Abstract
A method is provided for processing a workpiece by means of a drill, wherein the drill extends along a longitudinal axis and has a drill tip with a nose angle (S) that is less than 180, wherein the drill has a lateral surface, on which at least one side blade is formed, which is designed for milling by means of a feeding in a transverse direction (Q) to the longitudinal axis (L), wherein the workpiece has a surface (O), through which a drill hole is drilled, in that in a first step a plane surface is milled into the surface (O) and subsequently in a second step the drill hole is drilled from the plane surface outwards, wherein the plane surface is milled by means of the side blade of the drill in that it is fed forward in a transverse direction (Q) to the longitudinal axis (L), wherein the drill hole is drilled by means of the same drill in that it is fed forward in the direction of the longitudinal axis (L). Further, a corresponding drill is provided.
Claims
1. A method comprising processing a workpiece by means of a drill, wherein the drill extends along a longitudinal axis and has a drill tip with a nose angle that is less than 180, wherein the drill has a lateral surface, on which at least one side blade is formed, which is designed for milling by means of a feeding in a transverse direction to the longitudinal axis, wherein the workpiece has a surface, through which a drill hole is drilled, in that in a first step a plane surface is milled into the surface and subsequently in a second step the drill hole is drilled from the plane surface outwards, wherein the plane surface is milled by means of the side blade of the drill in that it is fed forward in a transverse direction to the longitudinal axis, wherein the drill hole is drilled by means of the same drill in that it is fed forward in the direction of the longitudinal axis.
2. The method according to claim 1, wherein, during milling, in a first step the drill is fed forward with an inclined longitudinal axis, in that the drill is positioned in such a way that the lateral direction forms an angle with the longitudinal axis that corresponds to half of the nose angle.
3. The method according to claim 1, wherein in a first step a lateral wall is formed by the side blade, which adjoins the plane surface and extends from the plane surface at an angle that corresponds to the difference between 180 and half of the nose angle.
4. The method according to claim 3, wherein the lateral wall is designed as a chamfer for the drill hole and serves as a guide during drilling.
5. The method according to claim 1, wherein, after milling of the plane surface in the first step and before drilling of the drill hole in the second step, the drill is inclined such that the longitudinal axis of the drill is vertical to the plane surface.
6. The method according to claim 1, wherein, after milling of the plane surface, the drill is pushed back counter to the transverse direction, so that a stage is formed by the plane surface when drilling the drill hole.
7. The method according to claim 1, wherein the drill hole is a pilot drill hole and is subsequently further formed by means of a separate deep hole drill as a deep drill hole.
8. A drill which extends along a longitudinal axis and comprises: a drill tip with a nose angle that is less than 180 for drilling a drill hole, a lateral surface, on which at least one side blade is formed, wherein the side blade is designed for milling by means of a feeding in a transverse direction to the longitudinal axis.
9. The drill according to claim 8, wherein the side blade is designed for milling with a clearance angle of at least 5 and no more than 50.
10. The drill according to claim 8, wherein the nose angle is no more than 170.
11. The drill according to claim 8, wherein the entire side blade is designed for milling.
12. The drill according to claim 8, wherein the side blade is designed only on a front-facing milling section for milling.
13. The drill according to claim 8, wherein the side blade is formed to be two-stage, in that a rear drilling section adjoins the front-facing milling section, wherein the milling section has a milling diameter that is less than a drilling diameter of the drilling section.
14. The drill according to claim 8, wherein it is designed as a pilot drill for the creation of a pilot drilling.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] In the following, exemplary embodiments of the invention are explained in greater detail by means of a drawing. The following are shown, each schematically:
[0040] FIG. 1 A drill and a workpiece with an inclined surface,
[0041] FIG. 2 a first step in the processing of the workpiece from FIG. 1,
[0042] FIG. 3 a second step in the processing of the workpiece from FIG. 1,
[0043] FIG. 4 the formation of a deep drill hole in the workpiece from FIG. 1,
[0044] FIG. 5 an enlarged view of the first step from FIG. 2,
[0045] FIG. 6 an enlarged view of the transition from the first step from FIG. 2 to the second step of FIG. 3,
[0046] FIG. 7 an enlarged view of the second step from FIG. 3,
[0047] FIG. 8 the drill from FIG. 1 in a front view,
[0048] FIG. 9 a detailed view of a section of the drill from FIG. 1,
[0049] FIG. 10 the drill from FIG. 1 in a cross-sectional view,
[0050] FIG. 11 the drill from FIG. 1 in a side view
[0051] FIG. 12 a variant of the drill and a workpiece in a side view,
[0052] FIG. 13 the arrangement from FIG. 12 in a top view,
[0053] FIG. 14 the arrangement from FIG. 12 in a first step,
[0054] FIG. 15 the arrangement from FIG. 14 in a top view,
[0055] FIG. 16 the arrangement from FIG. 12 in a second step,
[0056] FIG. 17 the arrangement from FIG. 16 in a top view,
[0057] FIG. 18 the workpiece from FIGS. 12 to 17 and a deep hole drill.
