WO1995008412A1

WO1995008412A1 - Forming cutter

Info

Publication number: WO1995008412A1
Application number: PCT/DE1994/001111
Authority: WO
Inventors: Rupert Heiss
Original assignee: Rupert Heiss
Priority date: 1993-09-22
Filing date: 1994-09-16
Publication date: 1995-03-30

Abstract

The invention relates to a forming cutter for making grooves, especially in non-metallic materials, with a shaft at the end of which there are regularly angularly spaced cutters having at least one peripheral and one face bezel. Prior art forming cutters have the drawback that only one bezel engages with the material of the workpiece at a time, giving rise to irregular cutting forces, uneven running and rapid wear. The feed rate is also relatively low. The invention obviates these drawbacks in that there are at least three bezels (2) at the end of the shaft (1) and the face bezels (7) are at an angle α1 to the radial direction of the forming cutter so that all the face bezels (7) lie substantially on a concave wedge surface. The forming cutter is designed for both clockwise and anticlockwise-rotating machines, in which the bezels and the face bezels for anticlockwise machines are mirror images of those for clockwise machines.

Description

Form milling cutter

description

The invention relates to a milling cutter according to the preamble of claim 1.

Milling cutters for producing dovetail grooves in non-metallic materials such as wood or plastic are known which have a cutter shank, at the end of which cutting elements are arranged at regular angular intervals, each of which has a peripheral cutting edge and a front cutting edge, an inner cutting edge A circumferential cutting section with a small cutting radius runs essentially axially and an oblique circumferential cutting section connects the inner circumferential cutting section with the end cutting edge, which has a larger cutting radius.

The spaces between the cutting bodies form the chip chambers of the form milling cutter.

Such form cutters are used in particular to retrofit dovetail grooves in window frames and sashes, door frames, etc., in which dovetail grooves ten sealing profiles for sealing the windows or doors can be inserted. For this purpose, the milling shank of the form milling cutter is clamped into the three-jaw chuck of a hand milling or drilling machine, which is guided along a reference edge of the frame or wing by means of a suitable guide device. The front end of the form cutter penetrates the wood or plastic material of the door or window and creates the dovetail groove in one operation.

The inner peripheral cutting section with the small cutting tradition creates the narrow opening gap lying in the area of the surface of the object to be processed. The oblique circumferential cutting edge sections create the oblique side flanks of the dovetail groove and the end cutting edge creates the base area of the dovetail groove.

Since the form milling cutter is clamped in a hand-held milling machine, which rests against the object to be machined with a suitable stop, it must be ensured that no excessive forces arise during the milling process, which forces the milling cutter transversely to the feed direction or out of the plane can push out the object to be processed. Excessive forces would make the handling of the hand milling device considerably more difficult and would lead to an irregular course of the dovetail groove.

The known form milling cutters for producing Schwalben¬ tail grooves have two diametrically opposed cutting bodies. The two cutting bodies have a relatively small end face, so that the chips generated during machining only exert a small force in axial direction. direction on the form cutter. There is therefore no danger that the form cutter will be pushed out of the plane of the object to be machined. A double-edged milling cutter has the essential disadvantage that only one cutting edge is in engagement with the material of the object to be machined. For this reason, quite irregular cutting forces arise and the double-edged milling cutter has an uneven running. Furthermore, the feed rate of the double-edged form cutter is relatively slow. Finally, the cutting edges of the double-edged milling cutter wear out very quickly and only allow the machining of approximately 30 to 40 m of wood-based material.

The object of the invention is to provide a form milling cutter which, with increased machining speed and stability, has a smoother run without inadmissibly high forces being generated during the milling process.

According to the invention, this object is achieved by the characterizing features of claim 1.

In the form cutter according to the invention, at least three cutting bodies are arranged at the end of the cutter shaft and the end cutters have an angle cq to the radial direction of the form cutter, so that all end cutters lie essentially on a concave conical surface.

