Hi Rainer & Eddie,
There is no practical way to avoid mixing infrared with forced convection, nor
is there a need to do so, nor is it desirable. By the very nature of having an
oven consisting of surfaces hotter than the PCB assemblies running through it,
you will get heat transfer by mid-range infrared radiation. Depending on the
convection gas, flow velocity and flow volume, and delta-T between oven and
assembly, the ratio heat transfer by convection and IR will vary. The so-
called Full Forced Convection ovens, have IR heat transfer contents of15 to
25%; conversely, with the so-called IR reflow ovens you get heat transfer from
convection as high as about 50%.
Having different heat transfer modes present actually contributes to more
uniform heating of your assemblies, because they have different shadowing and
therefore complement each other.

Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL  32174  USA
Phone: 904-437-8747, Fax: 904-437-8737
E-mail: [log in to unmask]

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
##############################################################