EP4143648A1

EP4143648A1 - Production using a machine tool of faces definable by cone segments

Info

Publication number: EP4143648A1
Application number: EP21746362.9A
Authority: EP
Inventors: Jochen Bretschneider; Lars Immenroth; André Vieweg
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2020-07-31
Filing date: 2021-07-07
Publication date: 2023-03-08
Also published as: US20230244206A1; EP3945381A1; CN116057483A; WO2022022963A1

Abstract

The invention relates to a method for producing and/or machining a non-conical face of a workpiece (5, 41, 43, W), which face can be defined by a segment of a cone (50, K), in particular a sealing face of a multiply eccentric shut-off valve (40), using a machine tool (20), the machine tool (20) having at least two linear axes (X, Y, Z) and at least one rotary axis (A, B, C) for generating a relative movement between a tool (1, 60) and the workpiece (5, 41, 43, W), and having a numerical controller (30) for controlling the axes (X, Y, Z, A, B, C), the method having the following steps: - a cycle (34) is provided on the numerical controller (30), - a user of the machine tool (20) retrieves the cycle (34), - the user parameterises the cycle (34), - a part program (33) that can be executed by the numerical controller (30) is generated by means of the cycle (34) and the numerical controller (30), - the part program (33) is carried out by means of the numerical controller (30) to generate the relative movement along a path (70) determined by the part program (33) to produce and/or machine the face of the workpiece (5, 41, 43, W).

Description

description

Production of surfaces defined by cone segments using a machine tool

The invention relates to a method for producing and/or machining a non-conical surface of a workpiece that can be determined by a segment of a cone using a machine tool, the machine tool having at least two linear axes and at least one linear axis for generating a relative movement between a tool and the workpiece Has rotary axis and a numerical control for controlling the axes. Furthermore, the invention relates to a cycle for carrying out such a method, a numerical control with such a cycle and a machine tool with such a numerical control.

Machine tools are nowadays controlled with the help of a control device, such as a CNC controller. The control device uses a parts program to "control" the movements of machine elements and thus the movements of a tool, which is introduced into the machine, for example via a tool holding device, relative to a workpiece, which is also introduced into the machine It is clear to the person skilled in the art that the term "control" is common usage and not "control" in the sense of control technology. "Control" here means above all the position control of axes, which includes control processes in the sense of control technology.

The parts program is composed at least predominantly of control commands that are read in and interpreted by the control device. According to the control commands, the control device controls the movements of the machine elements of the machine tool and thus the movement of the tool relative to the workpiece. To create a part program, a CAM system (Computer Aided Manufacturing) generates movement information about movements to be carried out of the tool, preferably in a standardized data format, and reads it in from a downstream postprocessor. Based on the movement information generated by the CÄM system, the kinematic and machine data of the machine tool and the instruction set of the CNC control and the instruction set of the PLC control, the post-processor creates a for the specific machine tool on which the machining process is to take place adapted parts program in the form of control commands adapted to the specific control device of the machine tool. In this way, the movement information generated by the CÄM system, preferably in a standardized data format, is converted by the post-processor into control commands that can be read in by the control device and are adapted to the respective control device.

In addition to the actually available CNC command set, the post-processor takes into account the specific machine-specific kinematic conditions of the machine tool, such as kinematics, geometric proportions, maximum travel ranges of the drive axes and maximum speeds of the machine elements. This data is in the form of machine data. Furthermore, machine-specific PLC functionalities (programmable logic control) such as lubrication, tool change, door locking etc. are taken into account by the postprocessor when generating the control commands, with the specifically available PLC functionalities being available to the postprocessor in the form of PLC command sets stand.

Cycles are programs stored in the CNC control, which can be called up in the form of a subprogram and enable both programming and the execution of special machining conveniently directly on the machine, i.e. without resorting to an external CÄM system. In most cases, only the cycle call and the input of a few parameters are required for programming or machining the user required. The CNC control then automatically generates or parameterizes the corresponding part program for processing the workpiece. The creation and use of drilling cycles, milling cycles or turning cycles is known. In particular, turning cycles are known, by means of which a rotationally symmetrical cone can be turned on a component, in particular a shaft, by specifying two radii and a height specification.

