Homebrew PCBs

Hi guys, I have now set my plotter up for scratch-etching (carbide 
tipped modified plotter pen)
I am not able to understand how to get the plotter to scratch though 
a resist to expose copper to etch away and isolate tracks.
I have Eagle (free version) and Proteus PCB software packages...
What is the process to go from a PCB in gerber or hpgl to an HPGL 
code file that will trace the outlines of the tracks??

thanks, PK

Try this

http://mynock.dhs.org/pcbmilling/


--- In Homebrew_PCBs@yahoogroups.com, "onenastyviper"
<oneNastyViper@h...> wrote:

> 
> Hi guys, I have now set my plotter up for scratch-etching (carbide 
> tipped modified plotter pen)
> I am not able to understand how to get the plotter to scratch though 
> a resist to expose copper to etch away and isolate tracks.
> I have Eagle (free version) and Proteus PCB software packages...
> What is the process to go from a PCB in gerber or hpgl to an HPGL 
> code file that will trace the outlines of the tracks??
> 
> thanks, PK

Thanks for your reply, I did check this website and it gave me a clue 
about what these ULP files were used by Eagle for...
I managed to get my scribe to trace the isolations required for one 
of the installed demo boards.
Ok, it was directly onto the copper foil and not through a resist 
layer. The traces seemed well formed and once the stylus wobble 
problem was solved (thank god for polymorph;-)
I am now going to try a circuit with a resist and try etching 
it...fingers crossed.

regards, PK

--- In Homebrew_PCBs@yahoogroups.com, "crankorgan" <john@k...> wrote:

> 
> Try this
> 
> http://mynock.dhs.org/pcbmilling/

PK,
	How did you solve the stylus wobble problem? (i.e. what is polymorph?)

*Brian

-----Original Message-----
From: onenastyviper [mailto:oneNastyViper@...] 
Sent: Saturday, February 05, 2005 3:04 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Re: Scratch & Etch Process




Thanks for your reply, I did check this website and it gave me a clue 
about what these ULP files were used by Eagle for...
I managed to get my scribe to trace the isolations required for one 
of the installed demo boards.
Ok, it was directly onto the copper foil and not through a resist 
layer. The traces seemed well formed and once the stylus wobble 
problem was solved (thank god for polymorph;-)
I am now going to try a circuit with a resist and try etching 
it...fingers crossed.

regards, PK

-- 
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.300 / Virus Database: 265.8.5 - Release Date: 2/3/2005

Hi Brian,
Polymorph is a low-fusing temp thermoplastic that can be moulded by 
hand or hot air. http://www.mutr.co.uk/prodDetail.aspx?prodID=576
gives some info and ordering although I bought it at maplins in the 
UK.

To stop the wobble...
The HP stubby pen holder on the 7475A has enough structure to firmly 
hold the pen *if* pressure can be applied to the pen to hold it 
against the holder. 
I tried the traditional elastic band but this couldn't handle the 
torque and the pen wobbled.
I then tried the polymorph by using it to force and hold the pen into 
position when set...so far it has worked well.
I will put photos of what it looks like.

The stylus was created from an old stubby pen holder and a tile 
scribe/cutter with a solid tungsten carbide bit bought at wickes in 
the UK.

Hope this helps?

regards PK.


--- In Homebrew_PCBs@yahoogroups.com, "Brian Schmalz" <brian.s@l...> 
wrote:
> PK,
> 	How did you solve the stylus wobble problem? (i.e. what is 
polymorph?)
> 
> *Brian

On Sun, 06 Feb 2005 19:09:43 -0000, onenastyviper  
<oneNastyViper@...> wrote:

>
> Hi Brian,
> Polymorph is a low-fusing temp thermoplastic that can be moulded by
> hand or hot air. http://www.mutr.co.uk/prodDetail.aspx?prodID=576
> gives some info and ordering although I bought it at maplins in the
> UK.
> To stop the wobble...
> The HP stubby pen holder on the 7475A has enough structure to firmly
> hold the pen *if* pressure can be applied to the pen to hold it
> against the holder.
> I tried the traditional elastic band but this couldn't handle the
> torque and the pen wobbled.
> I then tried the polymorph by using it to force and hold the pen into
> position when set...so far it has worked well.
> I will put photos of what it looks like.
> The stylus was created from an old stubby pen holder and a tile
> scribe/cutter with a solid tungsten carbide bit bought at wickes in
> the UK.
> Hope this helps?
> regards PK.

I exchanged the spring in the pen holder with a stronger one, if that is  
any help.

ST

Hi,

personally, I was a bit frightened about using a stronger spring. In 
In my opinion, the plastic used in the penholder has very little give 
and tends to fracture rather than bend...but that might be down to 
regional differences??

regards, PK

PS: put the photos in onenastyviper's emporium photo section

On Sun, 06 Feb 2005 19:23:13 -0000, onenastyviper  
<oneNastyViper@...> wrote:

> Hi,
> personally, I was a bit frightened about using a stronger spring. In
> In my opinion, the plastic used in the penholder has very little give
> and tends to fracture rather than bend...but that might be down to
> regional differences??
> regards, PK


I had the same fear, but i thought if it breaks i can still think about  
more sturdy methods.
I think the hp plotters were the same all around the world.
Because the process did't work as well as i wished i only did a few  
testplots and can't tell if the clamp would have broken later.

ST

--- In Homebrew_PCBs@yahoogroups.com, "onenastyviper"
<oneNastyViper@h...> wrote:
> 
...
> PS: put the photos in onenastyviper's emporium photo section

Nice!

I think that is called "Friendly Plastic" in the US. I hope not, as
Friendly Plastic has a problem- in a few years it breaks down and
becomes extremely brittle and easily broken.

There is also that clay-like epoxy.

Steve Greenfield

Hi Steve,
Breakdown? I hope not...although if it does take a few years I 
wouldn't mind. I hope I have a CNC built/bought by then;-)

PK

> Nice!
> 
> I think that is called "Friendly Plastic" in the US. I hope not, as
> Friendly Plastic has a problem- in a few years it breaks down and
> becomes extremely brittle and easily broken.
> 
> There is also that clay-like epoxy.
> 
> Steve Greenfield