Re: Seig X1 / X2 table extension for second High Speed Spindle

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "William Perun Sr"
<wperun1@...> wrote:

>> Unless, one were going to machine one half of a "part" with one
>> spindle and G-code, and then the other half with the other spindle
>> and different G-code. WILD.

Bill,
That's exactly what I am doing.

Part of the reason for going down this route was that it adds the
ability to use two different cutting tools on one workpiece. An auto
toolchanger is too expensive, too complicated and too time consuming
to implement for now.. I need to cut parts !

The Proxxon spindle is drilling the holes in shaped circuit boards and
the 3mm endmill in the original spindle (uprated to 9,500 rpm) is
cutting the boards out.
My machine is not the fastest on the planet, but it is currently
cutting 103 holes in 9 minutes and then cutting around the board in a
further 3 minutes. This means I have 12 minutes to run a couple of
vacuum formings or injection moudings off between boards.
Although I could probably fit two boards on at once, It all becomes a
bit of a fiddle and I am liable to forget something as I did this
evening.. the spring clip (a cut down clip that used to hold paper to
a drawing board) obscured one of the holes and the carbide bit bit the
dust when it made contact.

I have a nice piece of 1/2 inch aluminium sheet which I will use to
make the plate once I have run these boards through. I have a bag full
of 5mm hex screws so I guess the holes will be 5mm. I will follow
advice and alternate with plain holes for locating pins.

Aluminium is the right choice for my little X1 as I don't want to
increase the weight too much... inertia is a killer with tiny steppers.

If anyone else decides to drill many pcbs on a machine of this type I
have a couple of tips.

1. use a single locating pin near the middle of the board and align
the board by eye against a datum line on the table/jig.
2. set the locating pin as the x/y origin and the surface of the
board as the z origin.

Thes first allows for quick swapping of boards and spreads any
inaccuracy in the etching process evenly across the board

The second allows the machine to be quickly set up when refitting the
jig to the machine.

Chris

>
> Response to #88940
> Chris, as others have responded, the drilled and tapped plate idea
> has been around for a long time. So it is not my idea. But I will
> be doing the same thing. What you have done is clarified that
> nothing is lost when adding a spindle next to the stock spindle, if
> the X axis table is extended the like amount. It should have been
> obvious to me, since KDN Tool had mentioned it to me.
>
> But you have uncovered something important, that is the "table" can
> be made as large as you want, if you mount a second spindle to
> access that new work area. Of course mount deflections have to be
> taken into consideration given the the cutter forces in the vertical
> direction. Stiffness is also important because it is a spring mass
> system. But again given the tiny chip loads when engraving, the
> offset can be large. If one really wanted to get carried away, he
> could double the X axis work area, by mounting a third spindle in
> front on the stock spindle. Again all of the spindles must be
> cutting to the same G-code, and so are making identical parts.
>
> Unless, one were going to machine one half of a "part" with one
> spindle and G-code, and then the other half with the other spindle
> and different G-code. WILD.
>
> Bill Perun
>
> "Chris Horne" <chris@> wrote:
> > Bill, I can't remember who it was to give them credit (please
> speak up if it
> > was you !) but I read somwhere about adding an Aluminium or Steel
> > plate to the top of the table, CNC drilling a grid of holes and
> then tapping them for use fixing down work. I don;t remember if they
> > suggested running a flycutter over it?
> >
> > It seemed a good idea at the time as it should be possible to
> relocate
> > jigs, fixtures etc. much more accuately than using the 'T' slots.
> >
> > By 'extending' this idea and extending the plate to cover the extra
> > 'X' required... it would provide the proverbial two bird lunch !
> >
> > I will probably do this and add into the equation, some threaded,
> > shouldered dowels to fit the holes, as they will provide a more
> > accurate location than just bolts.
> >
> > The final addition to this addition would be a plastic tray fitted
> and
> > sealed between the existing table and the new plate. This would
> make
> > it easy to use coolant without it getting all over the ways as
> well as
> > catching most of the chips when machining dry.
> >
> > I don't think a small amount of coolant would add significantly to
> the
> > inertia of the table as it would tend to slop around.
> >
> > Chris
> >
>