The end cutting edges preferably have an angle cq of at least 5 °, preferably 15 °, to the radial direction of the milling cutter. In the case of a milling cutter with at least three cutting bodies, at least two cutting edges are simultaneously in engagement with the material to be machined, so that the fluctuations in the cutting forces are very small. Since the three cutting bodies have a larger end face than two cutting bodies, there is a risk that the form milling cutter may be removed from the dovetail groove by machining chips which lie between the base area, in particular a dovetail groove and the end face of the form cutter is pushed out. This danger is eliminated in that the end cutting edges are inclined inward by at least 5 ° and preferably 15 ° to the radial direction of the form milling cutter in the direction of the clamping end of the milling cutter shaft. As a result, only the outer tips of the cutting edges are in contact with the material to be processed. The inner areas of the end faces lie essentially on a concave conical surface and provide sufficient space for the depositing and the removal of the machining chips.

The form cutter has a first circumferential cutting section with a small cutting radius and at least a second circumferential cutting section between the end cutting edges and the first circumferential cutting section, the second circumferential cutting section at least partially having a larger cutting radius than the first circumferential cutting section.

The cutting edges of the second U cutting edge sections can run both in the direction of the axis of the form cutter or at an angle to this. The cutter shank and the cutting bodies are preferably connected to one another in one piece. Like a twist drill, the form cutter can be manufactured from a rod-shaped blank.

In order to avoid overheating of the cutting edges, which are in contact with the base surface of the groove or the machining chips deposited between the base surface and the end surface during the entire processing time, the end cutting edges preferably have a clearance angle of at least 7 ° and preferably 15 ° on. As a result, the surface pressure between the end faces of the cutting bodies and the machining chips is additionally reduced and the cutting bodies are sufficiently cooled in the area of the end cutting edges.

The clearance angle of the peripheral cutting edges is preferably 30 to 60 °. In order to produce a sufficient cooling effect on the free surfaces of the peripheral cutting edges, the free surfaces can be angled or arched. This results in a smaller clearance angle in immediate vicinity of the ^'Umfangs¬ cut and the stability of the peripheral cutting edges is in particular in the corner region of the cutting body in which the peripheral cutting edges are adjacent to the Stim cutting, erhöht.Mit further distance to the circumferential cutting edges, the relief angle and the cooling magnified the open space is increased.

As with conventional twist drills for hand drills, it is also advantageous with the form milling cutter according to the invention if the radius of the milling cutter shaft is at least as such is as big as the cutting radius of the sti cut. Thus, as mentioned above, the milling cutter according to the invention can be machined out of a rod-shaped metal body.

In this case, it is also possible to provide both ends of the cutter shaft with cutting bodies, so that if one end of the form cutter is worn, it can be turned and work can continue with the second cutter end. The circumferential cutting and end cutting of the cutting bodies, which do not protrude from the contour of the milling shank, are not damaged when the milling shank is clamped in a three-jaw chuck of a hand milling machine.

A form cutter which is particularly suitable for producing a dovetail groove in a window frame or sash for attaching a sealing profile has the following dimensions:

Milling shank diameter: 6 mm

Cutting radius of the face cutting edges: 3 mm Cutting radius of the inner peripheral cutting edge sections: 1.4 mm Angle of the oblique peripheral cutting edges to the axial direction: 30 °.

This creates a dovetail groove with an approximately 2.8 mm wide opening gap and an approximately 6 mm wide base. The depth of the dovetail groove depends on the depth of the opening gap. The depth of the opening gap should not be greater than 1 mm, so that there is a total groove depth of about 3.3 mm. In order to achieve the longest possible service life of the form milling cutter, it should consist of a hard metallic material. Widia steel, a hard metal such as K30 or a sintered metal such as GT20 are suitable. Three-edged form cutters made of such materials have almost twice the service life of double-edged form cutters.

