Homebrew_PCBs

> i like the idea of making me own laserplotter.
>
> tested: a pointerlaser (some cheap thing) with an extra focus lense, a
> red sensible film gave me super fine lines (close to a single cloth
> fiber).
>
> did any of us fouling around with this idea !!
>
> tips and suggestions always welcome:)
>
> gr Roel (holland)
>
>

>
> roel_cnc wrote:
> > i like the idea of making me own laserplotter.
> >
> > tested: a pointerlaser (some cheap thing) with an extra focus

> > red sensible film gave me super fine lines (close to a single

> > fiber).
> >
> > did any of us fouling around with this idea !!
> >
> > tips and suggestions always welcome:)
> >
> > gr Roel (holland)
> >
> >
>
> Are you talking a rotating drum laser photoplotter ?
>
> Any idea of suitable low cost (<$5 A3 sheet) red light

>
> There is also the problem of developing red light sensitive films!
>
> Alternative is green, blue or even UV laser diodes. Choice depends

> photofilm and laser diode availability. Maybe the best approach is

> look at traditional black&white photographic films, and then decide

> suitable laser diode wavelength. Use common B&W films that are

> with a standard red safe lights.
>
> At say 20um wide pixel, that gives 15000 drum revolutions to scan a
> length of 300mm. If drum spins at 1000 RPM, thats 15 minutes to
> complete, which is acceptable.
> Regarding film mounting, it is ideal to have the film placed on the
> inside of a drum cylinder. The drawback with this approach is

> single sided bearing mount system for the drum. I guess thats all

> degree of mechanical balancing.
>
> Would be interesting hearing ideas too.
>
> Adam
>

>
> hi Adam,
>
> Drum type would be nice but controlling and software tooks a great
> deal of time to create i think !
> must be somthing like a tv set creating a image on the screen with
> sync goto next line :) lol
>
>
> gr. Roel

----- Original Message -----
From: "Adam Seychell" <a_seychell@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, January 23, 2006 2:40 AM
Subject: Re: [Homebrew_PCBs] Re: homebrew laser plotter


> roel_cnc wrote:
>
>>
>> hi Adam,
>>
>> Drum type would be nice but controlling and software tooks a great
>> deal of time to create i think !
>> must be somthing like a tv set creating a image on the screen with
>> sync goto next line :) lol
>>
>>
>> gr. Roel
>
>
> I'd be interested what you have discovered about photofilms for a home
> made plotter. Let us know anything that converts your cheap laser into
> raster scanning 20um beam projection. I think more brain power would be
> required to devise software to compensate fringing of the projected beam
> as would to the accurate and well predicted spiral mapping in a drum
> plotter. If one were to build a < 50um resolution photoplotter then the
> only feasible method is with a rotating drum. I'd be interested any
> anyone's thoughts.

Mega Electronics sells film for use with their laser plotter (it uses a
drum).

Leon
--
Leon Heller, G1HSM
leon.heller@...
http://www.geocities.com/leon_heller

> roel_cnc wrote:
>
>>
>> hi Adam,
>>
>> Drum type would be nice but controlling and software tooks a great
>> deal of time to create i think !
>> must be somthing like a tv set creating a image on the screen with
>> sync goto next line :) lol
>>
>>
>> gr. Roel
>
>
> I'd be interested what you have discovered about photofilms for a home
> made plotter. Let us know anything that converts your cheap laser into
> raster scanning 20um beam projection. I think more brain power would be
> required to devise software to compensate fringing of the projected beam
> as would to the accurate and well predicted spiral mapping in a drum
> plotter. If one were to build a < 50um resolution photoplotter then the
> only feasible method is with a rotating drum. I'd be interested any
> anyone's thoughts.

>> roel_cnc wrote:
>> i like the idea of making me own laserplotter.

> Adam Seychell wrote
> Are you talking a rotating drum laser photoplotter ?

> Any idea of suitable low cost (<$5 A3 sheet) red
> light photosensitive film ?

> At say 20um wide pixel, that gives 15000 drum
> revolutions to scan a length of 300mm. If drum
> spins at 1000 RPM, thats 15 minutes to complete,
> which is acceptable.

> Would be interesting hearing ideas too.

> Lez wrote:
> Yes, pics please!

> I am intersted in how your going to get the bmp out
> to a laser diode etc.

>
> Like the blue circuit board pic, whats it done with?
>

On 28/04/06, cunningfellow <andrewm1973@...> wrote:
> --- In Homebrew_PCBs@yahoogroups.com, Lez <lez.briddon@...> wrote:
> >
> > Like the blue circuit board pic, whats it done with?
> >
>
> Alt-PrintScreen and a bit of elbow grease.
>
>
>
>
>
>
> 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
>
>
>
>
>
>
>


--



Lez

- Looking for early starwars (episode 4, original starwars)
recordings, even pirate
-
- I dont need your originals just some information about running time
- and scene cut points
-
-
- also looking for a car, silver or white, 4 doors -
- diesel with a bosch pump, abs and pas -
- aircon would be nice, and not a ford -

> > > Lez Wrote:
> > > Like the blue circuit board pic, whats it done with?
> > >
> > Andrew wrote:
> > Alt-PrintScreen and a bit of elbow grease.
> >
> Lez wrote:
> Thats where I'm going wrong, I'm using time and diptrace.

>--- cunningfellow <andrewm1973@...> wrote:
>
>Have speced/thought out an interface to dump a BMP
>file from a PC out to a laser (synced to the PLL
>above)
>
>Whats everyone elses idea ?
>
>Also do people want to see what I have done so far ?

> >andrewm1973@ wrote:
> >Have speced/thought out an interface to dump a BMP
> >file from a PC out to a laser

> Roger Lucas wrote:
> I am just starting to try to figure out BMP to raster
> for the PCB EDM MILL for which I have just finished
> the drive electronics <SNIP>

> Would be interested in your approach <SNIP>

> Are you dumping the BMP file to
> a separate micro or driving an interface direcly from
> the PC? <SNIP>

> To all who are interested in the progress of the PCB
> EDM MILL, I have produced a very simple clone of the
> Garden of Edm circuit, modified with some hints from
> Curt Richards (Curt are you still out there?).

> Just got to figure out BMP to Raster scan
> interpolation. If anybody else has any ideas please
> say.

