RE: [CAD_CAM_EDM_DRO] Re: tooling table ideas

The older commercial machines use thick MDFback board with waste board on
top, something like hardboard, or 3mm mdf.

The idea is the thick board gives a level surface which shouldn't get cut,
and thinner is sacrificial

You have to watch the dust from MDF, but then again PCB dust ain't good for
you.



Newer machines have a base board that is like PCB material but not copper
clad and the drill bits just enter this, the same back board is kept for
that production run.

Then there are taught structures, these use metal frames, the PCB board is
supplied with edge piercings, or are punched for them, these fit the frame
and it is all held taught.

Some even fit a conveyer with multiple drilling heads, the number of holes
grow as the board passes along a bed many meters long until PCB drop down on
the a rubber conveyer as they are routed off the frame.

These machines are amazing to see in operation.



For DIY, mdf, or hardboard are nice cheap options.



Regs Mark



_____

From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of lcdpublishing
Sent: 27 October 2006 13:52
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Re: tooling table ideas



Hi Bill,

I am about in the same situation, I think. I am not sure of what you
question is though.

I think you are referring to what to use for a backer board to hold the
PCBs while milling and drilling, if that is the case, that is where I
am at as well.

As you know, when drilling, the drill bits will pass through the PCB
into a backer board of some sort. That is generally a waste material
of some sort - perferably something cheap and it is often called a
spoil board.

On my machine, I am pretty limited in height so I am currently planning
on using tempered hardboard (AKA Masonite). It's cheap, relatively
uniform in thickness and easy to cut into various sizes.

For holding the PCB while machining, right now double sided tape
appears to be the easiest and quickest method. However, that is not
without problems. If you drill or mill into that tape, it will gum up
the tool and cause the chips to stick to it. For drills, this should
not present too much trouble, however, for milling it could cause
problems.

I have yet to get to that point but have been giving thought to it and
have yet to come up with a universal "Clamp" that I like. Several
ideas, but nothing I have put on paper yet.

Chris

--- In CAD_CAM_EDM_ <mailto:CAD_CAM_EDM_DRO%40yahoogroups.com>
DRO@yahoogroups.com, "wdavis364" <wdavis364@...>
wrote:

>
> I,m Posting this on several groups.
> Building a cnc machine.
> I'm at the point where I need to come up with ideas for the tooling
> table. My base plate is 14"x8"x1/4 aluminum. What kind of material
> should I be looking at to use for routing and drilling circuit boards?
> Maybe some of you could tell me what works best for you.
> thanks
> bill
>

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