DESC:FIELD
The present disclosure relates to the field of machining methods.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Machining of components is carried out to obtain the finished version of the cast or fabricated components. To obtain a desired coplanarity value on a surface, a certain amount of cutting speed of the machining head and a cutting feed is fixed. The combination of the cutting speed and the cutting feed is maintained constant for every machining pass to obtain the desired coplanarity value. However, this results in increased machining time, as time spent in each machining pass is constant. Additionally, this results in increased machining cost of the component. Moreover, the desired coplanarity value is not achieved with the conventional machining process.
There is therefore, felt a need of a method of machining components by a robotic apparatus that alleviates the aforementioned drawbacks.
OBJECTS
Some of the objects of the present disclosure are described herein below:
One object of the present disclosure is to provide a method of machining components by a robotic apparatus that reduces machining time.
Another object of the present disclosure is to provide a method of machining components by a robotic apparatus that optimizes number of machining passes.
Another object of the present disclosure is to provide a method of machining components by a robotic apparatus that reduces machining cost.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure discloses a method of machining components by a robotic apparatus comprising the following steps:
o mounting a component to be machined on a platform;
o displacing a robot having a machining head relative to a surface of the component to be machined;
o sensing by a sensor mounted on the machining head, the coordinates of a set of predefined locations on the surface with respect to a datum coordinate system;
o calculating the distance for each of the set of predefined locations relative to the surface;
o determining a maximum deviation and a minimum deviation of the set of predefined locations based on the calculated distances;
o determining a first coplanarity value for each of the set of predefined locations relative to the surface, the first coplanarity value calculated based on the maximum deviation and the minimum deviation;
o machining the surface of the component with a first depth of cut and/or a first cutting speed of the machining head for a first set of machining passes corresponding to the first coplanarity value;
o determining a second coplanarity value for each of the set of predefined locations relative to the surface at the end of the first set of machining passes, the second coplanarity value calculated based on the maximum deviation and the minimum deviation with respect to the calculated distance for each of the predefined locations;
o machining the surface of the component with a second depth of cut and/or a second cutting speed of the machining head for a second set of machining passes corresponding to the second coplanarity value;
o determining a third coplanarity value at the end of the second set of machining passes for each of the set of predefined locations relative to the surface, the third coplanarity value being within a predefined limit.
In a preferred embodiment, the step of calculating the distance for each of the set of predefined locations relative to the surface includes a substep of reorienting or correcting a robot path along which the robot is displaced.
In a preferred embodiment, the substep of reorienting or correcting the robot path is based on the offset of the component mounted on the platform with respect to the datum coordinate system.
In another embodiment, the first coplanarity value is greater than the second coplanarity value, and the second coplanarity value is greater than the third coplanarity value.
In another embodiment, the third coplanarity value is a desired final coplanarity value.
In another embodiment, the first cutting speed, the second cutting speed, the first depth of cut, the second depth of cut are programmed by a user.
In another embodiment, the first cutting speed is configured to vary during the machining of atleast one of the predefined set of locations on the surface of the component.
In another embodiment, the second cutting speed is configured to vary during the machining of atleast one of the predefined set of locations on the surface of the component.
In another embodiment, the first depth of cut is configured to vary during the machining of atleast one of the predefined set of locations on the surface of the component.
In another embodiment, the second depth of cut is configured to vary during the machining of atleast one of the predefined set of locations on the surface of the component.
In another embodiment, the first cutting speed is different than the second cutting speed.
In another embodiment, the number of the first set of machining passes is different than the number of the second set of machining passes.
In another embodiment, the first depth of cut is different than the second depth of cut.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
A method of machining components by robotic apparatus, of the present disclosure, will now be described with the help of the accompanying drawing, in which:
Figure 1 shows an isometric view of the apparatus, in accordance with an embodiment of the present disclosure;
Figure 2 shows a top view of the component being machined with the predefined locations marked thereon;
Figure 3 shows a plot of robot feed speed and stock removal per pass for the predefined locations 50, 51, 52, 53, 54 along with the respective determined deviations, before first set of machining passes;
Figure 4 shows a plot of robot feed speed and stock removal per pass for the predefined locations 50, 51, 52, 53, 54 along with the respective determined deviations, after first set of machining passes; and
Figure 5 shows a plot of pre-grinding coplanarity scan and post-grinding coplanarity scans of the predefined locations 50, 51, 52, 53, 54, after second set of machining passes, as compared with the existing method.