> Regarding film mounting, it is ideal to have the film placed on the
> inside of a drum cylinder.

> The drawback with this approach is building
> single sided bearing mount system for the drum. I guess thats all up to
> degree of mechanical balancing.

> > Roger Lucas wrote:
> > I am just starting to try to figure out BMP to raster
> > for the PCB EDM MILL for which I have just finished
> > the drive electronics <SNIP>
> >
> > Are you dumping the BMP file to
> > a separate micro or driving an interface direcly from
> > the PC? <SNIP>


> Andrewm with the goat blood on his hands wrote:
> <Snip marraige proposals>
> I am dumping the BMP file to a seperate Micro.

> <Snip>
> The idea is to have the ATMEL sit on a seriel port,
> then you run some terminal software on the PC and
> xmodem transfer the file to it.

> <Snip>
> I was going to use TIFF file format with G3 fax
> compression instead of BMP. On most PCB files you will
> get about a 10:1 compression ratio with G3.

> <snip>
> Worst case senario and I can't get an atmel to decode
> G3 fax - I will hang my head in shame, do my own
> RLE compression in software on the PC side and admit
> to the world in general that pop-up-toasters do in
> fact need 1 gighertz embeded Power-PCs.

> I will over the next few weeks cut-paste/write
> atmel code to:
>
> - Act as a terminal
> - Accept an X-Modem-CRC/128 file transfer
> - Decode the TIFF header info and report if the
> file is suitable
> - Decompress the RLE/Huffman data into a stream
> of black and white pixels
>
> If your EDM hardware uses an ATMEL you are more
> than welcome to the code. Even if you use another
> micro you might like to look at the flow/logic/
> pseudo/comments to see if you want to convert the
> thing to run on your micro.

> Me wrote:
>
> I have finished reading the TIFF specifications
> carefully and also looked at some TIFF/G3 files in
> a hex editor. It is very doable from a seriel
> stream as long as the saving application does not
> put the segments of the picture out of order.
>
> Most of the apps I have looked at so far have saved
> the TIFF in a suitable format.

> Andrewm with the goat blood on his hands wrote:
> <Snip marraige proposals>
> I am dumping the BMP file to a seperate Micro.

> <Snip>
> The idea is to have the ATMEL sit on a seriel port,
> then you run some terminal software on the PC and
> xmodem transfer the file to it.

> <Snip>
> I was going to use TIFF file format with G3 fax
> compression instead of BMP. On most PCB files you

> get about a 10:1 compression ratio with G3.

> <snip>
> Worst case senario and I can't get an atmel to

> G3 fax - I will hang my head in shame, do my own
> RLE compression in software on the PC side and admit
> to the world in general that pop-up-toasters do in
> fact need 1 gighertz embeded Power-PCs.

> The good news is I wrote a quick and dirty TIFF
> file decoding application in C on the PC this
> afternoon.

> Me wrote:
>
> I have finished reading the TIFF specifications
> carefully and also looked at some TIFF/G3 files in
> a hex editor. It is very doable from a seriel
> stream as long as the saving application does not
> put the segments of the picture out of order.
>
> Most of the apps I have looked at so far have saved
> the TIFF in a suitable format.

>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
>
>

>
>
> 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

>

> 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

> Good to hear you got such good results.
>
> I don't have any specific concerns why it would not
> work, never had after
> some manual tests with a simple power supply.
>
> But i don't currently have the time to build a CNC,
> although i have most
> components set aside for a while now.
>
> The electrode erosion thing was discussed back then,
> if i remember
> correctly the thinking was that one would advance
> the electrode until a
> spark of the correct voltage is occuring. One would
> need to decide if the
> energy was sufficient to blast out the pixel or if
> it must be re-done.
> But your approach seems a good idea also.
>
> Keep us updated, i definitely plan to build the CNC
> but it will be months
> for sure. If i use it for drilling of inkjet printed
> PCBs or if EDM will
> be an option is to be seen.
>
> what material is your electrode wire made of?
>
> ST
>
>
> On Tue, 02 May 2006 18:07:19 +0200, roger lucas
> <ralucas4277@...>
> wrote:
>
> > Well, I finally motivated myself this holiday
> weekend

> I know that it should have worked in theory, but I was
> surprised at how well it actually turned out.

> Hi Stefan,
>
>
> I know that it should have worked in theory, but I was
>
> surprised at how well it actually turned out.
>
>
> I tried with tinned copper wire and a tinned steel
>
> sewing needle (purloined from my wife's needlework
>
> box), essentially the wear was about the same for
>
> both. The eroded pixel diameter is directly related to
>
> the electrode dia, as the sewing needle eroded the
>
> pixel became larger.
>
> I need to try to obtain some half hard or hard 10 mil
>
> brass wire for the next trial.
>
>
> The setting of the spark parameters before sparking is
>
> essentially to eliminate the uncertainty of whether
>
> pixels have been fully eroded or not, especially where
>
> electrode wear is high. I might just try some broken
>
> carbide drill bits, the tungsten might resist erosion
>
> better, trouble is carbide only goes to 0.5mm dia.
>
>
> Will post some sample photos after next revision and
>
> trials.
>
>
> Roger

On Tue, 02 May 2006 18:50:19 +0200, Alan King <alan@...> wrote:

> Don't you want to try changing every other variable first, to see if
>
> you can eliminate the erosion problem first, then adjust everything else
>
> to match? With the same distance everything else could be just as well
>
> known with 1/4 the spark energy and 4x the rate for the same total,
>
> seems you could simply be too close for the instantanious spark energy
>
> you are using or something similar..

> Roger
>
> --- Stefan Trethan <stefan_trethan@...> wrote:
>
> > Good to hear you got such good results.
> >
> > I don't have any specific concerns why it would not
> > work, never had after
> > some manual tests with a simple power supply.
> >
> > But i don't currently have the time to build a CNC,
> > although i have most
> > components set aside for a while now.
> >
> > The electrode erosion thing was discussed back then,
> > if i remember
> > correctly the thinking was that one would advance
> > the electrode until a
> > spark of the correct voltage is occuring. One would
> > need to decide if the
> > energy was sufficient to blast out the pixel or if
> > it must be re-done.
> > But your approach seems a good idea also.
> >
> > Keep us updated, i definitely plan to build the CNC
> > but it will be months
> > for sure. If i use it for drilling of inkjet printed
> > PCBs or if EDM will
> > be an option is to be seen.
> >
> > what material is your electrode wire made of?
> >
> > ST
> >
> >
> > On Tue, 02 May 2006 18:07:19 +0200, roger lucas
> > <ralucas4277@...>
> > wrote:
> >
> > > Well, I finally motivated myself this holiday
> > weekend
>
>
>
>
>
>
> ___________________________________________________________
> Win tickets to the 2006 FIFA World Cup Germany with Yahoo!

