Homebrew_PCBs

 

Hi All,

I am considering buying a CNC engraver to manufacture protype PCBs on..
Just wondering What experiance everyone has with this...

Any information greatly apreciated..

Thanks in advance,

Peter T.

Hi All,

I am considering buying a CNC engraver to manufacture protype PCBs on.. 
Just wondering What experiance everyone has with this...

Any information greatly apreciated..

Thanks in advance,


Peter T.

Steve,

This is Liquid Crystal Thermography. Find a detailed paper here: www.srmuniv.ac.in/sites/default/files/files/SpecialimagingTech.pdf or just Google Liquid crystal thermography, and find out more than you ever want to know.

In a previous life, my Failure Analysis lab used them to locate microscopic shorts in semiconductor devices. The ones we used had a very short temperature range under which they would show color, otherwise they were clear. We used them with a black coating between them and the device we were examining, so that we could see the colors. I think the entire range that they would show color was approximately 5°C, with different materials for different temperatures.

Harvey

 

Saw some videos on what looks like an LCD type of chemical that changes
color with temperature.
Im looking to experiment with some chemicals that change color with
temperature, sort of like
a thermometer read by color instead of numbers.

Any ideas or sugguestions out there? I remember a couple of people here
seemed very good with
knowledge of chemicals. I happened to skip chemistry class in high school -
hehe.

Steve Hearns
Technotronic Dimensions, VT [USA]
WWW.TECHNOTRONIC-DIMENSIONS.COM
1.518.663.3421 (MAIN)
1-877-817-9885 (Voice / Fax Toll Free - US Only)
E-Mail: Steve@...
--
Webmaster, Parts-Link: (http://www.parts-link.com)
Group Moderator:
TV-Repair (http://groups.yahoo.com/group/tv-repair)
Monitor-Repair (http://groups.yahoo.com/group/monitor-repair)

----- Original Message -----
From: "Dennis Shelgren nojoeco@... [Homebrew_PCBs]"
<Homebrew_PCBs@yahoogroups.com>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, August 27, 2017 11:28 AM
Subject: RE: [Homebrew_PCBs] Re: Chemical question


Long ago I worked at Intel in "package, noise, and thermal". We had a bunch
of companies demo their individual products for finding hot spots, shorts,
etc.
One of the companies had a liquid crystal system. There were different ways
to apply it, and it was actually pretty neat to use. Of course the quicker
the process and more temperature zones we needed the more expensive it got.
For the boards we were working with, we actually had to "paint" it in
zones, i.e. broad temperature over most of the board, high temperature on 3
chips, and then some sensitive formula where needed.
Although it was cheaper than a thermal camera up front, we had to do a ton
of prep work each board. Afterward we had to photograph the board and
annotate the photos with the zones, temperatures, etc.
The sampler kit was something around $500, and it was composed of 75%
consumables.
After adding up all the prep time, unknown amounts of replacement "paint",
margin of error on thickness, and of course the occaisional need to replace
a chip on a coated board, it ended up being cheaper to get a $10-15k
thermal camera.
Nowadays, there are low res thermal cameras that snap onto a cell phone
starting at a couple hundred bucks. The software has only gotten better
over the years as well.

On Aug 27, 2017 8:05 AM, "'keith printy' keethpr@...
[Homebrew_PCBs]" <Homebrew_PCBs@yahoogroups.com> wrote:

>
>
> I used to have one. I remember 2 digits showing but if you knew how you
> could accurately read it.as I recall it was green when it was exactly
> that temperature and would turn more brownish below that temperature,above
> that temperature it was more bluish.by which numbers were lit you could
> figure out within about a degree what the temperature was.
>
>
>
> Also had a replica of a galileo thermometer with the floating spheres
> inside, this wasn’t very accurate the lcd was much closer.
>
>
>
>
>
> *From:* Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@
> yahoogroups.com]
> *Sent:* Saturday, August 26, 2017 10:43 PM
> *To:* Homebrew_PCBs@yahoogroups.com
> *Subject:* [Homebrew_PCBs] Re: Chemical question
>
>
>
>
>
> Probably a liquid crystal thermometer - they were sort of popular a few
> years ago, I haven't seen one in a while. From what I remember, their main
> problem was that they didn't jump discretely from one temperature reading
> to another - there were usually 2 different numbers showing at the same
> time.
>
>
>
> < https://en.wikipedia.org/wiki/Liquid_crystal_thermometer >
>
>
>
> Roy
>
>
>
>
>

