Topics

pcb-gcode usage


axtein <a_eckstein@...>
 

Hi all,
Well as there seem to be no messages yet, might as well kick it off.
I have recently downloaded JJs excellent add on and look forward to
using it for a "winter project" that I have.
One crevat that all should be aware of:
READ THE MANUAL
The first few times I attempted run the ulp, I tried to do it from the
menu and of course it didn't work. You have to do as stated and run it
in the command line.

The only other problem I have is with cncsimulator as it doesn't like
the G82 code and will not properly simulate the location of the holes
when I tried to simulate the test board.

Now having said that, I will be using my mill/drill to do the milling
and drilling. I have adapted a 5/8" pencil die grinder to fit in the
R8 spindle and feed it with air through a 1/8" pipe "drawbar". So far,
testing shows it should work just fine (just got the adapter made
today).

My next question concerns holding the PCB stock. What is everyone
using to hold their boards down and properly located???

Later,
Country Bubba


John Johnson <johnatl@...>
 

On 06-Dec-2005, at 14:58, axtein wrote:

Hi all,
Well as there seem to be no messages yet, might as well kick it off.
Thanks CB!

My next question concerns holding the PCB stock. What is everyone
using to hold their boards down and properly located???
If you look in the group photos, in JJ's Album, you can see what I use. A small board with a pocket milled in it about the thickness of the PCB. Small screws at the corners hold it steady, and I usually use a few squares of fiberglass carpet tape in the middle.

If space and design permits, sometimes I put a small screw towards the center of the board, rather than the tape.

The tape works really well. The screws, if over tightened, can cause slight humps in the board. Since I use a 90 degree cutter, each 0.001" the board goes up means the tracks get 0.002" narrower, so flatness is very important. When using a very small (0.010", 0.015") end mill, height control is just as critical, since 0.005" can be the difference between cutting the board and breaking the end mill. Using 0.020" or larger are more forgiving.

If I ever get my machine back together, I am going to look into some sort of floating cutter setup.
I like the sound of your die grinder setup. Keep us posted.

Regards,
JJ

---
Help everyone. If you can't do that, then at least be nice.


Art Eckstein <a_eckstein@...>
 

JJ,
Thanks for your info. I had noticed that and am "thinking" (yeh, I know that is strain for the ole boy) of making a vacuum box. Am hoping somebody can jump in here and give some pros/cons or if it is even worthwhile considering. Based on some reading I have done, a shop vac might jut do for the motive power.

By the way, I noticed on one of your sites, a mention of a "fat pad" library and have been hunting for weeks to try and find it to see if I want to incorporate that into my project(s). Sounds like it will be easier on the eyes to try and solder; but can't locate the source. By any chance could you tell me where to find it???

Early tests on the die grinder look promising. Had a meeting this evening so haven't done to much yet other than prove that it will fit and move air through it. Will take a couple of pictures of the finished product and put them up in the files section if interested.

CB


l0bulls <andy@...>
 

My next question concerns holding the PCB stock. What is everyone
using to hold their boards down and properly located???
If you look in the group photos, in JJ's Album, you can see what I use.
A small board with a pocket milled in it about the thickness of the
PCB. Small screws at the corners hold it steady, and I usually use a
few squares of fiberglass carpet tape in the middle.
Hullo,

A while back I came across this link with some great PCB hold down ideas.

http://www.cag.lcs.mit.edu/~cananian/Projects/FabClass/tools/Modela/

In a dull moment I intend to try these sort of things using old CDs or
maybe 'reject' PCBs...I've got a bit of a collection of those from
good ole etching days.

I used to use carpet tape a lot but it's a bit of a pain. My current
setup uses clamps similar to yours JJ (though not as good).
A vacuum table is on the drawing boards...

Another thought I had was a sort of 'picture frame', that would hold
the board around the 4 edges, but leave the top and bottom faces exposed.
The frame could have registration pins so you do one side, then just
flip the board+clamp over and do side 2.
I'm not sure if the sag in the middle would cause a problem.
...maybe use a foam backed MDF or HDF insert for the bottom side to
help with sag...and for drilling....hmmm....
I think I'm going to need to draw something.

Hey! if the foam insert was quite spongy and the registration pins (or
some other alignment system) prevented lateral movement, this may even
work as a sort of 'floating table' instead of a floating spindle.

Phew....I'd better get another coffee on....

Have fun!

Andy


John Johnson <johnatl@...>
 

On 06-Dec-2005, at 20:32, John Johnson wrote:
A small board with a pocket milled in it about the thickness of the
PCB. Small screws at the corners hold it steady, and I usually use a
few squares of fiberglass carpet tape in the middle.
I forgot to mention: Since the boards I use are the same size as the pocket, I can mill the top layer, flip the board in the X direction, move my machine to the right side of the pocket (I forget the dimension), zero the axes, and start milling the bottom layer.



If space and design permits, sometimes I put a small screw towards the
center of the board, rather than the tape.

The tape works really well. The screws, if over tightened, can cause
slight humps in the board. Since I use a 90 degree cutter, each 0.001"
the board goes up means the tracks get 0.002" narrower, so flatness is
very important. When using a very small (0.010", 0.015") end mill,
height control is just as critical, since 0.005" can be the difference
between cutting the board and breaking the end mill. Using 0.020" or
larger are more forgiving.

If I ever get my machine back together, I am going to look into some
sort of floating cutter setup.
I like the sound of your die grinder setup. Keep us posted.

Regards,
JJ

---
Help everyone. If you can't do that, then at least be nice.





Yahoo! Groups Links






---
Help everyone. If you can't do that, then at least be nice.


Art Eckstein <a_eckstein@...>
 

That sure give some food for thought. I like the idea of a variable sized work platform. I just may knock something like that up and see how it works.

A while back I came across this link with some great PCB hold down ideas.

http://www.cag.lcs.mit.edu/~cananian/Projects/FabClass/tools/Modela/

In a dull moment I intend to try these sort of things using old CDs or
maybe 'reject' PCBs...I've got a bit of a collection of those from
good ole etching days.

I used to use carpet tape a lot but it's a bit of a pain. My current
setup uses clamps similar to yours JJ (though not as good).
A vacuum table is on the drawing boards...

Another thought I had was a sort of 'picture frame', that would hold
the board around the 4 edges, but leave the top and bottom faces exposed.
The frame could have registration pins so you do one side, then just
flip the board+clamp over and do side 2.
I'm not sure if the sag in the middle would cause a problem.
...maybe use a foam backed MDF or HDF insert for the bottom side to
help with sag...and for drilling....hmmm....
I think I'm going to need to draw something.

Hey! if the foam insert was quite spongy and the registration pins (or
some other alignment system) prevented lateral movement, this may even
work as a sort of 'floating table' instead of a floating spindle.

Phew....I'd better get another coffee on....

Have fun!

Andy