Re: Opinions on $250 cnc machine

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "agerooo12000"
<agerooo12000@y...> wrote:

>
>
>
> > It's the standard table moves x-y design but
> > It's made of 1.5" industrial polyurethane.
> >
> > Every bit as solid as aluminum but the design is
> > reproducable.
> >
> > In three years of playing with cnc designs I hardly
> > ever see this material used but it has serious
> > advantages to it. There's a section on polyurethanes
> > in McMaster-Carr that tells about the material.
> >
> > My design is also modular meaning one could simply
> > change the length of the drill rod I use to make the cutting
> > area larger, though I do think up to approx. 20" is about
> > the max for this particular design.
> >
> > Thanks Again -John
> >
>
> What makes your plastic machine different from other plastic machines?
>
> What diameter drill rod do you use?
>
> Do you support it just on the ends or in the middle also?
>
> What sort of fit do the linear ways have and do you see problems with
> temperature changes?
>
> How large of an endmill/cut can this machine handle?
>
> Drill rod is unhardeed tool steel and is prone to flexing, do you see
> flex in your system? Chatter?
>
> How long has your machine been running and what does it cut? Do you
> have a video of it in motion?
>
> I'm interested, but I have many doubts about the use of plastic for a
> metal cutting machine
>
> Bill
>

Thank you all!

Great questions!
This design used 1/2" drill rod and 1/4-20 threaded rod.
Oilite bushings. Supported on ends. That's why it's a small
machine. Prototype uses a dremel tool to cut wood & plastics
I'm making tooling right now to use 3/4 rod with 3/8 threaded
rod. I fully expect to run a laminate trimmer on one soon.

The nuts are polyethylene or brass. Been using one all day long
for several months.

It's mostly intended for PCB's, engraving, & fine detailed
stuff. Not for machining steel.

I do understand about the "plastic" doubts, but this stuff
is different from "plastic"(though it IS plastic).

You can fix it if you drill a hole in the wrong place.

It's VERY solid for small things.

I'm not a salesman but I am convinced an affordable,DEPENDABLE,
machine can be made.

How do I send a picture?

Thank You -John