LIST OF REFERENCE NUMERALS
100 – apparatus
10 – platform
20 – component
30 – machining head
40 – robot
50, 51, 52, 53, 54, 55, 56, 57, 58, 59 – set of predefined locations
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
When an element is referred to as being "mounted on," “engaged to,” "connected to," or "coupled to" another element, it may be directly on, engaged, connected or coupled to the other element. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Terms such as “inner,” “outer,” "beneath," "below," "lower," "above," "upper," and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
Referring to the figure 1-4, a method of machining components by a robotic apparatus 100 comprising the following steps:
o mounting a component 20 to be machined on a platform 10;
o displacing a robot 40 having a machining head 30 relative to a surface of the component 20 to be machined;
o sensing by a sensor mounted on the machining head 30, the coordinates of a set of predefined locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 on the surface with respect to a datum coordinate system;
o calculating the distance for each of the set of predefined locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 relative to the surface;
o determining a maximum deviation and a minimum deviation of the set of predefined locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 based on the calculated distances;
o determining a first coplanarity value for each of the set of predefined locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 relative to the surface, said first coplanarity value calculated based on the maximum deviation and the minimum deviation;
o machining the surface of the component 20 with a first depth of cut and/or a first cutting speed of the machining head 30 for a first set of machining passes corresponding to the first coplanarity value;
o determining a second coplanarity value at the end of the first set of machining passes for each of the set of predefined locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 relative to the surface, said second coplanarity value calculated based on the maximum deviation and the minimum deviation with respect to the calculated distance for each of the predefined locations;
o machining the surface of the component 20 with a second depth of cut and/or a second cutting speed of the machining head 30 for a second set of machining passes corresponding to the second coplanarity value;
o determining a third coplanarity value at the end of the second set of machining passes for each of the set of predefined locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 relative to the surface, said third coplanarity value being within a predefined limit.
In a preferred embodiment, the step of calculating the distance for each of the set of predefined locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 relative to the surface includes a substep of reorienting or correcting a path along which the robot 40 is displaced. The substep of reorienting or correcting is based on the offset of the component 20 mounted on the platform 10 with respect to the datum coordinate system.
In a preferred embodiment, the first coplanarity value is greater than the second coplanarity value, and the second coplanarity value is greater than the third coplanarity value. This facilitates achieving coplanarity in a stepped manner. The third coplanarity value is a desired final coplanarity value. The first cutting speed is different than the second cutting speed. The number of first set of machining passes is different than the number of second set of machining passes. The first depth of cut is different than the second depth of cut.
In a preferred embodiment, the first cutting speed is configured to vary during the machining of atleast one of the predefined set of locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 on the surface of the component 20. The second cutting speed varies during the machining of atleast one of the predefined set of locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 on the surface of the component (20). This results in machining only a desired number of the predefined set of locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 thereby reducing the machining time.
In a preferred embodiment, the first depth of cut is configured to vary during the machining of atleast one of the predefined set of locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 on the surface of the component 20. The second depth of cut is configured to vary during the machining of atleast one of the predefined set of locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 on the surface of the component 20. This results in machining only a desired number of the predefined set of locations thereby reducing the machining time.
In another embodiment, the first depth of cut is configured to vary during each of the first set machining passes for machining atleast one of the predefined set of locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 on the surface of the component 20. The second depth of cut is configured to vary during each of the machining passes for machining atleast one of the predefined set of locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 on the surface of the component (20). This facilitates reducing the machining time.
In another embodiment, the first cutting speed is configured to vary during each of the first machining passes for machining atleast one of the predefined set of locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 on the surface of the component (20). The second cutting speed is configured to vary during each of the machining passes for machining atleast one of the predefined set of locations 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 on the surface of the component 20. This facilitates reducing the machining time.
Referring to the figure 1-4, an apparatus 100 for machining a component 20 is shown. The component 20 is mounted on a platform 10. A machining head 30 is attached to a robot 40 for performing machining operation on the component 20.
