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Lambis777
06-23-2011, 03:17 PM
Hello

Which material gives best result with clean surface when is milling with cnc?

i have try polyethylene but i am not so happy.
the pvc is very better with clean suface.

Any other suggestions?

As i say the PVC is good but i can`t find 12mm thick that i want.
I want to use it to make my new 777 thrust levers.

Lambis
Greece

Hessel Oosten
06-23-2011, 03:36 PM
Hi Lambis,

I.m.o. Acrylic (Plexi) has the best surface.
You can "glue" some plates with a dedicated glue or chloroforme (vulcanizes) to your desired thickness.
Saw also several good results with "Trespa" (R), Google for it. Very nice hard, very good "millable".

Hessel

Westozy
06-23-2011, 09:01 PM
I agree with Hessel,
I use black or white acrylic for machining TQ levers, and normal superglue is great for sticking it together. I use 10mm clear superglued to 6mm clear to form B737 landing gear handle wheels, the super glue welds the clear acrylics together and the optical clarity is maintained. Acrylic sheeting is reasonably cheap too, wear a dust mask because acrylic swarf looks harmless but it can make your nose bleed if you get too much dust!

Cheers Gwyn

Lambis777
06-24-2011, 12:58 AM
First time i hear about the Trespa material , i will give it a try.
About the acrylic that you say Gwyn is the normal plexi or different ?. You know a good internet store that i can get?

Lambis

riche543
06-24-2011, 10:57 PM
Hi lambis

Could also be called cast acrylic
Cheers

Westozy
06-25-2011, 03:54 AM
I think plexiglass is the same as cast acrylic, I have a plastics supplier close to home called 'Plastral', I've never bought it from the net!

Cheers Gwyn

Hessel Oosten
06-25-2011, 05:10 AM
There are 2 types of acrylic=accryl=plexi=plexie:

Extruded is preesed under high presssure to it's shape.
Casted is hmmm..., simply casted (if you want to see this process e.g. http://www.topacryl.ch/).

Differences: Extruded is much cheaper, more vulnerable to heat during milling (water/air needed; single flute (!) mill needed), you can get it at every building market, you can get in in every vilage > 2000 inhabitants....:-). Casted the inverse of before and sold only in special plastic companies, is tensionfree, less risk of crackles in the edge (but can be avoided by reducing heat).

So if you can cool buy extruded !

Here you can see my simple cooling with compressor air.
http://www.elektor.nl/StreamFile.lynkx?path=Uploads/Forum/Posts/P1140873.JPG
Much people prefer nevertheless water (with some liquid dishwash detergent to reduce the surface tension and keep the water were it belongs...).

Hessel

Lambis777
06-25-2011, 11:54 AM
Thanks for the great infos.

I want to use PVC because is flexible and is not broken easy as plexi.
And the part that holds the handle of the thrust lever is only 3mm thick. i think the plexi is not for that job.
The polyethylene is ok but is not give good result when is milling.

Lambis

mondo50m
06-26-2011, 12:07 PM
Just my 2 cents worth, but I have been using polycarbonate (lexan) quite a bit lately. It seems to cut easier and is not as hard as plexiglass. Gluing is a bit more problematic. I have just finished cutting out all of the panels for a 737 pedestal and it was much smoother going than using plexi. I have also used PVC quite extensively. It cuts and mills nicely, but melts easier than lexan. I use them both and prefer either one to plexi.

Milt

spitfire9
06-26-2011, 09:21 PM
I like to use Lexan as well . You can cut it with a table saw or scroll saw and it won't break. Also, drilling is no problem.