A particular challenge in path generation is the generation of movement paths for the manufacture of valve seats or closures of shut-off valves. For example, in the chemical industry, the oil & gas industry, or the water & waste water industry, the use of so-called eccentric shut-off valves is common. In addition to 2-way offset valves, 3-way offset valves (triple offset butterfly valves) and also 4-way offset valves are increasingly being used in industry.

Due to the eccentricities, the sealing surfaces of the valves have a complicated surface geometry, in particular with regard to a surface normal of the relevant components or a workpiece axis, which is not rotationally symmetrical and therefore not conical way with means of CAD/CAM system and postprocessor are required.

A method for controlling a machine tool is known from publication DE 102019 100 474 A1, comprising: providing a machine tool; providing a manufacturing sequence that includes a plurality of manufacturing steps, wherein at least one tool and a tool path are defined for each manufacturing step; Generation of control data, the control data comprising: control commands, the control commands specifying machining operations of the machine tool according to the manufacturing steps of the manufacturing sequence and the machine tool is set up to convert the control commands into the machining operations, and additional data, the additional data comprising at least one list specifying parameters extracted from the control commands; Providing the control data in a control unit of the machine tool; receiving input data at the controller, where the input data indicates user input; Generating modified control commands by means of the control unit, the modified control commands being generated from the control commands in accordance with the additional data and the input data; and activation of the machine tool by the control device using the modified control commands.

Document EP 2216 698 A2 discloses a method and a device for generating transformed control data for controlling a tool on a machine tool for machining a workpiece clamped in a clamping means of the machine tool by machining, with the method step of determining control data that specifies Which first tool path is to be traversed by the tool of the machine tool with which first tool orientation for machining the clamped workpiece when the workpiece is placed in the clamping means according to a clamping situation target state that indicates a target state of a clamping situation of the workpiece clamped in the clamping means is clamped, characterized by the further method steps: determination of a clamping situation actual state, which indicates an actual state of the clamping situation of the clamped workpiece in the clamping means, determination of a clamping situation deviation ung between the actual clamping situation and the desired clamping situation state, which indicates a deviation between the actual clamping situation and the desired clamping situation state, and generating transformed control data by carrying out a transformation of at least part of the specific control data as a function of the determined Clamping situation deviation, the transformed control data indicating which second tool path is to be traversed by the tool of the machine tool with which second tool orientation for machining the clamped workpiece, when the workpiece is clamped in the clamping means according to the determined clamping situation actual state with the determined clamping situation deviation.

Document EP 3 151 073 A1 discloses a method for generating control data for controlling a tool on a machine tool for machining a clamped workpiece through a machining process, in particular machining, with the machine tool comprising a control device and a tool, for Controlling the tool in relation to the clamped workpiece with a three-dimensional free tool movement by generating a path program based on target parameters generated from a target geometry for controlling the machine tool, with the path program describing at least one path, the path consisting of a number of support points and line elements consists and each line element connects a pair of support points to one another, and the machine tool is controlled in accordance with the path program generated. The method comprises the following steps: - Recording actual parameters of the machining process using a feedback loop, - Iterative optimization of the path program using the recorded actual parameters to generate a new path program_new with a new path_new, which is fed to the machine tool during processing and which replaces the previous path program and dynamically change and/or dynamically replace the previous trajectory.

An object of the present invention is to simplify the manufacture or machining of sealing surfaces in multi-eccentric check valves.

This object is achieved by a method for producing and/or machining a non-conical surface of a workpiece that can be determined by a segment of a cone using a machine tool, the machine tool having at least two linear axes and to generate a relative movement between a tool and the workpiece at least one Has a rotary axis and a numerical control for controlling the axes, with the following steps:

- provide a cycle on the numerical control,

- calling up the cycle by a user of the machine tool,

- cycle parameterization by the user,

- Generation of a part program that can be processed by the numerical control using the cycle and the numerical control,

- Execution of the part program by means of the numerical control for generating the relative movement along a path for the production or machining of the surface of the workpiece.