Experiment 1: Machining with Conventional method
With the conventional method, machining was performed with a constant depth of cut, and a constant cutting speed for every machining pass which resulted in a machining time of approximately 300 minutes.
The location 50 had the minimum deviation of 1 mm and location 54 had the maximum deviation of 11 mm. The target coplanarity value is calculated as maximum deviation minus minimum deviation. The target coplanarity value is calculated as 10 mm which is 1 less of 11. The predefined locations 50, 51, 52, 53, 54 are machined with a constant depth of cut of 0.5 mm and a constant cutting speed 10 mm/sec for every machining pass. Hence, 20 number of machining passes were required to achieve the target coplanarity of 10 mm. Machining time was observed to be 300 minutes. In a preferred embodiment, the apparatus 100 is a computer numerical control machine which is configured to be programmed by a user. The parameters controlled by the apparatus 100 include selection of the set of predefined locations, the first coplanarity value, the second coplanarity value, the third coplanarity value, the first set of machining passes, the second set of machining passes, the first cutting speed, the second cutting speed, the first depth of cut, the second depth of cut. The parameters mentioned above are programmable by a user via an interactive display provided on the apparatus 100 for ease of operation.
Experiment 2:
Referring to the example shown in figures 2 and 3, location 50 has the minimum deviation of 1 mm and location 54 has the maximum deviation of 11 mm. Minimum deviation location is location 50 at 1mm and Maximum deviation is observed at location 54 which is 11 mm. Grinding operation is considered as an example machining method explained.
The first coplanarity value is calculated as 10 mm which is 1 less of 11. The predefined locations 52, 53, 54 lie approximately above minimum deviation of 1 mm i.e. 1 mm plus 2.2 mm are machined. The value of 2.2 mm above 1 mm is selected based on prior performed experiments. So, the amount of material removed is 2.2 less 10 mm which is 7.8 mm. Machining with a first depth of cut 1 mm and a first cutting speed of 10 mm/sec is performed for the locations 52, 53, 54. The locations 50, 51 are machined with a first cutting speed of 100 mm/sec, as no material is removed for locations 50 and 51. This is because at the locations 50, 51 the coplanarity lies below as shown in the table of the figure 3. This facilitates optimization of the machining time as machining operation is selectively performed on the set of predefined set of locations 50, 51, 52, 53, 54. Hence, 7 first number of passes are required to remove material of 7 mm. Coplanarity achieved after machining with the first depth of cut and the first cutting speed after the first set of machining passes is 11 minus 7 which is 4 mm. So, the second coplanarity is 4 mm which is determined after the first set of machining passes.
Referring to the figure 4, location 50 still has the minimum deviation of 1 mm and location 54 has the maximum deviation of 4 mm. Minimum deviation location is location 50 at 1 mm and maximum deviation location is location 54 at 4 mm.
The second coplanarity value is calculated as 3 mm which is 1 less of 4. So, the amount of material to be removed was 3 mm. Machining with a second depth of cut 0.7 mm and a second cutting speed of 15 mm/sec was performed for the locations 51, 53, 54. The locations 50, 52 are machined with a second cutting speed of 100 mm/sec. So, no material is removed for locations 50 and 52 as shown in figure 3. Hence, the second number of passes required to remove material of 3 mm is 4. The third coplanarity achieved after machining with the second depth of cut and second cutting speed after second set of machining passes was 1.9 minus 1 which is 0.9 mm. Figure 5 shows comparison of coplanarity values before first set of machining passes, after first set of machining passes and after second set of machining passes. Machining time required was approximately 165 minutes with the method of the present disclosure. It can be observed that the machining time with the method of the present disclosure was significantly reduced by approximately 50 percent as compared to the machining time with the method of the existing method (300 minutes). As shown in figure 5, comparison of the two bottom rows of the table reveals that the final coplanarity achieved by the method of the present disclosure (i.e. 0.9 mm) was the same as the final coplanarity achieved by the conventional method (i.e. 0.9 mm). However, the machining time with the method of the present disclosure (i.e. 165 minutes) was significantly lower than the machining time with the existing method (i.e. 300 minutes).
