RE: [CAD_CAM_EDM_DRO] Positioning

Hanero is welcome to prove me wrong by posting those photos. How many years
is it now?



Or hell, even that Excel / Rhino macro he claimed he could knock up in 5
minutes a couple of months back.



Yeah sure.



FWIW I didn't just Google how accurate capacitive scales are like most
people, I clamped a set onto a machine and ran them back and forth for a
while. Y'know, actually did something in the real world rather than imagine
it.



Somewhere I've got written down how fast you need to move before they skip,
I can't remember but it's faster than you think. (None of my stuff has
scales or needs them, all steppers and I try not to overload them.)



Yeah, those scales will measure to a thou in most cases, a bit less over
longer distances. And what's wrong with that?



Seriously, how many of us machine to a micron over 600mm? (Fantasy land
inhabitants need not answer.)



Tony







From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com]
Sent: Wednesday, 4 June 2014 5:39 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: RE: [CAD_CAM_EDM_DRO] Positioning





Hiya Tony:



While you may be correct in your assessment (I surely don't know), I will
have to ask you to keep the conversation polite.



Please make your point without name-calling.



Thanks,



Andy Wander

Moderator

_____

From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com]
Sent: Tuesday, June 03, 2014 3:12 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: RE: [CAD_CAM_EDM_DRO] Positioning





Hanero is a bullshit artist - the perfect example of "talk is cheap".

When asked for photos or details of the machines or items he claims he
makes....

Tony

(One day we'll take up a collection to buy him a camera. No doubt his dog
will eat that one too)
(Hey Ballendo, is that you?)

> Being right or not, being a jerk and getting personal takes away from your
> credibility.
>
>
> Focus on the issues, not the person.
>
>
> I'll now return to lurking mode.
>
>
>
>
> Christopher Erickson
> Consulting Engineer
> Summit Kinetics
> Waikoloa, HI 96738
> www.summitkinetics.com
>
>
>
>
>
>
> -----Original Message-----
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com]
> Sent: Monday, June 02, 2014 11:02 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: RE: [CAD_CAM_EDM_DRO] Positioning
>
>
> Capacitive type scales are cheap because of the way they are manufactured,
> that doesn't not affect their accuracy.
>
>
>
>
>
> It's the same reason why bolts are cheaper than nuts - you can forge and
> roll the thread on a bolt, while you need to cut the thread on a nut. The
> operations to make a bolt are cheaper than making the nut for it.
>
>
>
>
>
> Most capacitive scales have a resolution of 0.0005" of an inch, and can be
> made to measure less than that. Yes, even under a micron (and mostly

better

> electronics, btw).
>
>
>
>
>
> If you have a source for their inaccuracy (apart from your rather fertile
> imagination) let's see it. 0.04mm? Hah.
>
>
>
>
>
> Capacitive scales have two drawbacks - they're affected by oil & crud and
> have slow-ish data rates (50 readings per second?). Doesn't stop people
> using them though. The 'jitter' people find with those scales is power
> supply problems, usually caused when powered from a DRO rather than
> battery.
> Or RF, but that happens to everything.
>
>
>
>
>
> If you bothered to calculate the thermal coefficient of your 600mm screw,
> you'd find for every degree (Celcius) change in temperature it will expand
> by that micron you claim to machine all of your parts to (including those
> "high-precision" spanners you were going to make - your funniest post

ever).

>
>
>
>
>
> Unless you have a temperature controlled room (to a degree!) AND are
> keeping
> every part of your machine at that temperature, your parts are not the

size

> you imagine they are. And don't forget your scales are change shape at a
> different rate. Oh, and of course your screws are liquid cooled as well.
>
>
>
>
>
> Sure, add scales. In theory they should tell you where everything thing is
> (you believe the brochure?), in practice close enough. I realise that's
> unsuitable for the fantasy-land you do your machining in, but anyway.
>
>
>
>
>
> Machines with backlash shake themselves apart? Lol.
>
>
>
>
>
> You really should do some machining one day, you might learn something.
>
>
>
>
>
> Tony
>
>
>
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>
>
>
>
>
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com]
> Sent: Tuesday, 3 June 2014 6:10 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [CAD_CAM_EDM_DRO] Positioning
>
>
>
>
>
> The specs on the screw accuracy are irrelevant.
> What IS relevant is that there be no slop, as a machine with

dual-feedback,

> ie glass scales, will shake itself to pieces is it has backlash.
>
>
> Thats why you cannot use the crap chinese scales, because they are off, ie
> inaccurate, by upto 0.00" or 0.04 mm, in short distance, and the error
> varies.
> So using such, would make the machine jitter (sometimes, in some places).
>
>
> This causing back-and forth motion, upto hundreds of times a second,
> depending on how fast the secondary positoning error-correction mechanism
> is.
>
>
> It is impossible to make a (working) secondary-feedback mechanism if you
> have backlash in the system.
>
>
> Tony..
> Unlike some people here, I try to be factual and polite.
> Grin.
>
>
> Re: screw accuracy.
> Everything is inaccurate. Its just a question of how much.
> One good part about glass scales, is that they are usually accurate (to 1
> micron, or down to 0.01 micron with some Mori Seiki machines).
>
>
>
>
>
>
>
>
>
>
>
> Sure, when you read the specs on the average screw, and that "Dummies

Guide

> To Fantasy Machining" you've got.
>
>
> Do you know what a drunken thread is?
>
>
> Do you know what a temperature coefficient is? (Go work out the expansion

on

> a 600mm steel screw for a 1 degree delta.)
>
>
> Tony
>
>
> (You and your microns, lol)
>
>
>
>
>
>
>
>
>
>
> --
> -hanermo (cnc designs)
>
>
>
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>
>
> [Non-text portions of this message have been removed]
>
>
>
>
>
>
> ------------------------------------
> Posted by: "Tony Smith" <ajsmith1968@...>
> ------------------------------------
>
>
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if

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> ------------------------------------
> Posted by: "Christopher Erickson" <christopher.k.erickson@...>
> ------------------------------------
>
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>
> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:
> aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it

if

> you have trouble.
> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a

sister

> site to the CCED group, as many of the same members are there, for OT
> subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING
> THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> bill
> List Mom
> List Owner
>
> Yahoo Groups Links
>
>
>

[Non-text portions of this message have been removed]