In a preferred embodiment of the invention, the workpiece is machined in the form of turning. However, the invention is not limited to this embodiment. For example, milling to produce the workpiece is also possible.

Furthermore, the invention is not limited to the chip-removing Bear processing of a workpiece, but other processing is also possible, for example material processing.

The part program that can be processed by the numerical control can be generated directly after the cycle has been called and the required parameters have been entered by the operator using the cycle and the numerical control. Furthermore, the part program that can be processed by the numerical control can also be generated by the control at runtime, i.e. during the processing of a higher-level CNC program at the time the cycle is called.

The invention offers the advantage that now also by a segment of a cone determinable non-conical surfaces by means of the so-called "workshop-oriented programming" can be "programmed" directly on the CNC control, i.e. without resorting to an external CAM system. However, this is not programming in the classic sense, in which the relative movement between the tool is programmed block by block and the workpiece must be specified ("programmed"), but the process is limited to calling and entering the parameters (parameterization) of the relevant cycle, through which the path to be followed for machining the workpiece is then automatically generated by the CNC control .

This procedure also allows the machine operator to make simple, situation-dependent adjustments without having to recreate the CNC program at an external workstation. Examples of such adjustments are:

- Consideration of the specific clamping of the workpiece, e.g. by specifying offsets;

- Specification of tool radius or tool wear;

- Inclusion of the dynamic values of the axes involved (e.g. maximum speed);

- Checking or determining the available workspace for production (e.g. axis limitations);

- Checking or specifying the correct axis identifier (e.g. x, z, cl);

Other advantages of this type of workshop-oriented programming are:

- All input parameters of the cycle in the part program are retained for documentation purposes;

- No time-consuming work preparation necessary.

By definition, a cone is a geometric body that is created when all the points of a delimited and connected area lying in one plane are connected in a straight line with a point (the apex) outside the plane. The area is called the base, the boundary line of which is the directrix and the point is the tip or apex of the cone. A cone has a vertex (the vertex), an edge (the directrix) and two faces (the mantle and the base). If the area (the base) is a circular disk, the body formed in this way is called a circular cone. However, the base area can be of any design, in particular not circular or not elliptical.

A distinction is made in particular between cones with a circular base and a height line running vertically through the center of the base (straight circular cone or rotary cone) or circular cones with a circular base whose height line does not include the center of the circle (oblique circular cone or elliptical cone).

A "conical surface" or cone for short is a rotationally symmetrical surface that corresponds to the shape of the lateral surface of a truncated cone of a right circular cone (rotary cone).

As a "segment of a cone" (cone segment) in the sense of the inventions, any area on the lateral surface of a cone is understood.

For many technical applications and in particular applications in connection with the invention, the production or processing of such surfaces is of particular interest, which can be determined by segments of oblique cones, in particular oblique circular cones.

In addition, in connection with the invention, the production or processing of such surfaces, which is of interest for many technical applications, should be emphasized by a segment of a cone, in particular a right circular cone, with a height line that is not parallel to a workpiece Normal is aligned, are determinable. The cone in question is therefore not aligned parallel to the workpiece (to a surface normal of the workpiece), but is pivoted ("rotated") in space relative to it of the right circular cone, and thus of a rotationally symmetrical body, a non-rotationally symmetrical and therefore not conical (intersecting) surface is created on the workpiece.

The creation of a "non-conical surface" of the workpiece within the meaning of the invention can therefore result from the fact that the cone in question is not itself rotationally symmetrical, e.g. an oblique cone, or that the cone is rotationally symmetrical (i.e. a rotary cone), but this is relative to the workpiece - is pivoted in space - as described above.

If a cone is cut through 2 planes, the part of the lateral surface in between is referred to below as a ring-shaped closed cone segment. Accordingly, the two planes and the cone segment form a coherent, closed surface. The two planes create a self-contained band on the lateral surface of the cone.

For technical applications, those ring-shaped, closed cone segments that result from the intersection of a cone with two parallel planes are of particular interest.

However, the invention is not limited to the above-mentioned preferred geometric variants of cone segments, but can be used in principle for any non-conical surfaces that can be determined (geometrically described) by a segment of a cone.