Steve,

There are two different types of temperature indicating "paints." The type we have been discussing is part of a class of liquid crystal materials that are reversible. In other words, when ever you reach their temperature sensitivity range, they change color. Outside that range they are clear or black. You can do this over and over. As pointed out by Dennis, these materials are quite expensive. The other type is a material that is available as a paint or a waxy stick or as a stick on label. This material is applied as a small drop that has a particular color. When it's temperature range is exceeded, it undergoes a physical change, such as changing from dull to glossy. This is frequently used to determine if a piece of equipment has been subjected to excessive temperatures. This is a one shot deal. Manufacturer website: http://www.tempil.com/

 

Interesting.

So there is some kind of paint that I guess u can put on something,
and its color reflects the temperature of what its painted on?

Steve Hearns
Technotronic Dimensions, VT [USA]
WWW.TECHNOTRONIC-DIMENSIONS.COM
1.518.663.3421 (MAIN)
1-877-817-9885 (Voice / Fax Toll Free - US Only)
E-Mail: Steve@...
--
Webmaster, Parts-Link: (http://www.parts-link.com)
Group Moderator:
TV-Repair (http://groups.yahoo.com/group/tv-repair)
Monitor-Repair (http://groups.yahoo.com/group/monitor-repair)

----- Original Message -----
From: "Dennis Shelgren nojoeco@... [Homebrew_PCBs]"
<Homebrew_PCBs@yahoogroups.com>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, August 27, 2017 11:28 AM
Subject: RE: [Homebrew_PCBs] Re: Chemical question

Long ago I worked at Intel in "package, noise, and thermal". We had a bunch
of companies demo their individual products for finding hot spots, shorts,
etc.
One of the companies had a liquid crystal system. There were different ways
to apply it, and it was actually pretty neat to use. Of course the quicker
the process and more temperature zones we needed the more expensive it got.
For the boards we were working with, we actually had to "paint" it in
zones, i.e. broad temperature over most of the board, high temperature on 3
chips, and then some sensitive formula where needed.
Although it was cheaper than a thermal camera up front, we had to do a ton
of prep work each board. Afterward we had to photograph the board and
annotate the photos with the zones, temperatures, etc.
The sampler kit was something around $500, and it was composed of 75%
consumables.
After adding up all the prep time, unknown amounts of replacement "paint",
margin of error on thickness, and of course the occaisional need to replace
a chip on a coated board, it ended up being cheaper to get a $10-15k
thermal camera.
Nowadays, there are low res thermal cameras that snap onto a cell phone
starting at a couple hundred bucks. The software has only gotten better
over the years as well.

On Aug 27, 2017 8:05 AM, "'keith printy' keethpr@...
[Homebrew_PCBs]" <Homebrew_PCBs@yahoogroups.com> wrote:

>
>
> I used to have one. I remember 2 digits showing but if you knew how you
> could accurately read it.as I recall it was green when it was exactly
> that temperature and would turn more brownish below that temperature,above
> that temperature it was more bluish.by which numbers were lit you could
> figure out within about a degree what the temperature was.
>
>
>
> Also had a replica of a galileo thermometer with the floating spheres
> inside, this wasn’t very accurate the lcd was much closer.
>
>
>
>
>
> *From:* Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@
> yahoogroups.com]
> *Sent:* Saturday, August 26, 2017 10:43 PM
> *To:* Homebrew_PCBs@yahoogroups.com
> *Subject:* [Homebrew_PCBs] Re: Chemical question
>
>
>
>
>
> Probably a liquid crystal thermometer - they were sort of popular a few
> years ago, I haven't seen one in a while. From what I remember, their main
> problem was that they didn't jump discretely from one temperature reading
> to another - there were usually 2 different numbers showing at the same
> time.
>
>
>
> < https://en.wikipedia.org/wiki/Liquid_crystal_thermometer >
>
>
>
> Roy
>
>
>
>
>