Or new stencils or better board designs, or different paste, squeegees, or
what ever it is that is causing all those misprints.

-----Original Message-----
From:   Tempea, Ioan [mailto:[log in to unmask]]
Sent:   Friday, August 04, 2000 8:12 AM
Subject:        Re: Cleaning Of Misprinted Boards

Hi Martin,

I know this is not what you want to hear, but a whole system just to clean
misprinted boards seems far from being cost effective. How many misprinted
boards do you produce? If the answer is more than 2 or 3 per shift, you will
have to address your printing process. Maybe you'd be better off spending
money on a new printer.

And the no-clean paste goes very easily with IPA, don't have to buy fancy
solvents.

Just a thought,
Ioan

> -----Original Message-----
> From: Martin Bourke [SMTP:[log in to unmask]]
> Sent: Friday, August 04, 2000 6:56 AM
> To:   [log in to unmask]
> Subject:      [TN] Cleaning Of Misprinted Boards
>
> I am trying to source a system to clean misprinted PCB's from an SMT
> manufacturing process. The system needs to have the capability to remove
> both solder paste and (or) glue. It also needs to be able to cater for a
> wide range of double sided PCB's which are already built on one side using
> a
> No-Clean soldering process.
>
> We are currently using a manual washing process which consists of a soft
> brush which has a solvent is pumped through it ( Axarel 2200). The slovent
> is circulated through a large filter and re-used. The boards are passed
> through an Aqueous wash before going back into production.
>
> Option 1 - Ultrasonic's
> I have some concerns about the use of Ultrasonic's because we assemble a
> wide variety of products for various customers ranging from RF devices to
> P.C. motherboards and medical devices. I am nervous that the ultrasonic's
> may cause damage to some of the components on the PCB of affect the
> overall
> life-span and long term reliability of the product.
> Q1. Are these concerns justified ?
> Q2. Is there anyone else cleaning side 2 of PCB's which are already built
> on
> side 1 using an ultrasonic system ?
> Q3. Have there been any studies carried out on the effects of ultrasonics
> on
> discrete components, IC's, Tantalum Capacitors, Diodes, Transistors or
> Co-Axial Resonators ?
>
> Option 2 - Spray Wash System
> I have also been looking at what types of Industrial Spray cleaning
> systems
> are available. Are spray washing systems effective for the removal of
> solder
> paste and glue from via holes and plated through holes ? How successful is
> this type of system for cleaning misprinted intrusive reflow PCB's. Most
> of
> these systems use a water based cleaning agent in the washing cycle. This
> cleaning agent then needs to be rinsed off the PCB's before the board can
> be
> built through the rest of the process.
> Q1. Is anyone out there familiar with this type of system ?
> Q2. How is the rinse water treated / filtered before it goes to drain ?
> Q3. Are there any problems with the cleaning agent contaminating the water
> going to drain ?
>
>
>
> Martin Bourke
>
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