>

--- In Homebrew_PCBs@yahoogroups.com, roger lucas <ralucas4277@...> wrote:
>
> Hi Stefan,
>
> I know that it should have worked in theory, but I was
> surprised at how well it actually turned out.
>
> I tried with tinned copper wire and a tinned steel
> sewing needle (purloined from my wife's needlework
> box), essentially the wear was about the same for
> both. The eroded pixel diameter is directly related to
> the electrode dia, as the sewing needle eroded the
> pixel became larger.
> I need to try to obtain some half hard or hard 10 mil
> brass wire for the next trial.
>
> The setting of the spark parameters before sparking is
> essentially to eliminate the uncertainty of whether
> pixels have been fully eroded or not, especially where
> electrode wear is high. I might just try some broken
> carbide drill bits, the tungsten might resist erosion
> better, trouble is carbide only goes to 0.5mm dia.
>
> Will post some sample photos after next revision and
> trials.
>
> Roger
>
> --- Stefan Trethan <stefan_trethan@...> wrote:
>
> > Good to hear you got such good results.
> >
> > I don't have any specific concerns why it would not
> > work, never had after
> > some manual tests with a simple power supply.
> >
> > But i don't currently have the time to build a CNC,
> > although i have most
> > components set aside for a while now.
> >
> > The electrode erosion thing was discussed back then,
> > if i remember
> > correctly the thinking was that one would advance
> > the electrode until a
> > spark of the correct voltage is occuring. One would
> > need to decide if the
> > energy was sufficient to blast out the pixel or if
> > it must be re-done.
> > But your approach seems a good idea also.
> >
> > Keep us updated, i definitely plan to build the CNC
> > but it will be months
> > for sure. If i use it for drilling of inkjet printed
> > PCBs or if EDM will
> > be an option is to be seen.
> >
> > what material is your electrode wire made of?
> >
> > ST
> >
> >
> > On Tue, 02 May 2006 18:07:19 +0200, roger lucas
> > <ralucas4277@...>
> > wrote:
> >
> > > Well, I finally motivated myself this holiday
> > weekend
>
>
>
>
>
>
> ___________________________________________________________
> Win tickets to the 2006 FIFA World Cup Germany with Yahoo!
Messenger. http://advision.webevents.yahoo.com/fifaworldcup_uk/
>

>. You should be able to find .3mm
> leads at an art or architectural supply store.

>Electrode erosion is quite normal with EDM, it is not a fault as such that
>can be eliminated.
>
>Probably can be reduced though..
>
>
>

> -----Message d'origine-----
> De : Homebrew_PCBs@yahoogroups.com
> [mailto:Homebrew_PCBs@yahoogroups.com] De la part de roger lucas
> Envoyé : mai 2 2006 13:57
> À : Homebrew_PCBs@yahoogroups.com
> Objet : Re: [Homebrew_PCBs] PCB EDM MILL Initial Tests
>
>

>
> Will post some sample photos after next revision and
> trials.
>
> Roger
>

> Roger wrote:
> I have just completed some EDM tests (see separate
> post), and certain requirements have come to light
> which means that ideally I would like to read a BMP
> and send it to the target byte by byte, (I need to add
> extra commands after certain sequences of OFF pixels
> in the target processor).
>
> Sorry if this causes extra work, I know how difficult
> it can be in the land of the Amber Nectar to motivate
> oneself after lunch. LOL.

> Dave H wrote:
>
> I've used the libtiff library
> (www.libtiff.org) on previous projects and
> it seems to work quite well. It also has
> lots of utilities for manipu;ating TIFF
> files (compressing/uncompressing, resizing,
> etc).

> roger lucas wrote:

> This is really looking as if direct raw copper board
> to finished pcb is going to be possible.

> lcdpublishing wrote:
>
> VERY COOL! ;-) I am glad to hear that
> no goats were harmed in the production
> of those EDM cut PCBs :-)

> AlanK wrote:
>
> even to the point of feeding blasting
> caps to the goats in the backyard before
> giving up.. Keep them away from the back
> wall unless you want a mess. And keep a
> camera handy, you will want a pic of the
> PETA girl's face.

> AlanK wrote:
>
> Also start thinking now about two
> electrodes. Could cut both sides with
> a 2 tooth tip, but independent control
> would be better.

> For my purposes - I will still need to compress them
> (G3 my pref) just to get them down to the plotter in
> under 4 hours.

--- In Homebrew_PCBs@yahoogroups.com, roger lucas <ralucas4277@...> wrote:
>
> Hi Stefan,
>
> I know that it should have worked in theory, but I was
> surprised at how well it actually turned out.
>
> I tried with tinned copper wire and a tinned steel
> sewing needle (purloined from my wife's needlework
> box), essentially the wear was about the same for
>

> Roger wrote:
>
> I am very interested in your approach, code
> etc etc, although I will probably use a PIC
> for the raster handling since I already have
> a PIC controlling the 3 axes and the spark
> control. I never thought of the TIFF format.
> Please post anything you develop, all will
> be gratefully received.

> DaveH wrote:
>
> G4 should give even better compression.
> It requies a bit more memory to
> decompress since you need to use the
> previous line as a reference line.
>

> 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.

>
> 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
>

> Curt AND Roger wrote - lots about EDM....

> Curt then wrote :
>
> <SNIP>
> using IGBTs designed for auto igniton
> system. That rate gives me about an
> hour and a quarter pocessing time for
> an 8 inch by 12 inch PCB using .001
> inch brass wire as an electrode. It
> makes a real nice board, but I can use
> Toner Transfer and CuCl2 bubble etching
> to make five boards in the same time!
>
> I'll be interested in your advances to
> the art, but right now it looks to me
> like the direct print inkjet system
> will replace TT and EDM for homebrew
> PCB prototyping.

