Did i miss something? Are there any links to photos of the results.
Thanks,
David
roger lucas wrote:
> Well, I finally motivated myself this holiday weekend
> to get my PCB EDM lash-up to cut copper, and, YES, it
> does cut clean lines thru the copper without board
> burning or marking. Shine a torch through the tracks
> from the rear of the board and there is a faithful
> line of light, (no firstborn goats or pentagrams
> neccessary).
>
> With my highest power lens and head magnifier I could
> see no trace of copper whiskers on the EDM'd track.
> Interestingly, the copper is blasted away entirely
> below the cross section of the wire, there is no
> 'erosion bleeding' into the surrounding copper outside
> of the wire dia.
>
> Have only cut straight lines so far with 26 swg and
> with a 0.2 mm step increment, (need to modify the
> stepper gear ratio), and with multiple (continuous)
> sparking between increments, (no on/off sparks or
> raster yet).
>
> One significant problem has emerged which Curt
> Richards did not address, (or if he did, he did not
> mention it). The wire electrode erosion is
> significant, and will require an active Z axis
> correction to maintain as consistent a spark gap
> distance as possible between the electrode and pcb
> surface. To do this I will insert a routine to 'touch
> down' the electrode on the copper to zero the gap,(no
> spark, closure sensed by two PIC output/inputs for
> voltage present), and then retreat the electrode to a
> standard clearance before any track eroding is
> commenced, (Andrew, this is why I need the BMP byte by
> byte transfer). This will also tend to compensate for
> any board distortion.
>
> Used tapwater as a dielectric with no problems, (the
> modified Garden of EDM circuit controls the
> electrolysis with no problems).
>
> Curt controlled his spark discharge voltage by
> dynamically adjusting the electrode gap on the fly. I
> think that for pcb work this is not the correct
> approach because of the wire erosion problem, since
> one needs to KNOW the gap distance AND available
> discharge energy BEFORE discharge, which is why I am
> going for the touch down zeroing method, (slower but
> speed is not significant at the moment). The discharge
> energy will be set by presetting the voltage level
> required and capacitor selection, (simple comparator
> control integrated into the spark control). I think
> this is the secret of successful pcb edm'ing.
>
> This is really looking as if direct raw copper board
> to finished pcb is going to be possible.
>
> Roger
>
>
>
>
> ___________________________________________________________
> Yahoo! Photos – NEW, now offering a quality print service from just 7p a photo http://uk.photos.yahoo.com
>
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
> ∗∗ ACCEPT: CRM114 PASS Markovian Matcher ∗∗
> CLASSIFY succeeds; success probability: 1.0000 pR: 69.2692
> Best match to file #0 (nonspam.css) prob: 1.0000 pR: 69.2692
> Total features in input file: 5621
> #0 (nonspam.css): features: 1574864, hits: 168951, prob: 1.00e+00, pR: 69.27
> #1 (spam.css): features: 700736, hits: 79657, prob: 5.38e-70, pR: -69.27
>
> -=-Extra Stuff-=-
>
> From sentto-4505361-14046-1146586123-yahoo=dcureton.com@... Wed May 03 02:09:25 2006
> Return-path: <sentto-4505361-14046-1146586123-yahoo=dcureton.com@...>
> Envelope-to: yahoo@...
> Delivery-date: Wed, 03 May 2006 02:09:25 +1000
> Received: from n16a.bullet.scd.yahoo.com ([66.94.237.45])
> by whitetail with smtp (Exim 4.50)
> id 1FaxRE-0001NB-O5
> for yahoo@...; Wed, 03 May 2006 02:09:25 +1000
> Comment: DomainKeys? See http://antispam.yahoo.com/domainkeys
> DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=lima; d=yahoogroups.com;
> b=Deo1r8Ca+ejr1GQGHFZDSS1S34fOlWbQd4wm9Xos6yJIVm6p8WvXAr2mUZ/RhXmB/a6A/tbLoiQ9VXVaM3t1vHq1Sk+YyfALAKxRt/ePyVI0NAzh37/VGKyftBT/PKTH;
> Received: from [66.218.69.5] by n16.bullet.scd.yahoo.com with NNFMP; 02 May 2006 16:08:52 -0000
> Received: from [66.218.66.36] by t5.bullet.scd.yahoo.com with NNFMP; 02 May 2006 16:08:52 -0000
> X-Yahoo-Newman-Property: groups-email
> X-Yahoo-Newman-Id: 4505361-m14046
> X-Sender: ralucas4277@...
