WO2018086890A1

WO2018086890A1 - Method for producing a component

Info

Publication number: WO2018086890A1
Application number: PCT/EP2017/077323
Authority: WO
Inventors: Hans Jürgen MAIER; Kai Möhwald; Christian Klose; Ulrich Holländer; Florian Nürnberger; Thomas Hassel; Wilfried Reimche; Dmytro RODMANN
Original assignee: Gottfried Wilhelm Leibniz Universität Hannover
Priority date: 2016-11-11
Filing date: 2017-10-25
Publication date: 2018-05-17
Also published as: DE102016121656B3

Abstract

The invention relates to a method for producing a component, wherein the component is produced at least to some extent from a workpiece which is machined by means of at least one cutting tool, wherein, during the machining, supply of a gaseous medium creates a protective atmosphere at least around the point of engagement between the cutting tool and the workpiece, and this protective atmosphere prevents oxidation on the surface of the cutting tool and/or on the surface of the workpiece and/or on the swarf resulting from the machining and/or removes oxidation which is already present there. The invention also relates to a cutting tool which is suitable for the aforementioned method, but can also be used for other methods, and to a device having an air-tight enclosure.

Description

Method for producing a component

The invention relates to a method for producing a component, wherein the component is at least partially made of a workpiece by means of at least one cutting tool by machining.

Generally, the invention relates to the field of industrial manufacturing processes, especially in the metalworking industry. Such manufacturing processes are usually carried out in a natural air atmosphere. As a result, a permanent oxidation of metal surfaces takes place, which causes differently thick oxide layers depending on the process temperature and reactivity of the metal. This applies to machining processes (also called machining processes) equally for the workpiece that is being machined, as for the cutting tool. However, apart from some applications in which thin, dense oxide layers can also produce advantages for passivation, such oxidation is predominantly a disruptive factor. In machining processes, particularly high-performance, interrupted-cut machining, such as machining. During the milling and grinding of titanium alloys, the surface oxidation at cutting of cutting tools causes an increased wear progress and thus limits both the cutting performance and the tool life. This applies in particular to metal oxide coated and diamond coated tools.

From EP 0 91 1 1 13 A2 a method for cutting metallic and non-metallic materials in a nonflammable gas atmosphere is known.

From DE 2 100 906 A a method and an apparatus for the production of chemically highly reactive metal shavings is known.

From DE 10 201 1 009 964 A1 a method for soft, hard and high temperature soldering is known.

From DE 102 51 922 A1 a sample milling machine is known. DE 694 09 475 T2 discloses a method and a device for the dry fl uencing of metallic surfaces prior to soldering.

WO 2008/104341 A1 discloses a method for processing workpieces with nitrogen supply.

From US 5,645,382 a controlled-atmosphere machining process is known.

DE 1 1 2009 000 226 T5 discloses a machining of aluminum surfaces.

The invention is therefore based on the object of specifying a method for producing a component using machining, in which the aforementioned problems do not arise or are at least reduced. Furthermore, a cutting tool is to be specified with which the aforementioned problems can also be avoided or reduced.

This object is achieved by a method for producing a component according to claim 1, wherein the component is at least partially made of a workpiece by means of at least one Zerspanwerkzeugs by machining. In this case, during the machining at least in the vicinity of the point of engagement between the cutting tool and the workpiece by supplying a gaseous medium, a protective atmosphere created by the oxidation of the Zerspanwerkzeug surface and / or the workpiece surface and / or at the Prevents machining chips occurring and / or there already existing oxidation is removed. According to the invention, the air and the associated oxygen are thus displaced not only in the region of the intervention site by the supplied gaseous medium, but additionally any residual concentrations of oxygen, which can not be avoided by a pure displacement effect, counteracted by an oxidation of the cutting tool Surface and / or the surface of the workpiece and / or at the machining process. chips is prevented. An already existing oxidation can also be removed. This can be achieved in particular in the high-performance cutting material improvements in terms of cutting performance and the life of the tools. Longer tool life makes tool change less frequent, which also improves the efficiency of machining.

