PROCESS AND APPARATUS FOR CREATING SEQUENCES FOR NUMERICALLY CONTROLLED MACHINE TOOLS

Abstract: A process and an apparatus are described for creating sequences of working directives for machine tools, that allow performing the steps of: reading a mathematical description of an object to be worked; optionally computing a mathematical model of the object based on obtained data; preparing a working area for the object; defining working parameters by translating working and technologic data being input by an operator into a plurality of parameters with values adapted to be modified by an end user; creating working paths; and using stage by stage, by the end user, the working paths being created to control the machine tool, with possible modification of the parameter values.

Description: PROCESS AND APPARATUS FOR CREATING SEQUENCES FOR NUMERICALLY CONTROLLED MACHINE TOOLS The present invention refers to a process and an apparatus for creating sequences of working directives for numerically controlled machine tools . Processes of this type and apparata to realize them are known in the art. So far, it was common practice that the working paths were created by the Computer Aided Manufacturing (CAM) designer operator and were transferred or transmitted to the workshop operator, that took care of putting them into practice. Should the final workpiece not be optimally obtained, the workshop operator had to confer with the CAM operator, that went on performing possible modifications to the created paths, in order to supply again the new paths to the workshop operator. A series of following recalibrations had therefore to be carried out, based on practical final results, and the number of such recalibrations could also be great Therefore, these processes, with the outcome of an always increasing specialization in this field, began posing problems in medium-big-sized companies, also due to the trend of providing more responsibilities for a workshop operator, that has anyway such features and practical expertises as to allow him to effectively recalibrating the program based on the obtained results. Thereby, system were developed that allowed the workshop operator a more direct interaction with the machine-controlling programs, in order to improve the path directly "in the field". These systems, however, bring about organization and personnel problems, because in this case the CAM operator is the one that as a result is being deprived of part of his coordinator role, that in medium-big-sized companies is also a guarantee of compliance with the general guidelines developed by the company itself, due to the centralization of working orders for which generally CAM operators are responsible. Object of the present invention is thereby solving the above prior art problems, providing a process and an apparatus that reduce realization 9/61963 costs of working paths for numerically controlled machine tools. A further object of the present invention is optimizing the development of human resources potentialities applied to the above realization, on one hand increasing the responsabilization and therefore the satisfaction of workshop operators in these preparation steps, and on the other hand maintaining for CAM operators a general addressing function in preparing working orders. The above and other objects and advantages of the invention, as will appear from the following description, are obtained with a process and an apparatus like those respectively disclosed in Claims 1, 2 and 8. Preferred embodiments and non- trivial variations of the present invention are disclosed in the dependent Claims. The present invention will be better described by some preferred embodiments thereof, provided as a non-limiting example, with reference to the enclosed Figure 1 of the drawings, that is a schematical block diagram of a preferred embodiment of a system that carries out the present invention. With reference to Fig. 1, an embodiment of a system to carry out the invention comprises, as is well-kow in the art, a work-station 1, that can be commonly composed of a Central Processing Unit (CPU) 3, a video 5 and a keyboard 7. The workstation 1 is connected through lines 9 or equivalent means to a computerized numerically controlled unit 11, that can be also composed of a CPU with video and keyboard, which is in turn connected to a machine tool 13, for example a milling machine. The apparatus of the present invention is located partly into the work-station 1, for all aspects related to design and definition of working steps by a CAM operator, and partly into the computerized numerically controlled unit 11, for all aspects related to recalibration of parameters relating to working stages and to the generation and execution of tool paths associated therewith by a workshop operator. In fact, due to the process and the apparatus of the present invention, it is possible on one hand to assign to the workshop operator that part of the recalibration work of the parameters, created by a CAM operator, that is simplified by his direct knowledges and practical experiences, and that allows saving the long, intermediate steps of the previous processes, and on the other hand to assign to the CAM operator the general preparation of working orders. According to the invention, a process is provided with a series of steps, that are put into practice by a related apparatus suitable for this purpose: to simplify the description, therefore, only the