JP2002337017A - Formed cutter device and manufacturing method for formed cutter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device having the high shape precision of a formed cutter device including a complicated form, easily retaining the device shape precision after the regrinding, and reducing the manufacturing cost and to provide its manufacturing method. SOLUTION: This formed cutter device used by using a machine tool in a machining center, etc., and its machining method are characterized in that the surface property of a flank of the formed cutter device has multiple projecting thread traces formed by pitch feeding of a grinding wheel and extending approximately in parallel to a cutting blade ridge from the cutting blade ridge part to a device rotation rearward direction, and has a multistage shape with the multiple projecting traces parts, which have approximately projecting circular shape in the rotation cross sectional view, set to respective vertices.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved form milling tool and a method of machining a form milling tool using a machine tool such as a machining center.
The present invention relates to an improvement in the shape of a tool flank and a cutting method.

[0002]

2. Description of the Related Art A general form milling tool is for transferring a general form to a work material side and obtaining a predetermined shape by cutting.
Processing accuracy is required in a wide variety of shapes such as a Christmas cutter disclosed in Japanese Patent No. 5112 and having an inverted Christmas tree-shaped overall form described in JIS-B0172. In addition, the form milling tool generally has a high tool cost due to the above-mentioned contents, and when machining accuracy cannot be maintained due to tool wear, it is re-ground and reused, so the repetition accuracy by re-grinding and the number of re-grindable times are also important Is seen.

[0003] In addition, the flank forming method of the flank of the forming milling tool requires two forms, ie, contour profiling grinding and secondary grinding, since the forming form is complicated and requires high precision.
It is almost limited to the types and is used properly according to the user's request. Here, in both of the above-mentioned processing methods, the grinding wheel axis and the tool axis are set substantially parallel or slightly inclined, and the contour scanning grinding is performed by grinding and feeding in the grinding wheel axis direction substantially along the contour of the form. This is a machining method to obtain a form and a flank at the same time.The second grinding process uses a specially designed grindstone that corresponds to the overall form in the cross section of the grindstone shaft, and feeds in an arc shape eccentric to the tool rotation axis. This is a processing method in which the shape of the grinding stone is transferred to the tool side to obtain a full-form foam.

[0004]

However, as for the shape of the flank by the contour copying grinding, an arc shape having a diameter of a grindstone is transferred to the tool side. It has an arc shape, the strength of the cutting edge is inferior, chipping and chipping easily occur, and there is a problem in tool life. Also, since the clearance angle is constant regardless of the change in the tool diameter, that is, the amount of fall of the flank changes, the re-grinding is performed from the flank side accompanying the shape grinding of the general form to maintain the accuracy of the general form. This made it difficult to reproduce the form, and there was a problem with re-grinding accuracy. Here, the drop amount of the flank is defined as the intersection of the circle including the shape of the flank formed in the approximate convex arc shape in a cross section perpendicular to the axis and the axis passing through the tool center of the subsequent next cutting edge in the rotation direction, and Indicates the distance to the next cutting edge.

[0005] Further, since the tool life and the re-grinding accuracy are required for a complex shape milling machine having a complicated shape, the machining is mainly performed by the second cutting grinding process. A specially-shaped grindstone corresponding to the foam is required, and a plurality of specially-shaped grindstones are required to suppress grinding wheel interference and grinding resistance. Therefore, if the edge of the cutting edge is inferior, for example, a step or a projection appears at each seam of the processing part at the joint of the cutting edge, and if the cutting edge has a twist angle to improve the sharpness, the overall shape due to grinding wheel interference In the case of a form milling tool that is difficult to produce a foam and has a more complicated shape, several types of grindstones of a special shape are required, and there has been a problem that the manufacturing cost is further increased.

[0006]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above-mentioned background, and has a high machining accuracy, a long tool life, and a tool for forming all types of milling tools including complicated forms. It is an object of the present invention to provide a full-form milling tool and a method of manufacturing the full-form milling tool, which have good shape accuracy, easily maintain the tool shape accuracy after re-grinding, and can reduce the manufacturing cost.