>>Roger wrote:
>>
>>I am very interested in your approach, code
>>etc etc, although I will probably use a PIC
>>for the raster handling since I already have
>>a PIC controlling the 3 axes and the spark
>>control. I never thought of the TIFF format.
>>Please post anything you develop, all will
>>be gratefully received.
>
>
> Roger - I missed this part in the TIFF FAQ
>
> <Quote from a TIFF faq>
>
> Question 7. Can I not stream TIFF? Why does my
> library need seeking forward and backward in
> my TIFF file?
>
> TIFF is not a streamable format. It is its
> very nature that all data blocks can be
> written in any order that is convenient for
> the particular application and/or TIFF
> encoding library.
>
> </Quote>
>
> The first TIFFs I looked at where suitable
> for streaming. They had the information
> header in front of the actual picture data.
>
> However the main app I use, and I guess a lot
> of people do, is irfanview. It saves TIFF
> with the header at the end of the file.
> Many other apps probably do the same.
>
> This just can't work for the plotter (or I
> guess for your EDM). This is because the
> ATMEL (or PIC) does not have enough memory
> to hold the whole file. It has to burn each
> line as it receives it and then discard that
> data to buffer the next line.
>
> Problem here is that you don't get to find
> out things like how wide and how long the
> file is in pixels until you get to the end
> of it.

> > andrewm wrote:
> > Problem here is that you don't get to find
> > out things like how wide and how long the
> > file is in pixels until you get to the end
> > of it.

> Russel wrote:
> Just get the PC to re-order the file before
> sending it.

> Decent software decomposes the data (in
> whatever image format) to specialized control
> instructions for the machine anyway.

>>>andrewm wrote:
>>>Problem here is that you don't get to find
>>>out things like how wide and how long the
>>>file is in pixels until you get to the end
>>>of it.
>
>>Russel wrote:
>>Just get the PC to re-order the file before
>>sending it.
>
>
> The original plan was to not have to write
> ANY software on the PC ('cause we all hate
> doing that).
>
> It was just going to be use hyper terminal to
> send the TIFF file to the plotter/EDM unit.
> (X-Modem-CRC)
>
> Seeing as we can't be sure that a TIFF file
> is written in order - I HAVE to write some PC
> software.
>
> Either software to read a TIFF and re-order
> it so it can be sent OR software to just
> read a BMP/TIFF and send it to the plotter
> myself (without hyper terminal)
>
>
>>Decent software decomposes the data (in
>>whatever image format) to specialized control
>>instructions for the machine anyway.
>
> A Decent machine doesn't need specialised
> control instructions. It just reads a native
> file from the control source :D

> Seeing as my machine does not have enough
> memory to read an abitary TIFF or enough
> bandwidth to read a BMP. I am going to
> have to compromise and only have a 1/2
> decent machine that needs some special
> control instructions.

> The original plan was to not have to write
> ANY software on the PC ('cause we all hate
> doing that).
>
> It was just going to be use hyper terminal to
> send the TIFF file to the plotter/EDM unit.
> (X-Modem-CRC)
>
> Seeing as we can't be sure that a TIFF file
> is written in order - I HAVE to write some PC
> software.

>
> --- Andrew <andrewm1973@...> wrote:
>
>>The original plan was to not have to write
>>ANY software on the PC ('cause we all hate
>>doing that).
>>
>>It was just going to be use hyper terminal to
>>send the TIFF file to the plotter/EDM unit.
>>(X-Modem-CRC)
>>
>>Seeing as we can't be sure that a TIFF file
>>is written in order - I HAVE to write some PC
>>software.
>
> what about using any 'fax' program?
>
> the nasty thing about PC software is it has to be multi-platform these days.
> the old days of 'only' M$ are over...

>>> andrewm wrote:
>>> Seeing as we can't be sure that a
>>> TIFF file is written in order - I
>>> HAVE to write some PC software.

> > Herbert wrote:
> > what about using any 'fax' program?

> > the nasty thing about PC software
> > is it has to be multi-platform these
> > days. the old days of 'only' M$ are
> > over...

> Russell wrote:
> Multi-platform is easy as long as you
> exclude M$;)
>

>>AlanK wrote:
>>
>> Also start thinking now about two
>>electrodes. Could cut both sides with
>>a 2 tooth tip, but independent control
>>would be better.
>>
>>
>
>I don't understand why independant control
>would be advantagous. The EDM was going
>to be done raster not vector.
>
>
>

>However - I agree that extra wires would
>be cool.
>
>Make it like a 24 pin dot matrix printer
>(pins offset so they dont inter-pin-spark)
>
>
>

> Russell wrote:
> Most "real" machines read G-code, that has
> been generated from the original CAD data
> such as DXF (gerber is G-codes).

> By converting all external data types to one
> format suited to the machine, machine
> complexity is minimized.

> Even if it could read tiff, that would
> mean that any other data type would need
> to be converted to tiff.

>>>>andrewm wrote:
>>>>Seeing as we can't be sure that a
>>>>TIFF file is written in order - I
>>>>HAVE to write some PC software.
>
>>>Herbert wrote:
>>>what about using any 'fax' program?
>
> I think a fax program would have a fit
> if you gave it a BMP that was 12000 x
> 20000 dots. It is normally dealing
> with files that are 204x204 DPI not
> 2000x2000 dpi.
>
>>>the nasty thing about PC software
>>>is it has to be multi-platform these
>>>days. the old days of 'only' M$ are
>>>over...
>
>>Russell wrote:
>>Multi-platform is easy as long as you
>>exclude M$;)
>>
>
> Multi platform is so easy if all you
> need a a terminal program someone else
> wrote :D

>
> andrewm - Who is wondering if the
> russell(dot)AU is from SE Qld.

> >andrewm wrote:
> >I don't understand why independant control
> >would be advantagous. The EDM was going
> >to be done raster not vector.


