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Re: [mach1mach2cnc] Re: Alternative To the SS

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  • Daniel
    Mark, Yes, from what you describe as typical work of the rigid tapping guys, it really looks as not healthy for the bearings. But I am not in production as
    Message 1 of 88 , Sep 1 12:15 AM
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      Mark,

      Yes, from what you describe as typical work of the rigid tapping guys, it really looks as not "healthy" for the bearings.

      But I am not in production as they are, and don't have to tap tens of holes per part against time. So for me tapping at 200RPM is more than I could ask for (at this point), and I only do this once in along while. That's where my earlier comment came from.

      Daniel




      ________________________________
      From: Dr Mark Vaughan <mark@...>
      To: mach1mach2cnc@yahoogroups.com
      Sent: Tuesday, September 1, 2009 8:49:49 AM
      Subject: RE: [mach1mach2cnc] Re: Alternative To the SS

      Hi Stan

      There’s plenty of evidence though from many industrial processes that suggests changes in direction do shorten bearing life.

      The big issue then becomes as you say how hard you push the machine, and where that wear goes exponential. For a normal machine just milling, many of us can a slow power up which will be good for the bearing, and performed once in the machine program won’t make much difference to the job time, or wear and tear. But as soon as you get into rigid tapping that means you are probably going to be doing loads of holes and that dwell time now accumulates to become significant in the job time meaning people are going to start pushing their VFD’s for maximum accelerations. That could be enough to change the bearing life by many factors so a machine where the bearings have lasted ten years and will last another ten years, may now fail in a much shorter time. Since many people here have nice machinery with limited maintenance budgets being a big reason they went for mach3, I don’t want them to be shocked when an expensive bearing starts to regularly fail.



      As I said I know several firms on 6 month bearing changes which as you say may be how hard they push the machine. There are other issues that may cause this short lifetime. Could be that newer machines run higher bearing speeds and so wear out more quickly. Could be newer machines are built to a limited cost and have poorer bearings, certainly the newer machines even if not driven hard are finished often in five years whereas the old metal was designed to last the lifetime of the operator.



      I still feel there’s an unknown to be weary of.



      Regs Mark



      Dr. Mark Vaughan Ph'D., B.Eng. M0VAU

      Managing Director

      Vaughan Industries Ltd., reg in UK no 2561068

      Water Care Technology Ltd, reg in UK no 4129351

      Addr Unit3, Sydney House, Blackwater, Truro, Cornwall, TR4 8HH UK.

      Phone/Fax 44 (0) 1872 561288

      RSGB DRM111 (Cornwall)



      From: mach1mach2cnc@yahoogroups.com [mailto:mach1mach2cnc@yahoogroups.com] On Behalf Of Stan Telus
      Sent: 31 August 2009 22:42
      To: mach1mach2cnc@yahoogroups.com
      Subject: Re: [mach1mach2cnc] Re: Alternative To the SS





      Hello Mark

      I would think that if your not pounding the machine to get product flow
      rates up real high, your bearings would last just as long doing ridged
      tapping.

      production madness can be a funny thing, some get so focused on
      production they forget to look at the bottom line. we run the machine to
      make money, if we over drive the production past the brake even point
      (even close to brake even point is no good, as we get into diminishing
      returns and start to work hard for just a little extra money), it starts
      to cost money, most do not stop to think about that, they are so focused
      on production and the blind belief that more parts per hour per machine
      is more money for them or the company. take in tool wear, broken tools,
      bearings toasted, machine beat all to hell in a few years that would
      last decades if not hammered so hard, and what ever else that goes wrong
      with pushing to hard. you may be much further ahead and more money in
      the bank, not to mention far less head aches by getting more machines or
      taking on less work.

      I have a friend that owns a dairy farm, you may wonder how the 2 are
      connected, but they are, about 15 years ago he was on this max milk per
      cow kick, he was hitting them with hot gains and pounding the meds
      through them and doing all he read in the dairy magazine to boost
      production to the max, he was riding the raged edge, and proud that he
      could get the max per cow that he was getting. thing was the cows were
      sick and would last only 1 to 2 years, $1500 on a good month for vet
      bills with meds on top of that, and on a bad month, over $5k, cost of
      feed through the roof, and the head aches and hassles where very high.
      he ended up getting cancer, had to slow down and rest while he beat the
      cancer, so he made some life changes and slowed the pace down from where
      he was, he now has healthy cows over 10 years old, and still milking,
      hardly ever see the vet, stopped feeding hot gains so his feed costs are
      way down, he grows all his own feed now, the down side is he milks more
      cows as each cow give less milk, so he spend more time milking every day
      but he is making way more money now then before and has a running record
      of the best quality milk produced of all the other farms in the area. so
      fasted bigger better is not alway the best way to go.

