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Diamond polishing

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Viewing 13 posts - 1 through 13 (of 13 total)
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  • #39411

    Raju
    Participant

    Hi,
    Anyone there to help me out?
    Thanks,
    How to imlement six sigma where the manufacturing process is non standard(not measurruble)

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    #119738

    Titu John
    Member

    Hi,
    I do understand the nature of your industry its basically  a manual job or an art . You must understand the fundamental saying that “Thing  which cannot be measured ,can’t be improved “. so without measures you cannot use any statistical tools.
    Regards,
    Titu

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    #119739

    Nahas
    Participant

     
    Raju,
    If it’s not measurable, how do you know if it’s working? What’s good and what’s bad? And if you can’t measure it, how will you know when you’ve improved it? Can you give more specifics?

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    #119752

    BTDT
    Participant

    I’m not sure how you say diamond polishing is non-measurable.
    What is the margin on princess vs. SRB cuts?
    How well does final polished valuation meet with incoming quality of rough from different suppliers?
    What is the angle between the [111] cleavage planes and the final polished faces?
    Is the throughput of the polishers constrained by the throughput of the cutters?
    What is the spread of the meet points of the polished product?
    I assume you are mostly dealing with Argyle rough?
    BTDT

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    #119755

    Mike Carnell
    Participant

    BTDT,
    Someone walked right into your area of expertise!
    Regards

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    #119756

    Mike Carnell
    Participant

    Raju,
    Since polishing can’t be measured why don’t you save money and stop polishing them? An unpolished one looks the same as a polished one, right?

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    #119759

    BTDT
    Participant

    Raju:The simplest project I can think of would be based on weight retention from rough. The financial benefits are easy to calculate and the potential influencing factors could come from technical issues to work scope definition and training.
    Too much variation during polishing will result in low quality polished. The relationship between the largest size with the best cut can be modelled using existing standards for the GIA or AGS, and combining those with market prices for loose stones. Our analysis showed Table, Polish and Symmetry as contributing equally to the price of the final polished stones. The error in the model was 1.31% for SRB. We did not include the smaller, single cut stones you may be working with.
    Get yourself a Sarin machine for facet measurement and incorporate periodic measurements as part of your Control plan.
    BTDT

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    #119783

    BTDT
    Participant

    Mike:Diamond in the rough :)BTDT

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    #120158

    Raju
    Participant

    Hai and thnks everyone responded to my topic.
    I am still not sure how to implement 6 sigma in this industry.
    A breif to who new to diamond industry,We are working with 3 to 6mm diameter diamonds.the accuracy needed in microns and while polishing on the machines it is difficult to check the angle and size.
     

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    #120159

    Raju
    Participant

    hai BTDT
    The sarine machine is an excellent tool to meassure but the limitation is it is done only after an operation ,as you know it is very difficult to repair a diamond.If we get the job done @ first time we are also saving the yield.
    Thanking you for your interest and valueable suggetion
    regards raju

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    #120163

    BTDT
    Participant

    Raju:My point was NOT that you have a monitoring program while the diamonds are on the dop chuck. You apply Six Sigma to the entire process of polishing. This includes the accuracy of the dial stop gauges, grinding/checking time intervals, pressure, lap speed, different index wheels, etc.
    Checking angles and meet points on the final stones is done after they are removed from the chuck. This data is used to identify to sources of variation in the final product.
    The amount of repair will decrease. This is related to the first-time-yield, also covered in a Six Sigma project.
    Whether you can get accurate measurements on 3-6mm stones will be part of a Gauge R&R study for any project directed at measuring the quality of the polish.
    BTDT

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    #120175

    Anonymous
    Guest

    Raju,
    Are you serious … microns … surely you mean nanometers? Don’t get me wrong … I’ve never worked with diamonds, or even diamond substrates, only optics – lenses and mirrors. In optics any variation of form by as much as a micron would be immediately noticeable.
    Regards,
    Andy

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    #122179

    mzs
    Participant

    Raju,
    While BTDT’s idea of tracking weight retention is a good basis he is incorrect about table, polish & symmetry. Beyond color  & clarity today’s quality criteria is based on light return (brilliance). The range of acceptable critical angles in the pavilion, in conjunction with the corresponding crown angles then table size and finally polish & symmetry result in the true cut grade.
    He is also correct about using a Sarin, it’s th only way you can plan or measure your results.
    mzs 

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