Re: [CAD_CAM_EDM_DRO] Plexiglass / Clear Polystyrene / Clear Plastics & Prototyping

Very interesting Marcus. I will save this one.
Jim

----- Original Message -----
From: "Marcus and Eva" <implmex@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Sunday, June 08, 2003 8:56 PM
Subject: Re: [CAD_CAM_EDM_DRO] Plexiglass / Clear Polystyrene / Clear
Plastics & Prototyping


> Hi Abby:
> Were you implying that you're using all three of these materials??
> Your post is unclear...it seems to suggest that PVC, polystyrene and
> Plexiglas are all the same material; they're not, of course.
> May I recommend Acetal (Delrin) as an alternative for machined
> prototypes...it's a very strong polymer, that machines beautifully.
> It's only downside is that it cannot be easily glued.
> PVC is also a good material for prototypes, but it has the drawback that
it
> releases corrosive gases when it is heated. (even the heat of machining is
> enough to create "that smell")
> The odour is quite distinctive, and in reasonable concentrations, it will
> rust your equipment. (in high concentrations it will injure you!!!)
> It machines quite freely, however, and in contrast to Delrin, it glues
> readily.
> Styrene is the material that is used in the clear components of most
plastic
> airplane and car models.
> It is quite brittle, and does not have very good physical properties...I
> don't recommend it.
> Plexiglas is acrylic...it is also somewhat brittle, but is very commonly
> used for fabricated items that are clear.
> I personally prefer polycarbonate for those applications...it is clear as
> well, handles similarly to Plexiglas, but has far better impact
resistance.
> It can be glued and solvent welded as readily as Plexiglas, and machines a
> little better.
> Hope this helps.
> Cheers
>
> Marcus
>
> ----- Original Message -----
> From: "Abby Katt" <abbylynx@...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Sunday, June 08, 2003 10:00 AM
> Subject: [CAD_CAM_EDM_DRO] Plexiglass / Clear Polystyrene / Clear Plastics
&
> Prototyping
>
>
> > A while back I remember some discussion upon the subject of
> > prototyping materials.
> >
> > I remember relating my stories on the horrors of prototyping with
> > wood - the fine powdery dust getting into leadscrews and gears,
> > mopping up the oil and lubricatant and making a black mushy sticky
> > goo! Still, wood is a lot faster to cut than metal and you're less
> > likely to break small end-mills on it. But for all the inconveniance.
> >
> > I recently started using clear-PVC/(polystyrene sheet as it's called
> > in the UK or Plexiglass as it's called in the States). This stuff is
> > great! Sure, there are a few things you should know about it - like
> > clamping it between two pieces of wood so it doesn't vibrate and
> > crack when you're sawing it, but it mills just fantastic, to a great
> > finish and at a very high cutting rate. The only thing, of course, it
> > to keep spindle speed somewhat low, so as to not MELT it and thus
> > cause it to stick up your cutting tool. I've not found that problem
> > yet - and spray it with a little WD40 as it's getting cut. The swarf
> > is a flakey white heap like coconut and cleans up really easily with
> > a vavuum cleaner (it's a lot easier if you've used WD40, since it all
> > sticks together in a neat clump).
> >
> > Also, it's dead easy to super-glue sheets together if you need to
> > prototype on something slightly thicker than what sheeting is
> > available.
> >
> > And, as a bonus, you can boast to your friends that your prototype
> > was made on a StereoLithography machine. :P
> >
> > Just a 2p tip.
>
>
>
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