Cooling recommendations for getting polycarbonate machined ??

I have just finished the design for my new poly waterblock and am in the process of looking for somewhere to do the machining for it.
The 2 top layers are made from 10mm poly.
The base is cast from silver.

Any recommendations as to where I can get it done (UK).
Budget is a bit if a constraint at the mo as I am moving house, so I wouldnt want to pay too much.

Will post renders shortly

Flymo

 

Look in Yellow Pages for "plastic stockholders".

They will stock the usual engineering plastics, and many
have in-house CNC capability - particularly for the chemical,
pharmaceutical & food industries who use it extensively.

They may suggest other materials to polycarbonate,
however make sure they know the application is water.
Reason being some plastics (eg, Nylon) take up water
and are dimensionally altered by such takeup.
--
Dorothy Bradbury
www.stores.ebay.co.uk/panaflofan (Ebay)
http://homepage.ntlworld.com/dorothy.bradbury/panaflo.htm (Direct Prices)

 

PICS::
1. complete acrylic parts



2. bottom acrylic part from above



3. same again with poly transparency turned off so you can see the details better



4. bottom acrylic part from below



5. same again with transparency of the block turned off so u can see the base better



6. top part




Flymo

 

Interesting, albeit complex design.

o Yes acrylic is better than polycarbonate
o However, even so, let them tap any holes - espec hose-fittings
---- Acetal/Nylon can be easily tapped
---- Acrylic on the other hand is less forgiving

One asset of Acrylic is the plate uniformity, and maintenance
of that with exposure to water. However, I see a lot of what
seem to be peg/screw-holes in the drawing.
o Pricing is usually based on time/complexity
o Economising on the design may aid assembly & cost

Check the online plastic stock-holders, some cater to the
plastic prototyping industry & prototyping in foams etc. They
have lower setup costs & overheads for unitary orders.

You may also want to check out Canada - they are often
very cheap on prototype-quantity CNC work. USA too, but
that doesn't offer the same exchange rate benefit as CDN$.

Just a thought
--
Dorothy Bradbury
www.stores.ebay.co.uk/panaflofan (Ebay)
http://homepage.ntlworld.com/dorothy.bradbury/panaflo.htm (Direct Prices)

 

I can modify the cad drawing to remove all the screw holes (except for the mounting holes which I would prefer to be accurately done with cnc). I could then do all these holes myself, thus reducing the cnc costs. Location of these isnt as critical as the machhining of the other parts as they are just for attaching the parts together. A vise, clamps and drill press would be sufficient for these parts.

I think shipping costs from canada to UK would probably offset any savings I made by getting the parts made there, esp if there turned out to be problems and it needed to be redone.

Flymo

 

That's one of your problems:
o Do everything to avoid iterative design
o Reworking is not going to be cheap -anywhere-

Getting the design right first time is important, and hard

For mechanical objects, foam CNC can be used which has a
far faster machining speed. For "production" testing in your
application I don't think this is going to be possible.

Worth enquiring around though, quotes will vary a lot
A lot of plastic stockholders in the UK do it as a value added
service, and competition is tight so it comes down to whether
they load the setup fee (bad for 1-off) or time/complexity fee.

Good luck.