From a mathematical point of view, any surface intended for manufacture or processing according to the invention can be passed through specify the geometry of the cone in question, as well as the size and position of the area on the lateral surface of the cone, by appropriate user input directly on the control.

Advantageously, in connection with the invention, the geometric description of the relevant surface of the finished workpiece (ie the workpiece surface) is sufficient for the cycle to be able to generate the appropriate part program from it. If, for example, the production of a desired surface (workpiece surface) is not possible in one work step, e.g. because the greatest possible infeed with the tool used does not allow this, the CNC control in connection with the cycle takes care of this - in a manner known per se - automatically the division into several steps.

The method according to the invention is particularly suitable for processing or producing a sealing surface of a closure part or a valve seat (the corresponding counterpart to the closure part) of a shut-off valve. A hollow-cylindrical metal part is usually used as the workpiece blank for such a valve seat, and a cylindrical metal part is used for the closure.

The advantages of the invention are particularly evident when the shut-off valve is an eccentric shut-off valve, in particular a multiple eccentric shut-off valve, e.g. a triple eccentric shut-off valve (triple offset butterfly valve). Due to the complicated geometric shape of the sealing surfaces of such valves, it is no longer possible to "manually" program the paths required for processing. Without the invention, the necessary part programs could no longer be run on the CNC control itself, but only on an external CAM system can be created by trained experts.

For the production of the sealing surfaces of a multi-eccentric shut-off valve by turning, there are several There are different possibilities, which also depend on the type of machine used.

On the one hand, a compensating movement required to generate the eccentricity can take place radially in a linear axis and be programmed accordingly.

In this embodiment, the part program is preferably generated in polar coordinate format. In addition to the linear axis mentioned, the infeed axis (Z direction) and a rotary axis are required as additional axes. Machining is therefore possible with a relatively simple 3-axis machine.

Another variant provides for a compensating movement radially in two linear axes required to generate the eccentricity. The parts program is advantageously generated in Cartesian format, including orientation, which must be based on an active transformation.

The machine tool must have the following kinematics:

- A positionable rotary axis

- A linear axis collinear to the rotary axis (feed movement)

- A linear axis radial to the rotary axis (infeed movement/compensation movement)

At least a 4-axis machine is therefore required to carry out the machining.

The geometric information required for manufacturing the sealing surface is advantageously entered into the CNC control by the operator via a cycle mask. The object stated at the outset is also achieved by a cycle for a numerical control for carrying out a method according to claim 14.

The task stated at the outset is also achieved by a numerical control for executing a cycle according to claim 15.

The object set at the beginning is also achieved by a machine tool with a numerical control according to claim 16.

The invention is explained in more detail below with reference to exemplary embodiments. show:

1 shows a machine tool for carrying out a method according to the invention,

2 shows a triple eccentric shut-off valve,

3 shows a triple eccentric shut-off valve in a schematic representation,

4 shows a turning of a sealing surface of a triple eccentric shut-off valve shown in FIGS. 2 and 3 with a compensating movement through a linear axis of the machine tool,

5 shows some parameters queried when the cycle is called and relating to the geometry of the sealing surface,

6 shows a tool path composed of a large number of directly adjacent splines,

FIG 7 Representation of points on ellipse segments for spline formation,

8 shows a spline segment for one revolution, 9 shows method steps when carrying out a method according to the invention.

A machine tool 20 is shown schematically in FIG. As part of the exemplary embodiment, machine tool 20 has six machine axes, through which a relative movement occurs between a tool 1, which is in the form of a turning tool 1 in the exemplary embodiment, and a workpiece 5, indicated in the exemplary embodiment as a valve seat 5 of a multi-eccentric shut-off valve , can be carried out. The tool 1 is clamped in a tool holder 2, which is connected to a tool spindle 21, which is driven by a position-controlled motor 22 is. The workpiece 5 is fastened to a workpiece table 7 by clamping means 6 .