      I do think rigid tapping would be good if your not running it hard,
      bearings do not care the direction they turn or that they change
      directions, as long as they are not getting beat to death in the process.

      that is my 2 cents worth, maybe a tad more

      Stan

      Dr Mark Vaughan wrote:
      >
      >
      > Honestly Daniel I don’t know by how much for sure, but it seems it
      > could be significant.
      >
      > If you think about it, starting and stopping must take an bit of extra
      > toll on the bearings, and a slow start and stop is probably better
      > than a high acceleration one.
      >
      > Rigid tapping guys tend to have very high acceleration and
      > decelerations, less than a second, so they can do lots of holes
      > quickly, whereas for normal milling an acceleration of several seconds
      > wouldn’t really hurt the total job time since it only occurs once.
      >
      > I know firms with machines run at high speeds both machining and
      > tapping, knocking parts out every few seconds with several thread
      > holes and they replace spindle bearings every 6 months, I’m not sure
      > how much is due to the tapping, and how much the machining, but I do
      > know they complain about the costs.
      >
      > I also used to work around a big steel rolling mill with some big
      > rollers, the first roller went in one direction only, we hardly ever
      > changed its bearings, not in three years while I was involved with
      > them, but we did other rollers which reversed regularly. There was
      > massive torque here as they just swapped the DC motor supply, and
      > frequently sheered 6 inch diameter shafts, but all those that
      > reversed, and the motorised conveyor rollers which reversed had
      > regular bearing services, and harmonic monitoring to try to see when a
      > bearing was starting to fail, those that didn’t reverse seemed to
      > never be down for service. To me that says that reversing a bearing is
      > not good for it, but in that environment it could have been other factors.
      >
      > I suppose the big proof if you believe it comes from Tapmatics
      > website. They have some data that suggests it does really effect the
      > bearings, of course it’s in their interests to say so, but if true,
      > many of us here aren’t into that high profit area of machining where
      > we can afford spindle bearings every few months, or come to that wish
      > to strip the head to change the things. Even if I had several years
      > before a bearing job, I’d still swear a lot, my machine is still on
      > its original bearings fitted in 1989 and they are still good, that
      > might mean they are so tough they can take anything, or it might mean
      > a bit of rigid taping with hi accelerations would kill them. I’d
      > rather not find out, and because I have a tapmatic (copy) I’ll use
      > that instead until know for sure.
      >
      > Regs Mark
      >
      > Dr. Mark Vaughan Ph'D., B.Eng. M0VAU
      >
      > Managing Director
      >
      > Vaughan Industries Ltd., reg in UK no 2561068
      >
      > Water Care Technology Ltd, reg in UK no 4129351
      >
      > Addr Unit3, Sydney House, Blackwater, Truro, Cornwall, TR4 8HH UK.
      >
      > Phone/Fax 44 (0) 1872 561288
      >
      > RSGB DRM111 (Cornwall)
      >





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      ------------------------------------

      www.machsupport.com - Web site AccessYahoo! Groups Links






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    • agm@agm.win.net
      In my experience the most power was consumed by starting and stopping the heavy tooling. I prefer smaller tooling for small jobs. Bob ... From:
      Message 88 of 88 , Mar 1, 2010
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        In my experience the most power was consumed by starting and stopping the
        heavy tooling. I prefer smaller tooling for small jobs.

        Bob



        -----Original Message-----
        From: mach1mach2cnc@yahoogroups.com [mailto:mach1mach2cnc@yahoogroups.com]
        On Behalf Of Ron Thompson
        Sent: Wednesday, September 02, 2009 4:55 AM
        To: mach1mach2cnc@yahoogroups.com
        Subject: Re: [mach1mach2cnc] Re: Alternative To the SS





        Doesn't small holes mean they are running max rpm? That would seem to
        shorten bearing life.