apparatus of the present invention will be described, the process steps performed thereby being evident from its own composition. Therefore, the apparatus for creating working paths for numerically controlled machine tools of the invention comprises, first of all, in a known way, means for reading a mathematical description of an object to be worked. These means are composed, for example, by a file written complying with one of the formats for describing mathematical surfaces, like IGES (Initial Graphics Exchange Specification) or VDA-FS (Verband der Automobilindustrie Flaechen Schnittstelle) . The apparatus further comprises means for computing the internal mathematical model of the object based on data obtained from the means for reading the mathematical description; these means comprise algorithms of a general and known type, suitable to approximate mathematical surfaces with adequate representations. In practice, this step could also be removed or anyway could be a lot different from one system to another. Moreover, there are also means for preparing the working area for the object to be worked starting from the computed mathematical model, which means comprise general known algorithms for managing the operator interface that are adapted to allow defining the areas themselves by means of pointing devices (like mouses or graphic tablets), or inserting through a keyboard parameters and their related values suitable to describe the area. Means are then provided for defining working parameters based on the object to be worked and on the prepared working area, which means comprise specific algorithms adapted to store into a text file a plurality of parameters and their related values defined by the operator for the current working. An example of the procedure being produced in this step, and being composed of a plurality of Commands and Parameters with their related values, is shown in Table I. Table I Procedure Example > ProjectOpen FileName = D:\input\vda\TAPPO\ttap01.PRJ > RoughingTool ToolDiam = 10.000000 ToolRad = 0.000000 ToolLen = 0.000000 > RoughingMachining StartZ = 0.001000 EndZ = -21.593000 SecurityZ = 100.001000 Stock = 1.000000 Zdec = 1.000000 ToolOn = 1 Cooling = 0 ApprFeed = 2000 Spindle = 3000 WorkFeed = 3500 > RoughingCompute FileName = D:\input\vda\TAPPO\rou000.ISO ToolCentre = 0 These means for defining working parameters translate working data and technologic data that were input by the operator into a plurality of parameters with related values: one of the novel aspects of such operation is that the values of such parameters are adapted to be modified by the end user, being stored into a file of parameters and values that is displayed on a screen under the form of windows that are adapted to be modified according to common methods in the art. For example, according to another possile variation that allows such modification, the file of parameters and values is displayed on the screen under the form of a program that is adapted to be directly modified by the user. The inventive apparatus further comprises means for creating working paths based on the prepared working area and on the prepared working parameters; these means in a pratical embodiment comprise algorithms adapted to write a file containing a plurality of parameters and their related values into an ordered sequence in order to allow to a numeric control to interpret them and to consequently move the tool. The file is written into one of the formats that are commonly interpreted by numeric controls (for example ISO 6983), and an example of a tool path being generated is shown in Table II. Table II ISO Part Program N12G17Q1 N13M03S3000 N14G00Z100.001 N15G00X-21.900Y24.021 N16Z-0.999F2000 N17Y16.828F3500 N18X-16.364Y22.364 N19G02X-12.846Y24.538T-10.000J16.000 N20X-6.846Y26.538 N21G02X-4.000Y27.000T-4.000J18.000 N22X0.000 N23X4.000 N24G02X6.846Y26.538I4.000 N25X12.846Y24.538 Finally, the apparatus comprises means for using, by the end user, the working paths being created to control the machine tool to realize the object, according to the common practice in the field. The means for using working parameters allow, in a novel way, a stage-by-stage usage by the end user, that is enabled to modify the parameter values in each one of the working stages according to the practical results that he wishes to obtain. The flexibility of the apparatus of the present invention implies that all the above means for reading the mathematical description, for computing the model, for preparing the working area, for defining the working parameters and for creating the paths, translate and express their own control data into a plurality of parameters with related values that are adapted to be modified by the end user. The apparatus of the invention allows dividing the tasks in a CAM environment into two different phases: in the first one, the CAM operator with specific design knowledges, by complying also with company directives, defines strategies and all parameters for generating tool paths; in the second phase, aboard the machine, the workshop operator receives what has been defined in the first phase and starts the process of generating the paths with their following operation on the numerically controlled machine, with the chance of intervening for a possible modification of the above parameters in order to better cope with the current working needs, for example by revising what has been defined, adding or removing some stages, etc.