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENT
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a method of machining components by a robotic apparatus that:
• reduces machining time;
• optimizes number of machining passes; and
• offers reduction in machining cost.
The foregoing description of the specific embodiments so fully reveals the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element or group of elements.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, apparatus, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:WE CLAIM:
1. A method of machining components by a robotic apparatus (100) comprising the following steps:
o mounting a component (20) to be machined on a platform (10);
o displacing a robot (40) having a machining head (30) relative to a surface of the component (20) to be machined;
o sensing by a sensor mounted on the machining head (30), the coordinates of a set of predefined locations (50, 51, 52, 53, 54, 55, 56, 57, 58, 59) on the surface with respect to a datum coordinate system;
o calculating the distance for each of the set of predefined locations (50, 51, 52, 53, 54, 55, 56, 57, 58, 59) relative to the surface;
o determining a maximum deviation and a minimum deviation of the set of predefined locations (50, 51, 52, 53, 54, 55, 56, 57, 58, 59) based on the calculated distances;
o determining a first coplanarity value for each of the set of predefined locations (50, 51, 52, 53, 54, 55, 56, 57, 58, 59) relative to the surface, said first coplanarity value calculated based on the maximum deviation and the minimum deviation;
o machining the surface of the component (20) with a first depth of cut and/or a first cutting speed of the machining head (30) for a first set of machining passes corresponding to the first coplanarity value;
o determining a second coplanarity value for each of the set of predefined locations (50, 51, 52, 53, 54, 55, 56, 57, 58, 59) relative to the surface at the end of the first set of machining passes, said second coplanarity value calculated based on the maximum deviation and the minimum deviation with respect to the calculated distance for each of the predefined locations;
o machining the surface of the component (20) with a second depth of cut and/or a second cutting speed of the machining head (30) for a second set of machining passes corresponding to the second coplanarity value;
o determining a third coplanarity value at the end of the second set of machining passes for each of the set of predefined locations (50, 51, 52, 53, 54, 55, 56, 57, 58, 59) relative to the surface, said third coplanarity value being within a predefined limit.
2. The method as claimed in claim 1, wherein the step of calculating the distance for each of the set of predefined locations (50, 51, 52, 53, 54, 55, 56, 57, 58, 59) relative to the surface includes a substep of reorienting or correcting a robot path along which the robot (40) is displaced.
3. The method as claimed in claim 2, wherein the substep of reorienting or correcting the robot path is based on the offset of the component (20) mounted on the platform (10) with respect to the datum coordinate system.
4. The method as claimed in claim 1, wherein said first coplanarity value is greater than the second coplanarity value, and said second coplanarity value is greater than the third coplanarity value.
5. The method as claimed in claim 1, wherein said third coplanarity value is a desired final coplanarity value.
6. The method as claimed in claim 1, wherein said first cutting speed, said second cutting speed, said first depth of cut, said second depth of cut are programmed by a user.
7. The method as claimed in claim 1, wherein said first cutting speed is configured to vary during the machining of atleast one of said predefined set of locations (50, 51, 52, 53, 54, 55, 56, 57, 58, 59) on the surface of the component (20).
8. The method as claimed in claim 1, wherein said second cutting speed is configured to vary during the machining of atleast one of said predefined set of locations (50, 51, 52, 53, 54, 55, 56, 57, 58, 59) on the surface of the component (20).
9. The method as claimed in claim 1, wherein said first depth of cut is configured to vary during the machining of atleast one of said predefined set of locations (50, 51, 52, 53, 54, 55, 56, 57, 58, 59) on the surface of the component (20).
10. The method as claimed in claim 1, wherein said second depth of cut is configured to vary during the machining of atleast one of said predefined set of locations (50, 51, 52, 53, 54, 55, 56, 57, 58, 59) on the surface of the component (20).
11. The method as claimed in claim 1, wherein said first cutting speed is different than said second cutting speed.
12. The method as claimed in claim 1, wherein the number of said first set of machining passes is different than the number of said second set of machining passes.
13. The method as claimed in claim 1, wherein said first depth of cut is different than the second depth of cut.
Dated this 14th day of November, 2023

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI