A NEW APPROACH OF SURFACE ENVELOPING, BASED ON THE DISCREETLY SURFACES REPRESENTATION, IN ORDER TO ALGORITHMIZE AND INFORMATIZE THE GENERATING TOOLS PROFILING

 

1. The enveloping generating tools profiling methodic is a basic fact for tools precision increasing and as effect of enveloping generating surfaces.

2. They are known the analytical methods, based on the basic theorems of surfaces enveloping (tools for pump and helical compressors worm generation, tools for ball circulating screw etc.).

The methods have the disadvantage that needs to known the analytical form of surfaces and is difficult to profile the tools for correction.

3. The modern means for surfaces form investigation, by OMM methods need to realize new interpretation of actual piece form, in which the surface is known in discreetly form, in order to make the corrections: the kinematics, in case of generating machine‑tools chain for numerical command action or corrective re‑profiling of generating tools.

4. They are more situations when the realization of the surfaces form characteristically imposes to generate a surface with complex generatrix, sometimes a non‑analytical one, which imposes a new approach for tools profiling.

Project objective is to increase the complex surfaces machining precision (helical surfaces and surfaces curls associated with a couple of rolling centrodes) by actions which presumes: inspection of surfaces generated on machine‑tools; obtained data processing in order to correct the tools profile for correcting the generatrix form of generated surfaces.

All of these a realized based on the new approach of tools profiling and on the creating specialized software, with results which may be transferred on integrated CAD/CAM/CAI systems, in order to adjust the errors.

The project general objective is the realization of a new coherent approach and with an important versatility degree by changing the concepts of enveloping study based on the surfaces analytical representation to a representation of surfaces in forms those results by OMM. In the same time will be realized some specifically algorithms for generating tools profiling, as so as, some new software dedicated to these problems, in order to correct the form of generating tools and to adjust the generating errors of machined surfaces.

From the general objective derive the specifically objectives:

1. Elaboration of discreetly representation form models of surfaces generated by enveloping, as result of information obtained by OMM, by numerical description of a surfaces real generatrix the tangents method and the method of polyhedron representation.

2. The synthesis of representation by poles of coordinates matrix which represent generatrix of generated surfaces.

3. Elaboration of an error prediction and adjustment model, by simulating a fictive target surface and correction profiling of tool regarding these new models of surface to be generated.

4. Elaboration of algorithms able to quickly and exact estimate the enveloping conditions expressed in discreetly form, with results which may be transferred in order to corrective profiling of generating tools.

5. Elaboration of algorithms for corrective profiling of generating tools in order to adjust the generating errors, with applications at generation with rack‑gear tools, gear shaped tools and worm cutter.

6. Elaboration of new algorithms for corrective profiling of tools bounded by peripheral primary revolution surfaces (disc tool, and mill tool, ring tool) in order to iterative correct the generated helical surface, integrated on CAD/CAM system.

7. Synthesis of dedicated software, based on the discreetly representation of surface (polyhedron representation or representation by poles), as solution for corrective representation of tools which generate complex surfaces (active surfaces of pump and compressors worms), with results which are transferable on CAD/CAM/CAI systems.

8. Extended the discreetly representations models at tools profiling for form correction of tools with helical channels in order to improve the cutting capability tool.

The original elements are:

- a new approach regarding the surfaces enveloping, in which the surfaces are described in discreetly form, by matrix of points coordinates, as they are described by OMM measuring;

- elaboration of new models for generation error prediction and correcting, based on OMM inspection, for generation process based on the rolling method, as so as, for helical surfaces generation with revolution surfaces bounded tools;

- elaboration of new algorithms for discreetly represented surfaces model, in order to profile the generating tools;

- synthesis of new software with results which may be transferred on CAD/CAM/CAI systems in order to increase the generating precision of obtained surfaces.

The importance for machining technology of this project is the creation of a new methodology for generation process study, for surfaces known in accordance with the technological reality, by points coordinates, OMM measured and which will allow a corrective re‑profiling of generating tool regarding the actual surface, not the analytical surface.

On this base, the machining precision will be increased on the generating error decreasing.

We have to notice that a re‑correction of tools allow the geometrical precision of the generated surface.

 

 

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