JP2017154202A - Processing method and processing device by end mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing method capable of reducing straightness even when there is swinging of an end mill.SOLUTION: A processing method for cutting a work by an outer peripheral blade by rotating an end mill of forming a plurality of strips of outer peripheral blades, corrects a notch quantity in the radial direction of the end mill 1 by a correction value, by determining the correction value (an offset value) of a processing margin such as the whole blades abut on the work W, when there is a blade of not abutting on the work W, by determining the processing margin of the respective blades by referring to a swing quantity of the respective blades to a cutting margin determined by a processing condition, by calculating the swing quantity of the respective blades from an edge part 5, by acquiring the edge part 5 of the outer peripheral blade as shape data of the plurality of strips of outer peripheral blades by swing measurement means 4 by rotating the end mill 1.SELECTED DRAWING: Figure 15

Description

  The present invention relates to a processing method and a processing apparatus using an end mill that perform cutting using an outer peripheral blade provided on a side surface of the end mill.

The purpose of cutting is to bring a cutting tool into close contact with the workpiece and remove a part of the workpiece to obtain a predetermined shape. Among cutting tools, an end mill having blades on the side surface and bottom surface can cope with various machining shapes and is used for machining various parts. The accuracy required for end milling includes dimensional accuracy, surface roughness, squareness, straightness, and the like.
Machining with an end mill is a method in which a part of the workpiece is cut and removed by contacting the workpiece while rotating the end mill to obtain a machined surface. Since the resistance and the direction of its action fluctuate, the work is cut while the rotation center axis of the end mill is deformed. Therefore, the machined surface is not a straight line but a wave shape, and the straightness increases. In order to bring the shape of the processed surface close to a straight line, it is necessary to take measures such as reducing the fluctuation of the cutting force, or reducing the cutting force itself to relatively reduce the fluctuation amount.

In response to these problems, for example, when the end mill is brought into contact with the work surface of the workpiece and cutting is performed, the variation in cutting resistance is suppressed by keeping the sum of the contact lengths of the outer peripheral blades involved in the cutting constant, An end milling method is disclosed that suppresses fluctuations in the amount of tilting of the cutting tool due to fluctuations in cutting resistance and reduces straightness (see, for example, Patent Document 1).
In addition, a processing method for reducing the straightness by measuring the rotational vibration of the end mill and the processing machine in advance and calculating the mounting method of the end mill that reduces the straightness from the data is also disclosed (for example, patents). Reference 2).

JP 2004-34171 A (page 2-3, FIG. 2) Japanese Patent Laying-Open No. 2010-240802 (page 4-5, FIG. 10)

In the processing method of Patent Document 1, there is a case where the blade of the tool does not hit due to tool runout caused by tool manufacture, tool runout caused by attachment to the processing machine, spindle of the machine, etc. When the contact length of the blade fluctuates, there is a problem that the cutting resistance fluctuates, and the fluctuation of the cutting resistance increases the amount of tilting of the cutting tool and increases the straightness.
In the processing method of Patent Document 2, it is necessary to attach to the processing machine in accordance with the calculated end mill attachment method. However, since the end mill is usually attached to the processing machine via the holder, in actuality, the deflection caused by the accuracy of the holder, and Because it is necessary to consider the influence of runout caused by attaching the end mill to the holder, the shake may increase due to adhesion of dust or rust, and these installation operations are usually performed manually. There was a problem that it took time to install and adjust. In addition, since the blade with large runout and wear are large, there is a problem that the state of runout changes with the progress of tool wear, and the predicted result and the machining result are different.

  The present invention has been made to solve the above-mentioned problems, and can suppress fluctuations in the contact length of the outer peripheral blade even when there is a runout. An object of the present invention is to provide a processing method and a processing apparatus that can reduce the size of the substrate.

  A processing method using an end mill according to the present invention is a processing method in which a work is cut with an outer peripheral blade by rotating an end mill on which a plurality of outer peripheral blades are formed. Obtain the shape data of each edge of the peripheral blade, calculate the amount of runout of each blade based on the shape data, and refer to the amount of runout of each blade with reference to the amount of runout of each blade against the cutting allowance determined by the processing conditions The machining allowance is calculated, and if there is a blade that does not touch the workpiece, the machining allowance correction value is calculated so that all the blades come into contact with the workpiece, and the end mill radial cutting depth is corrected by the correction value. is there.

  Further, it is a processing method in which an end mill formed with a plurality of outer peripheral blades is rotated to cut a workpiece with the outer peripheral blade, and a life machining allowance of the end mill is set in advance in consideration of the tool life. Rotate to obtain the shape data of each blade of the outer peripheral blades by the runout measurement means, calculate the runout amount of each blade based on the shape data, and each blade for the cutting allowance determined by the processing conditions If the machining allowance of each blade is determined by referring to the amount of run-out, and the machining allowance of each blade is all greater than the life machining allowance, the end mill It corrects the cutting depth in the radial direction.

  Further, the processing apparatus according to the present invention includes an end mill having a plurality of outer peripheral blades formed thereon, a main shaft for rotating the end mill, a runout measuring means for acquiring a runout amount of each of the plural outer peripheral blades, and a runout measurement. And a control unit that calculates the correction amount of the cut amount in the radial direction of the end mill based on the deflection amount obtained from the means and corrects the movement of the spindle.

  According to the processing method by the end mill of the present invention, with respect to the cutting allowance determined from the processing conditions, the machining allowance of each blade is obtained with reference to the amount of deflection of each blade, and when there is a blade that does not hit the workpiece, Since the correction value of the machining allowance is calculated so that all the blades are in contact with the workpiece, and the amount of cut in the radial direction of the end mill is corrected by the correction value, even when the runout is large and the number of simultaneous cutting edges fluctuates, By correcting, the amount of cutting in the radial direction is adjusted to stabilize the number of simultaneous cutting edges, and the variation in cutting resistance can be reduced, so that the straightness can be reduced.

