I can only agree with Brian, you need to check the actual work. [I don't
think you could even rely on it producing a relative/comparative check for
the reasons given by Brian.]
I have seen people under cleaning badly after using a transparent test piece
intended for solder wave checking for visual cleaning check.
Also people over and under specifying their cleaning after putting
inappropriate coloured and fluorescent dyes into flux and looking for
absence of that post cleaning. They either overlooked that 'cleanability' of
the dye was far less/more than their flux, or that the die was not heat
stable and went clear on reflow, or chose a fluorescent die that was barely
soluble in the flux and so on.
Hazards of under cleaning are obvious, but over specifying can also be
hazardous - wasting a few ten thousands on capital equipment and ongoing
with excessive material and process control costs is a good way to damage
competitiveness.
Regards
Mike
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Brian Ellis
Sent: Thursday, June 16, 2011 12:34 PM
To: [log in to unmask]
Subject: Re: [TN] TRANSPARANT BARE BOARD FOR CLEANING TESTING
If I understand what you are trying to do, there is a strong chance you
may be disappointed. To do cleanliness testing, you simply cannot change
the base material because the hydrogen bonding and adsorption
characteristics of the contaminants will be different. To take extreme
examples: FR-4 and borosilicate glass. Because FR-4 is organic and the
glass is inorganic, the glass will normally be cleaner, as the flux
residues will be organic. Then the FR-4 does not have a smooth surface,
which the glass does, making physical adhesion stronger with the FR-4
because of the greater surface area. The FR-4 surface is porous and the
pores open when passing the glass transition temperature of the epoxy
substrate, allowing contaminants to be trapped in the first µm or two of
the surface. Glass does not have a porous surface to the same extent.
Sorry if I have the wrong end of the stick.
Many, many years ago, I came across a thick, transparent,
non-reinforced, copper-clad laminate made from a styrene copolymer. It
was designed for precise low-loss reflection-free microwave
applications. I remember that it cost an arm and a leg but I cannot
recall the details. I can't remember the manufacturer (Rogers Corp.?????)
Brian
On 16/06/2011 10:16, Lars Wallin wrote:
> Hello All of You,
>
> Does anyone of you know anyone who can manufacture the following types of
boards?
>
> Volume: 200.
> Size: 100 by 100 mm
> Layer: 1.
> Base Material: Transparent (This is a must)
> Thickness: 2-3 mm.
> Solder mask: Green.
> Surface finish: At your choice.
> Delivery time: Short.
> Gerber files for Cu pads and tracks plus solder mask will be supplied.
>
>
> Best Regards
> Lars Wallin
> IPC European Representative
> Location: Stockholm, Sweden
> Phone: +46 8 26 10 07
> Mobile: +46 70 212 74 39
> Email: [log in to unmask]<mailto:[log in to unmask]>
>
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