The hard materials can be processed by grinding machines, for example CNC grinding machines with diamond grinding wheels, to form the milling cutters. The advantageous shaping of the form milling cutter enables a quick and inexpensive manufacturing process by means of form grinding. In a first operation, the at least three chip chambers are produced with the end face and the peripheral surface of a shaped grinding wheel. Afterwards, the free surfaces of the cutting edges are produced using the face grinding process. The free angle of the free surfaces of the cutting edges must be exactly observed by programming the CNC milling machine. Finally, the free surfaces of the circumferential cutting edges are created with a shaped grinding wheel. The desired, optionally curved or angled course of the free surfaces of the peripheral cutting edges can be produced by suitable guiding of the shaped grinding wheel.

A further embodiment of the form milling cutter according to the invention has an additional circumferential cutting edge section which runs in an arc shape. This form cutter serves in particular to make the dovetail grooves at right-angled inner angles of a frame or sash rebate. The hand milling machine is guided in the fold such that the Axis of the milling tool lies on the bisector of the inner angle. The form cutter penetrates into the material to such an extent that it produces the dovetail groove and two free cuts with an arcuate cross section lying to the right and left of the dovetail groove. The free cuts are produced by the arcuate peripheral cutting sections lying above the inner peripheral cutting sections in the axial direction of the milling cutter.

The silicone sealing profiles which are to be held by the dovetail groove have a dovetail-shaped anchoring which is pressed into the dovetail groove and a tubular sealing body. The arcuate free cuts serve to receive the area of the tubular sealing body adjacent to the anchoring of the sealing profile.

A further embodiment of the invention provides that the features described so far, which have been explained for milling cutters for right-turning machines, also be provided for left-turning machines. The cutter differ ^'is da¬ by that for milling tools for left-turning machines, the cutting body and the end cutting edges are mirror images gegen¬ provided over a cutter for right-turning machines. The use of machines with different directions of rotation is particularly useful for hand-held machines. Milling work with the aid of hand-held machines is generally carried out using a stop. If the stop is on the right side of the hand-held machine, it is advisable to use a right-turning machine with an appropriate milling cutter. The machine becomes involved in the milling process constantly pressed against the stop, so that a smooth groove can be produced which corresponds to the course of the stop.

If, on the other hand, the stop is on the left side of the machine, there is a risk of a right-hand milling cutter being moved away from the stop. By constant counter pressure against the machine, a groove can also be produced in this case, which follows the stop. However, the wall of the groove has a slight wave shape. If a left-hand milling cutter is used in this case, the same advantages result as those mentioned for the right-hand milling cutter when there is a right hand stop.

Further features of the invention result from the description of the drawing that follows.

The drawings show in:

FIG. 1: the side view of one end of the form milling cutter according to the invention,

Figure 2: the top view of the form cutter from Figure

1,

FIG. 3: the entire form milling cutter in a side view,

FIG. 4: one end of the form cutter in engagement with the object to be machined, 5 shows a plan view according to FIG. 2, with alternative courses of the open areas of the circumferential cut

FIG. 6: an alternative embodiment of the form cutter in engagement with the object to be processed,

FIG. 7: the side view of the end of the shaping cutter with circumferentially sloping edges,

FIG. 8: the top view of the form milling machine according to FIG. 7,

FIG. 9: the side view of the end of the milling cutter with circumferential cutting edges running parallel to the axis of the milling cutter,

Figure 10: The top view of the form cutter according to

Figure 9,

FIG. 11: a partial view of the end of the milling cutter with circumferential sheaths running parallel to the axis of the milling cutter,

Figure 12: a partial view of the end of the milling cutter with offset oblique peripheral cutting. FIG. 13 shows the side view of one end of the form milling cutter according to the invention for left-turning machines for the production of dovetail grooves;

14 shows the top view of the form milling cutter according to FIG

Figure 13,

FIG. 15 shows the side view of one end of the form cutter for left-turning machines with circumferential cutting edges running obliquely inwards;

Figure 16 shows the top view of the form cutter

Figure 15,

FIG. 17 shows the side view of one end of the milling cutter for left-turning machines with circumferential cutting edges running parallel to the axis of the milling cutter;

Figure 18 shows the top view of the form cutter

Figure 17.