DETAILED DESCRIPTION
[0058] FIGS. 1 to 7 show sections of a method in which a workpiece 4 is processed by means of a drill 2. FIGS. 5 to 7 show excerpts of the process from FIGS. 2 and 3 in an enlarged view. The drill 2 is shown in more detail in FIGS. 8 to 11 in various views. The drill 2 extends along a longitudinal axis L and has a drill tip 6, which is designed to be front-facing on the drill 2, i.e. pointed frontwards. As is discernible in FIGS. 5 to 7, in particular, but also in FIG. 11, the drill tip 6 has a nose angle S that is less than 180 and, here, no more than 170, so that the drill 2 is formed flat overall. The drill tip 6 with the special nose angle S serves for drilling a drill hole 8. The drill 2 has a lateral surface 10, on which at least one side blade 12 is formed, which is clearly discernible in the enlarged section of FIG. 9, in particular. The side blade 12 is designed for milling by means of a feeding in a transverse direction Q to the longitudinal axis L, whereby the transverse direction Q does not necessarily run vertically to the longitudinal axis L. Here, the side blade 12 is designed to be high-cutting, in that it is formed with a clearance angle F greater than 0. The transverse direction Q is a milling direction and corresponds to a feeding direction of the drill during milling.
[0059] In FIGS. 1 to 7, the workpiece 4 has a surface O, through which a drill hole 8 is drilled. For this purpose, as shown in FIGS. 1 and 2, a plane surface 14 on the surface O is milled in a first step. In FIG. 1, the drill 2 is first guided to the workpiece 4 and then inserted into it laterally in FIG. 2. Then, as shown in FIG. 3, in a second step the drill hole 8 is drilled from the plane surface 14 outwards. The surface O is an inclined surface O and, here, completely curved and, in any case, not level. By contrast, the plane surface 14 is a level surface and serves to prepare the drilling on the otherwise inclined surface O. The surface O is thus first milled to be level by means of milling of the plane surface 14, as shown in FIG. 2, in order to then form the drill hole 8, as shown in FIG. 3. The method thus generally comprises two steps, namely a preparatory step as shown in FIG. 2 as a first step and a drilling as shown in FIG. 3 as a second step. A special drill 2 is used here, which is a drill in and of itself having an additional milling function. The drill 2 is therefore a multifunction tool here. In the first step, the milling function of the drill 2 is used to prepare the surface O of the workpiece 4 for the subsequent drilling. Here, the drill 2 is moved sideways, as shown by arrows in FIGS. 1 and 2. Then, a drilling function is used in order to drill the drill hole 8, as shown in FIG. 3. A tool exchange is omitted here.
[0060] In the exemplary embodiment shown, the drill hole 8 is used as shown in FIG. 4 in order to drill a deep hole by means of a deep hole drill 16. In the exemplary embodiment shown, the original drill hole 8 thus serves as a pilot drill hole for a deep hole drilling. The drill 2 is accordingly a pilot drill and, after drilling of the drill hole 2, there is a tool exchange. Alternatively to a deep drill hole as shown in FIG. 4, in a variant not shown, only a drill hole 8 is drilled as seen in FIGS. 1 to 3, wherein the step in FIG. 4 is omitted and thus no deep drill hole is drilled.
[0061] The drill 2 generally has a length E and a diameter D. To reduce friction in the drill hole during drilling, in a variant not shown, the drill 2 is tapered to the rear, thus having a diameter D which is reduced starting from the drill tip 6 and running backwards in the longitudinal axis L.
[0062] In FIG. 3, the drill hole 8 is drilled by means of the same drill 2 with which milling is performed in FIG. 2 in that this drill 2 is fed forward towards the longitudinal axis L. In doing so, the drill 2 removes material from the workpiece 4 on the front side by means of the drill tip 6. During drilling, the drill 2 is further arranged in such a way that the longitudinal axis L is vertical to the plane surface 14, so that lateral forces on the drill 2 are avoided. The finished drill hole 8 then extends vertically with respect to the previously formed plane surface 14.
