There are benefits to the higher Tg but most companies using lead-free do
not use it yet as the standard Tg for laminates has increase over the years
anyway. I have been running some trials specifically on standard and
material with a Tg of 170 but no interesting results from a process
prospective yet.

In the case of maximum temperature the problem is the variability that the
industry will see in reflow and rework hence the suggested need of 260C.
This gives process guys like me more tolerance in the process. Currently the
processes I have been working with can reflow at maximum of 245 for
convection, 230 for VP and 265 for wave. Remember many passives and active
parts go through the wave in the real world.

Rework can be controlled below 250 with the correct preheat. The key issue
is more attention to profiling boards, since the introduction of convection
many engineers don't spend the time on profiling?

Bob Willis
2 Fourth Ave, Chelmsford, Essex, CM1 4HA
Tel: 01245 351502
Fax: 01245 496123
Mobile: 07860 775858
Email: [log in to unmask]
Web: www.leadfreesoldering.com
Web: www.bobwillis.co.uk



-----Original Message-----
From: Leadfree [mailto:[log in to unmask]]On Behalf Of Reuven
ROKAH
Sent: 11 August 2003 07:37
To: [log in to unmask]
Subject: Re: [LF] Component Maximum Reflow Temperature Requirement


Hi All,

When designing a new PWB or making it to be LF comply, what requirements
are needed for each component or PCB, such as:

1.    PCB Tg. = 170 deg. C
2.    Components to be comply with reflow temp. of 250 deg. C

There is any agreed list of requirements?

Best  Regards

ROKAH Reuven

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