Abrading – Precision device or process - or with condition responsive... – Computer controlled
Reexamination Certificate
2000-01-05
2001-09-18
Hail, III, Joseph J. (Department: 3723)
Abrading
Precision device or process - or with condition responsive...
Computer controlled
C451S008000, C451S010000
Reexamination Certificate
active
06290571
ABSTRACT:
FIELD OF THE INVENTION
The invention relates in general to a system for generating, varying and/or displaying programs for machine control. In particular, the invention relates to a system for generating, varying and/or displaying programs for controlling grinding machines.
BACKGROUND OF THE INVENTION
Machine tools are as a rule program-controlled in that machining operations which are to be performed on a workpiece proceed under program control. To generate a relative motion between the tool and the workpiece, a plurality of NC (numerically controlled actuators) axes are provided. For example, a grinding head is supported on a suitable linear guide, which in turn is provided with an NC drive mechanism, or machine controlled actuator. Actuating one or more such acuators creates a positioning motion. In grinding spiral grooves on drilling tools, for instance, a plurality of motion components must be superimposed in order to achieve a suitable relative motion between the workpiece and the tool.
Numerically controlled machine tools, and control programs for them, are known. European Patent Disclosure EP 0 530 364 A1, for example, discloses an interactive numerical control that produces a display of a workpiece on a monitor on the basis of existing NC data. An interactive variation of the NC data can be displayed directly. Effects of data changes are thus made immediately visible. The system includes storage means, calculation means, display means and input means. From the display of the machining process on a monitor, the NC data can be corrected directly on the screen.
Programming NC machines demands certain skills, both in the programming language used and in terms of the special conditions involved in machining certain surfaces of the workpiece.
SUMMARY OF THE INVENTION
It is an object of the invention to make it easier to operate NC machines.
This and other objects of the invention are attained by a system that has a teach-in module, which can be embodied by a computer program running on suitable hardware, for instance. The teach-in module allows a visual, preferably three-dimensional display of a workpiece and a working tool. This is possible even if a machine control program of any kind is not yet available. Presume, for example, that it is desired to form a machined tool from a workpiece. A blank, or an incompletely machined tool, is then displayed as the workpiece. The blank or the partially machined tool can be electronically stored in a memory and then retrieved from the memory, for example. Alternatively, the teach-in module may be provided with the capability of putting together blanks or starting bodies for producing machined tools from simple geometric shapes, such as cylinders, parallelepipeds, cubes, or the like. The teach-in module can be provided with suitable scaling functions, so that the working tools, blanks or basic bodies can be displayed visually in a desired size and with a required dimensional ratio.
The teach-in module is arranged to display an operator-specified motion of the workpiece and the working tool relative to one another in response to suitable manual inputs. The motions can be input as single motion steps, for instance, or as motions that follow a predetermined path. Specifying a path can be done for instance using typical paths, such as straight lines, helical lines, or similar courses, that are stored in a memory. Once again, a scaling function may be provided. It is also considered expedient to enable either incremental positioning or input of a motion path. Smoothing functions can be introduced via a manually input path.
One component of the teach-in module is that a machine control program is generated or modified on the basis of the relative motion which is input into the teach-in module, between a display of the working tool and a display of the workpiece. While the teach-in module is displaying the machining progress resulting from the relative motion between the workpiece and the working tool, or in other words is displaying the recesses generated virtually on the blank, for instance by means of a grinding wheel, the machine control data that correspond to such a machining operation are generated at the same time. In this way, the machine control program can be generated by virtual teaching-in. If the machine control program already exists, then it can be modified by the virtual teach-in method. This simplifies the operation of a corresponding numerically controlled machine tool considerably. It makes it possible in a simple manner to manipulate machine control programs, which describe not only the motion sequence but also the speeds of the actuators of a grinding machine as well as status changes at the inputs of a control unit. Such a control unit can be a memory programmable control (referred to herein as “SPS”). This type of control does not use a microprocessor but, rather, a memory such as a PROM which supplies a programmable output for each input signal. As a rule, such machine control programs comprise not only individual commands regarding single motions of the machine actuators but also SPS control commands. Program lines and program blocks made up of a plurality of program lines control the motion of one or more actuators between two points in space. The virtual teach-in module now makes it possible for instance to vary existing program lines, or existing blocks composed of a plurality of program lines, to add new program lines or blocks, and to delete existing program lines or blocks.
To that end, the virtual teach-in module preferably has a storage means, which is arranged for storing in a memory tool data and operating instructions about the relative motions between the working tool and workpiece. To that end, a memory present in hardware form, for instance, is put under the control of a suitable program or program section, which is executed on a suitable computer. The computer also includes a calculation means, to which a corresponding program section and the hardware that runs that program or program section belong. The calculation means processes the work instructions that are present in and furnished by the storage means, so as to change or add to the workpiece data and/or working tool data in accordance with the work instructions, as appropriate for machining of the workpiece by the working tool in accordance with the relative motion defined by the work instructions. In this way, a material erosion, for instance, and/or optionally tool wear as well, can be modeled. This is displayed by the display means, which includes a display device and the corresponding program, which serves to make data graphically visible on the display device. An input means serves to detect desired relative motions between working tool and workpiece, which are converted into corresponding work instructions, which in turn are stored or buffer-stored in memory by the storage means. The input means can include input devices and a playback device, on which virtual input keys or the like can be shown.
In an advantageous embodiment, a transformation means is also present which converts the work instructions generated as above into a machine control program. Alternatively, the work instructions can correspond directly to a machine control program, in which case transformation can be dispensed with.
In the manipulation of the display provided by the virtual teach-in module, the machine control program is generated and/or varied. This can include both the above-described qualitative actions and changes in the machine control program and also changes in the data that are assigned to individual parts of the program.
The input means, which can be formed for instance by a special input device, or an input device in conjunction with input panels shown on a screen, can include both operator panels associated with individual machine axes, actuators and operator panels for configurable axes that do not match the machine axes and actuators. This makes operation even simpler.
The teach-in module can be contained in a simulation module, or vice versa. Also,
Dilger Christian
Huben Frieder
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Hail III Joseph J.
Ojini Anthony
Walter AG
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