Homebrew PCBs

OK I bit the bullet and made a tool collar setter last night. It 
unfortunately relies on the collars being the same thickness so I 
measure them first.

I have uploaded pictures to the photos section in the folder 'AWEM' 
which show the setting tool, and some drills and fish tail cutters 
adjusted to equal protruding lengths.

The collar is trapped between the coarse threaded male thread and the 
longer hexagonal part, and the tool pushed through by the finer screw 
until it touches the dial gauge plunger. To make the tool extended 
length the same as another all you have to do is insert the first,
zero 
the dial gauge, then fit the second and adjust the fine screw until
the 
gauge again reads zero.

Works a treat ! Although shown with a digital 'dial gauge' it works 
equally well with an analogue one as the mounting stems are a
standard 
at 8mm.

AWEM

ANdrew,

Sorry if this has already been asked/covered, but are you using these 
drills on a CNC machine?  If so, does that machine have tool length 
offsets?

If so, wouldn't it be easier to measure the tool length and change the 
offset than to change the physical length of the tool to match the 
offset?

I am just starting to tinker with PCBs on my CNC router so I am just 
trying to grasp the overall process that others are doing with PCBs 
and CNC machines.

Chris

--- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing" 
<lcdpublishing@y...> wrote:
> ANdrew,
> 
> Sorry if this has already been asked/covered, but are you using
these 
> drills on a CNC machine?  If so, does that machine have tool length 
> offsets?
> 
> If so, wouldn't it be easier to measure the tool length and change 
the 
> offset than to change the physical length of the tool to match the 
> offset?
> 
> I am just starting to tinker with PCBs on my CNC router so I am
just 
> trying to grasp the overall process that others are doing with PCBs 
> and CNC machines.
> 
> Chris

Chris,

Yes it's a Bridgeport Interact 1 using a Heidenhain TNC151 controller 
(1987 vintage), and although tool offsets can easily be set at the
time 
the code is generated they cannot be set 'on the fly' for programs 
longer than the memory can hold, which have to be 'drip fed', it's
also 
a problem when a drill breaks and another has to be inserted 
having 'paused'.

AWEM

Oh, that is bad. I have only worked with a couple of heidenhein 
controls and never felt they were too good.  But it seems as though 
you have a system in place to make it work for you so thats cool.

Chris





--- In Homebrew_PCBs@yahoogroups.com, "Andrew Mawson" <andrew@m...> 
wrote:
> --- In Homebrew_PCBs@yahoogroups.com, "lcdpublishing" 
> <lcdpublishing@y...> wrote:
> > ANdrew,
> > 
> > Sorry if this has already been asked/covered, but are you using
> these 
> > drills on a CNC machine?  If so, does that machine have tool 
length 
> > offsets?
> > 
> > If so, wouldn't it be easier to measure the tool length and 
change 
> the 
> > offset than to change the physical length of the tool to match 
the 
> > offset?
> > 
> > I am just starting to tinker with PCBs on my CNC router so I am
> just 
> > trying to grasp the overall process that others are doing with 
PCBs 
> > and CNC machines.
> > 
> > Chris
> 
> Chris,
> 
> Yes it's a Bridgeport Interact 1 using a Heidenhain TNC151 
controller 

> (1987 vintage), and although tool offsets can easily be set at the
> time 
> the code is generated they cannot be set 'on the fly' for programs 
> longer than the memory can hold, which have to be 'drip fed', it's
> also 
> a problem when a drill breaks and another has to be inserted 
> having 'paused'.
> 
> AWEM

Any idea where to find the cheapest UV laser?
Cristian

--- In Homebrew_PCBs@yahoogroups.com, cristian <cristianbip@b...> wrote:
>
> Any idea where to find the cheapest UV laser?
> Cristian

I seem to remember plans where you could build your own 
ultraviolet Nitrogen based laser (for little cost).  I think 
the plans may have been in Scientific American from about 30
years ago (+/- a bit).  However, that's probably not exactly 
what you were intending.

Dave

I remember that S.A. article. From back when the amateur scientist did some 
real science.
   It was cheap, but complex. Also I believe it was only pulse mode. I 
remember one of the suggested applications was to measure cloud height by 
timing reflected pulses.

   Not sure what wavelength the OP was looking for or what kind of power, 
maybe some of the newer UV leds may fit the bill.
    Not a laser, but certainly the cheapest.