The form cutter shown in FIGS. 1 and 2 consists of a round cutter shaft 1 and three cutting bodies 2 machined from the material of the cutter shaft 1. In plan view, three surfaces of the cutting bodies running essentially in the axial direction can be seen, namely the rake face 3 and the free surface 4 of the peripheral cutting edge 5 and the rear surface 6 of the cutting body 2. The rake surface 3 of the peripheral cutting edge 5 and the rear surface 6 of the adjoining chip body 2 form a chip chamber of the milling cutter. The peripheral cutting edge 5 is composed of an inner peripheral cutting portion 5 'and an inclined peripheral cutting portion 5''. The angle between the oblique peripheral cutting section 5 ″ and the axial direction of the form cutter is 30 °.

At the ends of the oblique circumferential cutting edge sections 5 ″, the end cutting edges 7 adjoin and run towards the axis of the form milling cutter. The course of the front cutting edge 7 can be seen in the left half of FIG. It has an angle cq of 15 ° to the radial direction of the milling cutter, so that all three cutting edges 7 lie on a concave conical surface. Enough space remains within this concave conical surface for the depositing and the removal of the machining chips during the production of the dovetail grooves.

The rake angle of the peripheral cutting edge 5 and the front cutting edge 7 is 0 °, so that the front cutting edge 7, the peripheral cutting edge 5 and the two cutting edges common cutting surface 3 ^' lie in one plane.

The end faces of the cutting bodies form the free surfaces 8 of the cutting edges 7. The clearance angle α-2 of the end cutting edges 7 shown in the right half of FIG. 1 is 15 °. The clearance angle 0: 3 of the peripheral cutting edges, which can be seen in FIG. 2, is 45 °. The entire form milling cutter can be seen in FIG. Since the maximum cutting radius of the form cutter, ie the cutting tradition of the cutting edges 7, is smaller than the radius of the cutter shaft 1, it is possible to attach a milling tool to both ends of the cutter shaft 1. When the milling shank 1 is clamped in, this milling tool cannot be damaged by the chuck.

All representations of the milling tool in the drawings are enlarged. The milling tool according to the invention has a length of approximately 60 mm and a diameter of approximately 6 mm, in particular for the intended manufacture of the dovetail grooves in door or window frames or sashes. The depth of the dovetail groove produced with such a milling tool is less than 4 mm.

FIG. 4 shows a milling tool according to the invention in engagement with the material 9 to be machined. The inner peripheral cutting section 5 'creates the narrow opening gap 10 of the dovetail groove. The oblique circumferential cutting edge section 5 ″ creates the side flanks 11 of the dovetail groove and the tips of the end cutting edges 7 create the base surface 12 of the dovetail groove.

FIG. 4 shows a top view of the form milling cutter according to the invention, in which alternative courses of the free surfaces of the peripheral cutting edges 5 are drawn. A dash-dotted line indicates a curved course 13 of the right circumferential cutting edge. The lower circumferential cutting edge has an angled course 14 along the dash-double-dotted line. Of course, the open spaces have the same course on all cutting bodies 2 of a form milling cutter, since the peripheral cutting edges 5 otherwise have different cutting and wear properties.

Due to the curved course 13 and the angled course 14 of the free surface, the clearance angle is small in the area near the peripheral cutting edge 5 and increases in the more distant area. Due to the smaller clearance angle in the front area, the peripheral cutting edge 5 has greater stability. The larger clearance angle in the rear area ensures sufficient cutting edge cooling.

FIG. 6 shows an alternative embodiment of the form cutter. At the inner peripheral cutting sections 5 ', an arcuate peripheral cutting section 5' "adjoins in the axial direction upwards.

