JP3694746B2 - Machine tool rigidity simple evaluation method and test piece used in the method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for evaluating machine tool rigidity, and more specifically, to an evaluation method that can easily evaluate the rigidity of a machine tool by simply cutting a test piece.
[0002]
[Prior art]
One of the factors that must be considered when selecting cutting conditions that have a large impact on production efficiency is the rigidity of the machine tool. Thus, although the static and dynamic rigidity of the machine tool is important, the measuring method is not defined by JIS or the like. At present, each manufacturer and research institution determines and implements mechanical property testing methods as appropriate.
As an example, there is a method in which a jig for transmitting a force is provided between a machine spindle and a table, a force is applied between the two, and a relationship between the force and a displacement of each part of the machine is obtained using a measuring instrument.
[0003]
[Problems to be solved by the invention]
However, it is said that the rigidity of the machine tool varies greatly depending on the manufacturer, type, and usage status of the machine tool, and it can be said that there is practically no way for the user to know it. Each user is forced to select cutting conditions based on experience using the machine, which is one of the reasons that the recommended conditions of the tool manufacturer are not used.
In addition, for each of the above manufacturers and research institutes, not only jigs and measuring instruments are required, but the work itself is difficult. There was a problem that it was difficult to compare the data.
[0004]
An object of the present invention is to provide a simple evaluation method capable of easily evaluating the rigidity of a machine tool by measuring a residual material due to bending of a mechanical system including a tool by a cutting force when cutting a test piece with the tool. And
[0005]
[Means for Solving the Problems]
The principle of the present invention is that uncut material is generated by the bending of the mechanical system including the tool due to the cutting force, and the amount varies depending on various conditions related to cutting. The amount of uncut material when a test piece that has been changed automatically is cut from the resulting dimensional value and converted into mechanical rigidity for evaluation.
In order to achieve the above object, the machine tool rigidity simple evaluation method of the present invention measures the amount of uncut residue when a test piece is cut using a tool, and evaluates the machine rigidity from the value of the measured uncut amount. It is characterized by.
Moreover, the test piece of the present invention is characterized in that the cutting surface has a shape that changes stepwise in a direction in contact with the cutting blade of the tool.
The test piece of the present invention is characterized in that the cutting surface has a shape that changes stepwise in the cutting direction of the cutting blade of the tool.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples.
[Embodiment 1]
FIG. 1 is a perspective view of a test piece 1 according to Embodiment 1. The test piece 1 has, for example, a material of S55C, a size of about 80 mm long × 45 mm wide × 40 mm high, Both sides of the upper side protrude horizontally with a predetermined width so as to have the reference surface 2 on one side and the cutting surface 3 on the other side. The upper surface of the test piece 1 is formed in a step shape, and the width of the cutting surface 3 located on the side surface is changed stepwise. That is, the width of the cutting surface 3 located on each side surface of the step-like first surface 4, the second surface 5, and the third surface 6 is increased stepwise as t1, t2, and t3. The width of the cutting surface 3 formed by the surface 7 is t1 and is equal to the width of the first surface 4.
In this case, for example, t1 = 3 mm, t2 = 6 mm, and t3 = 9 mm are set.
Note that the cutting surface 3 of the test piece 1 is not limited to this example, and may be composed of a plurality of cutting surfaces whose width changes in stages.
[0007]
FIG. 2 shows a state in which the test piece 1 is attached to the work table 11 of the machine tool 8, and a reference surface of the standard test piece 1 is mounted on the blade surface of a tool mounted on the spindle 9 of the machine tool 8, for example, the end mill 10. 2 or the cutting surface 3 is attached so as to face each other.
Since the commercially available end mill 10 normally has a cutting blade provided in a spiral shape, the bending at the time of cutting does not occur sharply. Therefore, if possible, a standard cutting blade is provided in parallel to the tool axis rather than obliquely. It is desirable to have a tool. Moreover, in order to remove the influence of tool fluff, a one-blade one is desired.
[0008]
Next, an operation procedure will be described.
(1) The reference surface 2 of the test piece 1 is opposed to the blade surface of the tool 10, and the reference surface 2 is cut while giving an appropriate cut and feed. By this cutting process, the reference surface 2 of the test piece 1 becomes a plane parallel to the feed direction of the tool 10.
(2) The cutting surface 3 of the test piece 1 is opposed to the blade surface of the tool 10, and the cutting surface 3 is cut while giving an appropriate cut (for example, 0.1 mm) and feeding (for example, 0.1 mm / blade) ( Preliminary cutting). This cutting process is performed in order to make the cutting surface 3 of the test piece 1 into a plane parallel to the feed direction of the tool 10.
(3) Next, the cutting surface 3 is cut (first cutting) while giving an appropriate cut (for example, 0.3 mm) and feed (for example, 0.2 mm / blade).
(4) Cutting again under the same conditions (second cutting). By cutting twice. Depending on the cutting location, the cuts are made equal.
(5) The test piece 1 is removed from the machine tool 8, and the distance between the reference surface 2 and the cutting surface 3 is measured with a micrometer or the like. There are four measurement points corresponding to the first surface 4, the second surface 5, the third surface 6, and the fourth surface 7.
[0009]
Four locations corresponding to the first surface 4, the second surface 5, the third surface 6, and the fourth surface 7 based on the measurement results of the four locations of the reference surface 2 and the cutting surface 3 measured as described above. Calculate the amount of uncut material.
