Re: Mechanics

-----Original Message-----
From: Arne Chr. Jorgensen <instel@...>
To: CAD_CAM_EDM_DRO@onelist.com <CAD_CAM_EDM_DRO@onelist.com>
Date: Thursday, July 22, 1999 9:45 PM
Subject: [CAD_CAM_EDM_DRO] Mechanics

>From: "Arne Chr. Jorgensen" <instel@...>
>

Hi Arne
Re the Gears
Yes your guess was right, they do run smoother, as the load is passed from
tooth to tooth with the angled teeth, the next tooth picks up the load
before the last one totaly releases it, so you have two teeth in contact at
one time, but you will still have backlash, maybe not as much as with
straight teeth but it will still be there.

Best Wishes

Peter Smith

>Hi,
>
>I have been "tinkering" with my amp attempt, and it's not going any
>way. I am starting over with another design, - so it will definitly
>take a while before I get anything running. - I hate it :-(
>
>Well, this was not what I wanted to let every one in on - I would
>prefer to hide away all my mistakes, but when I am going to make a
>fool out of my self, - then this was a nice beginning.
>
>Here is what:
>
>I took apart some geared servo motors, - just to check out the
>encoders. Well, this is embarrasing in a way, - I have seen it so
>many times, but I have never thought about it. That is the gears, -
>the cog wheels to be exact. They are not machined at a straight
>angle, but at 70 degrees I guess.
>Look like this:
>
>/////////////// - instead of a normal one like
>||||||||||||||| - this one.
>
>It is a dumb question, - but I don't have any good explaination for
>this. I guess it will run smoother,
>have less backlash. But how do they really work ?
>Let's say you could make the teerh to a +/- 2% fit, - straight or
>slant. Is there any formula that would tell me how much less of a
>backlash I would actual get, by slanting it 20 degree ? 30 degree ?
>
>Can anyone at shed some light on this ?
>
>I have seen it for years, buth I have not really thought of it. I
>have seen it on pinion racks too, - there must be a very good reason
>for this, 'cause I would believe they would be much more expencive
>to fabricate .
>
>----------
>
>By the way, - I have spent some time, browsing the site what I best
>could describe as the Norwegian answer to MIT. I was looking for
>something I found some years ago, but I was not able to find it. I
>think this research facility took out some patents on model making.
>I have film clips of it.
>They had something similar to a flat bed plotter, but instead of the
>table, they had a bath fill with polymer plastic ( something like
>the dentist are using ) They used a blue laser, and focused it on
>the liquid surface. They plastic hardened. After doing one layer of
>a 3D modell, they would just lower a platform inside the bath, -
>with - let say 1mm. Then they would bild up a new layer on top of
>that, until the model was finished. It was real neat. All the used
>was a retrofitted, flat bed plotter, and a step motor to lower the
>platform. The process was fast too. The only thing I remember, was
>that the plastic polymers they used, were pretty expensive. I think
>they sold the patent, and I don't really know if this had something
>to do with the plastic material, or what.
>
>Just to brag a little: They do a lot of high tech stuff here. The
>cellular phone system has a lot of it' s root here. Erricson - the
>Swedish company, bought up almost all telephone manufacturs in
>Norway.
>They have the european rocket launchers and test site here. The
>paperclip, the spaycan, the jet turbine is norwegian inventions. (
>The turbine is a less known subject, as Sir Whritle got the credits
>for it, - but he said it himself, that he had just use some the
>material from the norwegian scientist, and the proof of it is in the
>tecnical museum here. ) Another crazy story. Some friend of mine
>work in a research lab in Washington on deep dive scuba gears for
>the north sea. I worked on a hyperbaric chamber down in Florida
>Keys, and to my real big surprice - the Miller hat - dive helmet,
>that every one though of as "real" american, was actually fabricated
>here for Miller. I have come across so many strange things, because
>these things are not common knowledge here. I guess this adds to the
>phrase: You never becom a prophet in your own land.
>
>Well, I am actual proud to be american - it's just a shame that I
>don't master the language better, - so don't get me wrong, - I don't
>really like to "brag" about Norway. It's just that I am always
>amazed about all the turns and bends that technology have done.
>
>I am tired, - so then I often just keep on. I am very sorry if I
>bored anyone of you with this tale.
>
>//ARNE
>
>By the way, - DAN - I don't think you understood my questions about
>the servoes the other day.
>I asked if it at tacho feedback, - that is not the same thing as
>optical encoders. I refered to a
>closed velocity loop inside the servo amps itself. You should make a
>principle drawing of the setup, just in block format. The way it is
>presented right know - well I would never have bought it - without
>further details. What if I needed 4 axis, or just one. The system
>deserves a better presentation.
>As a small example:
> |---------- |
>command voltage > ------- | AMP | -----[ ( M ) ]
>
>| |
> over current < ------- | |
>
>| |
> disable > -------| |
> | --------- |
>
>+ Power input/ motor output specs.
>+ Adjustment for current, loop gain, zero adjust, etc.
>+ All pinouts / signals
>
>It can be done pretty simple, even like this - plain ascii. But as
>long as you have to do some assembly yourself, then you need to know
>something more than you have put up on your web.
>
>I am not sure, but if it really got what I am "reading between the
>lines" - then this one could have been the answer to a lot of the
>things I really needed. Now I have to rework all lot of my programs
>to run emc, because I had made a stepper system, - but couldn't get
>enough "juce" out of steppers.
>
>//ARNE
>
>
>
>
>
>
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