> wrote:
> I didn't really read every word of the
> rest so may have missed something about
> raster, but raster would take a tremendous
> amount of time vs vector, and the single
> wire CNC setup doesn't really have a
> reason to go over areas that aren't etched
>
><snip>

>>Russell wrote:
>>Most "real" machines read G-code, that has
>>been generated from the original CAD data
>>such as DXF (gerber is G-codes).
>
> I Assume "real" means real milling machine /
> drilling machine or something specific to PCB
> or engineering.
>
> Real plotters use HP/GL
> Real printers use postscript or PCL
> Real photo-printers (often) use TIFF

> My photoplotter will also be used to make photo
> tools for screen printing. That will be
> inherently raster stuff rather than bitmaps.
>
> Someone else has written the software to
> convert gerber to bitmaps so I dont have too :D
>
>
>>By converting all external data types to one
>>format suited to the machine, machine
>>complexity is minimized.
>
>
> There are lots of different standards out
> there. I would have liked to use one of
> them rather than make up my own.
>
>
>>Even if it could read tiff, that would
>>mean that any other data type would need
>>to be converted to tiff.
>
>
> Yes - but by some software someone else
> has written and that is also probably
> already availabe cross-platform.
>
> You do understand the concept and
> advantages of making the machine just a
> terminal that accepts a file via x-modem
> don't you ?

> The guy from victoria wrote:
>
> A terminal program just dumps files from
> the pc into the machine, which is no
> different if tiff or g-code is used.

> rshaw wrote:
>
> Yes, but i'd use a vector format like
> g-code, gerber, postscript, pcl, or some
> forth dialect because the file size
> would be a thousandth of a bitmap file
> size. For an edm or milling machine, the
> vector commands can be executed directly.
> For a raster output device such as a
> scanner, the machine controller can
> rasterize the vector output like laser
> printers do with postscript.

>If you just used a normal isolation milling
>CAM file (like you would with a mechanical
>router) then you might end up with an
>island of copper in the middle of the board
>with no ground connection.
>
>The EDN wont spark on that any more :(
>
>

>>The guy from victoria wrote:
>>
>>A terminal program just dumps files from
>>the pc into the machine, which is no
>>different if tiff or g-code is used.
>
>
> Well - In this application g-code is not
> suitable. If you remember the start of the
> thread - I am trying to make a cheap
> photoplotter anyone can replicate for a few
> $100 or so.
>
> Drum photoplotter means raster.
>
> Cheap means that I cant have enough CPU and
> RAM onboard to convert vector to raster
> internally.
>
> The board is planing on having an ATMEL,
> a analog PLL and not much else on it.
>
> 16 megahertz - 8 bit CPU
> 128K ROM
> 16K RAM
> couple of timers
> a UART
> and an SPI port.
>
> Call me a masochist I guess :D

>>The guy from victoria wrote:
>>
>>A terminal program just dumps files from
>>the pc into the machine, which is no
>>different if tiff or g-code is used.
>
>
> Well - In this application g-code is not
> suitable. If you remember the start of the
> thread - I am trying to make a cheap
> photoplotter anyone can replicate for a few
> $100 or so.
>
> Drum photoplotter means raster.
>
> Cheap means that I cant have enough CPU and
> RAM onboard to convert vector to raster
> internally.
>
> The board is planing on having an ATMEL,
> a analog PLL and not much else on it.
>
> 16 megahertz - 8 bit CPU
> 128K ROM
> 16K RAM
> couple of timers
> a UART
> and an SPI port.
>
> Call me a masochist I guess :D

> >I wrote:
> >If you just used a normal isolation milling
> >CAM file (like you would with a mechanical
> >router) then you might end up with an
> >island of copper in the middle of the board
> >with no ground connection.
> >
> >The EDN wont spark on that any more :(

> Alan wrote:
>
> Makes sense and easy enough and probably
> not even that bad with an intelligent skip
> of uncut areas.. I'd still rather see it
> draw the traces with electricity, shouldn't
> be too hard to figure out some type of
> useable sort and just more fun to watch.

> Russell wrote:
>
> At the data rates needed, you'll need
> to store the whole file in the machine
> controller.

> A 300mm drum has a circumference around
> 1000mm. Assume a pixel size of 0.01mm.
> If it rotates at 600rpm, the pixel rate
> is 1Mpixel/sec. A 100mm x 100mm plot
> will need 1000s or 17mins to scan. The
> averaged pixel rate will be 100k pixels
> /sec. The file size will be 100Meg
> pixels, which is impractical.

> The pc could send bitmap data while the
> machine is running, if the data rate is
> higher than 100k bits/sec. Fast rs-232,
> usb, or ethernet could do that.

>
> > >I wrote:
> > >If you just used a normal isolation milling
> > >CAM file (like you would with a mechanical
> > >router) then you might end up with an
> > >island of copper in the middle of the board
> > >with no ground connection.
> > >
> > >The EDN wont spark on that any more :(
>
> > Alan wrote:
> >
> > Makes sense and easy enough and probably
> > not even that bad with an intelligent skip
> > of uncut areas.. I'd still rather see it
> > draw the traces with electricity, shouldn't
> > be too hard to figure out some type of
> > useable sort and just more fun to watch.
>
>
> It would be an easy enough algorithm to to
> get all the vectors from the G-Code and
> z-sort them to avoid islands. But we are
> going to get back into the writing PC
> software argument again if we do :D
>
> I think the 24/32 wire EDM printer might
> win in a race with a vector one at the end
> of the day anyways.
>

>--- curt_rxr <cwrxr@...> wrote:
>
>Roger I used brass wire and distilled water and had
>arranged the servo
>circuit to feed the wire via a pinch roller and worm
>screw drive. the
>servo circuit is as per the NASA / Garden of EDM
>circuit.

>Roger the gap breakdown voltage controls the gap via
>the servo. As
>the electrode ( brass wire ) advances the gap closes
>until the spark
>after which the electrode retracts so the system is
>ready for he next
>spark.

>Hi Roger,
>
>I'm glad to see someone making progress. My system
>is stalled at a
>pulse repetition rate of 200,000 per second using
>IGBTs designed for

>hour and a quarter
>processing time for an 8 inch by 12 inch PCB >using

>as an electrode. It makes a real nice board, but I
>can use Toner
>Transfer and CuCl2 bubble etching to make five boards
>in the same time!
>
>I'll be interested in your advances to the art, but
>right now it looks
>to me like the direct print inkjet system will
>replace TT and EDM for
>homebrew PCB prototyping.
>
>Curt Richards

>No problems. BMP files are pretty easy to read.
>
>I will have a play around with them in the next few
>days.