The alternative embodiment of the form cutter is used to mill a dovetail groove into the right-angled inner angle of a workpiece, for example the fold of a frame or sash profile 15. The upper arcuate peripheral cutting section 5 ″ ″ in the areas of the side bordering on the narrow opening gap 10 arcuate cutouts 16 are produced for the material to be processed. The arcuate free cuts 16 serve to receive the lower areas of tubular sealing profiles which have a dovetail-shaped anchoring which can be inserted into the dovetail groove. The form milling cutter shown in FIGS. 7 and 8 is intended for producing a groove which is V-shaped, the groove base being flat. This form milling cutter also has an inner peripheral cutting section 5, an inclined peripheral cutting section 5 ″ and end cutters 7. The inner circumferential cutting edge section 5 "also creates a narrow opening gap of the groove in this milling cutter. The oblique circumferential cutting edge section 5" creates the side flanks of the V-shaped groove and the tips of the cutting edges 7 produce the base area of the groove.

FIGS. 9, 10 and 11 show form cutters according to the invention for producing a groove with parallel side flanks. The difference between the milling cutter shown in FIGS. 9 and 10, on the one hand, and FIG. 11, on the other hand, is that the former is used to produce a groove with a narrow opening gap, as in the previous exemplary embodiments, while the latter is made with a continuous peripheral cutting section 17 Groove with continuous side flanks is generated.

A groove with a so-called. Fir tree cross section can be produced. For this purpose, two peripheral cutting sections 18 ', 18 "are provided between the inner peripheral cutting section 5' and the end cutting edges 7, only one of which is shown in FIG. 12. Depending on the intended use of the groove, it is of course also possible to provide more than two peripheral cutting sections, for example three or even four. The form cutter for left-handed machines shown in FIGS. 13 and 14, like the form cutter for right-handed machines, consists of a round cutter shaft 21 and three cutting bodies 22 machined from the material of the cutter shaft 21. In plan view, there are three surfaces running essentially in the axial direction to recognize the cutting body, namely the rake face 23 and the free face 24 of the peripheral cutting edge 25 and the rear face 26 of the cutting body 22. The rake face 23 of the peripheral cutting edge 25 and the rear face 26 of the adjacent cutting body 22 form a chip chamber of the milling cutter. The peripheral cutting edge 25 is composed of an inner peripheral cutting section 25 'and an inclined peripheral cutting section 25 ". The angle between the inclined peripheral cutting section 25" and the axial direction of the milling cutter is 30 °.

At the ends of the oblique circumferential cutting edge sections 25 ″, the end cutting edges 27 join and run towards the axis of the form milling cutter. The course of the cutting edge 27 can be seen in the right half of FIG. It has an angle to the radial direction of the form milling cutter, so that all three cutting edges 27 lie on a concave conical surface. The end faces of the cutting bodies form the free surfaces 28 of the cutting edges 27.

All representations of the milling tool in the drawings are enlarged. In particular for the intended manufacture of the dovetail grooves in door or window frames or sashes, the milling cutter according to the invention has a length of approximately 60 mm and a diameter of approximately 6 mm. The form milling cutter shown in FIGS. 15 and 16 is provided for producing a groove which is V-shaped, the groove base being flat. This form cutter also has an inner circumferential cutting section 25 ', an oblique circumferential cutting section 25 "and end cutting edges 27. The inner circumferential cutting section 25' also produces a narrow opening gap of the groove in this milling cutter. The oblique circumferential cutting section 25 '' creates the side flanks of the V- shaped groove and the tips of the end cutting 27 produce the base of the groove.

