Cutting tool and method for manufacturing a cutting tool

Abstract

Cutting tools and methods for manufacturing cutting tools are disclosed. A cutting tool for machining a workpiece includes a shank and a cutting portion, wherein a coolant channel extends along a longitudinal axis from a free end of the shank through the cutting tool, the coolant channel having a peripheral wall and an end wall, wherein the coolant channel has one or more exit openings in the end wall through which coolant can exit the cutting tool. A method for manufacturing a cutting tool is also disclosed.

Description

TECHNICAL FIELD

[0001] The present invention relates to a cutting tool for machining a workpiece and to a method for manufacturing a cutting tool. BACKGROUND

[0002] When machining a workpiece using a cutting tool, in particular a rotary cutting tool, coolant is usually directed to the cutting edges and / or friction surfaces of the cutting tool which are particularly stressed in order to reduce the wear of the cutting tool caused by the heat generated by the friction in the cutting tool.

[0003] The coolant is usually directed to the particularly stressed areas by means of coolant channels which extend through the cutting tool.

[0004] However, the manufacture of these coolant channels in the cutting tool is relatively complex, in particular since a plurality of coolant channels or channel sections which lead to different locations on the cutting tool are usually provided in order to direct the coolant to the intended areas or to distribute the coolant uniformly along the cutting tool. SUMMARY

[0005] It is therefore an object of the present invention to define a cutting tool with an optimized channel design or an optimized method for manufacturing a cutting tool.

[0006] This object is achieved according to the invention by a cutting tool for machining a workpiece, the cutting tool comprising a shank and a cutting portion, wherein a coolant channel extends along a longitudinal axis through the cutting tool from a free end of the shank, the coolant channel having a peripheral wall and an end wall, wherein the coolant channel has one or more outlet openings in the end wall through which coolant can exit the cutting tool.

[0007] This cutting tool has the advantage of a particularly easy-to-manufacture coolant channel and outlet opening. It is particularly advantageous that only one (large) channel has to be formed in the cutting tool and at the same time very small outlet openings are sufficient.

[0008] A further advantage is that the outlet openings open directly into the outer surface of the cutting tool, i.e. there is no intermediate channel, so that coolant can exit the cutting tool directly through the outlet openings in the end wall of the coolant channel. Thus, at the beginning of the machining process, coolant is immediately available on the outer surface of the cutting tool, in particular on the cutting edges and friction surfaces.

[0009] The cutting tool in particular does not have side channels branching off from the central coolant channel.

[0010] For example, the cutting tool is a gun drill or a twist drill.

[0011] The coolant channel preferably extends straight along the longitudinal axis of the cutting tool only. This also contributes to the cutting tool being easy to manufacture. Due to the straight form of the coolant channel, the blank for manufacturing the cutting tool has no undercuts, so that the blank can be manufactured by injection molding in a tool mold. Alternatively, the blank can be placed in a mold and pressed to manufacture the blank. However, it is also conceivable to produce the coolant channel by drilling.

[0012] According to one embodiment, the plurality of outlet openings opens into an end face of the cutting tool. The end face is the surface that can be seen when looking down on the front end of the cutting portion. This design is particularly suitable for reamers, since for reamers the coolant must be available on the end face as quickly as possible.

[0013] Since the outlet openings open into the end face of the cutting tool, a longitudinal groove is not required at least in reamers. In conventional reamers, the function of such a longitudinal groove is to transport the coolant that is discharged laterally from the cutting tool to the end face. However, if the outlet openings open directly into the end face, this transport is not required. This greatly simplifies the manufacture of the cutting tool.

[0014] According to another embodiment, the plurality of outlet openings can open into a flute of the cutting tool. This design is particularly suitable for twist drills. In this case, the outlet openings can also be arranged near the front end of the cutting portion, for example at a distance of less than 3 mm from the cutting tip.

[0015] It is also conceivable that, in the case of a twist drill, the coolant channel is only milled in the flute exit region. Then, preferably, the coolant channel is only deep enough to reach the flute exit region.

[0016] For example, the coolant channel has a constant cross section. Such a coolant channel is particularly easy to manufacture. A slight tapering can be provided in order to facilitate removal from the mold. In the case of a coolant channel with only one such mold release bevel, the cross section of the coolant channel is still considered to be constant. However, a more pronounced tapering is also conceivable.

[0017] The coolant channel can alternatively be stepped, wherein at least one further outlet opening is formed on the stepped portion. This has the advantage that the coolant can be distributed better along the cutting tool. In particular, a plurality of outlet openings can be formed which are spaced apart in the longitudinal direction of the cutting tool.

