Robot base construction techniques?

"Chris Alas"

I just went through the exact same process not so long ago.

First thing I did was to dimension my base drawing to scale all the
components I foresee placing on the board. I've used CorelDraw to do that
because it is very accurate and easy to work with (at least for me). Some
folks prefer Adobe Illustrator but I think CorelDraw is more technical.
See the example:
http://www.merlotti.com/EngHome/cpu%20component%20placement%20revB.jpg

Then after making adjustments, I drew the schematics of the platform,
including drilling information.
http://www.merlotti.com/EngHome/cpu%20base%20-%20platform%20schematics%20-%20revC.jpg

I'm a huge fan of documentation. It not only gives it a professional look,
but also help later if you have to re-design or replace a damaged component.

Just my 2 cents


Padu

On Tue, 13 Sep 2005 17:28:07 -0400, "Chris Alas"


I don't think you need to mark holes "by eye". Go to Home Depot and
buy yourself a small combination square and a fine gradation steel
scale. I think you'll find the layout goes pretty quickly with just
those simple tools.

BRW

Sometimes basic manual drafting skills come in very handy.

snip


Yes, but where do you get a T square, drafting table, iso drawing paper,
compass, erraser, geometric templates, drafting paper.... etc.

Just kidding.

Thanks for the input! I will try out both methods, see which one works for
me. thanks again!

-Chris

Someone who was written up in "Battlebots the Official Guide" was
quoted as saying that he used CAD. As in cardboard assisted design.

So I figured "Yeah. Right!"

But I saw it used once and have since come to rely on it when I'm in
a hurry.

You just cut, fold, glue, tape... bits of cardboard to make a mockup.

It's surprisingly effective.

DOC

I use AutoCAD to quickly put in dimensions and drill locations using full
size inputs and then print with a ratio of 1:1 which gives me a paper I glue
onto whatever I'm to machine, drill or mill. It only takes minutes and is
accurate to within a few thousandths of an inch.

Wayne

I transfer the measurements, starting from a known datum (a straight
edge or centre-point) and then draw 6 zillion construction lines.
Being good at geometry helps, as does having a good collection of
squares, calipers and marking instruments.  A square, ruler, compass
and pen will do though.

The technique I used at school in the dim and distant past to make
PCBs might be easier though - tape a printout of the plan onto the
sheet, then use a centre-punch (a compass point may work fine for your
PVC) to mark through the plan onto the sheet. Remove the sheet, join
the dots and get going with the power tools.


Tim
--
You are being watched. This gives you power.

That's a very good method indeed. You can put a light tack on the back
of the paper, and it won't gum up the PVC. The stuff for "make your own
Post-its" works pretty well. However, if you get some residue on the PVC
it can be cleaned with denatured alcohol. Avoid varnishes, acetone, or
other solvents. PVC melts in most organic solvents.

-- Gordon

I use spray-on adhesives

Might be okay. Some spray-on adhesives use a solvent as part of the
binder. Expanded PVC is smooth and relatively soft, and solvents will
leave pockmarks.

What specific brand do you use?

-- Gordon

3M Super 77

I thought Super 77 was for permanent bonds. I think a lower tack is
useful for temporarily sticking a paper template to the plastic. I was
thinking more like "Restickable Adhesive Glue Stick," which is the same
low-tack adhesive they use for Post-Its.

-- Gordon


Wayne Lundberg wrote:

77 is permanent, and a real pain to remove.
Acetone softens it, but put a rag to it
then, and it will just smear all over the place.

I don't think I'd want post it glue, it is a bit
too sticky.

Glue Stick is a good idea.  Washes off with
water.  AKA paste from preschool....

Rich

Definitely want to keep acetone away from PVC, unless you want to melt
it or glue pieces together. Toluene is a pricinple solvent for PVC.

Post-it Glue is water soluble, so cleanup is easy. I think most folks
don't use it right. You put it on the paper, then let it "dry." *Then*
you stick it on the surface. If it's been appled to the paper correctly,
it will not leave a residue. (If it does, a stern letter to 3M is in
order. They promise that it won't!)

-- Gordon

I never noticed these problems. I use the 77 mostly on the paper to stick on
the detail and after drilling, milling, machining and sawing it's mostly
ragged mess that comes off by wiping mostly.

Wayne