Re: Help?? CNC PCB Drilling Machine

Hi Sammy,

can you offer some details of your final machine ?

how accurate do you need to be for your first machine ? routing a
board with thru holes and single traces between pads can be done with
little expense.

makeing a machine that is just drilling holes is easier, but making a
machine that can put 3 or 4 traces between pads of an IC will need to
be very accurate and will cost more.

The big costs are in the linear components such as rails and guides
(the things that slide on the rails) and leadscrews and anti-backlash
nuts.


Assuming a prototype as a fast build and learning machine, I would
considder wood for the frame and 'drill rod' for the rails. This is
a ground tool steel.

Also for a prototype, a all-thread will offer you some hands on
experiance but will not be good for a long term or high quality
machine.

Considder a main table that allows the table to move back and forth
as the main base.

then an overhead gantry that contains the drilling head. the drilling
head would move side to side and of course the drill would move up
and down.

Most of us use heavy steppers, but your unit could easily postion
the table(s) with a NEMA23 motor. this is 2.3 inches square and
about 3 inches long. These are very common motors and have more than
enough power to move the table.

Since you mentioned that you need to make the stepper drivers, I am
assuming you will use full step on the motors so a 10 thread per inch
screw (sorry for the American units) with a 200 step per revolution
motor will offer 2,000 steps per inch. this should be enough accuracy
and a finer thread will offer more theoretical accuracy, but once you
get into a half stepping driver for smooth operation, you double the
steps. having more thread will slow the posistioning down.

Check the photos section and the links sections to get an idea what
others have done.

A note here is that a high quality HEPA vacuum would be benneficial
both for our lungs and the moving metal parts.

Dave








--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Sammy" <sammytaggart@h...>
wrote:

> Hello all,
>
> Firstly, my apologises for my "newbieness". Im very sorry if i

annoy

> anyone cause what im doing sound a whole lot easier than what u

folks

> are all talking about.
>
> so, Im a final year technology and design (With education..teacher
> to be) student in Belfast, northern ireland and as part of my final
> year assignment i have chosen to design and manufacture a CNC PCB
> Milling machine.
>
> As most schools in northern ireland, i am forced to use PCB Wizard

as

> the mask creating software, but it produces an nc .drl file hich i
> can easily convert to g-code using a converter i found on the net.

I

> have then chosen to use Master 5 to control the system via parallel
> port. this i think is the most of the software/gcode problems

sort.

> the next and most ambitous problem is making the actual machine.
>
> Stepper motor control of and xy table with a gantry type z axis i
> feel would probably work best for me. My question is,
>
> what do i need to make such a board
>
> Is anyone aware of the stepper motor drivers required to operate a
> stepper frm the parallel port?
>
> What sort of stepper
>
> How do i make the xy table....
>
> im pretty new to all this so sorry again.
>
> Also i cant really buy "kits" or a complete xy table..i cant just
> assemble the thing..i must design and make the whole thing so thats
> going to be time consuming.
>
> I'd really appreciate help on this one. I'm only 22 with no
> qualifications/experience on this topic
>
> Any education from anyone about ANY of this stuff would be much
> appreciated
>
> THANK YOU
>
> Sammy Taggart
>
> Northern ireland