[0018] For example, in a stepped drill, such a stepped coolant channel can be used to provide coolant directly in the steps of the drill. A plurality of outlet openings is preferably also present on the stepped portion.

[0019] The cross section of the coolant channel can be circular, oval or polygonal. This applies both to coolant channels with a constant cross section and to stepped coolant channels.

[0020] According to one embodiment, on the end wall of the coolant channel, there is a lift which protrudes into the coolant channel. The lift is preferably arranged centrally on the end wall. Such a lift has a number of advantages. On the one hand, it strengthens the cutting tool in the region of the end wall. The lift also makes it possible to form a central hole. The lift further makes it possible to align the flow of coolant before the discharge outlet opening, whereby the direction in which the coolant is discharged from the cutting tool can be influenced.

[0021] At least in cross-section, the diameter of the coolant channel can be between 60% and 95%, in particular between 75% and 95%, of the nominal diameter of the cutting tool. For example, the wall thickness of the cutting tool is between 1 mm and 2 mm. For a non-circular cross-section of the coolant channel, at least in cross-section, the largest dimension of the cross-section of the coolant channel is in particular between 60% and 95%, in particular between 75% and 95%, of the nominal diameter of the cutting tool. The cross-section is a cross-section perpendicular to the longitudinal axis of the cutting tool. The cross-section thus chosen has the advantage that the use of material for manufacturing the cutting tool is significantly reduced compared to conventional cutting tools.

[0022] According to one embodiment, notches or recesses are configured in the end face of the cutting portion, which notches or recesses intersect the coolant channel. The notches or recesses are embodied deep enough to "cut" the coolant channel in order to create the outlet opening. Before the notches are formed, the coolant channel is closed at its end wall.

[0023] This has the advantage that a separate working step is not required to create the outlet opening, since the outlet opening is formed at the same time as the notches. Thus, the manufacture of the cutting tool is further simplified.

[0024] Furthermore, since the outlet opening is not created until the notches are formed, the same blank can be used as a base for a plurality of cutting tools. This is advantageous in terms of the manufacturing process, since larger batches can be manufactured from one blank.

[0025] The number and position of the notches can be variably selected. In addition, it can be determined whether the distance between the notches is uniform or non-uniform until the notches are formed. In this case, a circular cross-section of the coolant channel is advantageous since the shape of the coolant channel does not have to be taken into account when positioning the notches.

[0026] The notches can extend, for example, at an angle of between 40° and 50° to the longitudinal axis of the cutting tool. However, other angles are also conceivable.

[0027] Grooves which intersect the coolant channel (instead of notches) can extend along the cutting portion. Thus, the outlet opening can likewise be formed in the cutting portion.

[0028] The coolant channel terminates, for example, at a distance of less than 10 mm, in particular less than 2 mm, from the front end of the cutting portion. This simplifies the opening of the coolant channel, since only a small amount of material has to be removed from the end face of the cutting portion to create the outlet opening.

[0029] The objects of the application are further achieved by a method for manufacturing a cutting tool for machining a workpiece, in particular a cutting tool configured as described above, comprising the following steps:

[0030] - providing a blank having a shank, a cutting portion and a coolant channel having a peripheral wall and an end wall,

[0031] - forming a notch or recess in the end face of the cutting portion, thereby forming an outlet opening in the end wall of the coolant channel.

[0032] This method is particularly suitable for manufacturing a reamer. This method in particular makes it particularly easy to manufacture a reamer having a coolant channel.

[0033] The notch is formed, for example, by grinding or milling, in particular after sintering the blank. Thus, the exact shape of the cutting tool can be defined relatively late in the manufacturing process.

[0034] The objects of the application are further achieved by a method for manufacturing a cutting tool for machining a workpiece, in particular a cutting tool configured as described above, comprising the following steps:

[0035] - providing a blank having a shank, a cutting portion and a coolant channel having a peripheral wall and an end wall,

[0036] - forming a groove along the cutting portion, thereby forming an outlet opening in the end wall of the coolant channel.

[0037] According to one embodiment, the coolant channel is stepped and, when the groove is formed, the outlet opening is formed in the end wall of the coolant channel and on the stepped portion of the coolant channel. Thus, a stepped drill having an outlet opening in the region of the drill step can be manufactured in a particularly simple manner.

[0038] Alternatively, the coolant channel can be ground only in the flute exit region of the groove. In this case, the coolant channel extends only to the flute exit region.