[0007]

Therefore, the present invention provides
In a forming milling tool used by using a machine tool such as a machining center, the surface characteristics of a flank of the forming milling tool are substantially parallel to an outer peripheral cutting edge ridgeline. A general form milling tool characterized by having a plurality of protruding streaks caused by feeding, and having a multi-stage shape having the plurality of protruding streak portions having an approximate convex arc shape as a vertex in a cross section perpendicular to the axis.

Further, in a method of machining a forming milling tool used by using a machine tool such as a machining center, grinding of a flank of the forming milling tool is performed by using a forming form and an outer peripheral edge of the forming milling tool. Grinding feed along the lead, the flank surface by pitch feed from the cutting edge ridge line to the rear of the tool rotation so that the surface properties of the flank form a multi-stage shape of approximate convex arc in cross section perpendicular to the axis This is a forming method of a forming milling tool characterized by performing grinding.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS By applying the present invention, the machining accuracy is good, the tool life is improved, and the tool shape accuracy is good and the re-shaping is possible in all the form milling tools including complicated form. It has been possible to provide a full-form milling tool and a method of manufacturing a full-form milling tool that can easily maintain the tool shape accuracy after grinding and reduce the manufacturing cost.

In the present invention, the flank surface of the forming milling tool has a plurality of convex streaks caused by the pitch feed of the grindstone in a direction rearward of the tool rotation from the cutting edge ridge line substantially parallel to the cutting edge ridge line. Therefore, the contact area between the flank and the work material is reduced due to the convex streaks, and the steps and protrusions on the cutting edge ridge are markedly reduced and reduced. It was possible to suppress the progress of tool wear, chipping and chipping, and to reduce the cutting resistance because the contact area between the flank and the work material was small. Here, because the shape of the flank itself has a complicated overall form, due to whetstone interference during the grinding process, it is not possible to obtain convex streaks according to the pitch feed of the grindstone, and the width between adjacent convex streaks is reduced. Partially disturbed, or a part of the convex streak is erased, there may be an angle with the cutting edge ridge line, but it is needless to say that it is within the scope of the present invention, and it is approximately the cutting edge ridge line. The term “parallel” refers to a range of about 10 ° or less with respect to the cutting edge ridgeline. As described above, it goes without saying that even if the range partially exceeds this range, the scope of the present invention is also included.

In general, the tool life of a general milling tool is the accuracy of the machined shape on the work material side. Because of the multi-stage shape, re-grinding can be performed from the rake face side, and the tool shape accuracy after re-grinding can be easily obtained, as described above, high precision machining is maintained for a long time Not only was the abrasion possible, but the wear was uniform and minute abrasion without chipping or chipping, the number of regrinds was increased, and the overall life was improved.

Here, in order to maintain the shape of the overall form at the time of re-grinding, the clearance angle is changed according to the change in the tool diameter.
It is desirable to make the drop amount substantially constant. In this case, in particular,
Due to grinding wheel interference during grinding, convex streaks cannot be obtained according to the pitch feed of the grinding stone, the width between adjacent convex streaks is partially disturbed, or the convex streaks are partially erased, Although an angle with the cutting edge ridge line is likely to occur, it goes without saying that it is within the scope of the present invention. The length of the line connecting the vertices of the adjacent convex streaks corresponding to the grinding feed pitch in a cross section perpendicular to the tool axis is preferably in the range of 0.1 to 0.7 mm, and 0.1 to 0.7 mm.
If it is less than 1 mm, the machining time will be affected, and if it exceeds 0.7 mm, the edge strength will be slightly affected. Further, the tool material varies depending on the purpose of use, and high-speed tool steel such as powdered high-speed tool steel and ultra-fine-grain cemented carbide can be used. Still further, Ti
Needless to say, a longer life can be achieved by coating a hard film or a lubricating film such as N, TiCN, or TiAlN.

