Re: [Emc-users] Film Emulsion for Encoder Wheels?

[Peter C. W. <pc...@me...>]

On Tue, 28 Feb 2012, dave wrote:

> Date: Tue, 28 Feb 2012 22:04:50 -0800
> From: dave <den...@ch...>
> Reply-To: "Enhanced Machine Controller (EMC)"
>     <emc...@li...>
> To: emc...@li...
> Subject: Re: [Emc-users] Film Emulsion for Encoder Wheels?
> 
> On Tue, 28 Feb 2012 20:06:25 -0600
> Jon Elson <el...@pi...> wrote:
>
>> dave wrote:
>>> If anyone is really desperate I think I still have some KPR (Kodak
>>> photoresist) around. IIRC ... vacuum pull down the photomask over
>>> the substrate (board) expose with UV. Develop with toluene. Etch.
>>>
>>> Since I'm a packrat (I'm obviously relate to Neotoma cinerea ) ;-)
>>> the KPR is tucked away someplace. It may have auto-polemerized.
>>>
>> Arrgh!  Horrible stuff, horrible chemistry, terrible exposure control
>> and repeatability.
>> Use dry film resist, all aqueous processing with mild chemicals.
>> Vastly better
>> exposure control (I've used both, as you might tell from the above)
>> visible results after development so you know if the resist
>> expose/develop step went well before you try etching.  Think and
>> Tinker sells it in small quantities, I
>> believe.
>>
>> Jon
>
> Sorry you had such bad luck with it. I diluted it IIRC 1:1 with
> toluene, floated in on the copper, drained off any that would run off,
> let it dry, exposed it with a very intense UV lamp. Developed with
> toluene and then etched. Never had one fail.
>
> The UV lamp was the nasty part of it (about 1 KW); we used it to convert
> diethylstibesterol to a colored compound that could be measured in a
> spectrophotometer; not something one usually has laying around.
>
> Aqueous based chemicals are probably a safer way for most people to go.
> I did this a LONG time ago and was not aware of any alternatives.
>
> Dave



I used KPR many years ago and it worked perfectly (not too surprising as it 
was good enough for wafer masks. In fact I think the bottle I had came from 
Fairchild Semi's surplus store). It had extremely sharp line defnition and 
excellent development characteristics. I simply dipped bare cards in the KPR, 
baked in the oven, contact printed (sunlight!) with litho film I had exposed 
in a Speed Graphic 4x5 camera with a copy machine lense. At this point the 
KPR make a color change from greenish where unexposed to purplish where 
exposed.

Then I developed in the Xylene Toluene mix, no problems at all.

This is by no means a suggestion that anyone run out and buy some 
carcinogenic solvents and play with them in their kitchen (as I did)

>>
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>
> ------------------------------------------------------------------------------
> Virtualization & Cloud Management Using Capacity Planning
> Cloud computing makes use of virtualization - but cloud computing
> also focuses on allowing computing to be delivered as a service.
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Peter Wallace
Mesa Electronics

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