An example of the amount of uncut material measured with a micrometer was +26 μm for a 6 mm thick cut surface and +51 μm for a 9 mm thick cut surface with a 3 mm thick cut surface as a reference (± 0). .
FIG. 3 shows a cross-sectional curve of the cutting surface 3 of the test piece 1.
[0010]
This uncut amount can vary depending on the test piece material, tool edge shape, cutting conditions, and machine tool rigidity, but if the test piece, tool, and cutting conditions are made constant, it is considered to change depending on the machine tool rigidity. It is small in a machine tool with high rigidity and large in a machine tool with low rigidity.
In the machine tool shown in FIG. 2, the rigidity in the lateral direction of the main shaft 9 is mainly affected. In practice, however, the overall rigidity of the machine, the tool holder, and the work mounting relationship including the main shaft 9 is evaluated.
As an example, the value is obtained by dividing the remaining cutting amount of 26 μm with a thickness of 6 mm and the remaining cutting amount of 51 μm with a thickness of 9 mm. Specifically, since the thickness is based on 3 mm, it is divided by the increment of the cutting thickness. 26 / (6-3) = 8.66, 51 / (9-3) = 8.37, or an average value of 8.52 for each machine tool as an evaluation coefficient. Can be considered.
[0011]
[Embodiment 2]
FIG. 4 shows a case in which the rigidity of the entire machine, mainly the longitudinal rigidity of the rotary spindle 19 on which the tool 18 is mounted, is evaluated by cutting the upper surface of the test piece 13 with the end face of the end face cutting tool 18. It is a front view. In addition, since the operation procedure for evaluation is the same as that of the first embodiment, description thereof is omitted.
As shown in the drawing, the test piece 13 includes a first surface 14, a second surface 15, a third surface 16 whose thickness increases stepwise, and a fourth surface 17 having the same thickness as the first surface 14. (T1 <t2 <t3). When the tool 18 is rotated and sent in the direction of the arrow A with respect to the standard test piece 13, the first surface 14, the second surface 15 and the third surface 16 of the test piece 13 have different cutting amounts. The amount of uncut material on the surface is different. That is, the amount of uncut material on the second surface 15 and the third surface 16 increases with the first surface 14 as a reference.
[0012]
[Embodiment 3]
FIG. 5 is a plan view showing a case where the rigidity of the lathe is evaluated. In addition, since the operation procedure for evaluation is the same as that of the first embodiment, description thereof is omitted.
The test piece 20 has a cylindrical shape having a first surface 21, a second surface 22, a third surface 23 whose diameter increases stepwise, and a fourth surface 24 having the same diameter as the first surface 21. The rotation main shaft 26 is mounted (d1 <d2 <d3).
Now, when the tool 25 is sent in the direction of arrow B with respect to the test piece 20, the first surface 21, the second surface 22 and the third surface 23 of the test piece 20 have different cutting amounts. Uncut amount is different. That is, the amount of uncut material on the second surface 22 and the third surface 23 increases with the first surface 21 as a reference.
[0013]
Therefore, the machine tool whose rigidity is to be evaluated can easily have the rigidity by performing predetermined cutting using the test pieces of the first to third embodiments according to the shape of the machine tool. Can be evaluated.
Note that the test piece is not limited to the material, shape, and dimensions of the first to third embodiments, but may have other shapes depending on the shape of the machine tool. Further, the measurement of the uncut amount is not limited to the micrometer, and other measurement means can be applied.
[0014]
【The invention's effect】
The present invention has the following effects.
(1) By the universal work of cutting, the user himself can easily evaluate the rigidity including existing machine tools without requiring a special measuring instrument or the like.
(2) By cutting using a common test piece and tool, the rigidity of a plurality of machine tools can be objectively evaluated.
(3) The test piece can be manufactured by the machine tool itself used for the test.
(4) Any tool can be obtained by specifying the manufacturer and model.
(5) It is possible to efficiently select cutting conditions that have been performed by trial and error in the past, and the evaluation results can be used as data for maintenance of mechanical equipment.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a test piece according to Embodiment 1 of the present invention.
FIG. 2 is a front view showing a state in which a test piece is attached to the machine tool according to the first embodiment of the present invention.
FIG. 3 shows a cross-sectional curve of a cutting surface of a test piece.
FIG. 4 is a front view showing a test piece and a machine tool according to Embodiment 2 of the present invention.
FIG. 5 is a front view showing a test piece and a machine tool according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Test piece 2 Reference surface 3 Cutting surface 4 1st surface 5 2nd surface 6 3rd surface 7 4th surface 8 Machine tool 9 Spindle 10 Tool (end mill)
11 Work table 13 Test piece 14 First surface 15 Second surface 16 Third surface 17 Fourth surface 18 Tool 19 Spindle 20 Test piece 21 First surface 22 Second surface 23 Third surface 24 Fourth surface 25 Tool 26 Spindle

Claims (2)

Uncut remaining amount at multiple measurement points when using a tool to cut a test piece having a reference surface on one side and a cutting surface on the other side, and the width of the cutting surface changes stepwise A machine tool rigidity simple evaluation method characterized in that the machine rigidity is evaluated from the measured value of the remaining amount of cutting. In the test piece used for the simple machine tool rigidity evaluation means that measures the amount of uncut material when cutting a test piece with a tool and evaluates the machine rigidity from the measured amount of uncut material , a reference surface is provided on one side. A test piece having a cutting surface shape that has a cutting surface on the other side and the width of the cutting surface in contact with the cutting blade of the tool changes stepwise.

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