[0039] The blank for manufacturing the cutting tool can be manufactured by injection molding. Thus, a large number of blanks can be manufactured particularly easily and cost-effectively. BRIEF DESCRIPTION OF DRAWINGS

[0040] Further advantages and features of the application result from the following description and the referenced drawings. The drawings show:

[0041] - Figure 1This is a perspective view of the cutting tool according to the present invention.

[0042] - Figure 2 Is it through Figure 1 A longitudinal section view of the cutting tool.

[0043] - Figure 3 Is it through Figure 1 Another cross-sectional view of the cutting tool.

[0044] - Figure 4 yes Figure 1 A plan view of the end face of the cutting tool.

[0045] - Figure 5 yes Figure 1 Side view of the cutting tool.

[0046] - Figure 6 This is a longitudinal sectional view through a cutting tool according to another embodiment of the invention.

[0047] - Figure 7 It is a cutting tool according to another embodiment of the present invention.

[0048] - Figure 8 yes Figure 7 A detailed view of the cutting tool in the area of ​​the cutting tip.

[0049] - Figure 9 It is a cutting tool according to another embodiment of the present invention.

[0050] - Figure 10 This is a side view of a cutting tool according to another embodiment of the present invention.

[0051] - Figure 11 yes Figure 10 A plan view of the cutting tool, and

[0052] - Figure 12 yes Figure 10 The rear view of the cutting tool. Detailed Implementation

[0053] Figure 1 A perspective view shows the cutting tool 10 used for machining the workpiece. Figure 1 The cutting tool 10 shown is specifically a hole expander. The cutting tool 10 has a cutting portion 12 and a shank 14, wherein the shank 14 has been shortened in the figure.

[0054] The cutting tool 10 includes multiple outlet openings 16 through which coolant can be discharged from the cutting tool 10.

[0055] The outlet opening 16 opens into an end face 18 of the cutting tool 10. The end face 18 refers to the surface visible in a plan view on the tip of the cutting portion 12. Thus, coolant expelled from the outlet opening 16 is immediately available at the end face 18 upon exiting the cutting tool 10.

[0056] A plurality of notches 20 or recesses is also formed at one end of the cutting portion 12. The notches 20 extend from a front end 22 of the cutting portion 12 at an angle of 45° to the longitudinal axis of the cutting tool 10.

[0057] The notches 20 particularly form part of the end face 18.

[0058] The outlet opening 16 is arranged in the notch 20.

[0059] From the end face 18, a plurality of guide surfaces 24 extends along the cutting portion 12.

[0060] A cutting tip 26 is further provided at one end of the cutting portion 12, which facilitates, for example, the insertion of the cutting tool 10 into a pre-drilled hole.

[0061] Figure 2 A longitudinal sectional view through the cutting tool 10 is shown. Figure 1 A longitudinal sectional view through the cutting tool 10 is shown. Figure 3 A longitudinal sectional view through the cutting tool 10 is shown.

[0062] In the sectional view, it can be seen that a coolant channel 28 extends through the cutting tool 10. More precisely, the coolant channel 28 extends through the cutting tool 10 along the longitudinal axis L from the free end of the shank portion 14.

[0063] The coolant channel 28 extends linearly along the longitudinal axis L of the cutting tool 10 only. This means that the coolant channel 28 has no branches and that the coolant channel 28 is not sharply curved and / or turned.

[0064] The coolant channel 28 has a constant cross-section, particularly a circular cross-section (see also Figure 4 ). However, other cross-sectional shapes are conceivable as well.

[0065] The diameter of the coolant channel 28 can be between 60% and 95% of the nominal diameter of the cutting tool 10. In the depicted design example, the diameter of the coolant channel 28 is about 75% of the nominal diameter of the cutting tool 10.

[0066] The coolant channel 28 has a peripheral wall 30 and an end wall 32. The outlet opening 16 is formed in the end wall 32 of the coolant channel 28.

[0067] As Figure 2As can be seen in

[0068] As can be seen in Figure 2 As can be seen in

[0069] In the design example shown, the recess 20 extends at an angle of approximately 45° to the longitudinal axis L of the cutting tool 10, wherein the recess 20 is slightly curved when viewed in cross section.

[0070] The distance d of the end wall 32 to the front end of the cutting portion 12 is less than 10 mm, for example, in particular less than 2 mm.

[0071] Figure 4 A plan view on the cutting portion 12 is shown. Figure 4 The end face 18 of the cutting tool 10 is specifically shown. The cutting tool 10 is transparent in the drawing, so that the position of the coolant channel 28 in the cutting tool 10 and the contour of the coolant channel 28 are visible.