Another positive effect of the invention is that even oxidation of the resulting chips can be prevented or removed, so that the chips can be further processed oxidation-free, e.g. in a material recycling process. This is particularly important for high-quality materials such as titanium of great economic importance.

In this case, at least one of the workpiece and the cutting tool on an oxidizable surface or consist of oxidizable material. Both elements, i. Workpiece and cutting tool, in this sense be capable of oxidation.

The term "atmosphere" of the aforesaid protective atmosphere is not to be understood strictly in the sense that it must be a sealed, environmentally shielded atmosphere The method according to the invention, including the protective atmosphere formed, can also be carried out without special environmental shielding measures. However, this involves the disadvantage that a relatively large amount of gaseous medium has to be supplied since it volatilizes into the environment According to an advantageous development of the invention, therefore, the machining and the supply of the gaseous medium are shielded within one of the surroundings This chamber need not be sealed to the environment as much as possible, but should limit the outflow of the supplied gaseous medium to low levels.

The gaseous medium can thus prevent the oxidation of the surfaces mentioned or remove any existing there oxidation, for example, by chemical reactions of the gaseous medium with the other material, ,

- 4 - or by other physical reactions. For this purpose, the gaseous medium has an oxygen-absorbing precursor substance. The precursor substance is thus suitable for binding oxygen in gaseous form; moreover, it can bind oxygen from an already oxidized surface, ie dissolve it. The surface is deoxidized with it. The precursor may already be provided in gaseous form. Silane is advantageously used as precursor, in particular in the form of monosilane (SiH ₄ ). This has the advantage that the precursor substance is already present in gaseous form. However, it is also possible to use other precursor substances which are not available in gaseous form but, for example, can be added to a carrier gas of the gaseous medium in the form of small and very small particles.

The gaseous medium may be alone and completely formed by the oxygen-absorbing precursor. In some cases, however, this can in turn adversely affect the manufacturing process. According to an advantageous development of the invention, it is therefore provided that the gaseous medium has an inert gas and / or inert gas which does not react with oxygen. In this way, the gaseous medium may be at least partially formed by the inert gas and / or inert gas, whereby any undesirable reactions due to excessive concentration of the precursor can be avoided. The inert gas has an antioxidant effect, e.g. an inert gas, e.g. Argon, nitrogen or a mixture thereof. The inert gas serves to displace the air or the interfering oxygen. The shielding gas may e.g.

Be nitrogen. The gaseous medium can therefore be formed as a gas mixture.

According to an advantageous development of the invention, it is provided that the gaseous medium has a lower concentration of the precursor substance than the concentration of other gas components in the gaseous medium. In this way, a suitable adaptation of the gas mixture to the respectively used materials of the cutting tool and the workpiece can take place and the precursor material can be provided only in the concentration required for the oxidation prevention. Possibly. a certain oversupply of the precursors may be discontinued, but should be limited. According to an advantageous development of the invention, it is provided that the precursor substance volume fraction in the gaseous medium amounts to a maximum of 10%. In many cases, a precursor volume fraction of at most 4% is sufficient.

According to an advantageous development of the invention, it is provided that in the course of the machining, the proportion of the precursor substance in the gaseous medium is changed, in particular is increased in the course of the machining. Thus, e.g. an adjustment of the precursor concentration in dependence on cutting parameters of the machining can be performed. For example, the precursor substance concentration can be increased, the greater the advance of the cutting tool and / or the larger the

Cutting speed is. Depending on the cutting parameters used, an optimum can be found in this way, which ensures a maximum feed of the cutting tool, to which an optimum cutting speed can be adjusted. Suitably, the precursor substance concentration is adjusted.

The method according to the invention can be carried out, for example, in such a way that the mentioned protective atmosphere is already created before the beginning of the machining. Then the machining is started and in the course of machining the precursor concentration is adapted to the current requirements.

