Re: Re: Milling materials

Jon writes:

>Your comment on LOW speeds is interesting, I will have to try this
>some time. I generally try to keep the speeds up, but that requires
>the feed be kept up, too.
>Jon

The low speed is right on for acrylics such as plexiglas.
Also reduce the rake angle of the cutter if possible so it scrapes
more than cuts.

Another tip is to use dish soap(you're soaking in it now) as a
lubricant. This will do more to preserve the clarity than any other
lubricant, according to several long-time plastics guys. Works for me
too. Also good when drilling. According to Rohm and HAAS,plexi has a
significant WATER content!

As a side note, be careful what you use with polycarbonates (like
lexan and tuffek). Although they are tough as nails, they break down
and craze when exposed to hydrocarbons. The amateur aircraft guys on
the list know this already from canopies. Its good to "flame-treat"
(described earlier in thread)holes and edges of polycarb or stress
fractures are likely.

Re: the original material mentioned at the start of the thread:

Lumilite rings a bell, but I thought it was a sign material with
aluminum faces and a plastic(lite weight)core.(lumi with an i)

A similar word is used in the sign industry for a colored goo used to
"fake" neon signs. Luminite, see: http://www.luminartcorp.com/
It is applied with cnc, might be interesting to play with.

Also, I think I have heard "lumelite" used at trade shows to describe
plain acrylic which has been engraved and edge-lit so the incised
portions appear "lit".

Lastly, there is an injection molding company called Lumelite which
services the sign and trophy industry. IMO, This is probably what the
medallions were: An injection molded part to be engraved by a trophy
shop.

Hope this helps.

Ballendo