[0072] Figure 2 and Figure 4 The outlet opening 16 is shown to have a roughly split-elliptical shape in both side view and plan view. Thus, as a whole, the outlet opening 16 has a roughly elliptical shape.

[0073] Figure 5 A side view of the cutting tool 10 is shown. Figure 5 The cutting portion 12 is shown to taper towards the end face 18.

[0074] Figure 6 A longitudinal sectional view through a cutting tool 10 according to a further embodiment is shown. Figure 6 The embodiment depicted in Figures 1 to 5 The embodiment described differs from the embodiment with reference to

[0075] The elevation 34 ensures an increased stability of the cutting tool 10 in the region of the end wall 32.

[0076] Furthermore, the elevation 34 forms an annular channel section 38 of the coolant channel 28, which ensures that coolant flows in particular to the outlet opening 16.

[0077] The lifting section 34 also provides a sufficiently thick material in the region of the end face 18 of the cutting tool 10 to form a centered opening 40 in the end face 18. The centered opening 40 facilitates the clamping of the cutting tool 10, for example, for the purpose of readjusting the cutting tool 10.

[0078] In the design example shown, the lifting part 34 is cylindrical.

[0079] The lifting section 34 may optionally have a rounded or chamfered edge on its free periphery 36. This has a favorable effect on the flow behavior of the coolant in the coolant passage 28.

[0080] Figure 7 Another embodiment of the cutting tool 10 is shown. Figure 7 The cutting tool 10 shown is a twist drill, with multiple grooves 42 extending along the cutting portion 12 of the cutting tool.

[0081] according to Figure 7 The cutting tool 10 also includes a coolant channel 28.

[0082] Figure 7 The inlet opening 44 of the coolant passage 28 is shown. As in the foregoing embodiment, the end wall 32 of the coolant passage 28 is arranged near the front end of the cutting section 12, for example at a distance of less than 5 mm, and particularly at a distance of less than 2 mm from the cutting edge 48 of the cutting tool 10.

[0083] like Figure 8 As can be seen, it shows Figure 7 A detailed view of the cutting tool 10 in the area of ​​the cutting tip of the cutting tool 10, with the exit opening 16 arranged inside the groove 42.

[0084] Compared to the previous embodiment, the coolant channel 28 has a smaller diameter in the region of the cutting section 12, for example, less than 40% of the nominal diameter. Otherwise, the groove 42 would open the outlet opening 16 too large in the cutting tool 10. This can be achieved, for example, by making the coolant channel 28 stepped or by having a smaller cross-section along its entire length.

[0085] exist Figure 7 and Figure 8 In the illustrated embodiment, the outlet opening 16 is located only near the cutting tip, and the stepped portion is preferably located in the area of ​​the handle 14. The stepped portion is then used solely to facilitate the removal of the cutting tool 10 from the mold.

[0086] Figure 9 Another embodiment of the cutting tool 10 is shown. Figure 9 The cutting tool 10 depicted in the image is similar to... Figure 7 andFigure 8 The cutting tool 10 depicted in Fig. 1 has a stepped coolant channel 28. In order to better illustrate,

[0087] Figure 9 The cutting tool 10 depicted in Fig. 1 has a stepped coolant channel 28. In order to better illustrate, Figure 9 In Fig. 1 the coolant channel 28 is shown as a dashed line.

[0088] The stepped portion 46 makes it possible to easily produce a plurality of outlet openings 16 which are spaced apart in the longitudinal direction. At least one outlet opening 16 is arranged in particular on the stepped portion 46. In this case, the stepped portion 46 is arranged in the region of the cutting portion 12.

[0089] Below, a method for producing a cutting tool 10 according to Figures 1 to 6 is described, and a method for producing a cutting tool 10 according to Figures 7 to 9 is described.

[0090] In both cases, a blank having a shank 14, a cutting portion 12 and a coolant channel 28 is first provided, wherein the coolant channel has a peripheral wall 30 and an end wall 32.

[0091] The blank is produced, for example, by injection molding. The blank is then sintered.

[0092] Preferably, after sintering, the recess 20 is formed on the end face of the cutting portion 12, for example by grinding or milling. Thus, the outlet opening 16 is formed in the end wall 32 of the coolant channel 28.

[0093] Instead of the recess 20, it is also possible to form a groove 42 along the cutting portion 12. This likewise forms the outlet opening 16 in the end wall 32 of the coolant channel 28.