Next, in the forming method of the forming milling tool, grinding of the flank of the forming milling tool is performed by grinding and feeding along the forming form and the cutting edge ridge line of the forming milling tool. Grinding the flank surface by pitch-feeding the cutting edge ridge from the cutting edge ridge line so that the surface texture becomes a multi-stage shape of an approximate convex arc in a cross section perpendicular to the axis. The convex grinding streak due to the pitch is substantially parallel, and the convex grinding streak hardly appears at the cutting edge ridge portion, so that a uniform, smooth and accurate predetermined form can be obtained. Was. Here, since the shape of the flank itself has a complicated overall form, there is also a part where a predetermined overall form is obtained by using a grinding wheel interference or the like at the time of grinding processing in reverse, and in that case, the grinding feed is partially performed. It is needless to say that even if the direction is slightly changed with respect to the form or the edge of the cutting edge, it is within the scope of the present invention.

Further, the flank can be ground with a single kind of whetstone, which is tapered from the center of rotation of the whetstone to the outer circumference, and the outer end of the whetstone is rounded. The number of whetstones can be reduced, and the whetstone management can be easily performed. Here, regarding the shape of the grindstone, in consideration of the wear of the grindstone during processing, the radius of the tip of the outer periphery of the grindstone is desirably 0.1 mm or more, and particularly desirably in the range of 0.2 to 1 mm. Furthermore, the flank surface has a multi-stage shape with a convex arc shape as viewed in a cross section perpendicular to the axis, so that re-grinding can be performed by rake face grinding. It is possible to obtain a uniform, smooth and accurate predetermined form with almost no appearance at the ridge.

The machining method of the present invention can be applied to any form milling tool. For example, it can also be applied to a roughing type form milling tool having a corrugated shape having a different phase pitch for each cutting edge. The effect of reducing the processing cost is great. Further, by applying the processing method of the present invention, the degree of freedom in setting the clearance angle and the clearance amount of the flank increases.
Hereinafter, the present invention will be specifically described based on examples.

(Embodiment 1) FIGS. 1 and 2 show a state of a cutting edge of a forming milling tool according to an embodiment of the present invention. FIG. In addition, the length of a line connecting the vertices of the adjacent convex streak marks 4 in a cross-section perpendicular to the axis is 0.5 mm at the maximum. The vertices of the adjacent convex stripes 4 in a cross section perpendicular to the axis have a substantially linear shape, but strictly speaking, have a concave elliptical arc shape. Applied to a Christmas cutter made of powdered high-speed tool steel with an outer torsion angle of 10 °, a conventional contour profile grinding shown in FIGS. 3 and 4 and a double-cut grinding shown in FIGS. A cutting performance comparison test with a type milling tool was performed. Here, the tested tools were coated with 3 μm of TiCN, and the work material was made of Ti-6, which is often used for aircraft parts.
Al-4V material was used.

FIG. 7 shows the results of the measurement of the flank wear width at a cutting length of 5 m. In the case of contour contour grinding, the cutting edge strength is weak, and a defect exceeding 0.7 mm occurs. In the case of the second-order grinding, the convex grinding streak portion 4 of the cutting edge ridge line is slightly chipped, Although the wear value was as large as 0.4 mm, the example of the present invention has a flank surface having a multi-step shape of an approximate convex arc shape in a cross-section perpendicular to the axis, so that the flank has a strong cutting edge and The contact area with the material was small, the friction was uniform and fine, 0.1 mm, and the resistance during cutting was small.

(Embodiment 2) Next, FIGS. 8 and 9 are views showing a set state of an embodiment of the manufacturing method of the present invention. The form milling tool, which is the workpiece 6, has an outer peripheral helix angle of 10 mm.
° is a Christmas cutter made of powdered high-speed tool steel, and the shape of the grindstone 7 used is a CBN grindstone having a grindstone diameter of 120 mm, a grindstone opening angle of 6 °, and a tip radius of 0.2 mm. The grinding machine used is a 5-axis controlled CNC grinding machine, and the rotation axis of the grindstone 7 is 5 ° with respect to the rotation axis of the workpiece.
Is set at the position.