  In addition, the end mill life machining allowance is set in advance, the end mill is rotated, the shape data of each of the outer peripheral blades of the plurality of strips is acquired by the shake measuring means, and the amount of runout of each blade is calculated based on the shape data. Calculate and calculate the machining allowance of each blade with reference to the runout amount of each blade for the cutting allowance determined from the machining conditions, and if the machining allowance of each blade is greater than the life machining allowance, The end mill radial cutting amount is corrected so that the minimum machining allowance is the life machining allowance, so that the tool life can be extended while improving the straightness, reducing the tool cost and tool change cost. it can.

  In addition, according to the processing apparatus of the present invention, the end mill in which a plurality of outer peripheral blades are formed, the main shaft for rotating the end mill, the vibration measuring means for acquiring the amount of vibration of each blade of the plurality of outer peripheral blades, and the vibration Since it has a control unit that corrects the movement of the spindle by calculating the correction amount of the cutting amount in the radial direction of the end mill based on the deflection amount obtained from the measuring means, the fluctuation in cutting resistance can be reduced, The straightness of the processed surface can be reduced.

It is an external view of the end mill used for the processing method of Embodiment 1 of this invention. It is the figure which attached the end mill of FIG. 1 to the holder and the main axis | shaft. It is explanatory drawing of the measuring method of the runout of the end mill blade in the processing method of Embodiment 1 of this invention. It is explanatory drawing which shows the relationship between the shape data of the outer periphery blade obtained by the measurement of FIG. 3, and the position of the blade accompanying rotation. It is a figure which shows the relationship between the distance L to the edge part obtained from shape data, and rotation time. FIG. 6 is a diagram corresponding to FIG. 5 when the blade has runout. It is explanatory drawing which shoulders a workpiece | work with an end mill. It is the plane enlarged view of FIG. 7, and its side sectional drawing. It is explanatory drawing explaining the change of the edge part when there exists a shake in an outer periphery blade, (a)-(c) is side sectional drawing of the part corresponded to FIG.8 (b), (d)-(f) is. It is a plane sectional view of CC section corresponding to a figure just above. FIG. 9 is a diagram showing an example of each dimension in the same plane sectional view as FIG. 8. It is side surface sectional drawing of FIG. 10 corresponding to (a)-(c) of FIG. It is a top view explaining the cutting allowance of the next blade when the previous blade in FIG. FIG. 13 is a side view corresponding to (a) to (c) of FIG. 11 in the case of FIG. 12. It is a figure which shows the relationship between the maximum machining allowance per blade and cutting resistance in the end mill process with respect to the workpiece | work of SS400 material. It is a side view of the cutting part explaining the correction method by Embodiment 1. FIG. It is a figure which shows the cutting allowance and cutting resistance of each blade in the case of FIG. It is explanatory drawing explaining the other example of the deflection | deviation measuring method of an end mill. It is side surface sectional drawing of the edge part for demonstrating the processing method of Embodiment 2. FIG. 6 is a side cross-sectional view showing an example corrected according to Embodiment 2. FIG. It is side surface sectional drawing of the edge part for demonstrating the processing method of Embodiment 5, and is a figure which shows the machining allowance and cutting resistance of each blade in case of no correction | amendment for a comparison. It is a figure which shows the machining allowance and cutting resistance of each blade at the time of correct | amending with the processing method of Embodiment 1 for the comparison. FIG. 10 is a side cross-sectional view showing an example after correction, corrected in accordance with Embodiment 5. It is a figure which shows the machining allowance and cutting resistance of each blade in the case of FIG. It is a block diagram which shows the processing apparatus by Embodiment 7. It is a principal part block diagram of the processing apparatus by Embodiment 8. It is a principal part block diagram of the other example of the processing apparatus by Embodiment 8. FIG. It is explanatory drawing about the straightness improvement by improvement of an inclination component.

Embodiment 1 FIG.
1A and 1B are external views of an end mill 1 used in the processing method according to Embodiment 1 of the present invention. FIG. 1A is a side view and FIG. 1B is a bottom view. FIGS. 2A and 2B are side views showing the attachment state of the end mill 1. FIG. 2A shows a state in which the end mill 1 is attached to the holder 2, and FIG. 2B shows a state in which (a) is attached to the main shaft 3 of the processing apparatus. Yes. FIG. 3 is a side view showing a method for measuring the deflection of the blade of the end mill 1.

As shown in FIG. 1, the end mill 1 has a cylindrical shank portion 1a and a blade portion 1b. The blade portion 1b includes an outer peripheral blade 1c formed on the outer peripheral portion and a bottom blade 1d formed on the bottom surface portion. Consists of. The outer peripheral blade 1c is formed in a spiral shape with a predetermined twist angle around the axis of the end mill 1, and a plurality of strips are arranged at equal intervals in the circumferential direction at a predetermined pitch.
The end mill 1 is attached to the holder 2 as shown in FIG. The holder 2 has a collet 2a, a tapered surface 2b, and a pressing surface 2c. From the state of (a), the collet 2a is drawn into the main shaft 3, and the holder 2 and the end mill 1 are attached to the main shaft 3 by combining the tapered surface 2b and the pressing surface 2c of the holder 2 with the mounting portion of the main shaft 3. 2 (b). That is, the end mill 1 is attached to the main shaft 3 via the holder 2, and the end mill 1 is rotated by the main shaft 3 to process the side surface or the bottom surface of the workpiece with the outer peripheral blade 1c or the bottom blade 1d.

FIG. 3 is a diagram illustrating a method for measuring the deflection of the blade of the end mill 1 according to the first embodiment. The shake measuring means 4 having the light emitting part 4a and the camera part 4b is arranged so as to sandwich the part of the outer peripheral blade 1c of the end mill 1 attached to the main shaft 3.
In the state shown in FIG. 3, the end mill 1 is rotated, the light emitting unit 4 a emits light, and light is applied to the end mill 1 to clarify the outline, and the end mill 1 is continuously photographed by the camera unit 4 b. The captured image is subjected to image processing by a control unit (not shown), and the edge portion 5 (see FIG. 5) of the outer peripheral blade 1c of the end mill 1 is detected. The processing apparatus will be described later.