According to an advantageous development of the invention, it is provided that the gaseous medium is passed through at least one outlet opening provided in the cutting tool to the point of engagement between the cutting tool and the workpiece. This has the advantage that the gaseous medium can be very efficiently supplied to the desired location, namely the point of engagement between the cutting tool and the workpiece. As a result, the effectiveness of the method according to the invention is further increased. Another advantage is that no external hoses or similar elements for supplying the gaseous medium to the cutting tool or its tool carrier - 6 - must be arranged. This has the advantage that the mobility of the cutting tool is not limited by such additional elements. This is particularly advantageous for the field of high-performance machining. The gaseous medium can be passed, for example, through at least one hollow channel present in the cutting tool to the outlet opening or the outlet openings.

Alternatively or in addition to the aforementioned possibility of supplying the gaseous medium, the gaseous medium can also be supplied through an outlet spaced from the cutting tool, e.g. when the aforesaid chamber is provided for shielding from the environment, the gaseous medium may be supplied to the chamber through a supply port. For feeding the gaseous medium, e.g. a kind of shower or shower head are arranged near the point of engagement, from which the gaseous medium exits.

The method according to the invention is particularly suitable for the machining of workpieces made of high-quality materials, e.g. metallic titanium, which is widely used e.g. used in aerospace applications. The production of metallic titanium from the raw oxide deposits is energy and resource intensive and therefore associated with high costs.

For applications in aviation, ie the manufacture of aircraft parts, the production takes place mainly by cutting with plate-shaped raw material, ie the workpiece to be machined is provided as a large plate-shaped part, which is machined. In the integral construction of structural components of aircraft, chip rates of up to 95% of the blank weight occur, ie, 95% of the workpiece is processed into the resulting chips by machining. Apart from the fact that the chip removal is expensive at such a high chip rate, material recycling of the resulting chips due to the occurring during the manufacturing process oxidation of the chips is not economically possible in current manufacturing processes. Also in this respect, the present invention brings great advantages, since this oxidation of the chips can be prevented. According to an advantageous development of the invention, it is provided that the chips produced during machining are supplied to a material recycling process substantially free from surface oxidation by transporting the chips in an airtight manner to the material recycling process. For the first time, this makes it possible to economically recycle the high-grade titanium material which, as mentioned above, is obtained in particular in the manufacture of aircraft parts on a large scale. The airtight packaging of the chips can be supplemented by the fact that in the airtight packaging in addition an oxygen-absorbing precursor substance is present, in particular in gaseous form. As a result, the freedom from oxidation of the chips can be ensured over a longer period of time.

The invention therefore furthermore relates, as a result of a method of the aforementioned type, to a device with an airtight packaging in which chips of an oxidizable material obtained during a machining process are stored in the non-oxidized state with the exclusion of oxygen. As a result, the previously explained material recycling process can be promoted. The airtight packaging may e.g. a metal container or a glass container. It is also possible to use a plastic container, e.g. a bag, with metal-coated surface on the inside. Further, it is possible to provide the package of a combination of the aforementioned elements, e.g. a glass container with metal lid.

According to an advantageous development of the invention, an oxygen-absorbing precursor in the form of silane is present in the airtight packaging, in particular in gaseous form. As a result, the freedom from oxidation of the chips can be maintained long term.

To carry out the invention, a cutting tool, in particular cutting tool for machining a method of the type described above, wherein the cutting tool has at least one gas conveying arrangement, by the performed due to a tool movement carried out during the cutting operation of the cutting tool, a supplied gaseous medium - ö - is sucked and / or komprinnierbar. Such a cutting tool has the advantage that the gaseous medium can be conveyed and compacted, as it were, in place where it is needed. There is no separate one for this

Pump or a compressor required, instead, the cutting tool can fulfill this function, at least in part. The gas delivery arrangement may e.g. in rotating cutting tools, e.g. Drills, cutters, grinders, in the form of a kind of turbine, i. be formed with turbine blades, or in the form of an impeller. Already by the performed tool movement of the cutting tool, e.g. the rotation, the supplied gaseous medium can be sucked in and / or compressed.