[0063] For drilling, as seen in FIG. 8, the drill tip 6 has multiple main blades 18, and the nose angle S indicates at what angle the main blades 18 are positioned with respect to one another. Overall, the drill tip 6 is formed conically, where the main blades 18 lie on an imaginary conical lateral surface. The nose angle S then corresponds to a conical nose angle formed by the conical lateral surface. The nose angle S is positive, i.e. less than 180, so that the drill tip 6 points outwards.
[0064] A main blade 18 of the drill 2 extends from a center Z of the drill 2 outwards to the lateral surface 10. There, the main blade 18 ends in a cutting corner 20. The special side blade 12 of the drill 2 starts on the front side of the drill tip 6 and forms a continuation of the main blades 18 along the lateral surface 10. Starting from the cutting corner 20, the side blade 12 extends from front to rear with respect to the drill 2. As is discernible for example in FIG. 11, the side blade 12 follows a chip slot 22, which adjoins the main blade 18 in the rotational direction of the drill 2 and serves to remove chips.
[0065] Now, in order to realize the milling function, the side blade 12 for milling is formed by means of a feeding in the transverse direction Q, having a clearance angle F of greater than 0 for this purpose. For this purpose, the side blade 12 is ground during manufacture of the drill 2, as can be seen especially well in the enlarged view of FIG. 9, so that a cutting effect is achieved when operated as intended. The clearance F of the side blade 12 is between 5 and 30 here. A guide chamfer on the side blade 12 was omitted in the present drill 2. In an embodiment not shown, the side blade 12 has a clearance angle F of greater than 0 along its entire length. As a result, the manufacture of the drill 2 is particularly simple. In the variant shown, by contrast, the side blade 12 is formed only on a front-facing milling section 26 for milling, i.e. only on the front side and in the area of the drill tip 6.
[0066] The drill 2 shown differs from a mill not merely due to the special nose angle S and multiple main blades 18, but also due to a core diameter KD that is smaller compared to a mill. Here, the core diameter KD of the drill 2 is at most half of the diameter D of the drill 2. This is particularly clearly discernible in FIG. 10, which shows the drill 2 in a sectional view vertical to the longitudinal axis L.
[0067] In the embodiment shown, in the first step during milling, the drill 2 is fed with an inclined longitudinal axis L, as shown in FIG. 1 and discernible in FIG. 5 in detail. For this purpose, the drill 2 is positioned in such a way that the transverse direction Q forms an angle W1 with the longitudinal axis L corresponding to half the nose angle S. The drill 2 is therefore inclined with respect to the transverse direction Q. The incline is dependent upon the nose angle S and is selected such that when turning the drill 2, the imaginary conical lateral surface is ground over the plane surface 14. The drill tip 6 is therefore not used for the front-facing processing, but rather material is removed exclusively by means of the side blade 12. By contrast, the main blades 18 are not used during milling.
[0068] In the first step, a side wall 24 is formed by means of the side blade 12, said side wall adjoining the plane surface 14 when viewed in the transverse direction Q. This is shown in detail in FIG. 5, where the drill 2 is shown at somewhat of a distance from the workpiece 4 merely for better visibility. The side wall 24 is formed, in principle, parallel to the lateral surface 10 and extends from the plane surface 14 outwards at an angle that is also called a lateral angle W2. The lateral angle W2 generally corresponds to an angle of the drill 2 at the cutting corner 20, so that the lateral surface 24 forms the outer contour of the drill 2 in combination with the plane surface 14. In the drill 2 with a nose angle S of 178 shown, the main blade 18 and the lateral surface 10 form an angle of 92, and accordingly, the lateral angle W2 between the plane surface 14 and the side wall 24 is also 92. Due to the side wall 24, a stage is formed, which then delimits the plane surface 14 from the remaining surface O. The side wall 24 then defines a height H of the stage, which typically lies between 0.01 mm and 8 times the drilling diameter Db.
[0069] In the second step, the side wall 24 then forms a chamfer for the drill hole 8 and thus serves as a guide during drilling. This use of the side wall 24 as a guide is particularly suitable for deep hole drilling, as shown in FIG. 4, and when the drill 2 is used as a pilot drill. By means of the same drill 2, the plane surface 14 is first created, and then the drill hole 8 is used as a pilot drilling for the subsequent deep hole drill 16.