        Dr Mark Vaughan wrote:
        >
        >
        > Hi Terry
        >
        > I then wonder why a local firm that makes little metal things with tapped
        > holes on various machines but including names like Deckel Maho and Hass
        > which are better built than cheap stuff renews spindle bearings around
        every
        > six months, and they sound rough by that time. I phoned the owner last
        night
        > for a chat.
        >
        > They do run the machines hard, little parts dropping out in not many
        > seconds, but the holes are only little, M3 to M6 so not really much load,
        > and it's only the machines tapping that suffer. The machines are on BT50
        > tooling which I suppose means a larger bearing, but so is a lathe, and
        > bearings on lathes also pushed hard last a couple of years which still
        isn't
        > good. They now use a live head in the machining centres to do the tapping
        to
        > save spindles. The cost also doesn't bother them.
        >
        > I wonder actually what the lube systems are like, I know many firms
        > suffering from leaking slide way oil are now packing their lube pumps with
        > grease, these cut a hole around the intake and then stop pumping, the ones
        > with a pressure switch flag up an error, the ones with a float switch just
        > continue to run without any lube.
        >
        > Without feedback here from people running a little rigid tapping it's
        > difficult to know,
        >
        > Regs Mark
        >
        > Dr. Mark Vaughan Ph'D., B.Eng. M0VAU
        >
        > Managing Director
        >
        > Vaughan Industries Ltd., reg in UK no 2561068
        >
        > Water Care Technology Ltd, reg in UK no 4129351
        >
        > Addr Unit3, Sydney House, Blackwater, Truro, Cornwall, TR4 8HH UK.
        >
        > Phone/Fax 44 (0) 1872 561288
        >
        > RSGB DRM111 (Cornwall)
        >
        > From: mach1mach2cnc@ <mailto:mach1mach2cnc%40yahoogroups.com>
        yahoogroups.com
        > <mailto:mach1mach2cnc%40yahoogroups.com>
        > [mailto:mach1mach2cnc@ <mailto:mach1mach2cnc%40yahoogroups.com>
        yahoogroups.com
        > <mailto:mach1mach2cnc%40yahoogroups.com>]
        > On Behalf Of vmax549
        > Sent: 01 September 2009 23:44
        > To: mach1mach2cnc@ <mailto:mach1mach2cnc%40yahoogroups.com>
        yahoogroups.com <mailto:mach1mach2cnc%40yahoogroups.com>
        > Subject: [mach1mach2cnc] Re: Alternative To the SS
        >
        > (;-) Rigid tapping hard on spindles. I don;'t think so I can show you
        > machines that have drilled and tapped a zillion holes and still on the
        > original bearings,
        >
        > The MACHINES are made with that in mind.
        >
        > Mach and SRT work very well IF you have dynamic braking for your spindle
        > drive.
        >
        > I can save you some programing THE G84 TAPPING cycle works VERY WELL.
        >
        > JUST DO NOT USE SPINDLE SYNC with the G95 it is busted and causes the G84
        to
        > do weirds things in mill. Just let mach do a standard G95(IPR) and make
        sure
        > your spindle speeds are correct to programmed sppeds.
        >
        > You will need to use a T/C tap holder, it is easy enough to make one that
        > takes up no more room than a normal tool holder.
        >
        > M3 S200
        > G95
        > G84 Z-.625 X0Y0 R.1 F.0625
        > x1
        > x2
        > x3
        > G80
        > G94
        >
        > With a little practice and keeping good notes it is easy to get a 1-2
        thread
        > tolerance on thread depth. Piece of cake on through holes. I have tapped
        > from 50 to 1000 rpm on through holes. AND YES it is a little scarey at
        1000
        > RPM setting up the overrun distance BUT it does work. I normally tap at
        > 100-200 rpm (low range high torque)but then I am not in a big hurry
        >
        > AND IF you had a stepper or servo spindle you can acutally do rigid
        tapping.
        > NOW you do have to flip flop the spindle and B axis ( SWAPAXIS())and
        program
        > the B to do the threading, AND manually coding it but it works.
        >
        > I have also seen a tapping head assy run from a stepper/servo that
        installed
        > in the spindle like a tool. ALSO rigid tapping.
        >
        > I also have 2 tapmatics ( and NO spindle room with a kneemill)
        >
        > (;-) TP
        >
        > [Non-text portions of this message have been removed]
        >
        >

        --

        Ron Thompson
        Riding my '07 XL883C Sportster
        On the Beautiful Florida Space Coast,
        right beside the Kennedy Space Center,
        USA

        http://www.plansand <http://www.plansandprojects.com> projects.com
        My hobby pages are here:
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        projects.com/My%20Machines/

        Visit the castinghobby FAQ:
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        faq.bareboogerhost.com/

        Add yourself to the member map here:
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        Want to have some fun? The next time you're at McDonald's, wait until
        the kid has your change ready and then say "Wait, I've got the two cents."
        -Ron Thompson





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