Hi Technet,
this topic is being a hot and recurrent topic on this Net. Consequently, a
lot of the opinions are of value. However, it would be great to have more
specific data. The various parameters to monitor have been covered, but what
are the actual target values for the flux sprayed on the plate, for the
contact length, etc? And why?
Give my regards to broadnet,
Ioan
> -----Original Message-----
> From: Yves.Dupuis [SMTP:[log in to unmask]]
> Sent: Friday, October 05, 2001 2:01 PM
> To: [log in to unmask]
> Subject: Re: [TN] SPC @ WAVE SOLDER
>
> I agree that understanding the relationships, in your process, between the
> key variables is what matters most. SPC is a system designed to quantify
> your natural variation and provide visual tools to detect when your
> process
> is affected by some other cause of variation. The correlations between
> variable are usually determined under specific conditions. SPC is best
> used
> to detect changes in conditions that render the models you've developed
> invalid and/or inaccurate. For example, regardless of what the maintenance
> records say, I can tell when the schedule for pump cleaning has not been
> properly followed using my dwell time charts. Since the model which tells
> me
> which parameters are optimal (including pump speed) assumes this
> maintenance
> is done in a certain manner, when maintenance is late the process drifts
> away from optimal. The SPC charts warn me this is happening.
>
> yves
>
> > -----Original Message-----
> > From: Earl Moon [SMTP:[log in to unmask]]
> > Sent: Friday, October 05, 2001 12:08 PM
> > To: [log in to unmask]
> > Subject: Re: [TN] SPC @ WAVE SOLDER
> >
> > I still live in the glass plate and matrix world. Simple correlations
> > between variables as conveyor speed, temps, topside measurements,
> managing
> > fluxes and their applications, wave height, contact area parallelism and
> > dwell time all make solder joint attributes clearly acceptable or not.
> SPC
> > is used in a number of the variables and provides, again, correlation to
> > the
> > matrix (relative to PCB thermal mass, as an example) and the effects of
> > good
> > process management. Though wave soldering has a few more factors,
> compared
> > with hand or reflow soldering, the basics are all the same, to me, for
> > each.
> > I'm a simple fool and can't change at this point when it works.
> >
> > MoonMan
> >
> >
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