Claims: CLAIMS 1. Process for creating sequences of working directives for numerically controlled machine tools, said process comprising the steps of: reading a mathematical description of an object to be worked; computing a mathematical model of said object based on data obtained from said step of reading the mathematical description; preparing a working area for said object from the computed mathematical model; defining working parameters based on the object to be worked and on the prepared working area; creating working paths based on said prepared working area and on said defined working parameters; using, by an end user, the working paths being created to control the machine tool to realize the object; characterized in that: said step of defining the working parameters consists in translating working data and technologic data being input by an operator, into a plurality of parameters with related values, said values of said parameters being adapted to be modified by the end user; and said step of using working parameters is carried out stage by stage, the end user being enabled to modify said values of said parameters in each one of said stages. 2. Process for creating sequences of working directives for numerically controlled machine tools, said process comprising the steps of: reading a mathematical description of an object to be worked; preparing a working area for said object from a pre-established mathematical model; defining working parameters based on the object to be worked and on the prepared working area; creating working paths based on said prepared working area and on said defined working parameters ; using, by an end user, the working paths being created to control the machine tool to realize the object; characterized in that: said step of defining the working parameters consists in translating working data and technologic data being input by an operator, into a plurality of parameters with related values, said values of said parameters being adapted to be modified by the end user; and said step of using working parameters is carried out stage by stage, the end user being enabled to modify said values of said parameters in each one of said stages. 3. Process according to Claim 1 or 2, characterized in that said translation consists in creating a file of parameters with related values. 4. Process according to Claim 3, characterized in that said file of parameters and values is displayed on a screen under the form of windows adapted to be modified. 5. Process according to Claim 3, characterized in that said file of parameters and values is displayed on a screen under the form of a program adapted to be modified. 6. Process according to Claim 1 or 2, characterized in that all said steps of reading a mathematical description, optionally computing a model, preparing a working area, defining working parameters and creating paths are adapted to be translated and expressed into a plurality of parameters with related values adapted to be modified by an end user. 7. Process according to any of the previous Claims, characterized in that the end user is a workshop operator responsible for the workings on numerically controlled machine tools and the operator is a CAM operator. 8. Apparatus for creating sequences of working directives for numerically controlled machine tools, said apparatus comprising: - means for reading a mathematical description of an object to be worked; optional means for computing a mathematical model of said object based on data obtained from said means for reading the mathematical description; means for preparing a working area for said object from the computed mathematical model; - means for defining working parameters based on the object to be worked and on the prepared working area; means for creating working paths based on said prepared working area and on said defined working parameters; means for using, by an end user, the working paths being created to control the machine tool to realize the object; characterized in that: said means for defining the working parameters translate working data and technologic data being input by an operator, into a plurality of parameters with related values, said values of said parameters being adapted to be modified by the end user; and said means for using working parameters enable to use the working parameters stage by stage, the end user being enabled to modify said values of said parameters in each one of said stages. 9. Apparatus according to Claim 8, characterized in that said means for translating create a file of parameters with related values. 10. Apparatus according to Claim 9, characterized in that said file of parameters and values is displayed on a screen under the form of windows adapted to be modified. 11. Apparatus according to Claim 9, characterized in that said file of parameters and values is displayed on a screen under the form of a program adapted to be modified. 12. Apparatus according to Claim 8, characterized in that said means for reading a mathematical description of an object to be worked comprise a file written in compliance with one of the formats for describing mathematical surfaces, like IGES or VDA. 13. Apparatus according to Claim 8, characterized in that said means for computing the mathematical model of said object comprise algorithms of the general type suitable to approximate mathematical surfaces with equivalent geometric surfaces. 14. Apparatus according to Claim 8, characterized in that said means for preparing the working area for said object from the computed mathematical model comprise general algorithms for managing the operator interface that are able to allow defining the areas themselves by means of pointing devices, or inserting through a keyboard parameters and related values suitable to describe said area. 15. Apparatus according to Claim 8, characterized in that said means for defining working parameters based on the object to be worked comprise specific algorithms that are adapted to store into a text file a plurality of parameters and their related values defined by the operator for the current working. 16. Apparatus according to Claim 8, characterized in that said means for creating working paths comprise algorithms that are adapted to write a file containing a plurality of paameters and their related values into such an ordered sequence as to allow a numeric control to interpret them and consequently move a tool, said file being written into one of the formats that are commonly interpreted by numeric controls. 17. Apparatus according to Claim 8, characterized in that all said means for reading a mathematical description, optionally computing a model, preparing a working area, defining working parameters and creating paths translate and express their own control data into a plurality of parameters with related values adapted to be modified by an end user. 8. Apparatus according to any of Claims 8 to 17, characterized in that the end user is a workshop operator responsible for the workings on numerically controlled machine tools and the operator is a CAM operator.

Inventors: MORFINO GIUSEPPE, MORFINO, GIUSEPPE
Applicants: FIDIA SPA, MORFINO GIUSEPPE, FIDIA S.P.A., MORFINO, GIUSEPPE
Application year: 1999
Main classification: G05B19
IPC codes: G05B19