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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


IR oven profiling

#24498

IR oven profiling | 14 May, 2003

Does anybody have any advice on how to get a decent profile out of a 4 zone IR oven? Should top heat and bottom heat be proportionate? Are there any tricks to use?

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#24506

IR oven profiling | 15 May, 2003

Unless you have a reason, set your top and bottom to the same temperature.

Tip: Don't run dry cleaners bags through the oven.

Tell us about: * Paste you intend to use. * Specifics of your oven, including length of each of the heating and cooling zones. * Tools you plan to use to measure the temperature of the board while it is in your oven.

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#24526

IR oven profiling | 19 May, 2003

Hi, I can give you a few steps. 1. The solder paste. Take the profile that manifacturer gives for the paste. 2. Use termocouple to measure the tempereture. Put PCB and measure the temperature in equal terms. 3. Compare your profile to manifacturers one. If they match it's OK.If not do it again with other temperatures. About equal zones: If you make the first side -equal. If second-not.

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#24527

IR oven profiling | 19 May, 2003

Dave,

We are using Kester Easy Profile 256 No clean Sn62Pb36Ag02. The oven itself is a Dima SMRO-0252 which is a short oven, it has 13" of preheat, 13.5" of soak, 6.25" of reflow, and 10" of cooling on the way out of the oven. We are soldering multiple copy arrays from 7"x9" to 7"x13" in size which have chip resistors, ceramic chip caps, aluminum electrolytics, soic, crystals and melf diodes. The oven has inputs for 2 thermocouples and puts a graph up on its display showing time vs temp.

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#24528

IR oven profiling | 19 May, 2003

Curious. Are you finding no applications support from Dima or Manncorp (if a USA Dima customer) or Kester for that matter?

DIMA SMT Systems NL. B.V. Beukelsdijk 2 5753 PA Deurne Netherlands Tel: +31 493 352 752 Fax: +31 493 352 750 sales@dimasmt.nl www.dimasmt.com

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EnthDegree

#24542

IR oven profiling | 20 May, 2003

How are you attaching your thermocouples?

When using HT solder, the solder/TC surface of the joint can be reflective. This condition coupled with the IR can give you false temperature data since some of the heat is reflected away from the TC.

Let us know,

Cameron

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Brian W.

#24549

IR oven profiling | 21 May, 2003

Something else to keep in mind when you reflow using an IR (non-convection) oven. IR reflow is more susceptible to variations in board mass and coloration than convection ovens. Hi mass areas and dark colored parts will cause more variation in your profile. I would recommned using a thermal profiler with at least 6 thermocouples attached in different areas of he board. I did some comparisons back in the mid-90's between IR and convection ovens. Using the same process parameters (board, profile, thermocouple locations, etc), the variation on the convection oven was all within 10�C. The IR oven varied as much as 50�C. It is possible to get the board variation tighter on the IR oven, but it requires more attention to the board design and more repetitions.

Brian

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#24582

IR oven profiling | 23 May, 2003

Cameron, I am burying the thermocouple in high temp solder on the solder pad of the area I want to profile.

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Kris

#24585

IR oven profiling | 23 May, 2003

Hi,

I think using a epoxy glue will be a more approriate process for a IR oven than kapton tapes or high temp solder

Comments ?

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reflow oven profiler