🚀 go-pugleaf

"Gwen <The Anti-Cool>" <gnoel@home.com> wrote:
: Greetings!
: For a project at school, I need to find out such info on robotic arms as
: how much they cost, who sells them, what they are used for, ect.  Any
: help on where I could procure this info, ect, would be helpful.   Could
: you please reply via email, since I don't have much time to check lots
: of ngs?  TIA

  How about doing some research?  Dumping the job on us isn't doing 
research.  Web search engine, http://www.dejanews.com etc. allows you to
do that research.

  And no, I won't send email because this is a news group, and as such the
information is better distributed by a post.

How cheeky indeed!
DLC
-- 
============================================================================
* Dennis Clark  Aristocrat at heart  dlc@verinet.com  www.verinet.com/~dlc *
* Be well, do good work, and stay in touch -- Garrison Keillor             *
============================================================================

Dennis Clark wrote:

> "Gwen <The Anti-Cool>" <gnoel@home.com> wrote:
> : Greetings!
> : For a project at school, I need to find out such info on robotic arms as
> : how much they cost, who sells them, what they are used for, ect.  Any
> : help on where I could procure this info, ect, would be helpful.   Could
> : you please reply via email, since I don't have much time to check lots
> : of ngs?  TIA
>
>   How about doing some research?  Dumping the job on us isn't doing
> research.  Web search engine, http://www.dejanews.com etc. allows you to
> do that research.
>
>   And no, I won't send email because this is a news group, and as such the
> information is better distributed by a post.
>
> How cheeky indeed!

Well, here's a request from someone who is not a student.  I'm a software
engineer with 23 years experience who also tinkers with metal at home.  I have a
full machine shop with lathe, mill, bandsaws, forging, casting, sheet metal and
welding (MIG, TIG and stick) equipment.  It's where I go when I want to make
something tangible :-).

I'd like to build a cutting torch robot arm that will allow me to cut steel
plate using an oxy-propane machine torch head (this is a vertical head, can't be
hand-held).  While I'm neither an EE or ME, I believe I have the skills to build
this.  I am aware of steppers and how to use them.  I have a simple straight
line torch system, but I want to cut curves and fairly complex designs.  Of
course this can be done beautifully by hand with many, many years of experience
and very steady hand.  You can also cut over sized and then grind (and grind and
grind) down to the line, but this takes time and is not much fun.  There are
several designs for mechanical pattern followers and I have used one many
times.  A big problem is that the design shape must be reduced by some amount
and certain shapes are hard for the machine to follow.

I'd like to draw the shape on paper, slap it on the scanner and then position
the design on the steel, perhaps by using a laser pointer attached to the arm to
indicate certain points on the steel.  The design could be flipped or rotated to
make the best use of the stock and then cut.  The software is not a problem.
I'll be using RTLinux and a modified version of EMC to do the cutting.

Here is the problem:  I can easily build a gantry style system which is the way
most commercial systems work.  The problem is space used by it's working
envelope would be wasted or get in the way when not in use.  An arm design could
be raised to a vertical position and occupy about a square foot when not
needed.  I'm considering an Stanford arm design which is a square arm tube that
slides on bearings inside another tube that pivots and tilts.  On the end of the
arm tube is the wrist, which is not needed in version 1 of this design.  Using a
Stanford arm, I only need 2 DOF, the z axis (how close the torch is from the
plate should be a constant and can be adjusted manually.  Tilting the device
into it's vertical storage position can be done manually as well.  I'm thinking
about 3.5 feet by 90 degrees of working range on the arm

The design parameters are:

- The cutting speed must be kept fairly constant and adjusted manually, through
the software, between and range of say 4 inches per minute (ipm) and about 40
ipm.  Speeds of over 100 ipm might be needed if I buy a plasma cutter for thin
sheet metal, but for now that can be ignored.

- The accuracy of the device can be fairly crude compared to, say, a CNC mill
which should be a minimum of .001 inch and is usually much smaller.  In this
case, +/- .010 inch should be fine.  The problem is that the working envelope is
pie shaped which could mean that close to the pivot the steps might be too close
together and slow the cutting speed down while away from the pivot point the
reverse could happen.

- The movement must not allow any significant vibration to be transmitted to the
torch head.  A quality cut should look like it was cut with a saw, well, a
bandsaw at least.

- This process generates a lot of heat: the temperature at the tip is over 3500F
but a few inches away and to the side it's much lower, maybe 200F, but could get
hotter if it is used for long periods.  There is a lot of metal spatter and
smoke which should not interfere with the mechanism or electronics.  I'm
planning on the arm being about a foot above the surface and the head being
several inches out, but some kind of movable shield would still be needed.

After over a year of looking around the net, I've been unable to find any
detailed information about serious amateur (but approaching industrial quality)
robot arms.  I've found a few university sites but information tends to be
sparse.

Can anyone help?

Steve

go to divent.com
Gwen <The Anti-Cool> <gnoel@home.com> wrote in message
news:38A20F33.2DC0F170@home.com...
> Greetings!
> For a project at school, I need to find out such info on robotic arms as
> how much they cost, who sells them, what they are used for, ect.  Any
> help on where I could procure this info, ect, would be helpful.   Could
> you please reply via email, since I don't have much time to check lots
> of ngs?  TIA
> -- ___________________________________________________
> Gwen
> Rebel with half a dozen causes.
> My geeky Mac website ->  http://russet.8m.com/index.html?sig
>

Hi! this is Lycos, from portugal!
if ya wanna see some cool stuff, go at www.govsync.telnetinc.pt
You'll find that page to be more than rewarding!
bye
Gwen escreveu na mensagem <38A20F33.2DC0F170@home.com>...
>Greetings!
>For a project at school, I need to find out such info on robotic arms as
>how much they cost, who sells them, what they are used for, ect.  Any
>help on where I could procure this info, ect, would be helpful.   Could
>you please reply via email, since I don't have much time to check lots
>of ngs?  TIA
>-- ___________________________________________________
>Gwen
>Rebel with half a dozen causes.
>My geeky Mac website ->  http://russet.8m.com/index.html?sig
>