Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Reflow profile basics

snehal acharya

#28487

Reflow profile basics | 8 May, 2004

pls can any body throw some light on the reflow profiling? what r the basic requirements of thermal profiling? how we can achive better profiling? what is the need of doing profiling? what precaution should one take while doing profiling? profile is compared with what?

this r all basic question,which i want to know,since i have started this SMT now.nobody there to guide me.i'm refering the catloge & standerd procedure & doing it that way. but as an Engineer i want to do the thing systematically. so pls tell me in details . if anybody has time to answer my querries.

regards, Snehal Acharya. Production Engineer.

reply »

#28506

Reflow profile basics | 10 May, 2004

Q1: What are the basic requirements of thermal profiling? A1: Not sure what you�re looking for here, but when doing a profile, you�re trying to measure the temperature at specific points of the board, as the board moves through the oven.

Q2: How we can achieve better profiling? A2: Use a good profiler and thermocouple[s] and attach the thermocouple[s] properly.

Q3: What is the need of doing profiling? A3: Some purposes of profiling are: 1. Assuring that the settings of the zones of your oven a set to properly reflow solder. 2. Checking the proper operation of the oven 3. Measuring the temperature at specific points of the board, as the board moves through the oven. 4. Controlling reflow soldering process. 5. Qualifying ovens.

Q4: What precaution should one take while doing profiling? A4: Use hot pads when handling the type of profiler that travels through the oven.

Q5: A profile is compared with what? A5: Your profiler needs to be calibrated, your thermocouple needs to be correct type and operating properly.

To learn more: * Check profiler supplier [eg, KIC, ECD, etc] sites for technical papers * Search the fine SMTnet Archives for more on profiling and thermocouples. For instance: http://www.smtnet.com/Forums/index.cfm?fuseaction=view_thread&CFApp=1&Thread_ID=6929&mc=12

reply »

#28554

Reflow profile basics | 12 May, 2004

woow, slow down hot rod, hey davef, you are alright by me, good to see some one out there that has hands on experience rather than a theory nut.... any how, you need a top of the line profiler, super gold mole, or Kic.... these truly are the best and software is best... it is MOST important once again to establish compatibility between your oven configuration and the solder paste you are using, the information is to then help you adjust the profile base on the type of board configuration being processed, this will give you the most Robust profile and process. take the time to go to one of ECD's seminars in your area... sounds like you need to attend a SMTA meeting as well, if you are having problems with profiles, I would assume your experience with the paste and print process are limited as well.... 90% of all defects start with paste control, print and deposition..... you could use a basic profile and get great results... check were you need to be...

reply »


RDR

#28570

Reflow profile basics | 12 May, 2004

Mark @ SolderStar

#28571

Reflow profile basics | 12 May, 2004

In answer to your questions.

(1) pls can any body throw some light on the reflow profiling?

Reflow profiling is the process of confirming that you PCB's that pass through your reflow oven are produced within specifications provided by solder paste and component manufacturers. Each solder paste as a defined process window in which good solder quality will be achieved.

what r the basic requirements of thermal profiling?

Key parameters to be measured are; (i) Time above liquidus - time spend above liquidus temp. of solder paste (measure in seconds( (ii) Heating rates : ensures PCB/components are not thermally stressed (measured in C/Sec) (iii) Peak temperature : typically 20 - 30 C above liquidus temp. but not too hot else possible component damage etc. (iv) Cooling rates (v) Soak time : ensure delta across PCB is adequately low and that is flux activation is correct as per the definition of the paste guys. (vi) ..... and more

how we can achive better profiling? Get a pass through profiler (i.e. it passes behind the PCB through the machine), long thermocouples are a pain in the arse and repeatable results are not guaranteed. I have yet (thankfully) to see a reflow oven with profiling software that is any where near up to the job.

what is the need of doing profiling?

(1) Ensure solder quality is good (2) Optimise through put (3) Minimise recipe count (4) Reduce rework, early failures (5) Keep me in a job

what precaution should one take while doing profiling?

(1) Make sure you use the heatshield to protect your logger!! Your datalogger won't last long without it (2) Ensure your datalogger & test PCB is adequately cooled before performing your next run

profile is compared with what?

Any form of calibration or process control. The aim is the same. Machine go wrong, people lose oven setups or load the wrong one. The result is a bad process & unhappy customers.

I hope this helped,

Mark SolderStar - Temperature Profiling for Reflow & Wave www.solderstar.com

reply »

reflow oven profiler

Reflow Oven