>
>For my purposes - I will still need to compress them
>(G3 my pref) just to get them down to the plotter in
>under 4 hours.
>
>I don't quite understand the "motivate onesself
>after lunch" comment. Is this "lunch" you refer to
>something about 1/2 way through the day that we call
>"Rum o'clock" :D

>
>I think the 24/32 wire EDM printer might
>win in a race with a vector one at the end
>of the day anyways.
>
>
>

>
> Multi-platform is easy as long as you exclude M$;)
>

> I think a fax program would have a fit
> if you gave it a BMP that was 12000 x
> 20000 dots. It is normally dealing
> with files that are 204x204 DPI not
> 2000x2000 dpi.

> Most "real" machines read G-code, that has been
> generated from the original CAD data such as DXF
> (gerber is G-codes).
>
> By converting all external data types to one format
> suited to the machine, machine complexity is minimized.

>My boards are all 4 x 3 inches, but the attraction of
>EDM is it is the cheapest way to go, and it can be
>left on its one to process with virtually no board
>preparation, and no ink or etchant costs.
>
>Roger
>
>

On Wed, 03 May 2006 19:44:33 +0200, Alan King <alan@...> wrote:

> Inkjet is preeminiently reliable, with low costs and little extra work
>
> for etching. Far more likely to have to watch the EDM or have more
>
> often mechanical problems, plus wire and electricity isn't zero either,
>
> even expensive ink will work out very low cost per board when it's only
>
> used for PCB. All things considered it's unlikely to actually beat out
>
> the inkjet, and even if it did it'd be so marginal for the extra work of
>
> setting it up and keeping things running. Doing it for fun is one thing
>
> since it'll be very cool, but if you're expecting practicality I doubt
>
> it'll work out too well, just hard to see it coming out ahead by enough
>
> to make a difference.
>
>
> Alan

--- In Homebrew_PCBs@yahoogroups.com, roger lucas <ralucas4277@...> wrote:
>
> Hi Curt,
>
> Good to hear from you again.
>
>
> I am in the middle of designing an electrode feed
> system similar to yours. I have not heard of the NASA
> circuit, is it some sort of servo drive?

It's the circuit used in the Garden of EDM -- I'll be glad to e mail a
PDF of the original NASA Tech brief to you if you like.


>
> If I understand this right you are initiating the
> spark by advancing the electrode and retreating it at
> each point. How does this keep up with your scanning
> speed of approx 20 inches/sec? Or have I totally
> misunderstood the operation of the servo?

You've got it exactly right.

It's not a problem -- the pinch roller that feeds the wire through the
insulating sleeve is driven on the same principal as a voice coil
drive in a hard drive and doesn't need to move the electrode very much
at all.


>
> My early experiments included a solenoid armature
> oscillating an electrode at 50 Hz, amplitude about
> 1mm. This worked very well since the spark always
> initiated at the dielectric breakdown point. However,
> at the moment I can see no way of integrating the
> electrode feed with the solenoid arrangement. If I
> could it would answer a lot of problems.

There are two ways to implement the servo. One is to use a stepper to
control the pinch roller whichs feeds the brass wire through the guide
the other is to use a worm drive and dc motor.

Your vibrating electrode is the same approach Ben Flemming used in his
Ramah Tap Burner design and should work well for PCBs which are
*FLAT*. It would simplify the overall design a ton. Well Done!!




> My boards are all 4 x 3 inches, but the attraction of
> EDM is it is the cheapest way to go, and it can be
> left on its one to process with virtually no board
> preparation, and no ink or etchant costs.
>
> Roger


Yep!! And if you incorperate a drill head on the back of your gantry
you'll be able to drill the boards in water and save on dust collection.

Roger, I'm not saying the PCB EDM is a dead end -- just my system is
stonewalled! Since my major efforts in the spring and summer are
working on various Willys Jeep and Truck restoration projects and I
won't be much help in developing the PCB EDM until fall.

Good Luck to you Roger and feel free to ask me questions, I'll try to
be helpfull.

Curt Richards

> Curt wrote:
>
> Andrew I believe Stefan did some
> experiments with burning the copper away
> as opposed to the spark erosion of EDM.
> I'm not sure as to his results, but
> perhaps he could help with your TIG
> experiments.

> Roger wrote:
> My boards are all 4 x 3 inches, but the attraction of
> EDM is it is the cheapest way to go, and it can be
> left on its one to process with virtually no board
> preparation, and no ink or etchant costs.

> >andrewm wrote:
> >
> >I think the 24/32 wire EDM printer might
> >win in a race with a vector one at the end
> >of the day anyways.

> AlanK wrote:
> 24 things to fail at every step, better
> start now so it can work by 2012.. :)

>Alan wrote:
> Doing it for fun is one thing since it'll
> be very cool, but if you're expecting
> practicality I doubt it'll work out too
> well, just hard to see it coming out ahead
> by enough to make a difference.

> Them there fandangled ink jet printers have
>
> between 48 and 120 nozzels per colour and
>
> they don't break down more than 3 times a
>
> day
>

>
>
> EDM would have one step. Like mechanical
>
> isolation milling does. Turn it on, go and
>
> have a rum, come back an hour later.
>
>
> EDM is meant to be an unattended process.

> On Wed, 03 May 2006 22:16:23 +0200, Andrew <andrewm1973@...> wrote:
>
>> EDM would have one step. Like mechanical
>> isolation milling does. Turn it on, go and
>> have a rum, come back an hour later.
>> EDM is meant to be an unattended process.
>>
>
> Do you actually do mechanical milling?
> I don't, but as far as i am aware of it is far from trouble free and
> working well unattended.
>

> ST wrote
> Do you actually do mechanical milling?
> I don't, but as far as i am aware of it is
> far from trouble free and working well
> unattended.

> You get other stuff with EDM, like
> changing the water, caring and feeding
> of electrodes, ... stuff...

> ST wrote:
> Yea but they were built by some guy
> over at a garage shop called epson
> that builds a couple a day, and so
> he might have had a chance to work
> out the problems.

> If i was building a EDM with many
> electrodes it would be my first,
> so i think it would be best to
> start with one electrode instead
> and actually get it to work.

