Re: CNC and Welding Polyethelyne

Hans,

Is it really that different? Cut versus weld is simply changing heat,
concentration area, and speed.

I have a machine which "welds" poly sheet together for shipping bags.
It's nothing more than a hot wire with a fiberglas/silicone mesh over
it to keep the wire from dragging on the plastic sheet.

In both cases (RC model wing cutting, and poly sheet welding), you
need to control the heat of the wire, and the rate of the feed. I
would think that you might even be able to modify a soldering "gun"
to do duty as your welding head... Or a hot melt glue gun, with the
silicone gauze over the tip. These are available in craft stores for
a coupla bucks...

One thing you didn't say was whether you needed only straight lines
or arcs and curves? If straight, you can step and repeat, using a
short "wire" based welding head. For curves, the laser and the hot
air both seem like good ideas.

Does anyone know what the cost of a laser diode as suggested might
be? And where it might be purchased?

At 6-10 mil, you're still dealing with a very flexible sheet. Thicker
poly is welded with a hot air gun and welding "rods" of poly
material. Though some of these guns are several hundred dollars, HF
sells a version very inexpensively. It may be worth looking into, as
you would then have the capability for thicker material. Might also
pay to play with the cheap hot glue guns, and see if they can be
modified to work with these rods as well...

I know you only asked about 6-10 mils, but iothers inthe group may
get ideas for things from your question, and answers to it...

Hope this helps,

Ballendo


--- In CAD_CAM_EDM_DRO@yahoogroups.com, Hans Wedemeyer <xyz@h...>
wrote:

> Thanks for info.
> Airplane wing cutting is relatively simple using a hot wire

to "cut" foam. I need to Weld. which is a different issue.

>
> The CNC part is not a problem, I will write my own program for it.
>
> I need idea's on welding head design.
> So far suggestions are :
> Hot Air Gun and Laser.
>
> Best regards
> Hans W