US-12617055-B2 - Automated diamond polishing methods and systems

US12617055B2US 12617055 B2US12617055 B2US 12617055B2US-12617055-B2

Abstract

An automated gem polishing system comprising a computer-controlled polishing wheel; robotic apparatus, comprising multiple axis controllers and a gem holder; a digital microscope; and a computer having a processor and a memory, the memory including instructions that when executed by the processor implement the steps of registering and polishing a gem in the gem holder.

Inventors

Oded BEN SHMUEL

Assignees

ZALIRIAN LTD.

Dates

Publication Date: 20260505
Application Date: 20200315

Claims (16)

1 . An automated gem polishing system comprising: a computer-controlled polishing wheel; a robotic apparatus, comprising multiple axis controllers and a gem holder; a digital microscope; and a computer having a processor and a memory, the memory including instructions that when executed by the processor implement steps of registering and polishing a gem in the gem holder by: operating the robotic apparatus to move the gem to a field of view (FOV) of the digital microscope, to position the gem in multiple views with respect to the digital microscope, and to receive from the digital microscope multiple respective images of the gem; generating from the multiple respective images a current 3D model of the gem; registering coordinates of the current 3D model with a target 3D model of a finished gem; selecting a current facet of the gem to polish in order to achieve the target 3D model; determining an optimal polishing direction of the current facet; and operating the robotic apparatus to move the current facet into contact with the polishing wheel, and operating the polishing wheel to polish the current facet, in the optimal polishing direction; wherein the gem has a crystal structure defined by three orthogonal crystallographic axes, wherein said optimal polishing direction is one of said three crystallographic axes or a projection thereof onto said current facet, and wherein said robotic apparatus is configured to rotate said current facet on the polishing wheel into said optimal polishing direction.
2 . The system of claim 1 , wherein the polishing wheel has an adjustable, computer-controlled speed.
3 . The system of claim 1 , wherein said determining said optimal polishing direction of the current facet is based on previously determined polishing directions of other facets.
4 . The system of claim 1 , wherein registering coordinates of the 3D model of the gem with a target 3D model further comprises registering the current 3D model of the gem with respect to a known position of the holder.
5 . The system of claim 1 , wherein operating the polishing wheel to polish the current facet comprises operating the polishing wheel at a speed and duration determined by predefined rules.
6 . The system of claim 5 , wherein a selection of the predefined rules is determined according to artifacts on the current facet.
7 . The system of claim 1 , wherein operating the robotic apparatus to move the current facet to contact the polishing wheel further comprises operating the robotic apparatus to position the current facet in contact with the polishing wheel on a polishing wheel track and at a pressure determined by predefined rules.
8 . The system of claim 1 , wherein the instructions also cause the processor to select at least one of a polishing speeds, duration, track and pressure according to said optimal polishing direction of the current facet.
9 . The system of claim 1 , wherein the instructions also cause the processor to select at least one of a polishing speed, duration, track and pressure according to artifacts determined by analyzing an image of the polished surface after a polishing interval.
10 . The system of claim 1 , wherein the instructions also cause the processor to grade the gem by analyzing an image received from the digital microscope after a polishing interval.
11 . The automated gem polishing system of claim 10 , wherein the instructions to cause the processor to grade the gem include: to move the gem to the FOV of the digital microscope; to receive an image corresponding to a view of the current facet recorded by the digital microscope; to register the image corresponding to said view of the current facet to said current 3D model to determine a depth of polishing, wherein the current 3D model is registered to said target 3D model and to responsively determine that dimensions of the gem equal the dimensions of the target 3D model and that the polishing of the gem is complete; to position the gem in multiple views with respect to the digital microscope, to receive from the digital microscope multiple respective images of multiple facets of the gem; to responsively determine, for each of the multiple facets, artifacts of the multiple facets; and to grade the gem by determining a polish grade of the gem according to preset correlations between facet artifacts and polish grades.
12 . The system of claim 1 , wherein the instructions also cause the processor to operate the robotic apparatus to move the current facet after polishing to said field of view of the digital microscope; to optically determine a tilt of the gem holder, responsively adjusting the tilt; to subsequently generate a 2D image of the current facet; and to responsively create a new current 3D model having a new facet conforming to dimensions of the 2D image of the facet.
13 . The system of claim 12 , wherein the instructions also cause the processor to classify an artifact appearing in the 2D facet image, and, responsively to the artifact classification and the new current 3D model, to determine one or more control settings of the robotic apparatus for further polishing of the facet, wherein the control settings include holder tilt, polishing speed, duration, track and pressure.
14 . The system of claim 1 , wherein moving the gem to the field of view (FOV) of the digital microscope comprises automatically selecting a lens of the digital microscope according to a size of the gem.
15 . The automated gem polishing system according to claim 1 , wherein the memory also includes instructions that when executed by the processor implement steps of selecting polishing parameters of the gem in the gem holder by: operating the robotic apparatus to move the gem to the FOV of the digital microscope; receiving an image corresponding to a view of said current facet from the digital microscope; processing the image corresponding to said view of said current facet by an artifact recognition algorithm trained to recognize a set of surface artifacts correlated to a set of subsequent polishing parameters; identifying at least one surface artifact of said current facet and determining that no correlated set of polishing parameters exists; issuing an alert to a human operator to determine a set of polishing parameters.
16 . The automated gem polishing system of claim 1 , wherein the memory also includes instructions that when executed by the processor implement steps of controlling the polishing wheel, the robotic apparatus, and the digital microscope to determine a polish status of the gem in the gem holder by: operating the robotic apparatus to move said current facet of the gem into contact with the polishing wheel, and operating the polishing wheel to polish the current facet according to a set of polishing parameters; subsequently moving the gem to the FOV of the digital microscope; receiving an image corresponding to a view of the current facet recorded by the digital microscope; registering the image corresponding to said view of the current facet to said current 3D model to determine a depth of polishing; responsively determining that dimensions of the gem equal the dimensions of the target 3D model and that the polishing of the gem is complete.

