How do you machine polycarbonate and then make it clear?

[Dragonhunter]

Hi,

How can I machine polycarbonate and then make it totally transparent??

Thanks,
DH

[MM]

DG,

Vapor polishing.

Regards

Mark

Post by Dragonhunter
Hi,
How can I machine polycarbonate and then make it totally transparent??
Thanks,
DH

[Mitch]

Post by Dragonhunter
Hi,
How can I machine polycarbonate and then make it totally transparent??
Thanks,
DH

Very difficult. Polycarbonate is a PITA to try to polish. Too soft. I
have heard of people doing vapor polishing, hanging the parts over a bath of
warmed-up methylene chloride until the surface melts slightly and glosses
over, but I would not want to try that with any kind of mechanically
stressed parts, I don't know how this treatment affects the material's
properties.

Try to get as good a finish on the material as machined, use coolant and
sharp tools. At that point, you may be able to get a better surface by fine
sanding with micromesh and water, then polishing lightly with a wheel.
--
Cheers,

--Mitch


Millennium Workshop - ID models, prototypes and more...
www.millwork.ch

[Dragonhunter]

How about acrylic? Is that easier to get transparent?

Post by Mitch

Post by Dragonhunter
Hi,
How can I machine polycarbonate and then make it totally transparent??
Thanks,
DH

Very difficult. Polycarbonate is a PITA to try to polish. Too soft. I
have heard of people doing vapor polishing, hanging the parts over a bath of
warmed-up methylene chloride until the surface melts slightly and glosses
over, but I would not want to try that with any kind of mechanically
stressed parts, I don't know how this treatment affects the material's
properties.
Try to get as good a finish on the material as machined, use coolant and
sharp tools. At that point, you may be able to get a better surface by fine
sanding with micromesh and water, then polishing lightly with a wheel.
--
Cheers,
--Mitch
Millennium Workshop - ID models, prototypes and more...
www.millwork.ch

[Bill]

Post by Dragonhunter
How about acrylic? Is that easier to get transparent?

How will the finished parts be used? For display type pieces we would
polish as best as possible. Next, apply a coat of mineral oil then
wipe off with a soft cloth. The very slight oil content left fills the
micro scratches.

One other option which works for ABS (maybe for acrylic as well?) is
to immerse the part in a tub of acetone for a couple seconds, then let
drip dry. Maybe try a sample piece to see how it reacts.

--
Bill

[Dragonhunter]

How about acrylic? Is that easier to get transparent?

Post by Mitch

Post by Dragonhunter
Hi,
How can I machine polycarbonate and then make it totally transparent??
Thanks,
DH

Very difficult. Polycarbonate is a PITA to try to polish. Too soft. I
have heard of people doing vapor polishing, hanging the parts over a bath of
warmed-up methylene chloride until the surface melts slightly and glosses
over, but I would not want to try that with any kind of mechanically
stressed parts, I don't know how this treatment affects the material's
properties.
Try to get as good a finish on the material as machined, use coolant and
sharp tools. At that point, you may be able to get a better surface by fine
sanding with micromesh and water, then polishing lightly with a wheel.
--
Cheers,
--Mitch
Millennium Workshop - ID models, prototypes and more...
www.millwork.ch

[Cliff Huprich]

a bath of warmed-up methylene chloride

"... Methylene chloride is a known carcinogen and has been banned ..."

http://www.google.com/search?hl=en&ie=ISO-8859-1&q=%22methylene+chloride
%22+banned

[clay]

Clarification,

Methylene chloride has been banned in certain consumer applications (primarily as an aerosol propellant) but not in other industrial applications (paint stripping etc..) and has not been determined to be carcinogenic, but may be. (Some organizations have declared it so) I did not find specific references to vapor polishing. Recommended use is (of course) with adequate ventilation.

I have found machining (tapping) polycarbonate using a water based coolant (Hangsterfers 506) will cause stress fractures over time.

clay

Post by Cliff Huprich

a bath of warmed-up methylene chloride

"... Methylene chloride is a known carcinogen and has been banned ..."
http://www.google.com/search?hl=en&ie=ISO-8859-1&q=%22methylene+chloride
%22+banned

[Cliff Huprich]

Post by clay
I have found machining (tapping) polycarbonate using a water based coolant
(Hangsterfers 506) will cause stress fractures over time.

Oils & greases as well as strong bases seem to be problems. Even residual
oils on fasteners can cause stress fractures in the material it seems.

Tapping might also leave micro-fractures in the threads as failure initiation

points I'd guess.

[CDignition]

You can use a rosebud torch and quickly glaze the surface. This works
well, but it is for visual parts only, I dont know how it would affect
stressed parts (if you are using a plastic part fr a high load part,
your engineering is in question anyhow),lol..;) We made lids for
Vacuum chambers (microchip manufacturing) and they have bone crushing
Vacuum, and had no problems..;)

Hope this helps

Post by Mitch

Post by Dragonhunter
Hi,
How can I machine polycarbonate and then make it totally transparent??
Thanks,
DH

Very difficult. Polycarbonate is a PITA to try to polish. Too soft. I
have heard of people doing vapor polishing, hanging the parts over a bath of
warmed-up methylene chloride until the surface melts slightly and glosses
over, but I would not want to try that with any kind of mechanically
stressed parts, I don't know how this treatment affects the material's
properties.
Try to get as good a finish on the material as machined, use coolant and
sharp tools. At that point, you may be able to get a better surface by fine
sanding with micromesh and water, then polishing lightly with a wheel.

[Aluckyguess]

It is a 3 step process. You use sand paper I dont remember the grits, but
start out rough and work your way down.I had do to this on one job and it
worked out well.

ka

Post by Dragonhunter
Hi,
How can I machine polycarbonate and then make it totally transparent??
Thanks,
DH