Protel Notes from Hayes Raffle
I've spent the past couple days playing with scott's new software drivers and i've learned a few things. hopefully these tips will work for you, too.
Protel design:
make your traces as wide as possible. 0.030" traces work for me. Make sure your
clearances are all set at .030 too, and revise your board layout if neccessary.
protel output: make sure the origin is in the bottom left corner of the board.
in CAM Output settings, go to Advanced tab and select "relative origin" for
the output. After outputting your gerber files (f9) preview them with a gerber
viewer like the one reccommended on scott's site. it will save you a lot of
time if there are errors. make sure the origin is in the right place and everything
looks a-ok.
Using scott's software:
1. First, go to the modela and see what bits are available. i just threw out
about 20 broken bits that cut horribly (learned this the hard way). I'm using
the last .030 tapered bit, so when it breaks, we're s.o.l. "Tapered" means it
looks like a drill bit on the end, i.e. pointy. This is very important because
the flat end mills break.
2. Choose the bit you will use and verify the diam. with some dial calipers.
3. Go to scott's software and choose "advanced"
interface. Do everything he says about uploading files and such.
4. Choose your bit diameter, and 1 contour. This means it will outline your
traces only once. with an .030 bit, this is enough. (I find that calibrating
the depth the way scott did is very difficult. I plunge deep (about .030") which
cuts with the full bit diameter. This means that the mill width will be very
reliable even if the board is not completely flat.This is also the reason i
reccomended making your traces and clearances .030".)
5. Click OK and wait. And wait. And wait.
6. Do the other things scott recommends.
Circuit Board Fixturing:
1. I used double stick tape. There's a roll of nice thin, clear tape next to
the PC that drives the modela.
2. On the mill, you will hopefully find a chunk of black 1/2" aluminum plate
stuck to the mill bed. This raises your board to a height the mill can reach
with those little, short bits.
3. Take out the thumb screws and remove the bed. Stick a throw-away board to
the plate. During the hole-drilling process, this will allow the drilling bit
to go completely through your good board and provide a soft surface to continue
drilling through.
4. Stick your good board, copper side up, on top of the throw away board.
5. *Make sure your strips of double stick tape are very flat, and not overlapping
when you adhere the board. Push hard to make sure it's stuck really well. Push
on the board and see if it deflects in the middle, or if it's really stuck well
all over.
6. Put the bed back in the mill and secure it well with the thumb screws.
7. Finish following scott's directions on sending your file to the mill and
calibrating the bit depth.
Good luck.
-Hayes