Dental milling machine

Abstract

The invention relates to a dental milling machine which has a closed milling chamber (12). Said milling chamber has an air inlet opening and an outlet which are substantially opposite each other relative to the milling chamber and generate an air stream. Said air stream sweeps over a machining area in which a milling tool subjects the workpiece to a milling machining step. One end of the milling chamber (12), in particular the front end, has a door that can be opened. The base (42) of the milling space (12) runs at least partially at an angle and in particular is rounded off and the outlet (40) is connected to the lowest region of the base (42).

Claims

1. A dental milling machine comprising a closed milling chamber which has an air inlet opening and an outlet which are substantially opposite each other relative to the milling chamber and generate an air stream which sweeps over a machining area in which a milling tool subjects a workpiece to a milling machining step, wherein one end of the milling chamber has a first door that can be opened, wherein a base of the milling space runs at least partially at an angle, and is rounded off, the base being closed below the machining area and having substantially constant inclination, wherein the outlet is connected to a lowest region of the base, wherein the outlet is attached to an outer lower corner of the milling chamber, and wherein at least one air nozzle and/or the air inlet opening are situated at an upper corner, diametrically opposite of a suction connection.

2. The dental milling machine according to claim 1, wherein the milling chamber is essentially made out of a single-piece preform, which has a chip-repellent and/or non-adhesive surface.

3. The dental milling machine according to claim 1, wherein one side wall of the milling chamber has a movable partial wall or a second door for a passing-through of a milling workpiece and/or a milling tool.

4. The dental milling machine according to claim 1, wherein the base of the milling chamber is angled downwardly towards the outlet having an exhaust air opening and wherein the base forms a hollow fillet.

5. The dental milling machine according to claim 1, wherein at least one air nozzle comprises an air amplifying nozzle.

6. The dental milling machine according to claim 1, wherein a number of air nozzles and/or at least one deionizing electrode are arranged, wherein the air nozzles are partially closable and the deionizing electrodes are coverable, wherein the air nozzles are opened during wet milling and during milling of ceramic materials, and are closed during milling of plastic materials, and wherein the deionizing electrodes are separated via blocking elements from the milling chamber otherwise during the wet milling and during the milling of ceramic materials, and are positioned within the air stream during the milling of plastic materials.

7. The dental milling machine according to claim 1, wherein at least one air nozzle comprising one air amplifying nozzle and/or a number of air nozzles arranged next to each other, are oriented towards a machining area of the milling machine, and wherein the machining area extends, relative to a centre of the milling chamber above the centre and beyond the centre, viewed from the outlet of the milling chamber, wherein the number of air nozzles are attached at the top of the milling chamber and at least one air nozzle which is adjacent to a wall of the milling chamber extends with an axis at an angle relative to said wall.

8. The dental milling machine according to claim 1, wherein the milling chamber is formed entirely of one piece and free of obstacles or an undercut.

9. The dental milling machine according to claim 1, wherein the outlet is flange-mounted to a deepest point of the milling chamber and extends laterally away from said milling chamber, and wherein during wet working an outlet hose or an outlet tube extends laterally and/or downwards away from the outlet.

10. The dental milling machine according to claim 9, wherein a switching hatch or a switching valve for the outlet for switching between wet working and dry working is provided.

11. The dental milling machine according to claim 10, wherein for dry working, a suction line that may be put under a vacuum and acts on the outlet, and wherein for wet working, the outlet drains the wastewater and/or the milling sludge in a pressure-free fashion.

12. The dental milling machine according to claim 1, wherein a switching hatch that switches milling between wet milling and dry milling by closing the switching hatch for dry milling and opening or lifting the switching hatch for wet milling.

13. The dental milling machine according to claim 1, wherein an inclination of the base underneath the machining area and underneath the workpiece carrier and the tool, has an inclination angle of between 5 and 60 degrees, or between 15 and 25 degrees, or approximately 20 degrees.

