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  1. #11
    I had the accuracy of a mill in mind of course not a large router.

  2. #12
    Disagree.
    All commercial collet chucks run out at less than 0.01 mm, way out from the spindle.

    A typical iscar or similar collet chuck with tool mounted and tool, would run out maybe 5-8 microns 100 mm out from a typical ISO40/ISO30 spindle nose.

    A kaiser, bigx, schaublin, regofix, or anything good typically promises about 2-4 microns 5-10 cm out from the spindle.
    Lots of machines, tools, and setups do better.

    Nothing commercial runs out over 10 microns or 0.01 mm because it would break, shatter, or destroy life of all modern carbide tooling and diamond tooling.
    Standard basic TIR guarantee on machine tool spindles has been around 2 microns for a long time.

    All high end expensive machines do much better, like Heller (German 5 axis), Fehlmann, or any japanese maker (Mori Seiki, DMG, etc).
    Anyone can lap/fit/hone a tool and cone and taper to better than 0.01 mm / 5 cm length at home.
    Anyone professional can do much better.
    Amateurs hand-fit telescope lenses and mirrors to 30x better with no measurement equipment all the time.

    Hand lapping with rigid laps gets easily better than 1 micron accuracy in size, since about 1940.

    Gage blocks are machine lapped, cheap, and are lapped to 0.01 microns.
    According to moore&wright, premier authority on the planet.

    The runout on a tool mounted in a HAAS, ER collet chuck, needed to be 1-5 microns at 10.000 rpm trending low.
    To engrave custom electrodes in carbon fiber for EGM.
    I held the tool, the factory demonstrated success, I showed the tools and electrodes to press and about 200 industry reps. in us opening a 2011 year Barcelona HFO.
    Best in the world HFO, sales, 2012.

    Yes, I personally asked the factory to run the test and demo and we got back samples and video.
    The tool was maybe 2 mm thick and 100 mm long and the tip was only 0.02 mm.
    The tools and customer cases were in glass cases visible to several hundred visitors and pics with Gene Haas and US ambassador G. Philps and us are online in publications.

    Professional ethics and courtesy and practice are why I donīt share pics.

    Quote Originally Posted by Robin Hewitt View Post
    Let us consider one component, the run out on the collet chuck holding the tool... Standard precision 15-20 microns, Super precision 10 microns, Ultra precision 5 microns

  3. #13
    To achieve a decent level of accuracy heavy castings are handy to hold the tool or grinding wheel in position, preventing deflection and vibration. Even with grinding temperature control is not usually required, because the part used as the comparator can be kept at a similar temperature to the parts by immersion in coolant. The real accuracy trade off is space available and how much weight you can manage to install.

  4. #14
    That's a wordy response (can't be bothered to quote it) that appears to make some sense on the face of it until you scratch a micron below the surface and twig that there are some rather big dimensions missing.

    Unless you regulate the temperature of the table, frame and ballscrews, the coefficient of expansion becomes a significant issue. So if (like me) you have worked with suppliers that genuinely have 1um machines, you will see measures to address it. The machines have extensive heating and cooling circuits running continually and they are housed in air conditioned rooms. They are set up very painstakingly by experts who know what they are doing.

    Similarly, a machine that won't deflect by more than a total of +/- 0.5um under load ("within 1um") would require a truly impressive level of rigidity. To demonstrate willy waving levels of accuracy outside of the pub, you need to machine a part under realistic conditions and measure the results - over several samples, ideally in several locations.

    I doubt if any of us could even set up a machine to anything like the required level of accuracy before we even set up the work.

    For an insight into what you need to get to the micron level, here's a mate of mine describing some of the issues. About half way in he's discussing 1um machines:


    My big Japanese machine was originally designed and manufactured as a proper CNC machine with HSK bearings and ballscrews with a published achievable overall accuracy of 10um. Having said that, you'd need to allow for wear and adjust it carefully to get anywhere near that. I may achieve perhaps 25um on a good day and be happy enough with it. I'm not making watch or optical parts on it.

    What could you possibly make that requires 1um tolerances? But above all - how would you measure them?

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  6. #15
    Quote Originally Posted by Muzzer View Post
    To demonstrate willy waving levels of accuracy outside of the pub,
    I was having a shitty morning but that made me chuckle...Thank's.

    Couldn't agree more, people are off in La La land when they quote levels of accuracy they can't even measure.! . . . . The floor they are standing on will move more than they quote as they walk around and it heats up.!
    -use common sense, if you lack it, there is no software to help that.

    Email: [email protected]

    Web site: www.jazzcnc.co.uk

  7. #16
    m_c's Avatar
    Lives in East Lothian, United Kingdom. Last Activity: 3 Days Ago Forum Superstar, has done so much to help others, they deserve a medal. Has been a member for 9-10 years. Has a total post count of 2,908. Received thanks 360 times, giving thanks to others 8 times.
    I miss JohnS in these kind of discussions.
    I always remember a discussion somewhere (possibly on a ye olde usenet group), where somebody wanted to machine a bit steel to exactly 12" long, to within a stupid tolerance of a couple tenths.
    John simply asked at what temperature did he want the tolerance met?
    The guy didn't have a clue, and had to have it explained to him that for every degree of temperature change, the bar would grow/shrink by over a thou.
    Avoiding the rubbish customer service from AluminiumWarehouse since July '13.

  8. #17
    To get these levels of accuracy, grinding with in process measuring is required, or make a batch and reject/rework the ones out of tolerance.

  9. #18
    RobC's Avatar
    Lives in Leeds, United Kingdom. Last Activity: 30-12-2022 Has been a member for 5-6 years. Has a total post count of 116. Received thanks 16 times, giving thanks to others 21 times.
    Holding 0.01mm most of the time, often can be on the measurement I wanted. But my machine is far from perfect, I've had to do a lot of tramming and shimming to achieve such, I built my machine using a drill press and a myford lathe which too isn't perfect. The goal is, if you can't make it perfect, make it adjustable!

    This is my first build from no knowledge at all to being able to run it without a single problem which has taken me a few years.

    Click image for larger version. 

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  10. #19
    What a fabulous video! I want to be reborn, work harder at school and go to Cranfield University!

    Half a um is the wavelength of blue light. Just measuring to that accuracy is serious science in it's own right and then he says they can make parts accurate to a few nm! One of my colleagues from a past life ('Dr Dave') had got his PhD by 'photographing' the individual atoms in crystal layers without an electron microscope. In effect he was measuring the varying distance between a microscopic metal probe and the surface of the atoms (if an atom can be said to have a surface) as the probe was moved over the crystal . He gave us a talk on how it was done. Nearly 30 years later I still remember sitting there utterly gobsmacked.
    An optimist says the glass is half full, a pessimist says the glass is half empty, an engineer says you're using the wrong sized glass.

  11. #20
    Quote Originally Posted by m_c View Post
    I miss JohnS in these kind of discussions.
    Me too, I often see posts asking things like this and often think "I wish John was here to read this shit" . .. I can almost hear his sarcastic brutal reply's...
    -use common sense, if you lack it, there is no software to help that.

    Email: [email protected]

    Web site: www.jazzcnc.co.uk

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