Andrew,
This temperature data is used for a couple of things. The first is establishing a process. The temperature profile needed for a process is a function of the component mixture on the assembly, the distribution of the components on the assembly, the board laminate material and the flux formulation used in the solder paste. By far, the dominate factor in this list is the flux formulation. In many cases, the flux formulation determines the maximum ramp rates, peak temperature, flux activation temperature, etc. If you do not meet these flux requirements, the results can be disastrous. Problems from non-reflowed connections, solder balls, blow holes, poor wetting ...... the list goes on and on.
The second use for this type of information is to maintain your process. This means taking a profile before starting to run product on the line to confirm that the oven is working the same way it did yesterday. Also, it is a good idea to run a profile periodically to insure that nothing has gone haywire in the system.
If you need any more information, just let me know.
John Guy
ACI / EMPF
714 N. Senate Ave.
Indianapolis, IN 46202-3112
voice: (317) 655-EMPF ext.130
fax: (317) 655-3699
e-mail: [log in to unmask]
-----Original Message-----
From: Andrew J. Scholand [SMTP:[log in to unmask]]
Sent: Tuesday, July 22, 1997 11:54 PM
To: [log in to unmask]
Subject: RE: Reflow oven temperature
I'm curious as to what kind of use this data is put to after its obtained. Are there 'rules of
thumb' which allow you to troubleshoot the oven settings based on raw data (i.e. I'm
familiar with the < 3oC/sec temperature ramp rule for reflow ovens), or does it need to
be processed in some manner (FEA analysis for example) before it can be used to fine
tune the process?
Cheers,
Andy
----------
From: Frank Hinojos[SMTP:[log in to unmask]]
Sent: Monday, July 21, 1997 2:03 PM
To: [log in to unmask]; [log in to unmask]
Subject: Re: Reflow oven temperature
Richard,
It is true that reflow parameters are important not only for the
soldering process but also for components! We have used the Datapaq
Reflow Tracker with great success. It is what is often termed a
"temperature mole". The tracker rides in the furnace with the part
and has thermocouple probes which take measurements. Trackers can
transmit data to a computer which yields real time analysis of the
part, i.e., temps, ramps, max peak, etc.
Frank Hinojos
Watkins-Johnson Co.
______________________________ Reply Separator _________________________________
Subject: Reflow oven temperature
Author: [log in to unmask] at INTERNET
Date: 7/21/97 4:24 PM
I am more familiar with test than board manufacture and would welcome
an answer to a simple question. The quality of the connection depends
on a number of characteristics of a reflow oven - pre-heat,
temperature and time in the oven. CORRECT?
If so, is there something I can attach to boards as they go through
the system to ensure that the settings are correct for the particular
boards? I am thinking of a substance that changes characteristics,
say colour, at a rate depending on the temperature. We manufacture
small quantities but large variety and thus the settings are
potentially needing changing regularly.
I want to eliminate faults before I have to test. I would normally
ask the in-house expert but he is taking a well earned rest.
Thanks in advance.
Richard Philp,
Test Technologist
Matra BAe Dynamics
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]> *
* with <subject: subscribe/unsubscribe> and no text in the body. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
***************************************************************************
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]> *
* with <subject: subscribe/unsubscribe> and no text in the body. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
***************************************************************************
|