The turning tool 1 can be moved in a controlled translatory manner in the X, Y and Z direction la with the machine 20 shown in the exemplary embodiment with drives not shown in FIG. 1 for the sake of clarity. In addition to the three linear axes, the machine tool 20 shown also includes the position-controlled rotary axes A and B, which can also be seen in FIG 5 can be aligned.

In addition, the machine 20 has a third, position-controlled rotary axis C, which runs parallel to the Z-axis and with respect to which the workpiece table 7 is rotatably mounted relative to a stationary machine frame 23 . As a result, the workpiece 5 can also be positioned relative to the tool 1 in an angular position g. For the sake of clarity, the drive was not shown here either. Depending on the machining to be carried out, a speed-controlled operation with respect to the rotary axes A and/or C is also possible in the machine tool 20 shown.

The machine tool 20 according to the exemplary embodiment thus has six machine axes (the 3 linear axes X, Y and Z and the 3 rotary axes A, B and C), i.e. it is a so-called 6-axis machine tool (6-axis machine) 20 .

It should be noted at this point that the machine tool 20 can, of course, also have more, but also fewer than six machine axes.

The machine tool 20 is connected to a numerical control 30 which uses a part program 33 and/or a manual input to determine position setpoints x, y, z, , β and g for controlling a relative movement taking place between the tool 1 and the workpiece 5 . The numerical control 30 determines the position setpoints using the parts program 33, in which the movement to be carried out by the tool 1 in relation to the workpiece 5 is defined in the form of commands. Alternatively or additionally, the movement of the tool 1 and/or the workpiece 5 can also be specified by an operator on site at the machine tool 20 by means of a manual control input via an operating device 31 in conjunction with a display device 32 of the numerical control 30 . For this purpose, the operating device 31 has, in particular, input fields, buttons and rotary controls.

The parts program 33 is usually generated outside the numerical control 30 by an external CAM/CAD system (not shown) and a so-called post-processor (not shown) which may be connected downstream of the CAM/CAD system and from there transferred to the numerical control 30 gene. When processing the part program 33, the numerical control 30 generates in a specific cycle, the interpolation cycle, both position setpoints x, y and z for the linear axes and , ß and g (angular positions) for the rotary axes. The tool 1 is moved relative to the workpiece 5 along a movement path with a predetermined orientation by means of these reference position values.

According to the invention, on the numerical control 30, according to the exemplary embodiment, there is a cycle 34 for the production and/or machining of non-conical surfaces of the workpiece 5, which can be determined, that is to say mathematically described, by a segment of a cone. As indicated in the figure, the workpiece 5 in the exemplary embodiment is a valve seat 5 of a triple eccentric shut-off valve. Corresponding parameterization of Cycle 34, which will be discussed in more detail later, enables the desired machining, in particular turning, of the sealing surface.

In addition to the aforementioned turning of the valve seat 5, the 6-axis machine shown could also be used, for example, to perform a milling of the valve seat 5, in which the tool 1 is designed as a milling cutter (not shown) rotating about the spindle axis A, which is in X, Y and Z direction is positioned in a position-controlled manner and in which the Ven tilsitz 5 is preferably fixed in place. The milling cutter would be driven by the motor 22 and the spindle 21 in a speed-controlled manner.

FIG. 2 shows a triple eccentric shut-off valve (triple offset butterfly valve) as is used, for example, in the chemical industry, the oil and gas industry, or the water and wastewater industry. A particular challenge of these valves is the manufacture of the necessary sealing surfaces, such as the valve seat indicated in FIG. Programming for machine tools to produce these sealing surfaces was previously only possible using CAD/CAM systems.

3 illustrates a triple eccentric Absperrven til 40 in a schematic representation. From the figure, the valve seat 41 of the shut-off valve 40 with the sealing surface 42 can be seen. Furthermore, the rotatably mounted closure part 43 of the shut-off valve 40 with the sealing surface 44 is ersicht Lich.

The geometry of the sealing surfaces 42 and 44 can be described using an oblique circular cone 50 with the base area 51, the radius 52, the height 53, the tip 54 and the deviation 55, which can also be seen as an example in FIG. The two parallel surfaces of the valve seat 41 and the closure part 43 result in a ring-shaped closed cone segment 57 as an intersection on the lateral surface of the cone 50. The sealing surfaces 42 and 44 lie on this ring-shaped closed cone segment 57 of the lateral surface of the cone 50 and can therefore be calculated mathematically describe exactly.