>
>>AlanK wrote:
>> 24 things to fail at every step, better
>>start now so it can work by 2012.. :)
>>
>>
>
>Them there fandangled ink jet printers have
>between 48 and 120 nozzels per colour and
>they don't break down more than 3 times a
>day :D
>
>
>

> "
>
> presuming your equipment is reliable. If the equipment
>isn't suitable to the task or tends to fail you can waste a lot of time
>and materials whether you are watching it or not."
>
>

> AK wrote:
> Which inkjet also has 24+ independent complex
> mechanical systems that have to be maintained?

> It's a relative PITA to keep 2 or 3 of
> something like that working well. Heck took
> them 15 or 20 years to get inkjets even close
> to right, and even now much of the rightness
> is simply waste half the ink cleaning the
> nozzles.. They're reliable because they're
> simple and fluid instead of mechanical all
> around..

> Make you a deal, get just 6 working well
> for a week then you can tell me how it is
> so much better than an inkjet.. :) Again,
> I'll expect to hear back about it by at
> least 2012..

> AK also wrote:
> Getting 24 wire feeds to the point of not
> having hiccups will take a buttload of over
> engineering

> And it will likely still require an
> exploding goat here or there too..

> Do you actually do mechanical milling?
> I don't, but as far as i am aware of it is far from trouble free and
> working well unattended.

>
>Do you actually do mechanical milling?
>I don't, but as far as i am aware of it is far from trouble free and
>working well unattended.

> BillC wrote:
> I have a CNC machine, and the idea of
> leaving it unattended .... no.
>

>It's the circuit used in the Garden of EDM -- I'll be
>glad to e mail a
>PDF of the original NASA Tech brief to you if you
>like.

>> My early experiments included a solenoid armature
>> oscillating an electrode at 50 Hz, amplitude about
>> 1mm. This worked very well since the spark always
>> initiated at the dielectric breakdown point.
>>However,
>> at the moment I can see no way of integrating the
>> electrode feed with the solenoid arrangement. If I
>> could it would answer a lot of problems.

>There are two ways to implement the servo. One is to
>use a stepper to
>control the pinch roller whichs feeds the brass wire
>through the guide
>the other is to use a worm drive and dc motor.

>Your vibrating electrode is the same approach Ben
>Flemming used in his
>Ramah Tap Burner design and should work well for PCBs
>which are
>*FLAT*. It would simplify the overall design a ton.
>Well Done!!

>Yep!! And if you incorperate a drill head on the
>back of your gantry
>you'll be able to drill the boards in water and save
>on dust collection.

> For those interested, the vibrating electrode is
> driven by the solenoid arrangement in an aquarium
> aeration pump. Simple, cheap and very effective.
> However, production item may have to be a lighter
> design to increase the oscillation frequency.

>--- Codesuidae <codesuidae@...> wrote:
>
>roger lucas wrote:
>> For those interested, the vibrating electrode is
>> driven by the solenoid arrangement in an aquarium
>> aeration pump. Simple, cheap and very effective.
>> However, production item may have to be a lighter
>> design to increase the oscillation frequency.

>Isn't the frequency of an aquarium pump determined by
>the power line
>frequency? In the designs I've seen its just a coil
>driven from the
>power line pushing a magnet connected to a lever that
>moves a diaphragm
>attached to a cavity with holes covered by small
>rubber flap valves.
>
>Dave K

> Is that a CNC milling machine for
> cutting big hunks of metal - or one for
> cutting little bits of GRP and copper ?

>
> i like the idea of making me own laserplotter.
>
> tested: a pointerlaser (some cheap thing) with an extra focus lense, a
> red sensible film gave me super fine lines (close to a single cloth
> fiber).
>
> did any of us fouling around with this idea !!
>
> tips and suggestions always welcome:)
>
> gr Roel (holland)
>

>> Roel CNC wrote:
>>
>> i like the idea of making me own laserplotter.
>> tested: a pointerlaser (some cheap thing)
>> with an extra focus lense, a red sensible
>> film gave me super fine lines (close to a
>> single cloth fiber).
>>
>> did any of us fouling around with this idea !!
>>
>> tips and suggestions always welcome:)
>>

> Roel also wrote:
> Hi all,
> M i started this toppic - got lots of replys
> on it with ideas :)
>
> i gonna use Cunningfellow's pll thing some
> stepper for the laser and a dma-16 card -
> high speed dio card up to 250kB/s some code
> compiled (TPascal)that eats the the 274 (gerber)
> files and output to the drum

>>>>> Roel CNC wrote:
>>>>> <snip - "laser plotter anyone">

>>>> andrewm wrote:
>>>> <snip - "not a bad idea">

>>> lots of other people wrote:
>>> <snip - "how about doing it this way">

>> Roel wrote again:
>> <snip - "why the hell not">

> andrewm wrote again:
> <snip - other thoughts>
> The only other though I had from the PC side
> was to maybe write a GDI driver. That might be
> a bit out of my league though.

>
> >> Roel CNC wrote:
> >>
> >> i like the idea of making me own laserplotter.
> >> tested: a pointerlaser (some cheap thing)
> >> with an extra focus lense, a red sensible
> >> film gave me super fine lines (close to a
> >> single cloth fiber).
> >>
> >> did any of us fouling around with this idea !!
> >>
> >> tips and suggestions always welcome:)
> >>
>
> > Roel also wrote:
> > Hi all,
> > M i started this toppic - got lots of replys
> > on it with ideas :)
> >
> > i gonna use Cunningfellow's pll thing some
> > stepper for the laser and a dma-16 card -
> > high speed dio card up to 250kB/s some code
> > compiled (TPascal)that eats the the 274 (gerber)
> > files and output to the drum
>
> Roel - I have done a bit more work on the PLL
> thing. That one posted so far was just a test of
> concept / prototype. There are a few things
> un-needed and a few other things that are needed.
>

> It was built to do some tinkering with a
> commercial DC servo motor I had lying around.
> I finally want to just use a DC brushed motor
> with some optos ripped out of mice (to make it
> easier for others to get parts to build)
>
> Also - I was planning on getting the data out of
> a USB port (via an FT232) instead of some custom
> hardware in the PC (again ease to duplicate).
>
> The FT232 can do 4 Mb (which is same ballpark to
> 250 KB). However if you compress the 1000dpi
> data even with a simple algo like G3 fax you can
> fit the data stream down 100 kilo baud (assuming
> 1000dpi and 10" x 10" board in 10 minutes)
>
> I have sourced some toothed belts and linear
> shafts for moving the laser head. I have also
> found a source of cheapish lasers that can be
> focused down to small enough dot size if I can't
> find a simple repeatable solution for people to
> do the same with a cheap laser pointer.

