Hi Graham, no I think we are in agreement, or at least not in dispute.
Thanks for the opportunity to clarify.
- the amount of energy required to melt the solder is the amount required,
you have to pay for it irrespective of method. The medium for transferring
from the electrical heater to the solder is free if air not if chemical. I
agree that there will be differences in efficiency one machine type to
another, one medium to another and between realisations of the same process
between manufacturers, and this is what you have to evaluate as suggested.
Possibly the cost of the vapour may well not be incremental in that context.
My remarks were an opinion about saturated vapour phase, I should have said
batch saturated vapour phase, unsaturated or inline machines may well be
different, see above.
Kind Regards
Mike Fenner
Applications Engineer, European Operations
Indium Corporation
T: + 44 1908 580 400
M: + 44 7810 526 317
F: + 44 1908 580 411
E: [log in to unmask]
W: www.indium.com
Leadfree: www.Pb-Free.com
-----Original Message-----
From: Graham Naisbitt [mailto:[log in to unmask]]
Sent: Monday, May 27, 2002 5:05 PM
To: [log in to unmask]; [log in to unmask]
Subject: RE: [TN] SV: [TN] Vapor phase
Mike
Your info is not quite correct.
Consider: Running cost for latest VP system as my message described is
<US$2 per hour including capital amortisation. Air may be free, but
electricity isn't and nor is Nitrogen.
Regards Graham Naisbitt
Concoat Limited
Alasan House, Albany Park
Camberley GU16 7PH - UK
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Mike Fenner
> Sent: Monday, May 27, 2002 14:20
> To: [log in to unmask]
> Subject: Re: [TN] SV: [TN] Vapor phase
>
>
> Brian:, its not the dissolved oxygen so much as the fact the
> vapour doesn't displace all the air.
>
> Björn: At the risk of being pedantic, an advantage of
> saturated vapour phase, and a principal factor in its
> original introduction for back plane soldering, and
> subsequent adoption in surface mount, is its ability to heat
> very uniformly almost irrespective of work size or geometry.
> This uniformity allows ramp rates which are much higher than
> is possible with other mechanisms for heat transfer.
>
> Anyone: However VPR heat transfer fluids are more expensive
> than, and clearly have an environmental impact which is
> greater than, the most common alternative medium used in
> conventional reflow ovens. Air is free :)
>
> The process advantages of VPR - which I fully appreciate -
> have to be set against its costs and disadvantages on a case
> by case basis. IMHO I think that this sort of analysis will
> show that for odd geometries heavy parts mixed prototyping
> etc, and for adhesive [epoxy] curing, saturated VPR has some
> attractions. Certainly it's a process which is hard to get
> wrong on one offs, but its harder to get really optimum on
> longer runs.
>
>
> Kind Regards
>
> Mike Fenner
>
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