  The processing method by the end mill according to the first embodiment is characterized in that a correction amount is calculated based on the shape data obtained by the above-described runout measurement means 4 to correct the cutting amount in the radial direction of the end mill at the time of processing. The specific correction method will be described later. First, the relationship between the outer peripheral blade 1c and the captured image when the end mill 1 is rotated will be described.

FIG. 4 is an explanatory diagram of an image obtained by rotating the end mill 1 at a certain rotational speed, for example, 2.5 rpm, photographing the outer peripheral blade 1c portion of the end mill 1 with the camera unit 4b, and performing image processing. The number of blades indicates a case of 6, and symbols I to IV are attached to each blade. FIG. 4A shows images of X seconds, X + 1 seconds, X + 2 seconds, X + 3 seconds, and X + 4 seconds among the images subjected to image processing. (B) shows the change in the planar shape of the end mill 1, the rotation direction (arrow) of the end mill 1, and the position of the blades I to IV along with the rotation in the cross section of the broken line AA in FIG. Corresponds to the image of (a). In (a), the distance from the left end of the image at the AA line portion to the edge portion 5 obtained by the image processing of the end mill 1 is L, and this L is L _X in X seconds and L _{X + 1} in X + 1 seconds. It represents as follows.

FIG. 5 is a diagram showing a change in L with respect to time in FIG. L is the smallest when any of the blades I to IV comes on the broken line AA. When the blade II comes on the broken line A-A at X seconds, the angle between the rotation center and the blade I and the blade II is 60 degrees, and the distance from the rotation center to the blade I and the blade II is the same. If it exists, since the end mill 1 is rotating at 2.5 rpm, the time for rotating from the blade I to the blade II is 4 seconds. That is, the next blade I comes on the broken line A-A after X + 4 seconds.
In FIG. 4, the amount of runout of each blade at each position in the axial direction of the end mill 1 during rotation can be grasped by moving the broken line AA up and down and examining the change in L.
In this way, by grasping the change in L and the number of rotations, the amount of shake during rotation of each blade is grasped, and image processing is performed in a control unit (not shown) to acquire data of the edge portion 5. This edge part 5 is the shape data of each blade described in the claims.
In addition, in FIG. 5, the case where the distance to the blade center of a rotation center and each blade is equal is shown.

FIG. 6 shows changes in L over time when the distance between the blade I and the rotation center is smaller than the distance between the blade II and the rotation center, and the angle formed by the rotation center, the blade I, and the blade II is greater than 60 degrees. Is shown. Since the angle formed by the rotation center and the blades I and II is larger than 60 degrees, L corresponding to the blade I is larger than L _{X + 4} . In such a case, the time range is determined and the value of the peak is defined as blade II. For example, the range is from (X + 1) seconds to (X + 7) seconds. When the peak value at that time is L _{X + 4 + α} , the difference in shake amount can be calculated by an equation such as (L _{X + 4} −L _{X + 4 + α} ).

  7A and 7B are views showing shoulder cutting by the end mill 1, wherein FIG. 7A is a perspective view and FIG. 7B is a top view of FIG. Description of the holder 2 and the main shaft 3 is omitted. By rotating the end mill 1 and moving the end mill 1 relative to the workpiece W, the processing surface of the workpiece W is cut by the outer peripheral blade 1c and the bottom blade 1d of the end mill 1.

FIG. 8 is an enlarged view of the portion of FIG. (A) is a top view, (b) is side surface sectional drawing in BB of (a). In addition, the description about the fall of the end mill 1 by cutting resistance was abbreviate | omitted. That is, the case where the dimension from the center of the outer peripheral blade 1c to the blade tip of each blade is the same, there is no vibration, and the center axis of the end mill 1 and the rotation axis coincide is shown. The hatched portion indicates the machining allowance by the outer peripheral blade 1c of the end mill 1, and as shown in (a), the line BB passes through the portion where the thickness T of the processed portion is the thickest.
In the case of FIG. 8, all the blades of the outer peripheral blade 1c in contact with the workpiece W cut the machining allowance. However, in actuality, the outer peripheral blade 1c is subject to variations during manufacture of the end mill 1 and vibrations due to the attachment of the end mill 1, the holder 2, and the spindle 3 itself. Next, a case where there is such a shake will be described.

FIG. 9 is an explanatory diagram for explaining the change of the contour line, that is, the edge portion 5 when the outer peripheral blade 1c is shaken. (A)-(c) is side surface sectional drawing of the part corresponded to FIG.8 (b), and is displayed combining the edge part 5 obtained by image processing, and the cutting surface of the workpiece | work W. FIG. (D)-(f) is a plane sectional view of CC section corresponding to each of (a)-(c) of the above.
In (a) and (d), the blade I hits the workpiece W in the CC section and contributes to cutting, but in (b) and (e) rotated by one edge, the outer peripheral edge of the CC section The blade VI, which is swayed, does not hit the workpiece W due to this influence and does not contribute to cutting. In the following (c) and (f), the blade V hits the workpiece W and contributes to cutting. At this time, it is necessary to cut the blade V including the uncut portion by the blade VI. When the runout amount during rotation of the blade I and the blade V is the same, the cutting amount by the blade V is twice the cutting amount by the blade I. . That is, the maximum value of the cutting force becomes larger than when there is no runout, and the cutting force fluctuates.

Moreover, (a) has changed into four places, (b) has changed into three places, (c) has changed into four places. That is, when there is no run-out, there was no change in the number of cutting points (the number of simultaneous cutting edges), but when there is run-out, the number of cuts varies due to run-out, resulting in fluctuations in cutting resistance.
Hereinafter, the magnitude and amount of fluctuation of the cutting force in FIGS. 9A, 9B, and 9C will be described with specific examples.
FIG. 10 is a plan view when viewed in the same manner as (d) to (f) of FIG. 9 and shows an example of each dimension. 11 is a side view of FIG. 10 corresponding to (a) to (c) of FIG.