> X-Apparently-To: Homebrew_PCBs@yahoogroups.com
> Received: (qmail 5150 invoked from network); 2 May 2006 16:08:23 -0000
> Received: from unknown (66.218.66.166)
> by m30.grp.scd.yahoo.com with QMQP; 2 May 2006 16:08:23 -0000
> Received: from unknown (HELO web25911.mail.ukl.yahoo.com) (217.146.176.249)
> by mta5.grp.scd.yahoo.com with SMTP; 2 May 2006 16:08:22 -0000
> Received: (qmail 56193 invoked by uid 60001); 2 May 2006 16:07:20 -0000
> Message-ID: <20060502160720.56191.qmail@...>
> Received: from [195.93.21.34] by web25911.mail.ukl.yahoo.com via HTTP; Tue, 02 May 2006 17:07:19 BST
> To: Homebrew_PCBs@yahoogroups.com
> In-Reply-To: <20060502150532.7175.qmail@...>
> X-Originating-IP: 217.146.176.249
> X-eGroups-Msg-Info: 1:0:0:0
> From: roger lucas <ralucas4277@...>
> X-Yahoo-Profile: ralucas4277
> Sender: Homebrew_PCBs@yahoogroups.com
> MIME-Version: 1.0
> Mailing-List: list Homebrew_PCBs@yahoogroups.com; contact Homebrew_PCBs-owner@yahoogroups.com
> Delivered-To: mailing list Homebrew_PCBs@yahoogroups.com
> List-Id: <Homebrew_PCBs.yahoogroups.com>
> Precedence: bulk
> List-Unsubscribe: <mailto:Homebrew_PCBs-unsubscribe@yahoogroups.com>
> Date: Tue, 2 May 2006 17:07:19 +0100 (BST)
> Subject: [Homebrew_PCBs] PCB EDM MILL Initial Tests
> Reply-To: Homebrew_PCBs@yahoogroups.com
> Content-Type: text/plain; charset=ISO-8859-1
> Content-Transfer-Encoding: 8bit
>
>
> Well, I finally motivated myself this holiday weekend
> to get my PCB EDM lash-up to cut copper, and, YES, it
> does cut clean lines thru the copper without board
> burning or marking. Shine a torch through the tracks
> from the rear of the board and there is a faithful
> line of light, (no firstborn goats or pentagrams
> neccessary).
>
> With my highest power lens and head magnifier I could
> see no trace of copper whiskers on the EDM'd track.
> Interestingly, the copper is blasted away entirely
> below the cross section of the wire, there is no
> 'erosion bleeding' into the surrounding copper outside
> of the wire dia.
>
> Have only cut straight lines so far with 26 swg and
> with a 0.2 mm step increment, (need to modify the
> stepper gear ratio), and with multiple (continuous)
> sparking between increments, (no on/off sparks or
> raster yet).
>
> One significant problem has emerged which Curt
> Richards did not address, (or if he did, he did not
> mention it). The wire electrode erosion is
> significant, and will require an active Z axis
> correction to maintain as consistent a spark gap
> distance as possible between the electrode and pcb
> surface. To do this I will insert a routine to 'touch
> down' the electrode on the copper to zero the gap,(no
> spark, closure sensed by two PIC output/inputs for
> voltage present), and then retreat the electrode to a
> standard clearance before any track eroding is
> commenced, (Andrew, this is why I need the BMP byte by
> byte transfer). This will also tend to compensate for
> any board distortion.
>
> Used tapwater as a dielectric with no problems, (the
> modified Garden of EDM circuit controls the
> electrolysis with no problems).
>
> Curt controlled his spark discharge voltage by
> dynamic
>
>
> -0-0-0-
>