Furthermore, FIG. 3 shows the three eccentricities of the shut-off valve 40. A first eccentricity 45 results from an offset of a pivot point 48 of the closure part 43 relative to a first center line 59 of the shut-off valve 40 running in the vertical direction in the flow direction 49 of the shut-off valve 40. A second eccentricity 46 results from an offset of the pivot point 48 of the closure part 43 opposite a second horizontal center line 56 of the shut-off valve 40 in a direction perpendicular to the flow direction 49 of the shut-off valve 40. A third eccentricity corresponds to an angle 47 between the second horizontal center line 56 of the shut-off valve 40 and one through the center of the base of the cone 50 and the tip 54 of the cone 50 extending cone axis 58. FIG 4 illustrates the turning of the valve seat 41 (only the essentially hollow-cylindrical part of the valve seat 41 that is essential for the machining is shown) of the triple eccentric shut-off valve 40 according to FIG 3. The valve seat 41 rotates for machining (corresponding to the workpiece 5 from FIG 1 ) with a preferably constant Winkelge speed around the axis of rotation C (see also FIG. 1) and a lathe tool 60 adjustable in at least two linear axes (corresponding to the tool 1 from FIG. 1) carries out a cutting operation. What can be seen is a compensatory movement of the turning tool 60 to compensate for the eccentricities mentioned above along a first linear axis 61, for example the X-axis shown in FIG Valve seat 41 takes place. Furthermore, a second linear axis 62 for the infeed movement of the turning tool 60 can be seen, for example the Z axis shown in FIG.

In addition to the constant angular velocity of the rotation about the axis of rotation C already mentioned above, any angular velocity, even one that varies over time, can in principle be considered. In a preferred embodiment, the angular speed of the rotation is determined—in a manner known per se—in such a way that a constant cutting speed results.

According to the invention, a corresponding cycle is started and executed for the corresponding machining of the valve seat 41 on the CNC machine. The machining is preferably carried out starting with a hollow-cylindrical workpiece blank.

The geometric information required for manufacturing the sealing surfaces, as well as the production-related information, is queried particularly conveniently by the operator via a cycle mask displayed on an HMI screen of the CNC control. Alternatively, the manufacturing cycle could also with manual input of the parameters in the part program (without an HMI mask).

Table 1 below contains an example overview of interactively editable parameters on the CNC

Controller that can be queried after a corresponding cycle call using the cycle mask. In addition to a preferred designation of the respective parameter, Table 1 also shows a brief description and, if applicable, a unit of measure for the parameter in question. Depending on the form of the description, the specific parameter entries required can vary or can be derived from other information not mentioned here.

Table 1 : Input parameters for the machining cycle on the CNC control.

FIG. 5 graphically illustrates some of the parameters which are queried during the cycle call and can be seen from Table 1.

The visible parameters provide all the information required to determine the visible right circular cone K and thus for the geometric description of the surface to be produced. In particular, the figure shows that the cone K is pivoted ("rotated") in space relative to a surface normal of the workpiece running in the Z direction. That is, a height line h of the right circular cone with the center point M the base is not parallel to the surface normal of the workpiece and thus not parallel to the Z-axis of the machine tool.

After entering all the necessary parameters, a (CNC) part program is generated fully automatically using the CNC control, which can either be started immediately on the machine tool or, alternatively, is generated and executed based on user input at runtime. Thus, you don't need a special post-processor, as would be necessary when creating a program using a CAM system, since the required machine information (number, type and position of the axes; maximum traversing ranges of the axes, etc.) is directly available or can be processed by the algorithm. are known.

The tool path to be traversed by the tool relative to the workpiece runs generally on the lateral surface of the cone segment in question. In the exemplary embodiment, the cone is a right circular cone K and the cone segment is a ring-shaped closed segment of the man surface of the cone K, which results from the intersection of the cone K with the workpiece W. However, the invention is not limited to this cone or shell shape. In particular, surfaces that relate to an oblique cone, in particular an oblique circular cone, are also relevant for technical applications. The area sought is generally obtained from the intersection of the relevant cone with the workpiece blank (see FIG 5).