In FIG. 10, the distance from the rotation center of the end mill 1 to each outer peripheral edge of the blade IV is 10 mm, the cutting allowance of the workpiece W in the radial direction by the end mill 1 is 50 μm, and the feed amount of the blade is 0.05 mm / tooth. If the direction of rotation of the end mill 1 is the direction of the arrow, the machining allowance per blade is the shaded area in FIG. These are determined from the processing conditions.
At this time, assuming that the distance from the rotation center of the end mill 1 to the cutting edge is always constant, the maximum thickness T cut per tooth is about 7 μm from the geometrical relationship.

Here, assuming that the distance from the rotation center of the end mill 1 to the cutting edge of the blade VI is 10 μm smaller than the distance from the rotation center of the blades I to V to the cutting edge, side surfaces corresponding to FIGS. The figure is as shown in (a) to (c) of FIG.
In FIG. 11A, the machining allowances of the four blades that come into contact with the workpiece W are all 7 μm. In (b), the blade VI on the line CC is separated from the workpiece W by 3 μm. At this position, the machining allowance of the other blades above and below the blade VI in the axial direction is 7 μm. In the next position (c), the machining allowance of the blade V on the line CC and other blades in the axial direction is 7 μm. However, there are actually uncut areas.

FIG. 12 is a plan view for explaining the machining allowance of the next blade in the case where the previous blade in FIG. FIG. 13 is a side view corresponding to (a) to (c) of FIG. 11 when uncut portions are generated.
In the example shown in FIG. 12, the maximum thickness cut by the blade V that comes after the blade VI that did not hit is about 13 μm from the geometrical relationship, and this portion is the machining allowance of the blade V.
In FIG. 13, the machining allowance of each blade at each position (a) to (c) in the feed direction is the numerical value described in the upper part of the square in FIG. As can be seen from the drawing, at the position 13 (c), the machining allowance of the blade V is 13 μm including the uncut portion.

FIG. 14 shows the relationship between the machining allowance per blade (the maximum thickness per blade is cut) X (mm / tooth) and the cutting resistance Y (MPa) for end milling when the workpiece W is made of SS400. It is a figure. As the machining allowance per tooth decreases, the cutting resistance decreases. However, even when the machining allowance is zero, the cutting resistance does not become zero. This is because a friction component is included in the cutting force.
The cutting resistance Y of end milling in the case of SS400 can be expressed by the following formula (1) with respect to the maximum machining allowance X per blade.

  Y = 1430X + 96.2 (1)

Accordingly, the machining allowance X of each blade at each position shown in FIG. 13 is applied to the above formula (1) to calculate the cutting resistance Y, and the cutting resistance Y of each blade is shown in the lower part of the square in FIG. (The unit MPa is omitted. The same applies hereinafter).
For each of FIGS. 13A, 13B, and 13C, the sum of the cutting resistance Y of each blade is 433 of (c) and (b) 318 of the minimum, and the difference between the maximum and the minimum Is 115. The greater the difference, the greater the straightness of the processed surface of the workpiece W. That is, in order to improve straightness, it is desirable to reduce the variation in cutting resistance.

According to the above description, the shape data obtained by measuring the end mill 1 using the shake measuring means 4 including the light emitting unit 4a and the camera unit 4b as shown in FIG. 3, the amount of deflection of the end mill 1 and the cutting resistance. Have described the relationship.
The invention of the first embodiment is characterized in that the machining allowance of the end mill is corrected based on the relationship as described above. Next, this correction method will be described.

  FIG. 15 is an explanatory diagram for explaining a processing method by an end mill according to the first embodiment. The shape data obtained from the photographed image measured using the shake measuring means 4 as described with reference to FIG. 3 is, for example, an image like the edge portion 5 shown in FIG. 13 as described above. Therefore, in FIG. 15, a method of correcting the cutting amount of the end mill 1 using the shape data of FIG. 13 will be described.

The point of correction by the processing method of the first embodiment is a point to correct so that all the blades come into contact with the workpiece W.
In the case of FIG. 13, the blade VI is not in contact with the workpiece W at the position (b). Therefore, as shown in FIG. 15, the end mill 1 is corrected by 3 μm toward the workpiece W so that the blade VI contacts the workpiece W. That is, the offset amount is set to 3 μm with respect to the reference rotating shaft of the end mill 1, and this amount is offset toward the workpiece W side.
In the description of the offset direction (moving direction of the rotary shaft), when referring to the workpiece W side or the side away from the workpiece W, it refers to the direction indicated by the line BB in FIG. And

FIG. 16 is a diagram showing the machining allowance and cutting resistance of each blade after correction as shown in FIG. The upper part in the square shows the machining allowance, and the lower part shows the cutting resistance. The cutting resistance is calculated from the above formula (1) based on the machining allowance.
In FIG. 16, among the sum of the cutting resistance of each blade for each of (a), (b), and (c), the maximum is 452, the minimum is 429, and the difference between the maximum and minimum is 23. Before the correction, the difference was 115 as described above with reference to FIG. Regarding the cutting resistance value, after correction, the maximum value increases by about 4% compared to before correction, but the difference between the maximum value and the minimum value decreases by about 80%. Since the cutting resistance greatly affects the straightness, the straightness after the correction is about 80% smaller than that before the correction.

Thus, by measuring the run-out amount of each blade of the end mill 1 at the time of rotation and correcting the cutting amount (processing allowance) in the radial direction so that all the blades come into contact with each other, Even when the tool blades do not touch, the tool shake due to attachment to the processing equipment and the main spindle of the processing equipment will bring all the blades into contact with each other, suppressing fluctuations in cutting resistance and suppressing increase in straightness. it can.
Furthermore, since the end mill 1 is mounted on the spindle of the processing apparatus and rotated, the amount of deflection of each blade is measured. Therefore, the deflection caused by the accuracy of the holder, the influence of the deflection caused by the attachment of the end mill to the holder, and dust There is no need to consider the effects of adhesion and rust.
Moreover, since there is no big restriction | limiting in an installation operation, it does not require time for attachment and adjustment of an end mill. Furthermore, since the amount of runout of each blade of the end mill 1 during rotation can be measured, even when the state of blade runout changes due to wear of the endmill 1, the straightness can be prevented from deteriorating by changing the correction amount.