This is particularly advantageous for cutting tools in the form of drills, since a constantly growing cavity is produced during the drilling process, which can not optimally reach a gaseous medium supplied by external supply devices. Therefore, especially for drilling operations, the direct supply of the gaseous medium by at least one outlet opening provided on the cutting tool is particularly advantageous. In a drill, the at least one outlet opening is advantageously arranged on the front side in the region of the cutting edges.

The driven by the rotation of the cutting tool part of the gas delivery arrangement, ie, for example, the turbine or the impeller may be rigidly coupled to the rotating cutting tool, so that the rotating part of the gas delivery arrangement synchronously with the rotation of the cutting tool rotates, ie always the same speed Has. According to advantageous embodiments of the invention, a different type of coupling may be provided, for example, with a reduction or translation by a transmission. In this case, the rotating part of the gas delivery arrangement can rotate at a different speed than the cutting tool, but is still coupled to the movement of slip-free. It is also possible for the rotating part of the gas delivery arrangement to be slidably coupled with the cutting tool so that the rotating part of the gas delivery arrangement basically rotates independently of the speed of the cutting tool and in particular can have a varying phase shift, ie a rotational slip. The term of the cutting tool detects the actual tool with at least one cutting surface and / or a tool arrangement, which encompasses this cutting tool in the strict sense, including a tool carrier. Thus, for example, a hard metal can be used as the cutting material of the cutting tool, for example tungsten carbide or cobalt systems or Si 3 N ₄ . The workpiece may be, for example, a titanium plate.

The workpiece may also comprise copper or a copper alloy. The invention is thus particularly suitable for the manufacture of electrical circuit boards, e.g. in microtechnology. These printed circuit boards can then be manufactured without oxidation.

The invention will be explained in more detail by means of embodiments using drawings.

Show it

Figure 1 - a plant for carrying out the method according to the invention and

Figure 2 - a cutting tool in side view and

Figures 3 and 4 are enlarged perspective views of the middle

Part of a cutting tool.

In the figures, like reference numerals are used for corresponding elements.

The plant 1 shown in Figure 1 has a machine tool 8, on which a cutting tool 2 is arranged. The cutting tool 2 may for example be a milling cutter or drill, accordingly, the machine tool 8 may be formed, for example, as a milling machine or drill, in particular as a computer-controlled machine tool. The cutting tool 2 is connected via a tool shank 20 with the machine tool 8 in order to be driven, for example, to a rotary movement. In the area of the machine tool 8 or the cutting tool 2 is on a support surface 9 a ^

Workpiece 3 is arranged, which is to be converted by means of the cutting tool 2 by machining to form a component.

The aforementioned elements, i. the machine tool 8 with the cutting tool 2 and the workpiece 3 are located in a shielded from the environment chamber 7. In this chamber 7, a gaseous medium 4 is supplied via the cutting tool 2, through which the mentioned protective atmosphere is created by the oxidation the cutting tool surface, the workpiece surface and / or on the resulting chips is prevented. The gaseous medium 4 is fed to the machine tool 8 via a line 13. The plant 1 has to provide the gaseous medium 4, a first container 10 in which an oxygen-absorbing precursor substance 5 is present in gaseous form, and a second container 1 1, in which a protective gas 6 is present, which does not react with oxygen , The precursor substance 5 and the protective gas 6 are supplied via respective lines to a mixing device 12. By the mixing device 12, the respectively desired ratio between the precursor material and the protective gas is set in the gaseous medium to be dispensed. The provided by the mixing device 12 gaseous medium is supplied via the line 13 of the machine tool 8 and delivered by the cutting tool 2 in the vicinity of the engagement point between the cutting tool 2 and the workpiece 3, as shown by the gaseous medium 4 characterizing arrows.

The chamber 7 need not be completely closed, but may e.g. have an outlet opening 18 through which gaseous medium 4 can escape to reduce overpressure.

The system 1 also has, for the airtight provision of the resulting chips, a suction device 14, via which the chips can be sucked off. The suction device 14 is connected to a packaging device 15. In the packaging apparatus 15, the extracted chips are stored in airtight packages, whereby an oxygen-absorbing precursor substance can be added inside the airtight package 16. FIG. 1 shows by way of example three such packages 16 to the right of the packaging device 15 , ,

- 1 1 - arranged therein chips 17 in non-oxidized state. These chips 17, which are protected against oxidation in the packages 16, can then be sent to a material recycling process.

FIG. 2 shows by way of example as a cutting tool 2 a drill with a tool shank 20, with which the drill can be clamped in the machine tool 8, and a tool section 21 provided for the drilling process, at the front end of which outlet openings 22 for the exit of the gaseous medium 4 are present , Accordingly, inside the tool portion 21 are internal channels connecting the discharge ports 22 to one or more suction ports for sucking the gaseous medium at the junction between the tool portion 21 and the tool shaft 20. Such a suction opening 25 can be seen by way of example in FIG.

As can also be seen in FIG. 2, the cutting tool 2 has a gas delivery arrangement 23, which is designed for sucking and / or compressing the gaseous medium present there, so that the gaseous medium sucked in there is optionally conveyed to the outlet openings 22 with a certain overpressure , To further promote and support this suction and / or compression process of the gas pumping device 23 may be surrounded on the outer circumference by a sleeve-shaped body 24. Through the sleeve-shaped body 24 of the performed by the gas pumping device suction and compression process 23 is promoted in aerodynamically favorable manner. In the tool movement (rotation) of the cutting tool 2, the sleeve-shaped body 24 is not rotated.

FIG. 3 shows in a somewhat enlarged, perspective view the middle part of the cutting tool 2 with the gas-conveying device 23 and the surrounding sleeve-shaped body 24. , _

- 12 -

FIG. 4 shows, in an even more enlarged representation, the middle region of the cutting tool 2 without the sleeve-like body 24. In particular, the arrangement of a multiplicity of turbine blade-like elements which form the gas-conveying device 23 and an intake opening 25 can be seen.

Claims

claims

1 . A method for producing a component, wherein the component is at least partially made of a workpiece (3) by means of at least one cutting tool (2) by machining, wherein during the machining at least in the vicinity of the engagement point between the cutting tool (2) and the workpiece (3) by supplying a gaseous medium (4) a protective atmosphere is created by the oxidation on the Zerspanwerkzeug surface and / or the workpiece surface and / or on the costs incurred during machining chips (17) prevents and / or an existing there oxidation is removed, characterized in that the gaseous medium (4) has an oxygen-absorbing precursor substance (5) in the form of silane.

2. The method according to claim 1, characterized in that the gaseous medium (4) comprises an inert gas and / or inert gas (6) which does not react with oxygen.

3. Method according to the preceding claim, characterized in that the gaseous medium (4) has a lower concentration of the precursor substance (5) than the concentration of other gas components in the gaseous medium (4).

4. The method according to any one of the preceding claims, characterized in that the precursor volume fraction (5) in the gaseous medium (4) is at most 10%.

5. The method according to any one of the preceding claims, characterized in that in the course of the machining, the proportion of the precursor material (5) in the gaseous medium (4) is changed, in particular in the course of the machining is increased.

6. The method according to any one of the preceding claims, characterized in that the gaseous medium (4) by at least one in the cutting tool (2) existing outlet opening (22) to the point of engagement between the cutting tool (2) and the workpiece (3) is passed.

Method according to one of the preceding claims, characterized in that the chips (17) obtained during the machining are supplied to a material recycling process substantially free of surface oxidation, by transporting the chips (17) in airtight packaging to the material recycling process.

Method according to one of the preceding claims, characterized in that chips (17) of a material obtained during machining are stored in an unoxidized state with the exclusion of oxygen in an airtight packaging (16).

Method according to the preceding claim, characterized in that in the airtight packaging (16) an oxygen-absorbing precursor (5) in the form of silane is present, in particular in gaseous form.