Description

RELATED APPLICATIONS This application is a National Phase of PCT Patent Application No. PCT/IB2020/052352 having International filing date of Mar. 15, 2020, which claims the benefit of priority under 35 USC § 119 (e) of U.S. Provisional Patent Application No. 62/818,213 filed on Mar. 14, 2019. The contents of the above applications are all is incorporated by reference as if fully set forth herein in their entirety. FIELD AND BACKGROUND OF THE INVENTION The invention generally relates to gem polishing and grading, and in particular to automation of polishing and grading tasks. The process of polishing a rough diamond to create a finished gem involves multiple iterative steps. In general, these steps require a high degree of manual intervention, resulting in a time consuming and expensive process. Computer methods are known for assisting in planning the polishing of a rough diamond; for example, computer graphics may be used to plan a final, target gem, that is, the gem that will be created by the polishing process. However, after the plan is in place, the subsequent polishing process, by which each facet of the gem is cut and polished, generally requires repeated human intervention. High temperatures can affect the precision of mechanical parts of the grinding equipment. In addition, the polishing process may introduce “artifacts,” such as pits, scratches, polishing lines, etc., into the gem surface. Polishing is therefore stopped frequently to correct polishing deviations and facet flaws. Automation to reduce human intervention could reduce costs and delays. SUMMARY OF THE INVENTION Embodiments of the present invention provide methods and systems for automating the steps of gem polishing and polish grading. According to an aspect of some embodiments of the present invention there is provided an automated gem polishing system comprises: a computer-controlled polishing wheel; a robotic apparatus, comprises multiple axis controllers and a gem holder; a digital microscope; and a computer having a processor and a memory, the memory including instructions that when executed by the processor implement steps of registering and polishing a gem in the gem holder by: operating the robotic apparatus to move the gem to a field of view (FOV) of the digital microscope, to position the gem in multiple views with respect to the digital microscope, and to receive from the digital microscope multiple respective images of the gem; generating from the multiple respective images a current 3D model of the gem; registering coordinates of the current 3D model with a target 3D model of a finished gem; selecting a current facet of the gem to polish in order to achieve the target 3D model; determining an optimal polishing direction of the current facet; and operating the robotic apparatus to move the current facet into contact with the polishing wheel, and operating the polishing wheel to polish the current facet, in the optimal polishing direction; wherein the gem has a crystal structure defined by three orthogonal crystallographic axes, wherein the optimal polishing direction is one of the three crystallographic axes or a projection thereof onto the current facet, and wherein the robotic apparatus is configured to rotate the current facet on the polishing wheel into the optimal polishing direction. According to some embodiments of the invention the system wherein the polishing wheel has an adjustable, computer-controlled speed. According to some embodiments of the invention the determining the optimal polishing direction of the current facet is based on previously determined polishing directions of other facets. According to some embodiments of the invention registering coordinates of the 3D model of the gem with a target 3D model further comprises registering the current 3D model of the gem with respect to a known position of the holder. According to some embodiments of the invention operating the polishing wheel to polish the current facet comprises operating the polishing wheel at a speed and duration determined by predefined rules. According to some embodiments of the invention a selection of the predefined rules is determined according to artifacts on the current facet. According to some embodiments of the invention operating the robotic apparatus to move the current facet to contact the polishing wheel further comprises operating the robotic apparatus to position the current facet in contact with the polishing wheel on a polishing wheel track and at a pressure determined by predefined rules. According to some embodiments of the invention the instructions also cause the processor to select at least one of a polishing speed, duration, track and pressure according to the optimal polishing direction of the current facet. According to some embodiments of the invention the instructions also cause the processor to select at least one of a polishing speed, duration, track and pressure according to artifacts determined by analyzing an