  In the first embodiment, the end mill 1 including the outer peripheral blade 1c and the bottom blade 1d is exemplified as shown in FIG. 1, but only the outer peripheral blade 1c may be used. Moreover, although FIG. 1 is what is called a solid end mill, it is not limited to this, A brazing, a tip exchange type, and a throw away type may be used besides solid. Further, the holder 2 is not limited to the holder shape shown in FIG. Alternatively, the end mill 1 may be directly attached to the main shaft 3 without using the holder 2.

Moreover, although the measuring method of the blade runout of the end mill 1 at the time of rotation was demonstrated using FIGS. 3-6, it is not limited to this. For example, as shown in FIG. 17, the left edge 6 and the right edge 7 are detected, and a change in the distance L between the two points and a change in the position of the center position 8 are detected, whereby the blade runout of the end mill 1 during rotation is detected. May be measured.
Further, the blade runout of the end mill during rotation may be measured using a contact type sensor such as a touch sensor. Alternatively, a blade workpiece during rotation may be measured by preparing a dummy workpiece, machining the dummy workpiece with an end mill, and measuring the machining surface. Further, the correction amount of the machining allowance in the radial direction may be provided with an upper limit value because excessive correction may exceed the allowable accuracy.

As described above, according to the processing method using the end mill according to the first embodiment, the end mill in which a plurality of outer peripheral blades are formed is rotated to cut the workpiece with the outer peripheral blade, and the end mill is rotated. The shape data of each blade of multiple threads is acquired by the run-out measuring means, the run-out amount of each blade is calculated based on the shape data, and the run-out amount of each blade is referred to the cutting allowance determined by the machining conditions Then, calculate the machining allowance for each blade, and if there is a blade that does not hit the workpiece, calculate a correction value for the machining allowance so that all the blades abut the workpiece, and use the correction value to cut the end mill in the radial direction. Therefore, even if the runout is large and the number of simultaneous cutting edges fluctuates, the correction can adjust the radial cutting depth to stabilize the number of simultaneous cutting edges and reduce the fluctuation in cutting resistance. Can reduce the degree That.
In addition, since the end mill is rotated to measure the amount of shake of each blade, it is not necessary to consider the influence of the shake due to the attachment, and adjustment at the time of attaching the end mill is facilitated.

Embodiment 2. FIG.
The processing method according to the second embodiment focuses on the tool life of the end mill 1.
The end mill 1 using the shake measuring means 4 having the light emitting part 4a and the camera part 4b as shown in FIG.
Measuring the contour portion of the blade, detecting the edge portion 5 of the outer peripheral blade 1c of the end mill 1 by image processing, obtaining the shape data of each blade, and calculating the deflection amount of each blade based on the shape data. The same as in the first embodiment.

In the second embodiment, a machining allowance for obtaining an appropriate tool life for the end mill 1 to be used is set in advance as a “life machining allowance”. Since the tool life varies depending on the material of the end mill 1, the material of the workpiece W, machining conditions, and the like, the life machining allowance may be determined with reference to accumulated data. Specifically, the machining allowance is set to a known state, a life test is performed at various machining allowances, and a machining allowance that provides a desired life is defined as a “life machining allowance”.
Next, with respect to the cutting allowance determined from the machining conditions for the workpiece W to be processed, the machining allowance of each blade of the end mill 1 is obtained with reference to the amount of deflection of each blade.
When the machining allowance of each blade is greater than the life machining allowance, the radial cutting amount is corrected so that the minimum value of the machining allowance of each blade is the life machining allowance. The correcting means is provided in the control unit of the processing apparatus.

For example, as an example, the life machining allowance for obtaining an appropriate tool life is set to 3 μm. If the cutting allowance before correction is as shown in FIG. 18, the machining allowances are 7 μm, 6 μm, and 7 μm, respectively, and the minimum value of the machining allowance is 6 μm.
Accordingly, since the life machining allowance is 3 μm, the rotation center of the end mill 1 is corrected to be offset by 3 μm away from the workpiece W. If all machining charges are within the life machining allowance, there is no need for correction.

FIG. 19 is a side sectional view after correction. As shown in the figure, the machining allowance of (a) on the line CC is 4 μm, the machining allowance of (b) is 3 μm, and the machining allowance of (c) is 4 μm.
According to such a processing method, the cutting resistance can be reduced compared with the conventional one by approaching the life processing allowance, so that the straightness can be improved and the tool life can be extended. Tool replacement costs can also be reduced.

  As described above, according to the processing method using the end mill according to the second embodiment, the end mill in which a plurality of outer peripheral blades are formed is rotated to cut the workpiece with the outer peripheral blade, and the tool life is considered. Set the life machining allowance of the end mill in advance, rotate the end mill, acquire the shape data of each of the outer peripheral blades of the multiple strips by the runout measurement means, and calculate the amount of runout of each blade based on the shape data Calculate and calculate the machining allowance of each blade with reference to the runout amount of each blade for the cutting allowance determined from the machining conditions, and if the machining allowance of each blade is greater than the life machining allowance, Since the cutting depth in the radial direction of the end mill is corrected so that the minimum machining allowance becomes the life machining allowance, the tool life can be extended while improving the straightness, and the tool cost and tool change cost are also reduced. it can.

Embodiment 3 FIG.
The processing method according to the third embodiment adds the following points to the processing methods of the first and second embodiments. That is, it includes straightness predicting means for predicting straightness in advance from the shape data of the end mill 1, processing conditions, and the amount of deflection of the end mill 1 during rotation, and the processing method of the end mill according to the first or second embodiment is applied. If it is predicted that the predetermined straightness will not be entered even if corrected, the mounting state of the end mill 1 is changed, the measurement is performed by the shake measuring means 4 as in the first embodiment, and again, The amount of deflection of each blade of the end mill 1 is calculated, and if it is determined that a predetermined straightness is obtained, machining is started.
The change of the mounting state is to carry out any of the following.
(1) The tool is automatically changed to another end mill that has been waiting in the tool change area.
(2) The holder 2 is rotated from the main shaft 3 by a fixed angle different from 360 degrees to change the direction and is remounted on the main shaft 3. That is, it is rotated in the radial direction and fixed at a different position.

In the above description, the straightness predicting means is provided in the control unit of the machining apparatus. The straightness prediction is performed as follows, for example.
First, the cutting phenomenon is divided every minute time. A force is applied to the part where the end mill 1 is cutting the workpiece W. This force can be calculated from the shape of the end mill 1, specifically, the rake angle, the twist angle, the clearance angle, and the material of the workpiece W. The amount of deflection of the end mill can be determined by knowing the load location, its force, and the rigidity of the end mill 1. The deformation of the entire end mill is known from the amount of deflection, and the shape becomes the cutting surface. It is possible to predict the shape of the cut surface after end mill cutting by repeating this process every minute time. Straightness can be obtained from the shape of the cutting surface.
The predetermined straightness refers to the straightness of the workpiece machining surface desired by the user, and is determined in advance by the user.

  As described above, according to the processing method using the end mill according to the third embodiment, in addition to the method according to the first or second embodiment, the straightness is predicted in advance from the shape data, the processing conditions, and the runout amount of the end mill. If it is determined that the predetermined straightness cannot be obtained even if the direction cut amount is corrected, the end mill mounting state is changed and the runout amount of each blade of the end mill is calculated again to obtain the predetermined straightness. If it is possible, since the processing is started, it is possible to prevent the processing failure, reduce the line stop time, and contribute to the cost reduction.

Embodiment 4 FIG.
The machining method according to the fourth embodiment is the same as that of the third embodiment until it includes straightness predicting means for predicting straightness from the shape data of the end mill 1, machining conditions, and the amount of deflection of the end mill 1 during rotation. It is. In the fourth embodiment, a database of the relationship between the rotational speed and the blade runout and a database of the relationship between the rotational speed or the cutting speed and the cutting resistance are further provided, and a predetermined straightness can be obtained even if the cutting amount in the radial direction is corrected. If it is determined that the rotation speed cannot be obtained, the rotation speed is changed so that a predetermined straightness can be obtained by using the database of the relationship between the rotation speed and the blade runout and the database of the rotation speed or cutting speed and the cutting resistance. To do.

For example, the rotation speed is changed as follows.
(1) The rotational speed is reduced to reduce rotational runout.
(2) The feed rate is kept as it is, and the rotational speed is increased to increase the cutting speed to reduce the cutting resistance.

  As described above, according to the processing method using the end mill of the fourth embodiment, in addition to the method of the first or second embodiment, the database of the relationship between the rotational speed and the blade run-out, and the rotational speed or cutting speed and cutting resistance. If the straightness is predicted in advance from the shape data of the end mill, machining conditions, and runout amount, and it is determined that the predetermined straightness cannot be obtained even if the cutting amount in the radial direction is corrected Since the rotation speed is changed so that a predetermined straightness can be obtained by using the database of the relationship between the rotation speed and the blade runout, and the database of the relationship between the rotation speed or the cutting speed and the cutting resistance, the straightness It is possible to prevent the deterioration by suppressing the deterioration of the line, reduce the line stop time, and contribute to the cost reduction.

Embodiment 5. FIG.
In the fifth embodiment, the processing method of the first embodiment is provided with straightness predicting means for predicting straightness in advance from the shape data of the end mill 1, processing conditions, and the amount of deflection of the end mill 1 during rotation. When it is determined that the straightness is deteriorated with reference to the predicted straightness even when the processing method 1 is applied, the following correction is further performed.
That is, as a result of predicting the straightness in the straightness prediction means, if it is determined that the straightness deteriorates and the predetermined straightness cannot be obtained, machining in the end mill radial direction that minimizes the straightness in the runout amount A machining correction value is calculated, and the correction value is applied to the cutting depth in the radial direction of the end mill. Hereinafter, an example of an edge portion where the straightness is deteriorated will be described.

  FIG. 20 is a diagram corresponding to FIG. 13 described in the first embodiment, and shows a case where the blade runout amount on the line CC at the position (b) is 107 μm. The machining allowance of each blade when no correction is performed with this shape is shown in the upper part of the square in the figure. Further, the lower part shows the cutting resistance of each blade corresponding to the machining allowance. As shown, the cutting resistance is the same as in FIG. Of the sum of the cutting resistance of each blade at each position, the maximum is 433, the minimum is 318, and the difference between the maximum and minimum is 115.

FIG. 21 shows a correction value obtained by correcting the cutting depth in the radial direction with respect to the blade shape of each blade as shown in FIG. is there. Specifically, correction is made so that the rotation center of the end mill 1 approaches 100 μm with respect to the workpiece. The machining allowance of each blade at this time is shown in the upper part of the square in the figure, and the corresponding cutting resistance is shown in the lower part. As can be seen from the figure, the sum of the cutting resistance of each blade is 1001, the maximum is 843, and the difference between the maximum and minimum is 158.
When the machining method as in the first embodiment is applied, the maximum value of the cutting force is 2.31 times (433 → 1001) after the correction of the cutting amount (cutting allowance) in the radial direction, and the difference between the maximum and the minimum is 1. .38 times (115 → 158), the straightness increases. Thus, when the radial cut amount is corrected so that all the blades are in contact with each other, the straightness may be deteriorated.

  Therefore, in the fifth embodiment, when it is determined that the predetermined straightness cannot be obtained, the calculation is performed so that the straightness is minimized, and the cutting amount in the radial direction of the end mill 1 is corrected. That is, the radial cutting depth is corrected so that the difference between the maximum value and the minimum value becomes the smallest in the sum of cutting resistances.

  FIG. 22 is a diagram illustrating an example corrected by the processing method of the fifth embodiment. The blade shape of FIG. 20 is corrected as shown in FIG. Specifically, the rotation center of the end mill 1 is offset by 7 μm in the direction away from the workpiece. FIG. 23 is a diagram showing the machining allowance and cutting resistance of each blade in the case of FIG. 22. The machining allowance of each blade is shown in the upper part of the square in the figure, and the cutting resistance of each blade corresponding thereto is shown in the lower part. It shows. As can be seen from the figure, among the sum of the cutting resistance of each blade at each position, the maximum is 393, the minimum is 288, and the difference between the maximum and minimum is 105. Compared with FIG. 20 before correction, the maximum value of the cutting force is 0.91 times (433 → 393) and the difference between the maximum and minimum is 0.91 times after correction of the cutting amount (cutting allowance) in the radial direction. 115 → 105), the straightness is reduced.

  As described above, according to the machining method using the end mill according to the fifth embodiment, the straightness is predicted in advance from the shape data of the end mill, the machining conditions, and the runout amount, and the predetermined straightness is corrected even if the radial cutting amount is corrected. If it is determined that the degree of straightness cannot be obtained, the machining allowance correction value that minimizes the straightness is calculated, and the correction value is applied to the cutting depth in the radial direction of the end mill. When it is determined that the straight line is deteriorated, the straightness can be effectively reduced.

Embodiment 6 FIG.
In the machining method of the sixth embodiment, when the straightness is predicted in any of the machining methods of the third to fifth embodiments, the workpiece information and the end mill rigidity information are given in advance, and the machining load This predicts the deformation of the workpiece, the deformation of the end mill, and the shape of the machined surface, and calculates the straightness. According to such a configuration, the straightness can be predicted including the deterioration of the straightness caused by the workpiece and the end mill, and therefore, the correction can be made accordingly and the straightness can be improved.

  As described above, according to the machining method using the end mill according to the sixth embodiment, the end mill shape data, the machining conditions, the runout are obtained at the stage of having the workpiece information and the end mill stiffness information and predicting the straightness in advance. Since straightness is calculated in consideration of workpiece information and end mill rigidity information in addition to quantity, straightness can be predicted more accurately and straightness can be further reduced.

Embodiment 7 FIG.
The seventh embodiment relates to a machining apparatus for automatically carrying out the machining method using an end mill as described in the first to sixth embodiments.
FIG. 24 is a block diagram illustrating a processing apparatus according to the seventh embodiment. The end mill 1, the holder 2, the main shaft 3, and the shake measuring means 4 including the light emitting unit 4a and the camera unit 4b are the same as those described in FIG. In order to perform automatically, the tool changer 11 for automatically mounting the end mill 1, the tool magazine 12 for storing the spare end mill 1, the spindle 3 and other axes are controlled according to the built-in machining program, and A control unit 13 is provided that predicts straightness based on information from the shake measuring means 4, calculates the shake amount, and corrects the radial cut amount. The control unit 13 includes a storage unit that stores various data.

  Using the run-out measuring means 4, the run-out amount of each blade of the end mill 1 during rotation is measured prior to machining. The measurement result of the shake measuring means 4 is sent to the control unit 13. The control unit 13 extracts the figure of the edge part 5 of the end mill 1 from the machining conditions read from the machining program and the measurement result of the shake measuring means 4. Based on this, the amount of deflection of each blade is calculated, and the straightness prediction calculation is performed when the correction amount of the cutting in the radial direction is changed. Based on these results, the position of the rotary shaft of the end mill 1 is corrected and processed with the correction amount of the radial incision that decreases the straightness by using any one of the first to sixth embodiments.

  When the straightness calculation result in the control unit 13 is greater than a predetermined straightness, the end mill 1 and the holder 2 are removed from the spindle 3 using the tool changer 11 and stored in the tool magazine 12. The main shaft 3 is provided with an encoder rotation position detection mechanism and a servo motor, and can be rotated at an arbitrary angle. The main shaft 3 with the end mill 1 and the holder 2 removed is rotated by an angle other than a multiple of 360 degrees, and the end mill 1 and the holder 2 are mounted on the main shaft 3 again using the tool changer 11.

Since the state of run-out may change due to tool wear or the like, the run-out measuring means 4 measures the run-out of each blade of the end mill 1 again for every fixed number of machining operations, and the control unit 13 performs the straightness prediction calculation again. It is desirable to carry out and update the correction amount of the radial cut.
In addition, although movable axes other than the main axis | shaft 3 are not described, there may exist a movable axis in each of the main axis | shaft 3 and the workpiece | work W side. In addition, although a vertical type is illustrated, a horizontal type processing apparatus may be used.

  As described above, according to the processing apparatus of the seventh embodiment, the end mill in which a plurality of outer peripheral blades are formed, the main shaft that rotates the end mill, and the deflection measuring unit that acquires the deflection amount of each blade of the end mill, Because it is equipped with a control unit that controls the movement of the spindle by calculating the correction amount of the end mill radial cutting amount based on the deflection amount obtained from the deflection measurement means, so that fluctuations in cutting resistance can be reduced The straightness of the processed surface can be reduced.

  In addition to the above, since the tool magazine for storing the end mill and the tool changer for automatically attaching and detaching the end mill to and from the main shaft are provided, the end mill can be easily attached and detached.

Embodiment 8 FIG.
The eighth embodiment is the same as the seventh embodiment but further includes a tilting means for changing the tilt of the end mill. FIG. 25 is a view showing the tilting means of the end mill 1.
Specifically, in addition to the configuration of the seventh embodiment, as shown in FIG. 25, the turntable 14 capable of controlling rotation by fixing the work W, the movable plate 15 to which the main shaft 3 is attached, and the movable plate 15 are fixed. A fixed plate 17 fixed via a portion 16, the fixed plate 17 has a guide rail 18 having a curvature, and the movable plate 15 has a movable portion 19 that moves along the guide rail 18. Yes.