14. The dental milling machine according to claim 1, wherein the air stream has a current which extends along the base and is directed towards the outlet.

15. The dental milling machine according to claim 5 comprising a control device for the air stream via which the air nozzles may be supplied with pulses of compressed air subsequently to a milling step.

16. The dental milling machine according to claim 15, wherein the control device switches on a suction air stream during the milling step at a suction power which is reduced compared with a maximum suction air stream, and the suction air stream sucks in air through the air nozzles.

17. The dental milling machine according to claim 2, wherein the single-piece preform is made of plastic.

18. The dental milling machine according to claim 3, wherein the one side wall of the milling chamber is a rear wall.

19. A dental milling machine comprising a closed milling chamber which has an air inlet opening and an outlet which are substantially opposite each other relative to the milling chamber and generate an air stream which sweeps over a machining area in which a milling tool subjects a workpiece to a milling machining step, wherein a number of air nozzles and/or at least one deionizing electrode are arranged, wherein one end of the milling chamber has a first door that can be opened, wherein a base of the milling space runs at least partially at an angle, and is rounded off, the base being closed below the machining area and having substantially constant inclination, wherein the outlet is connected to a lowest region of the base, wherein the air nozzles are partially closable and the deionizing electrodes are coverable, wherein the air nozzles are opened during wet milling and during milling of ceramic materials, and are closed during milling of plastic materials, and wherein the deionizing electrodes are separated via blocking elements from the milling chamber otherwise during the wet milling and during the milling of ceramic materials, and are positioned within the air stream during the milling of plastic materials.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Further advantages, details and features result from the subsequent description of several exemplary embodiments of the invention with the help of the drawings, which show:

(2) FIG. 1 a schematic view of one embodiment of a dental milling machine in accordance with the invention;

(3) FIG. 2 a side view of the milling chamber of the machine according to FIG. 1;

(4) FIG. 3 a horizontal cut through the embodiment according to FIGS. 1 and 2;

(5) FIG. 4 a schematic view of one embodiment of a milling chamber in accordance with the invention of a dental milling machine;

(6) FIG. 5 a detailed view about one embodiment of a dental milling machine in accordance with the invention;

(7) FIG. 6 a schematic depiction of another embodiment of the invention;

(8) FIG. 6a a cut through an air amplifying nozzle to be preferably employed in accordance with the invention;

(9) FIG. 7 a cut through the embodiment according to FIG. 6, however from a position rotated by 90 degrees; and

(10) FIG. 8 a time diagram for the control in a dental milling machine in accordance with the invention.

DETAILED DESCRIPTION

(11) The dental milling machine 10 which is depicted in FIG. 1 has a milling chamber 12 which is designed in a particular fashion. Milling chamber 12 is a closed element and is made of some material with a smooth and non-adhesive surface, such as a plastic material, for example. In a basically known fashion, it accommodates a spindle 14 which serves as a tool and is driven by a spindle motor 16. Further, it accommodates workpiece 19 which is mounted in a workpiece holder 22. Via a number of movement axes, the relative position between workpiece 18 and spindle 14 may be modified, for example in five axes.

(12) For the change of the workpiece, a rear wall of milling chamber 12 is provided with a door, and behind the milling chamber a magazine with further workpieces is arranged, out of which another workpiece 24 is visible in FIG. 1.

(13) Further, the front wall of milling chamber 12 is provided with an access door in its upper region.

(14) The left upper side, in the depiction according to FIG. 1, of milling chamber 12 accommodates an air inlet opening 26 which is provided with a number of nozzles each. The nozzles are mainly directed to a machining area 30 in which the spindle machines the workpiece. Nozzles 32 are attached to a nozzle carrier 34 which in turn is attached to milling chamber 12 from the outside.

(15) Within the area of nozzle carrier 34, electrodes 36 are arranged in addition which are supplied with electric voltage for deionizing the air let in. The supply is done during dry operation, while the electrodes are closed by a sliding device, which is not depicted, during a wet operation of dental milling machine 10. Thus, either deionizing electrodes 36 or nozzles 32 may be covered by the sliding device.

(16) Starting from the left upper corner, according to FIG. 1, the inlet air provided will flow to machining area 30 and beyond it to an outlet 40. Outlet 40 is positioned diametrically opposite of air inlet opening 26. Floating particles, such as milling dust, for example, are thus removed from the milling chamber and are carried away with the air stream.

(17) In many cases, however, milling chips are created which fall down, into the area of the base 42 of the milling chamber, due to their weight. In accordance with the invention, the base 42 of the milling chamber should now be inclined, which is, in such a fashion that it will drop towards outlet 40, in particular at an essentially constant slope. The milling chips tend to slide in this direction due to their own weight.

(18) In a particularly favourable embodiment, a directed carrier stream is additionally provided for the base, which stream is created by a nozzle 44. Nozzle 44 causes air to flow vertically downwards along side wall 46. At the bottom, adjacently to side wall 46, a stream re-directing device 48 is arranged, which has a very large radius of, for instance, half the diameter of the milling chamber. The stream from nozzle 44 will therefore be essentially laminar over the stream along side wall 46, further along stream re-directing device 48, and then across base 42. There, this carrier stream 50 will take away chips which are present there, and will supply them to outlet 40.

(19) For this purpose, outlet 40 is preferably connected, via an aspiration line 52, with a source of vacuum which is not depicted. Therefore, a vacuum is created at outlet 40, which increases the flow velocity there.

(20) As a result of the carrier stream 50 created, it is additionally possible to observe that some milling chip falling down will not even reach base 42, but rather be immediately carried away by carrier stream 50 and supplied to outlet 40.

(21) It can be taken from FIG. 2 in what fashion milling chamber 12 may be formed in a lateral vertical view. Milling chamber 12 is formed, in the area of base 42, in the fashion of a hollow fillet and has an essentially “U”- or “V”-shaped appearance. In a similar fashion as, for instance, a rain gutter, milling dust which is flying around is supplied to the central area 54 of base 42 and may thus be supplied to outlet 40 together with carrier stream 50.

(22) It can also be taken from FIG. 2 that a door 60 is formed in the upper/front region of the milling chamber, via which door the milling chamber may be opened.

(23) A back door 62, which is also positioned rather far upwards, is closed during the milling operation and serves for the purpose of exchanging the workpiece.

(24) From FIG. 3, a dental milling machine 10 in an embodiment in accordance with the invention is visible in a horizontal cut. Equal reference numbers indicate the same or corresponding parts here as well as in further Figures. As can be seen, milling chamber 12 has rounded corners 64 and 66, such that there is no danger of any milling chips depositing there.

(25) Another embodiment of a dental milling machine in accordance with the invention is visible schematically from FIG. 4. The machining area, and together with it, workpiece 18, are positioned in the left third of milling chamber 12, i.e. closely neighbouring nozzles 32. In this position, the air stream has a comparatively high flow velocity, whereas this is typically reduced in the direction towards outlet 40 due to the larger flow area. Base 42 is provided with a continuous inclination in the embodiment according to FIG. 4 as well.

(26) From FIG. 5, a switching device for wet and dry operation can be seen. A switching hatch 70 may be swivelled between the upper wet position 72 which is depicted in FIG. 5, and the lower dry position 74 extending vertically. The axis of switching hatch 70 is positioned upside at the corresponding lead.

(27) In dry position 74, switching hatch 70 is closed. The air stream through outlet 40 is in the direction towards aspirational lead 52, which branches off switching hatch 70. At switching hatch 70, deposits 80 may form in this embodiment.

(28) When switched to wet operation now, switching hatch 70 is swivelled to wet position 72. In this position, deposits 70 lie freely inside the washing water which passes through outlet 40, such that the water current will take deposits 70 with it and will supply them to waste water connection 82.