-carl

At 02:56 PM 10/10/2005, you wrote:

>--- In Homebrew_PCBs@yahoogroups.com, cristian <cristianbip@b...> wrote:
> >
> > Any idea where to find the cheapest UV laser?
> > Cristian
>
>I seem to remember plans where you could build your own
>ultraviolet Nitrogen based laser (for little cost).  I think
>the plans may have been in Scientific American from about 30
>years ago (+/- a bit).  However, that's probably not exactly
>what you were intending.
>
>Dave
>
>

News?
The schematic?
Cristian

nitrogen laser is only good as a source of koherent light for
experiments that require it. Otherwise- useless for drilling and
cutting.  Mike

--- In Homebrew_PCBs@yahoogroups.com, "Dave" <wa4qal@y...> wrote:

>
> --- In Homebrew_PCBs@yahoogroups.com, cristian <cristianbip@b...> wrote:
> >
> > Any idea where to find the cheapest UV laser?
> > Cristian
> 
> I seem to remember plans where you could build your own 
> ultraviolet Nitrogen based laser (for little cost).  I think 
> the plans may have been in Scientific American from about 30
> years ago (+/- a bit).  However, that's probably not exactly 
> what you were intending.
> 
> Dave
>

At 02:05 AM 10/15/2005, you wrote:
>nitrogen laser is only good as a source of koherent light for
>experiments that require it. Otherwise- useless for drilling and
>cutting.  Mike

I'm looking for an UV laser to expose the presensitized PCB.
IR laser is powerful enough for cutting/drilling but not for my project.
Cristiam

> > > Any idea where to find the cheapest UV laser?
> > > Cristian

IR is not nitrogen. Mike

--- In Homebrew_PCBs@yahoogroups.com, cristian <cristianbip@b...> wrote:

>
> At 02:05 AM 10/15/2005, you wrote:
> >nitrogen laser is only good as a source of koherent light for
> >experiments that require it. Otherwise- useless for drilling and
> >cutting.  Mike
> 
> I'm looking for an UV laser to expose the presensitized PCB.
> IR laser is powerful enough for cutting/drilling but not for my project.
> Cristiam
> 
> > > > Any idea where to find the cheapest UV laser?
> > > > Cristian
>

cristian wrote:

> At 02:05 AM 10/15/2005, you wrote:
> 
>>nitrogen laser is only good as a source of koherent light for
>>experiments that require it. Otherwise- useless for drilling and
>>cutting.  Mike
> 
> 
> I'm looking for an UV laser to expose the presensitized PCB.
> IR laser is powerful enough for cutting/drilling but not for my project.
> Cristiam
> 

Assuming you have a suitable UV laser at your disposal, how do you plan 
on directing its beam as accurately controlled pattern on the surface of 
the pre sensitized panel ?

Obviously you would be aiming for a resolution capable of significant 
improvement over the 0.010 inch line and space limitation (while 
remaining reliable) of conventional inkjet/transparency/UV lamp/contact 
exposure.

Adam

>
>Assuming you have a suitable UV laser at your disposal, how do you plan
>on directing its beam as accurately controlled pattern on the surface of
>the pre sensitized panel ?

Using my CNC drill/mill machine. Also used for drilling.

At 01:44 AM 10/15/2005, you wrote:
>At 02:05 AM 10/15/2005, you wrote:
> >nitrogen laser is only good as a source of koherent light for
> >experiments that require it. Otherwise- useless for drilling and
> >cutting.  Mike
>
>I'm looking for an UV laser to expose the presensitized PCB.
>IR laser is powerful enough for cutting/drilling but not for my project.
>Cristiam

Why do you need a laser? A UV LED with a collimating lens should be 
sufficient. You don't need coherent light, and the only advantage then to a 
laser is the smaller beam divergence initially.

>Why do you need a laser? A UV LED with a collimating lens should be
>sufficient. You don't need coherent light, and the only advantage then to a
>laser is the smaller beam divergence initially.

Right, but where to find the Collimator?
Cristian

>Why do you need a laser? A UV LED with a collimating lens should be
 >sufficient. You don't need coherent light, and the only advantage then to a
 >laser is the smaller beam divergence initially.

Right, but where to find the Collimator?
The 250mW UV led is 6 x 6 mm and the necessary collimated beam has to be of 
0.0254mm diam.
Any solution here?
Cristian




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----- Original Message ----- 

From: "cristian" <cristianbip@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, October 17, 2005 5:41 AM
Subject: Re: [Homebrew_PCBs] Re: Cheap UV laser?


>
>>Why do you need a laser? A UV LED with a collimating lens should be
>>sufficient. You don't need coherent light, and the only advantage then to 
>>a
>>laser is the smaller beam divergence initially.

UV LEDs don't have anything like enough power.

Leon 

---
[This E-mail has been scanned for viruses but it is your responsibility 
to maintain up to date anti virus software on the device that you are
currently using to read this email. ]

At 01:08 AM 10/17/2005, you wrote:

>  >Why do you need a laser? A UV LED with a collimating lens should be
>  >sufficient. You don't need coherent light, and the only advantage then to a
>  >laser is the smaller beam divergence initially.
>
>Right, but where to find the Collimator?
>The 250mW UV led is 6 x 6 mm and the necessary collimated beam has to be of
>0.0254mm diam.
>Any solution here?
>Cristian

You're going to have the same problem with a laser, except the beam will 
start out with a 1-2 mm diameter instead of a 15 degree divergence.

Your problem is the same as that of a microscope. So consider using the 
objective lens of a microscope possibly along with an ocular lens. Just as 
with a microscope, you'd have to manipulate the distance in order to focus 
on the object plane.

