Re: Which Mini CNC mill #mill

casy_ch@tbwil.ch
 

Hi

I tried to make suction/vacuum plates with styrofoam and it works quite well. It is easy and quick to make, once the drawing has been made
it just needs a soft rubber cord. I even milled small cases in hard plywood for measurement instruments on it

Jean.-Claude

Am 12.02.2020 um 07:01 schrieb joeaverage:

Hi,
I use doublesided tape to hold the PCB blank down and two 1.5mm diameter pins through the board to ensure
top and bottom side registration.

I use Autoleveller (freeware) as the height mapping utility. Today I did an circular PCB 80mm in diameter and there
was 0.18mm variation in height across the blank.  Autloeveller has a 3D visualizer that allows you to 'see' the variation.
If the variation exceeds 0.3mm over a 80 x 100mm blank I start looking for a reason, its not often necessary.


I don't have time to flycut the bed of my machine each time I make a board, I have ben making several a day at work
for some weeks now, I'd be lost without Autoleveller.

Craig


From: pcbgcode@groups.io <pcbgcode@groups.io> on behalf of John Ferguson via Groups.Io <jferg977@...>
Sent: Wednesday, 12 February 2020 4:47 PM
To: pcbgcode@groups.io <pcbgcode@groups.io>
Subject: Re: [pcbgcode] Which Mini CNC mill #mill
 
I agree that height mapping would be a good thing, but I don't have it. 
I hadn't thought of indicating my fixture after I install it but before
I fly-cut level it.  I can't get to this for a week or two, because I'm
building another shop setup, but when that's done, I'll show you what i
have.

john

On 2/11/20 9:19 PM, CJD wrote:
>
> I keep seeing this post about getting your bed flat.
>
> I don’t even worry about it.
>
> I get great results using the height mapping routine in candle.
>
> You cannot trust within .05mm a flat bed.
>
> When I height map there is almost always .5mm difference across a 10mm
> X 20mm piece of PCB.
>
> It gets even worse when the pcb piece is bigger.
>
> I don’t know how anyone can do this without height mapping.
>
> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
>
> *From: *John Ferguson via Groups.Io <mailto:jferg977@...>
> *Sent: *Monday, February 10, 2020 8:01 PM
> *To: *pcbgcode@groups.io <mailto:pcbgcode@groups.io>
> *Subject: *Re: [pcbgcode] Which Mini CNC mill #mill
>
> how did you get your bed flat?
>
> On 2/10/20 6:03 PM, Dan.Staver wrote:
>
> > I get good results using very thin double-sided sticky carpet tape to
>
> > hold the PCBs down for milling.
>
> >
>
> > Dan Staver
>
> > Tave Tech Corp.
>
> > 3130 Hollycrest Dr.
>
> > Colorado Springs, CO 80920
>
> > +1-719-359-5352 - office
>
> > +1-719-502-1675 - cell
>
> > tavetech - Skype
>
> > dan.staver@...
>
> > www.tavetech.com
>
> > W3QDO
>
> >
>
> >> On Feb 10, 2020, at 11:06 AM, John Ferguson via Groups.Io
>
> >> <jferg977@...> wrote:
>
> >>
>
> >> Maybe there should be a subject change. Have a look at the two
>
> >> fixtures whose photos I've attached.
>
> >>
>
> >> I make printed circuits which are about 2 inch by 3 inch. I found
>
> >> that I couldn't get reliable trace widths unless the board was
>
> >> absolutely level to the machine. So I started with an MDF fixture
>
> >> bolted to the milling table and drilled and tapped in four places so
>
> >> I could use nylon screws to hold the pcb down. Every time I do a new
>
> >> setup, I mill the surface of the fixture with a fly-cutter to level
>
> >> it.  This works 100% of the time. I've had no bad experience with
>
> >> PCB's not being of constant thickness.
>
> >>
>
> >> I had such good luck with the MDF board that I made a better one for
>
> >> HDPE. I also made a jig to drill the holes in the pcb so they would
>
> >> be sure to align with the ones in the fixture.
>
> >>
>
> >> Frankly, I don't see how you could ever get reliable cuts without
>
> >> leveling the surface the pcb is secured to while etching.
>
> >>
>
> >>
>
> >> john
>
> >>
>
> >>
>
> >> Attachments:
>
> >> DSC07301.JPG: https://groups.io/g/pcbgcode/attachment/8053/0
>
> >> pcb-etching-fixture&pcb-drill-jig.JPG:
>
> >> https://groups.io/g/pcbgcode/attachment/8053/1
>
> >>
>
> >>
>
> >>
>
> >
>
>





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