FIGS. 17 and 18 show a form cutter according to the invention for producing a groove with parallel side flanks. As in the previous exemplary embodiments, this is used to produce a groove with a narrow opening gap. This milling cutter also has an inner peripheral cutting section 25 ′. Instead of the oblique circumferential cutting edge sections 25 ″ of the preceding exemplary embodiments, in this exemplary embodiment an outer circumferential cutting edge section 25 ′ ″ is provided, which runs parallel to the milling cutter axis.

The description of the invention and the drawings relate to preferred embodiments of the invention. It is noted that changes and variations are possible by a person skilled in the art without leaving the scope of the invention according to the claims. In particular, the form milling cutter according to the invention is also advantageous in the manufacture Position of dovetail grooves or grooves with other shapes with other than the machine tools described in other than the materials described suitable.

Claims

claims

1. Form milling cutters for the production of grooves, in particular in non-metallic materials such as wood or plastic, with a milling shank, at the end of which cutting elements are arranged at regular angular intervals from one another, each having at least one peripheral cutting edge and one end cutting edge,

characterized,

that at least three cutting bodies (2) are arranged at the end of the milling cutter shaft (1) and the end cutters (7) have an angle cq to the radial direction of the milling cutter, so that all end cutters (7) lie essentially on a concave conical surface.

2. Milling cutter according to claim 1, characterized in that the end cutting edges (7) preferably have an angle cq of at least 5 °, preferably 15 °, to the radial direction of the milling cutter.

3. Milling cutter according to claim 1 or 2, characterized gekennzeich¬ net that a first peripheral cutting portion (5 ') is provided with a small cutting radius and at least a second peripheral cutting portion (5 ", 17, 18', 18") between the cutting edges ( 7) and the first peripheral cutting section (5 ') is provided, the second peripheral cutting section (5 ", 17, 18 ', 18") at least partially has a larger cutting radius than the first peripheral cutting section (5')

4. Milling cutter according to at least one of the preceding claims, characterized in that the cutting edges of the second peripheral cutting portions (5 ", 17, 18 '18") run in the direction of the milling cutter axis or at an angle to it.

5. Milling cutter according to at least one of the preceding claims, characterized in that the cutting body (2) and the cutter shank (1) are integrally connected to one another.

6. Milling cutter according to at least one of the preceding claims, characterized in that the clearance angle 0-2 of the cutting edges (7) is at least 7 °, preferably '15 °, be¬.

7. Form milling cutter according to at least one of the preceding

Claims, characterized in that the clearance angle 0.3 of the peripheral cutting edges (5) is 30 ° to 60 °, preferably 45 °.

8. Milling cutter according to at least one of the preceding claims, characterized in that the free surface (4) of the peripheral cutting edges (5) is angled or curved.

9. Milling cutter according to at least one of the preceding claims, characterized in that the radius of the cutter shaft (1) is at least as large as the cutting radius of the cutting edges (7).

10. Milling cutter according to claim 7, characterized in that at least three cutting bodies (2) are arranged at both ends of the cutter shaft (1).

11. Milling cutter according to at least one of the preceding claims, characterized in that the diameter of the cutter shank (1) 6 mm, the cutting radius of the stimulating cutters (7) 3 mm, the cutting radius of the inner peripheral cutting sections (5 ') 1 , 4 mm and the angle of the oblique peripheral cutting sections (5 '') to the axial direction is 30 °.

12. Milling cutter according to at least one of the preceding claims, characterized in that it consists of a hard metallic material, for example Widia steel, Hartme¬ tall or sintered metal.

13. Milling cutter according to at least one of the preceding claims, characterized in that with each cutting body (2) on the inner peripheral cutting portion (5 ') on the opposite side of the oblique peripheral cutting portion (5' ') an arcuate peripheral cutting portion (5 "' ) connects.

14. Milling cutter according to at least one of the preceding claims, characterized in that those are provided for right-turning and left-turning machines.

15. Milling cutter according to at least one of the preceding claims, characterized in that in milling cutters for left-turning machines, the cutting bodies and the forehead edges are arranged in mirror image relative to a milling cutter for right-turning machines.