This is why they call it "optoelectronics".

==========================================================
Robert A. LaBudde                      Email: ral@...
824 Timberlake Drive                   Tel: (757) 467-0954
Virginia Beach, VA 23464-3239          Fax: (757) 467-2947
==========================================================

At 02:19 AM 10/17/2005, Leon wrote:
> >>Why do you need a laser? A UV LED with a collimating lens should be
> >>sufficient. You don't need coherent light, and the only advantage then to
> >>a
> >>laser is the smaller beam divergence initially.
>
>UV LEDs don't have anything like enough power.

What's the power requirement to expose a photosensitive board?

Remember a 5000 millicandela LED will focused down to a 0.0254 mm point.

--- In Homebrew_PCBs@yahoogroups.com, Robert LaBudde <ral@p...> wrote:
>
> At 02:19 AM 10/17/2005, Leon wrote:
> > >>Why do you need a laser? A UV LED with a collimating lens should be
> > >>sufficient. You don't need coherent light, and the only
advantage then to
> > >>a
> > >>laser is the smaller beam divergence initially.
> >
> >UV LEDs don't have anything like enough power.
> 
> What's the power requirement to expose a photosensitive board?
> 
> Remember a 5000 millicandela LED will focused down to a 0.0254 mm point.
>

It becomes a problem of parallax error.

http://www.polyphoto.com/tutorials/LaserTag/ParallaxError01.pdf

You can reduce the apparent size of the source by either cutting off
the end of the LED flat, moving it further from the lense, or choking
it off with a pinhole.

It seems to me someone calculated all this in the past and it came out
to taking a ridiculously long time to expose a board this way.

Steve Greenfield

>You're going to have the same problem with a laser, except the beam will
>start out with a 1-2 mm diameter

actually 0.2mm with low divergence. This was the real reason of choosing a 
laser.

>  instead of a 15 degree divergence.
>
>Your problem is the same as that of a microscope. So consider using the
>objective lens of a microscope possibly along with an ocular lens. Just as
>with a microscope, you'd have to manipulate the distance in order to focus
>on the object plane.

I'll do. Don't know its spectral response, but I'll check.
Cristian

> > What's the power requirement to expose a photosensitive board?
> >
> > Remember a 5000 millicandela LED will focused down to a 0.0254 mm point.
>It seems to me someone

It was me, Stevens. Here you are the calculations:

My calculation is  like this:
For a board of 10x16 cm=160 cm2.

If all need exposured (maximum, no traces at all), it need 16000 mJ.

A 100 mW  beam (laser, or whatever) it needs 160 seconds exposure to get 
16000 mJ.
that is 2.6 minutes, a 25 mW laser will take about 10 minutes.

If the requested polymerization energy of 100mJ/cm2 is correct,
the above calculation is correct.

More than that, I've found that the energy is around 50mJ/cm2 for a lot of 
suppliers and
the peak spectral response is on 400nm.


>calculated all this in the past and it came out
>to taking a ridiculously long time to expose a board this way.
>
>Steve Greenfield



[Non-text portions of this message have been removed]

On Mon, 17 Oct 2005, cristian wrote:

> > > What's the power requirement to expose a photosensitive board?
> > >
> > > Remember a 5000 millicandela LED will focused down to a 0.0254 mm point.
> >It seems to me someone
>
> It was me, Stevens. Here you are the calculations:
>
> My calculation is  like this:
> For a board of 10x16 cm=160 cm2.
>
> If all need exposured (maximum, no traces at all), it need 16000 mJ.
>
> A 100 mW  beam (laser, or whatever) it needs 160 seconds exposure to get
> 16000 mJ.
> that is 2.6 minutes, a 25 mW laser will take about 10 minutes.

Are you saying that it takes 2.6 minutes to expose a single dot or 2.6
minutes to scan over an entire board?


-- 
David Griffith
dgriffi@...

Steve wrote:

>It seems to me someone calculated all this in the past and it came out
>to taking a ridiculously long time to expose a board this way.
>
>Steve Greenfield
>  
>
  Heard that, off hand most generally over estimate an LED's output many 
times as compared to other light sources..  A 100W lightbulb is equal to 
about 1000-1500 average 5000 or 10000 MCD white LEDs, and the factor is 
probably worse than that heading into the UV range..  When you start 
converting lumens and candles and working out the tiny angle for LEDs 
into the sphere for lumens it adds up quick.

Alan

cristian wrote:

>It was me, Stevens. Here you are the calculations:
>
>  
>
  I think he was talking past calculations for LEDs maybe, not your 
laser calcs..

>My calculation is  like this:
>For a board of 10x16 cm=160 cm2.
>
>  
>
  But what market have you seen a useful low power UV laser used in?  
High power cutting makes sense, low power has pretty low usefullness.  
Low power is generally much cheaper with bulbs, and what might use a 
lower power UV like a 3d prototyping machine is still a fairly expensive 
niche product.  Might be out there but I haven't seen much below $500ish 
used cutting lasers for UV..

Alan