Next, in the actual grinding process, the cutting edge ridge line portion 2 is moved from the end side of the workpiece 6 to the shank direction by a lead corresponding to an outer peripheral torsion angle of 10 ° in the shank direction. Grinding along the form
In a similar manner, the multi-step pitch of the multi-step shape is set to 0.5 m so that the surface properties of the flank 2 form an approximate convex arc 5 in a cross-section perpendicular to the axis.
m, and from the cutting edge ridge 2 toward the tool rotation rearward,
Grinding was performed so that the flank 2 was formed sequentially. At this time,
By moving the grinding wheel axis, the unevenness of the form
Further, a predetermined clearance angle 10 and / or a clearance surface drop amount 11 in a cross section perpendicular to the axis of the outer peripheral cutting edge portion shown in FIG. 10 are obtained.

FIG. 11 shows the state of the cutting edge ridge line 1 and the flank 2 of the Christmas cutter machined by the above method. The cutting edge ridge line 1 and the convex grinding streak 4 due to the grinding pitch are substantially parallel, and the convex grinding streak 4 does not appear on the cutting edge ridge portion 2 and is uniform, smooth and accurate with a predetermined accuracy. A complete form was obtained. Further, the shape of the grindstone may be one of the above-mentioned types, and can be used for the grinding of the flank face of another form milling machine, so that the number of grindstones can be reduced and the grindstone can be easily managed. In fact, in this processing, a tool 1
Grinding of all flank faces of the book could be completed.

[0021]

From the above results, it can be seen that by applying the present invention, the machining accuracy is good, the tool life is improved, and the entire form can be easily produced even in all the form milling tools including complicated forms. Provided is a complete milling tool and a method of manufacturing a complete milling tool that have good tool shape accuracy, easily maintain the tool shape accuracy after regrinding, do not require a special-shaped grinding wheel, and can reduce the manufacturing cost. We were able to.

[Brief description of the drawings]

FIG. 1 is one embodiment of the present invention, and is an enlarged cross-sectional view at right angles to the axis of an outer peripheral cutting edge.

FIG. 2 is a perspective view seen from a flank side of FIG.

FIG. 3 is an enlarged cross-sectional view of an example of the related art, in which the outer peripheral cutting edge is perpendicular to the axis.

FIG. 4 is a perspective view of the flank of FIG. 4 as viewed from the flank side;

FIG. 5 is an enlarged view of another example of the related art, which is a cross-section perpendicular to the axis of the outer cutting edge.

FIG. 6 is a perspective view of the flank of FIG. 5 as viewed from the flank side;

FIG. 7 is an explanatory diagram showing a result of a comparison test between the present invention example and the conventional example.

FIG. 8 is a schematic view showing a setting state of an embodiment of the machining method according to the present invention, as viewed from a direction perpendicular to a tool axis.

FIG. 9 is a schematic diagram viewed from the tool axis direction in FIG. 8;

FIG. 10 is a schematic view showing a tool machined by the machining method of the present invention, showing a cross section perpendicular to the axis of an outer peripheral cutting edge portion.

FIG. 11 is an explanatory diagram showing a state of a flank of FIG. 10;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 cutting edge ridge line 2 flank 3 rake face 4 convex streak 5 approximate convex arc 6 workpiece 7 grinding wheel 8 grinding feed 9 pitch feed 10 clearance angle 11 flank drop amount

Claims (2)

[Claims] 1. A form milling tool used by using a machine tool such as a machining center, wherein the flank surface of the form milling tool is substantially parallel to an outer peripheral cutting edge ridge line, and is rotated from a cutting edge ridge portion to a rear side. A plurality of convex streaks caused by the pitch feed of the grindstone in the direction, and a multi-stage shape having the plurality of protruding streak portions of the approximate convex arc shape in a cross section perpendicular to the tool axis as vertices. Milling tool. 2. A method for machining a form milling tool using a machine tool such as a machining center, the method comprising: grinding a flank surface of the form milling tool; Grinding feed along the lead, the flank surface by pitch feed from the cutting edge ridge line to the rear of the tool rotation so that the surface properties of the flank form a multi-stage shape of approximate convex arc in cross section perpendicular to the axis A forming method of a form milling tool characterized by grinding.