[0094] When the coolant channel 28 is stepped, the outlet opening 16 can be formed in the end wall 32 of the coolant channel 28 and on the stepped portion 46 of the coolant channel 28 when the groove 42 is formed.

[0095] Figures 10 to 12 Another embodiment of the cutting tool 10 is shown, wherein Figure 10 The cutting tool 10 is shown in a side view, Figure 11 The cutting tool 10 is shown in a plan view on the end face 18, Figure 12 The cutting tool 10 is shown in a rear view.

[0096] In Figure 10 Fig. 1, it can be seen that the cutting tool 10 also has a shank 14 and a cutting portion 12.

[0097] The coolant channel 28 again extends along the longitudinal axis from the free end of the shank 14 through the cutting tool 10, which has two outlet openings 16 in the end wall through which coolant can exit the cutting tool 10.

[0098] Figures 10 to 12 The cutting tool 10 shown in Fig. 1 is a drill tip, which can be used as a wear part in a twist drill, for example.

[0099] According to Figures 10 to 12 the cutting tool 10 is essentially the same as the cutting tools shown in Figs. 1-3, but is considerably shorter in comparison. Figure 7 and Figure 8 the cutting tool 10 is essentially the same as the cutting tools shown in Figs. 1-3, but is considerably shorter in comparison.

Claims

1. A cutting tool for machining a workpiece comprising a shank and a cutting portion, wherein, The coolant channel extends along a longitudinal axis of the cutting tool from a free end of the shank through the cutting tool, the coolant channel having a peripheral wall and an end wall, wherein the coolant channel has one or more outlet openings in the end wall through which coolant can exit the cutting tool, characterized in that an end face of the coolant channel terminates at a distance of less than 10 mm from a front end of the cutting portion, and wherein one or more notches or grooves are milled or ground into the front end of the cutting portion until the one or more notches or grooves intersect the coolant channel, thereby forming the one or more outlet openings; wherein the cutting tool further comprises a riser on the end wall of the coolant channel, which riser protrudes into the coolant channel and which riser forms an annular channel section of the coolant channel to ensure coolant flow to the outlet openings.

2. The cutting tool of claim 1 wherein, The coolant channel extends in a straight line only along the longitudinal axis of the cutting tool.

3. The cutting tool of claim 1 wherein, The coolant channel has a constant cross section.

4. The cutting tool of claim 1 wherein, The coolant channel is stepped, wherein at least one further outlet opening is formed on the stepped portion.

5. The cutting tool of claim 1 wherein, The diameter of the coolant channel is between 60% and 95% of the nominal diameter of the cutting tool.

6. The cutting tool of claim 1 wherein, A notch is formed in an end face of the cutting portion, which notch intersects the coolant channel to form the one or more outlet openings in the end wall.

7. The cutting tool of claim 1 wherein, A groove extends along the cutting portion, which groove intersects the coolant channel to form the one or more outlet openings in the end wall.

8. The cutting tool of claim 1 wherein, The coolant channel terminates at a distance of less than 2 mm from a front end of the cutting portion.

9. A method for manufacturing a cutting tool for machining a workpiece, the method comprising the steps of: - providing a blank having a shank, a cutting portion, and a coolant channel having a peripheral wall and an end wall, wherein the coolant channel terminates at a distance of less than 10 mm from a front end of the cutting portion, - forming a notch or recess on an end face of the cutting portion to form an outlet opening in the end wall of the coolant channel; wherein the cutting tool further comprises a riser on the end wall of the coolant channel, which riser protrudes into the coolant channel and which riser forms an annular channel section of the coolant channel to ensure coolant flow to the outlet openings.

10. The method of claim 9, wherein, The blank is sintered and the notch or recess is formed by milling or grinding after sintering the blank.

11. A method for manufacturing a cutting tool for machining a workpiece, the method comprising the steps of: - providing a blank having a shank, a cutting portion, and a coolant channel having a peripheral wall and an end wall, wherein the coolant channel terminates at a distance of less than 10 mm from a front end of the cutting portion, - forming a groove along the cutting portion to form an outlet opening in the end wall of the coolant channel; wherein the cutting tool further comprises a lift on the end wall of the coolant channel, which lift protrudes into the coolant channel and which lift forms an annular channel section of the coolant channel to ensure coolant flow to the outlet opening.

12. The method of claim 11, wherein, The coolant channel is stepped and an outlet opening is formed in the end wall of the coolant channel and on the stepped portion of the coolant channel when the groove is formed.

13. The method of claim 11, wherein, The blank is manufactured by injection molding.

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