and ■ indicates table out. te(・ta.In contrast, the second
In the illustrated embodiment of the method of the invention, a true-in-gaycle is performed. However, the cutting speeds for rough cutting and finishing cutting @ are the conventional normal speeds (■ and ■).
The workpiece immediately after truing ■ is ground using a grinding cycle ■ that is reduced by approximately 1/2 K.

Furthermore, in the embodiment shown in FIG. 2, the hardness is HRC
58 quenched and tempered high carbon chromium steel workpiece
When performing infeed grinding with XXX grinding wheel, the normal cutting speed is ■=1.1wv/Ih1■=0.3III/
For swK, the cutting speed immediately after truing is Qsong = 0
．． When reduced to 6m1m, (4 seconds = 0.16--,
No welding occurred on the grinding wheel surface, and stable, high-quality precision grinding was possible from the beginning even without dressing, and this reduced grinding cycle was recognized to be only two.

Next, referring to Fig. 3, the rough and finish cutting speeds ■ and @ in the grinding cycle ■ immediately after truing are 0.4- and 0.154-, respectively, and the normal cutting speed ■ and One workpiece is ground at 1/3 of ■ (first stage grinding cycle ■ is reduced to 1/2, and the second and third workpieces are rough and finish cutting speed is 6) and O, respectively. 01- and 0
This shows an embodiment of the present invention in which grinding is performed in the reduced second-stage grinding cycle ■ to approximately 2/3 of 2-3, and thereafter grinding is performed in the normal fast grinding cycle ■. It has been confirmed that it is possible to perform in-feed grinding with a high quality that is as stable as or even more stable than in the case shown in the figure, and that the above-mentioned negative stock can be eliminated.

Next, the structure of an embodiment of a grinding machine embodying the method of the present invention will be described with reference to FIGS. 4 and 5.

FIG. 4 is a schematic plan view of the grinding machine, and shows a bed 10.
The headstock slide 11 placed on top can be fed into the cut in the direction of arrow A. Reference numeral 12 is a main shaft, and 13 is a cutting feed device, which has a built-in pulse motor or hydraulic attacher, etc. (and whose cutting feed speed is variable by a control signal 14 from a control section 15. 16 is an auxiliary machine of the control section 15, and is a reduced grinding cycle condition setting section.

Further, a grindstone shaft table 17 is mounted on the bed 10 so as to be able to traverse in the direction of arrow B.
A grindstone shaft 18 is mounted on 7. A truing device 19 is provided opposite the grindstone S. Reference numeral 20 is a diamond weight, and W is a workpiece.

Now, the control section 15 and the reduced grinding cycle condition setting section 1
6, as shown in the block diagram in FIG.
A command is issued to switch to a reduced grinding cycle, and the cutting cycle is switched to a reduced grinding cycle at a preset cutting speed (1 stage, ■ stage, etc.). Next, grinding using the reduced grinding cycle is repeated for a predetermined number of pieces. On the other hand, in the reduced grinding cycle condition setting section 16 (as shown in the figure), the cutting speed (1st stage, 15) is inputted at a timely manner.

In this manner, when the grinding of a predetermined number of pieces at each stage of the preset cutting speed is completed, a command to return to the normal grinding cycle is issued and executed. At this time, the cutting speed and number of pieces have returned to the normal values set in advance, and after the normal grinding cycle has been executed for the number of pieces set above, it is determined that the truing time has been reached, truing is performed, and then truing is performed again. A signal 21 is issued and the series of grinding cycles described above are automatically repeated.

Since the grinding machine of the present invention is configured as described above, there is no need to set up the conventional dressing-only device and its control equipment, and the control unit 15 for simply instructing, executing, and returning to the switching of the grinding cycle, By simply adding a setting section 16 for setting the conditions, an infeed grinding machine that executes the grinding method of the present invention can be obtained. Automatic grinding machine can be provided.

Furthermore, to summarize the effects of this invention, it is possible to perform high-precision truing under appropriate conditions to obtain Borazon abrasive quality, and by eliminating negative stock immediately after truing, it is possible to achieve high quality with high efficiency. In mass production precision grinding work that requires stable production, ×××
×Since it will be possible to expand the use of whetstones, the effect it will have on this industry will be truly significant (・.

[Brief explanation of the drawing]

1 to 3 are diagrams showing grinding cycles, in which FIG. 1 is a conventional grinding cycle, FIG. 2 is an embodiment of the present invention, and FIG. 3 is another embodiment of the present invention. Examples are shown. FIG. 4 is a schematic plan view showing one embodiment of the grinding machine of the present invention, and FIG. 5 is a block diagram showing the control section 15 and the reduced grinding cycle condition setting section 16 in FIG. ■
...... Rough cutting speed, ■, @, @, 1)...
・Finish cutting speed, 12... Spindle, 13...
... Cut feeder, 15... Control section, 16...
...Reduced grinding cycle condition setting section, 18...
・Whetstone shaft, 19...Truing device, 21・
...Truing completion signal patent applicant NSK Ltd. Figure 4 No. 5

Claims (1)

[Claims] (1) A method of grinding a workpiece made of hardened and tempered steel material using a ×××× grinding wheel, the method comprising: ×××× grinding wheel, which is characterized by actually grinding several pieces of diamond true at a cutting speed of 1/3 to 2/3 of the normal cutting speed, and then returning to the normal cutting speed. Grinding method used. , (2) IA at normal cutting speed immediately after truing
Claim 1, characterized in that a preset plurality of workpieces to be actually ground at a cutting speed of ~2/3 are further subdivided, and each group is ground at a different cutting speed. Grinding method using ×××× grinding wheel. (3) A grinding machine that grinds a workpiece made of a hard steel material that has been quenched and tempered using a XXXX grinding wheel, including a diamond truing means for truing the Mukuro XXXX grinding wheel, and a grinding cycle immediately after truing. a grinding cycle reduction switching means for switching the cutting speed to a cutting speed of 1/3 to 2A of the normal cutting speed; a reduced grinding cycle number setting means for setting the number of workpieces to be ground in the reduced grinding cycle; and a return means for returning the reduced grinding cycle to the normal grinding cycle when the grinding of the truing bale is finished, and the grinding cycle of the truing bale is automatically switched to KJJ. A grinding machine that uses a grinding wheel.