  According to such a configuration, the inclination of the end mill 1 can be adjusted on the plane along the fixed plate 17 by moving the movable portion 19 along the guide rail 18. Furthermore, the end mill 1 can be tilted at an arbitrary angle at an arbitrary position by rotating the turntable 14 and relatively moving the main shaft 3 and the turntable 14.

FIG. 26 is a diagram showing another example of the tilting means. In this case, instead of tilting the main shaft 3 as shown in FIG. 25, the turntable 14 is placed on the column 20, and a rotation mechanism for another axis is further provided on the column 20 to form a 5-axis processing machine. Is.
The straightness of the processed surface can be divided into an inclination component and a swell component as shown in FIG. Therefore, the straightness can be improved by tilting the end mill 1 in the direction opposite to the tilt component.

  As described above, according to the machining apparatus of the eighth embodiment, the tilting unit capable of tilting the axis of the end mill with respect to the machining surface of the workpiece is provided, and the tilt component at the time of machining is calculated in the control unit. Since the tilting means is controlled in such a direction that cancels out, it is possible to obtain a machining apparatus that suppresses the influence of blade runout during machining.

If the processing method described in the first or sixth embodiment and the processing apparatus described in the seventh to eighth embodiments are applied to scroll involute processing, a particularly great effect can be expected.
In the present invention, within the scope of the invention, the embodiments can be freely combined, or the embodiments can be appropriately changed or omitted.

1 end mill, 1a shank, 1b blade, 1c outer peripheral blade, 1d bottom blade,
2 Holder, 2a Collet, 2b Tapered surface, 2c Pressing surface, 3 Spindle,
4 shake measuring means, 4a light emitting section, 4b camera section, 5 edge section, 6 left edge, 7 right edge, 8 center position, 11 tool changer, 12 tool magazine,
13 Control part, 14 Turntable, 15 Movable plate, 16 Fixed part,
17 fixed plate, 18 guide rail, 19 movable part, 20 columns, W work

Claims (9)

A processing method of cutting a workpiece with the outer peripheral blade by rotating an end mill on which a plurality of outer peripheral blades are formed,
Rotating the end mill to obtain shape data of each of the peripheral blades of the plurality of strips by a shake measuring means, and calculating a shake amount of each blade based on the shape data,
With respect to the cutting allowance determined from the machining conditions, the machining allowance of each blade is obtained with reference to the amount of runout of each of the blades, and when there is a blade that does not hit the workpiece, all the blades are applied to the workpiece. A processing method using an end mill, wherein a correction value of the machining allowance is calculated so as to abut, and a cutting amount in a radial direction of the end mill is corrected by the correction value. A processing method of cutting a workpiece with the outer peripheral blade by rotating an end mill on which a plurality of outer peripheral blades are formed,
Considering the tool life, set the end mill life machining allowance in advance,
Rotating the end mill to obtain shape data of each of the peripheral blades of the plurality of strips by a shake measuring means, and calculating a shake amount of each blade based on the shape data,
For the cutting allowance determined from the processing conditions, refer to the runout amount of each blade to obtain the machining allowance of each blade, and when all the machining allowance of each blade is greater than the life machining allowance, A machining method using an end mill, wherein a cutting amount in the radial direction of the end mill is corrected so that a minimum value of the machining allowance of each blade becomes the life machining allowance. In the processing method by the end mill of Claim 1 or Claim 2,
Predicting straightness from the shape data of the end mill, the processing conditions, the runout amount in advance,
If it is determined that a predetermined straightness cannot be obtained even when the radial cut amount is corrected, the mounting state of the end mill is changed, and the runout amount of each blade of the end mill is calculated again. Machining method using an end mill, wherein machining is started when a straightness of is obtained. In the processing method by the end mill of Claim 1 or Claim 2,
It has a database of the relationship between rotation speed and blade runout, and a database of the relationship between rotation speed or cutting speed and cutting force,
Predicting straightness from the shape data of the end mill, the processing conditions, the runout amount in advance,
When it is determined that a predetermined straightness cannot be obtained even when the radial cut amount is corrected, a database of the relationship between the rotational speed and the blade runout, and a relationship between the rotational speed or the cutting speed and the cutting resistance A processing method using an end mill, wherein the rotational speed is changed so that a predetermined straightness can be obtained using the database. In the processing method by the end mill of Claim 1,
Predicting straightness from the shape data of the end mill, the processing conditions, the runout amount in advance,
If it is determined that a predetermined straightness cannot be obtained even if the cutting amount in the radial direction is corrected, a correction value for the machining allowance that minimizes the straightness is calculated, and the correction value is used as the end mill. A processing method using an end mill, characterized in that the processing is applied to the cutting depth in the radial direction. In the processing method by the end mill of any one of Claims 3-5,
Having information on the workpiece and rigidity of the end mill,
In the step of predicting the straightness in advance, in addition to the shape data of the end mill, the machining conditions, and the amount of runout, the straightness is calculated in consideration of the information of the workpiece and the rigidity of the end mill. A processing method using a featured end mill.   An end mill in which a plurality of outer peripheral blades are formed, a main shaft for rotating the end mill, a shake measuring means for obtaining a swing amount of each blade of the plurality of outer peripheral blades, and the shake measuring means obtained from the above A processing apparatus comprising: a control unit that calculates a correction amount of a cutting amount in a radial direction of the end mill based on a deflection amount and controls movement of the spindle. The processing apparatus according to claim 7.
Furthermore, the processing apparatus provided with the tool magazine which accommodates the said end mill, and the tool change apparatus which attaches / detaches the said end mill to the said spindle automatically. In the processing apparatus according to claim 7 or claim 8,
Inclining means capable of inclining the axis of the end mill with respect to the work surface of the workpiece,
A processing apparatus, wherein a tilt component at the time of machining is calculated in the control unit, and the tilting means is controlled in a direction to cancel the tilt component.

Images