[0070] In addition, in the exemplary embodiment shown after milling the plane surface 14 in the first step and before drilling the drill hole 8 in the second step, the drill 2 is inclined such that the longitudinal axis L of the drill 2 is vertical to the plane surface 14. This is shown in more detail in FIG. 6. The longitudinal axis L is thus brought into vertical alignment with the plane surface 14, so that during the subsequent drilling of the drill hole 8, the drill 2 is fed outwards from a surface O that is optimally milled to be level or generally smooth. The angle about which the longitudinal axis L is inclined is dependent upon the nose angle S and corresponds to half of the difference between a half angle of 180 and the nose angle S. In the exemplary drill 2 with a nose angle of 178 shown here, the longitudinal axis L is inclined by 1 between the first and the second step.
[0071] After milling of the plane surface 14, the drill 2 is fed back against the original transverse direction Q, so that when drilling the drill hole 8, a landing 28 is formed by the plane surface 14, as shown in FIG. 7. A distance A between the side wall 24 and the drill 2 is formed as a result of this back-feeding. The drill 2 is fed back by at least 0.05 mm and no more than 1 mm, so that the distance A to the side wall 24 is accordingly between 0.05 mm and 1 mm.
[0072] A variant of the drill 2 is shown in FIGS. 12 to 17. FIGS. 12 to 15 show the milling of the plane surface 14 in a first step, and FIGS. 16 and 17 show the drilling of the drill hole 8 in a second step. FIGS. 12, 14, and 16 each show the drill 2 and the workpiece 4 in a lateral view, and FIGS. 13, 15, and 17 show a top view of the workpiece 4 corresponding to the respective lateral view. The drill 2 is designed to be two-staged, i.e. the side blade 12 is two-staged, in that a rear drilling section 30 adjoins the front-facing milling section 26. The milling section 26 has a milling diameter Df, which is less than a drilling diameter Db of the drilling section 30. The milling section 26 and the drilling section 30 are thus arranged behind one another on the longitudinal axis L, wherein the milling section 26 is formed on the front of the drill 2 and the drilling section 30 is behind it. The side blade 12 is designed to be high-cutting on the milling section 26, as already described, but not on the drilling section 30, being formed there in the style of a drill. In FIGS. 13, 15, and 17, the drill is shown in a simplified view as a ring, in order to illustrate the milling diameter Df and the comparatively larger drilling diameter Db.
[0073] When processing the workpiece 4, the plane surface 14 is first milled, as already described. For this purpose, the drill is fed laterally, as shown in the FIGS. 12 and 13, and guided to the workpiece 4. In FIG. 13, the later plane surface 14 is already marked for better clarity, however, it is actually not yet incorporated into the workpiece 4. However, it is made clear that in the dimensioning of the plane surface 14, the larger drilling diameter Db is already taken into account, and the plane surface 14 should be milled in such a way that it is at least as large as the drilling diameter of Bd [sic: Db]. For this purpose, FIG. 15 shows a milling path P, along which the drill 2 is guided during milling of the plane surface 14. For better clarity, the milling path P is drawn in the offset position in FIG. 15. In addition, three positions of the drill 2 along the milling path P are identified by corresponding rings in FIG. 15. The milling path P comprises two longitudinal sections 32, 34 that are offset to one another, so that a plane surface 14 greater than the milling diameter Df is milled. As the milling path P further shows in FIG. 15, the drill 2 is then positioned centrally over the plane surface 14 and, as shown in FIGS. 16 and 17, inserted for drilling into the workpiece 4, in that the drill 2 is fed forward in the direction of the longitudinal axis L. In principle, the milling section 26 initially penetrates the workpiece 4, followed by the drilling section 30, which expands to the drill hole 8 to the drilling diameter Db.
[0074] Due to the different diameters Df, Db along the longitudinal axis L, there is a stage 36 at the transition from the milling section 26 to the drilling section 30, where the side blade 12 accordingly transitions from a high-cutting part to a non-high-cutting part. At this stage 36, there is an edge 38 in the radial direction, which bridges the difference between the two diameters Df, Db and connects the two parts of the side blade 12 to one another. Here, this edge 38 is designed as a blade, in order to continue removing material while in operation and to expand the drill hole diameter from the milling diameter Df to the drilling diameter Db. In a subsequent deep hole drilling, and in the deep hole drilling shown in FIG. 18 for example, the deep hole drill 16 used after the two-stage drill 2 preferably has a deep hole drilling diameter Dt corresponding to the drilling diameter Db but with a lower tolerance.