In the exemplary embodiment according to FIG. 5, in which a right circular cone K is rotated relative to a surface normal of the workpiece, ie pivoted in space, a section of the cone through a plane parallel to the workpiece surface of the workpiece W produces an ellipse.

If the infeed movement (Z-direction) were ignored, elliptical paths would result for the machining. Considering the infeed movement, the result is essentially elliptical path sections that run spirally around the lateral surface of the relevant cone segment, as is indicated by the curve shown in FIG. Such a tool path 70 (also called movement path or just path) is also illustrated by way of example in FIG. To process the corresponding workpiece W, the tool must therefore move relative to the workpiece substantially along elliptical shear, spiral path sections.

Advantageously, in the cycle according to the invention, the path of movement 70 is described or generated in the form of a large number of splines directly adjacent to one another, ie polynomials of the highest nth degree. This is particularly advantageous when splines of this type are processed directly by the CNC control, i.e. can be used to control the relative movement between tool and workpiece by calling up appropriate commands, as is the case, for example, with the SINUMERIK 840D CNC control from Siemens for polynomials up to the 5th degree is the case. The output format here is not the usual G code consisting of straight lines or circle segments, but a polynomial code. Analogously to the G code that is usual in part programs, the individual program instructions (commands) can be generated block by block in the form of polynomial calls and then processed. The spline (polynomial) code generated in this way enables the individual spline segments to merge "smoothly" (multiple, continuously differentiable) into one another.

The movement path 70 illustrated in FIG. 6 is made up of many path segments in the form of splines 71, that is to say polynomials which merge into one another in a multiple differentiable manner. Due to the "smooth" transition between the splines, the beginning and end of an individual spline 71 in the movement path 70 cannot be recognized.

A preferred embodiment of the path generation on the outer surface of the cone and thus of the specified splines is described below.

For the technological description, the web is (imaginatively) unrolled on the cone. A certain infeed per revolution must be observed. As an illustration, one can imagine a ball end mill milling around the conical surface rotates and continuously moves down (or up) on the cone.

To calculate a rotation from 0° to 360°, for example, it is subdivided into 32 angular segments. An angular segment is therefore 11.52° wide. Within an angle segment, six equally distributed horizontal sections are calculated between the start height of the angle segment and the end height of the angle segment. Six points on the ellipses are then determined. The first point is on the first ellipse at 0°. The second point is on the second ellipse at 2,304°. The third point is on the third ellipse at 4.608°. The other points are further determined according to this scheme.

The procedure shown is illustrated in FIG. Shown are the six above-mentioned ellipse segments E1 to E6 and the respective points PI to P6 lying on the ellipse segments. The points PI to P6 lying on the ellipses E1 to E6 are connected with a spline 80. With a continuous determination of the splines for the other angle segments, the coherent path can be determined for one run around the cone. A corresponding Bahnab section 81 is illustrated in FIG. Many contiguous path sections of this type ultimately result in the path 70 illustrated in FIG.

Advantageously, in connection with the invention, the tool path is not described in a Cartesian coordinate system, but in a polar coordinate system that is more suitable for at least essentially circular movements. The SINUMERIK 840D CNC control from Siemens is also ideally suited for this. A coordinate transformation between the different coordinate systems is also possible in one embodiment of a cycle according to the invention.

Furthermore, in a preferred embodiment of the invention when machining a workpiece by means of a Tool performed a known tool radius correction. Tool radius compensation allows the workpiece contour to be programmed independently of the geometry of the tool used. A tool radius, which is taken into account when generating the path using the numerical control, can therefore also be advantageously recorded when the cycle is parameterized.

The essential method steps in carrying out a method according to the invention are illustrated again below in the form of a flow chart according to FIG.

In a first method step S1, an executable cycle for producing and/or machining non-conical surfaces of a workpiece that can be determined by a segment of a cone is provided on a numerical control of a machine tool connected to the control.