(29) Above switching hatch 70, there is an additional maintenance duct 84 in the embodiment depicted here, which makes possible an occasional basic cleaning and maintenance in a basically known fashion.

(30) In FIG. 6, another embodiment of a dental milling machine in accordance with the invention is depicted. Equal reference numbers indicate the same or corresponding parts here as well as in the other Figures. The air nozzles 32 in accordance with the invention are formed as air amplifying nozzles, for which the design can be taken in detail from FIG. 6a.

(31) Three air nozzles 32 are provided, which are each arranged in an inclined position. The air amplifying nozzle 32 which is arranged to the far left, and which is arranged farthest away from outlet 40, has an inclination of approximately 20 degrees to the left, i.e. towards the side wall adjacent to it. The air stream is thus carried out following in a particular good fashion the internal radius 86 of base 42.

(32) The air amplifying nozzle 32 which is arranged to the far right is also facing its neighbouring side wall, also at an angle of 20 degrees as well. Deposits at the side walls may be prevented in this fashion.

(33) Central air amplifying nozzle 32 is translocated in the direction towards outlet 40 and inclined into the direction pointing away from the outlet, i.e. it predominantly supplies the central region of milling chamber 12.

(34) Further, air amplifying nozzles 32 are translocated into the direction towards door 60, i.e. towards the front inside milling chamber 12, as can be taken from FIG. 7.

(35) It is to be understood that the arrangement of air amplifying nozzles 32 may be adapted to the requirements to a great extent. They are fed together via a compressed air lead 88 with a distributor 90. Distributor 90 allows the relative adjustment of the current volumes towards the individual air amplifying nozzles 32.

(36) In the exemplary embodiment depicted, a pressure reducer 92 is further provided, and a valve 94 switches the compressed air, based on the signal of a control device 96.

(37) Valve 96 is connected to a compressed air network 98 on the input side, which network is under pressure, for instance 7 bar to 10 bar.

(38) A possible embodiment of an air amplifying nozzle 32 can be taken from FIG. 6a. Via supply line 100 and an annular gap 102, air is introduced at a high current velocity due to the narrowing of the annular gap. The current leans to the curved edge 104 of the nozzle. In the central entrance area 106, a considerable negative pressure is created which causes the aspirational air to be sucked in at a high current velocity and be blown out through the nozzle, wherein at the same time a high volume of air is achieved.

(39) If no inlet air is admitted inside through air inlet channel 100, the air amplifying nozzle 32 in accordance with the invention may act as an air inlet via its central opening 108, such that an equalization of pressure between the milling chamber and the ambient air may be carried out as a result.

(40) In accordance with FIG. 7, air amplifying nozzles 32, or at least a part of them, should be inclined diagonally in the direction towards door 60, and in addition be arranged adjacently to it.

(41) As a result, the door is blown free, such that the inside of the milling chamber is well visible.

(42) From FIG. 8, a time diagram for an embodiment of a milling machine in accordance with the invention is visible, which is controlled by control device 96.

(43) The aspirational air is depicted with interrupted lines, and the inlet air with solid lines. During milling step 110, vacuuming is carried out at an aspirational power of 50% of the maximum power. The milling step may last 10 min, for instance. Immediately subsequent to this, a blowing pulse 112 is output, such that air exits air amplifying nozzles 32 at high pressure and a large air volume. At the same time, or shortly after, the aspirational power is increased to 100%. This takes approximately 10 seconds. Subsequent to this, if necessary, a tool change is made in a tool-changing step 114, which, for example, takes 30 seconds to 1 minute. At this moment, both the blowing air and the aspirational air are switched off.

(44) Subsequent to this, another milling step 116 takes place, again with the aspirational air half switched on.

(45) It is to be understood that the exact timings, pressures and air volumes may be controlled depending on the dental restoration part to be milled, such that they may also be considerably shortened or extended.