>
> Very interested in your thoughts on the carraige
> part. You seem to have a lot more experience
> than I with CNC things (and PVC etch tanks).

> Do you think at 1000 (or 2000) DPI that there will
> be a sticktion problem? Do you think the tooth
> belt idea is going to be good enough or do you
> think that I might need to use a very fine pitch
> leadscrew?

>
> I have done some software on the PC to read a
> BMP file compress it and send it out to my
> hardware. I was just going to use and external
> gerber to BMP thing. However - I have no
> objections to reading geber directly if you would
> like to work together on the project.
>

> The only other though I had from the PC side
> was to maybe write a GDI driver. That might be
> a bit out of my league though.
>
> andrewm (or cunningfellow to some)
>

> Roel wreto:
> lots of schematics on the net for pll that
> can be used i think

> i was thinking to use a ldiode from a dvd
> burner they can trow up to 70mw and with a
> good lense a super ultra thin line

> a lead screw for this job will be expensive

> i think first touhts was to use a beld but
> after some thinking a steel wire is super
> stiff and easy to gear

> email me if you like Andrew or maybe msn
> its faster hey'

>
> --- In Homebrew_PCBs@yahoogroups.com, "Andrew" <andrewm1973@>
> wrote:
> >
> > >> Roel CNC wrote:
> > >>
> > >> i like the idea of making me own laserplotter.
> > >> tested: a pointerlaser (some cheap thing)
> > >> with an extra focus lense, a red sensible
> > >> film gave me super fine lines (close to a
> > >> single cloth fiber).
> > >>
> > >> did any of us fouling around with this idea !!
> > >>
> > >> tips and suggestions always welcome:)
> > >>
> >
> > > Roel also wrote:
> > > Hi all,
> > > M i started this toppic - got lots of replys
> > > on it with ideas :)
> > >
> > > i gonna use Cunningfellow's pll thing some
> > > stepper for the laser and a dma-16 card -
> > > high speed dio card up to 250kB/s some code
> > > compiled (TPascal)that eats the the 274 (gerber)
> > > files and output to the drum
> >
> > Roel - I have done a bit more work on the PLL
> > thing. That one posted so far was just a test of
> > concept / prototype. There are a few things
> > un-needed and a few other things that are needed.
> >
> lots of schematics on the net for pll that can be used i think
>
> > It was built to do some tinkering with a
> > commercial DC servo motor I had lying around.
> > I finally want to just use a DC brushed motor
> > with some optos ripped out of mice (to make it
> > easier for others to get parts to build)
> >
> > Also - I was planning on getting the data out of
> > a USB port (via an FT232) instead of some custom
> > hardware in the PC (again ease to duplicate).
> >
> > The FT232 can do 4 Mb (which is same ballpark to
> > 250 KB). However if you compress the 1000dpi
> > data even with a simple algo like G3 fax you can
> > fit the data stream down 100 kilo baud (assuming
> > 1000dpi and 10" x 10" board in 10 minutes)
> >
> > I have sourced some toothed belts and linear
> > shafts for moving the laser head. I have also
> > found a source of cheapish lasers that can be
> > focused down to small enough dot size if I can't
> > find a simple repeatable solution for people to
> > do the same with a cheap laser pointer.
>
> i was thinking to use a ldiode from a dvd burner they
> can trow up to 70mw and with a good lense a super ultra thin line
> >
> > Very interested in your thoughts on the carraige
> > part. You seem to have a lot more experience
> > than I with CNC things (and PVC etch tanks).
>
> > Do you think at 1000 (or 2000) DPI that there will
> > be a sticktion problem? Do you think the tooth
> > belt idea is going to be good enough or do you
> > think that I might need to use a very fine pitch
> > leadscrew?
>
> a lead screw for this job will be expensive i think
> first touhts was to use a beld but after some thinking
> a steel wire is super stiff and easy to gear
> >
> > I have done some software on the PC to read a
> > BMP file compress it and send it out to my
> > hardware. I was just going to use and external
> > gerber to BMP thing. However - I have no
> > objections to reading geber directly if you would
> > like to work together on the project.
> >
>
> > The only other though I had from the PC side
> > was to maybe write a GDI driver. That might be
> > a bit out of my league though.
> >
> > andrewm (or cunningfellow to some)
> >
> email me if you like Andrew or maybe msn its faster hey'
>
> gr Roel
>

>> Roel, Andrew and others wrote:
>> <Stuff about a drum plotter>

> Loco labs wrote:
>
> im building a small CNC type machine using
> steppers and belts to move a dremel in 3
> axis, controlled from parallel port. I will
> use eagle pcb and then create a gcode file
> for mach3 to route the isolation.

> for moving a laser diode around you will
> not need any torque at all, so it would be
> possible to get away with using a few
> small stepper motors from printers or
> using the assembly from flatbed scanners
> to perform x and y movement. but it will
> be very slow.

> if you google up 'orbit
> picstep' you will find a very nice stepper
> driver that has step, direction & enable
> signals.

> I know of UV sensitive boards, where can
> i get the red sensitive ones as mentioned
> before?

> Have you tried the dremel tool to mill
> fiberglass PCB ?

>"loco_labs" wrote:
> <snip>
> as for the sticktion, one idea i had was; you
> see where on the older carriages of printers/
> scanners they had bronze guides that slide
> around a steel rod, what if there were a few
> holes drilled into the bronze around the
> diameter and a small pump would supply some
> oil/air under pressure into the holes. then
> the fluid should slowly leak out around the
> rod and hopefully it floats on a pillow of
> oil. or even pressurised air.
> <snip>

> 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
>
>
>
>
> ___________________________________________________________
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>
> Be sure to visit the group home and check for new Links, Files, and Photos:
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>
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> Date: Tue, 2 May 2006 17:07:19 +0100 (BST)
> Subject: [Homebrew_PCBs] PCB EDM MILL Initial Tests
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>
>
> 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-
>

> . 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