Re: How to use a hot wire (Kanthal) to cut a plastic bin containing a liquid

From: Lasse (lars.soderstrom_at_tfif.fi)
Date: 07/29/04 

Date: 29 Jul 2004 10:01:23 -0700

jerry Wass <wassbiplane@tds.net> wrote in message news:<4106B377.3170BD9@tds.net>...
> "Charles A. Sherwood" wrote:
>
> I think the current will be close to the same, whether the bin is filled or
> empty--
> The voltage will be less, because the wire in the liquid will be cooled and
> it's
> resistance lower---the rest of the wire,however that in the air outside,
> and within
> the molten plastic will still get hot... However,The temperature gradient
> from air to plastic, to liquid, may be such that you can't melt the plastic
> before the wire in the air burns out.

This sounds like a possible scenario. If true then this will be a
showstopper for this method.

Any other suggestions how to saw a plastic bin into 2-4 pieces with as
few moving parts as possible (to decrease the spill of the liquid that
pours from the bin to the mechanism&surroundings)?

A grid of wire saws maybe? Possibly the same way of setting up as a
hot wire (connected to a spring at the one end and the other end
connected to a oscillating force (e.g. rotating disc connected to a
rod):

|-\\\\\-o-----w-i-r-e---s-a-w-----o-<=osc motor=>

I can see one disadvantage, the liquid may become contaminated by
small plastic particles that need to be filtered out later. An
advantage is that the temperature of the liquid is not that important
for the process, it just makes cutting a bit slower.

/Lars

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