In a method step S2, the cycle is called up by a user of the machine tool on a graphical user interface of the numerical control of the machine tool.

In a method step S3, the user enters the technology and geometry data required for the production or processing of the intended surface of the workpiece on the graphical user interface of the numerical control. This "parameterizes" the cycle.

In a method step S4, taking into account the inputs made in method step S3 by the numerical control, a part program that can be processed by the numerical control is generated and stored in a memory of the numerical control. This means that the part program can be accessed again when manufacturing or machining identical workpieces. In addition to the usual G code instructions, polynomial code instructions are advantageously generated in the parts program generated in this way, so that the individual segments of the tool path defined by the parts program are not only made up of straight lines and circle segments, but at least in part also of polynomials -Assemble segments (splines).

In a method step S5, the parts program created in this way is executed on the numerical control and thus on the machine tool for producing or machining the non-conical surface of the workpiece that can be determined by a segment of a cone. This is accompanied by the relative movement between the tool and the workpiece defined by the parts program.

Claims

patent claims

1. A method for producing and/or machining a non-conical surface (42, 44) of a workpiece (5, 41, 43, W) that can be determined by a segment of a cone (50, K) using a machine tool (20), wherein the machine tool (20) for generating a relative movement between a tool

(1) and the workpiece (5, 41, 43, W) at least two linear axes (X, Y, Z) and at least one rotary axis (A, B, C) and a numerical control (30) for controlling the axes (X , Y, Z, A, B, C), with the following steps:

- providing a cycle (34) on the numerical control (30),

- Calling the cycle (34) by a user of the machine tool (20),

- parameterization of the cycle (34) by the user, acquiring at least one parameter related to the cone,

- Generating a part program (33) that can be processed by the numerical control (30) by means of the cycle (34) and the numerical control (30),

- Execution of the parts program (33) by means of the numerical control (30) for generating the relative movement along a path (70) determined by the parts program (33) for producing or machining the surface of the workpiece (5, 41, 43, W) .

2. The method according to claim 1, wherein the area can be determined by the segment of an oblique cone, in particular an oblique circular cone (50).

3. The method according to claim 1, wherein the area can be determined by the segment of a cone, in particular a right circular cone (K), with a height line (h) which is not aligned parallel to a workpiece normal.

4. The method according to any one of the preceding claims, wherein the surface as a ring-shaped closed cone segment (57) leads out.

5. The method according to any one of the preceding claims, wherein a turning of the workpiece (5, 41, 43, W) is performed.

6. The method according to any one of the preceding claims, wherein the surface is a sealing surface (44) of a closure part (43) or a sealing surface (42) of a valve seat (41) of a shut-off valve (40).

7. The method according to claim 6, wherein the shut-off valve (40) is an eccentric, in particular multiple eccentric shut-off valve (40).

8. The method according to claim 7, wherein a compensating movement to compensate for an eccentricity takes place radially in at least one linear axis (X) of the machine tool (20).

9. The method according to any one of the preceding claims, wherein the part program (33) is generated at least partially in a polar coordinate format.

10. The method according to any one of the preceding claims, wherein the parts program (33) is generated at least partially in a Cartesian format.

11. The method according to any one of the preceding claims, wherein geo metric information on the surface of the workpiece (5, 41, 43, W) and / or production engineering information on the manufacture or processing of the workpiece (5, 41, 43, W) via a be entered by the operator on a display device (32) of the numerical control (30) displayable cycle mask.

12. The method according to any one of the preceding claims, wherein the cycle (34) the web (70) at least partially in the form directly adjacent splines (71), in particular splines of the 5th degree, are generated.

13. The method according to any one of the preceding claims, wherein a tool radius can be specified for the tool (1, 60) used and the generation of the parts program (33) that can be processed by the numerical control (30) by means of the cycle (34) taking this radius into account, takes place in particular in the form of a tool radius correction.

14. Cycle (34) for a numerical control for carrying out a method according to any one of claims 1 to 13.

A single cycle numerical controller (30) (34) according to claim 14.

16. Machine tool (20) with a numerical control (30) according to claim 15.