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RoHS reflow ovens need more zones????

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RoHS reflow ovens need more zones???? | 6 November, 2006

Hi All,

I have vendors and even customers telling me that to properly run RoHS compliant products I should have ovens with more zones than my Heller 1500's. I have been running RoHS compliant product with these with very good results. So what are the reasons we need more zones? I understand the parameters of the reflow, and if there were throughput requirements then that would require more zones. I'm hitting the RoHS profile just fine with what I have, why do I need more zones??? I understand that the Oven MFG's want to sell more ovens, is that all this is?

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RoHS reflow ovens need more zones???? | 6 November, 2006

G, it is called, "I just went to a sales seminar on pbfree"

Show them your profile and call them to the table. Make them tell you specifically what is wrong with your profiles. and even better yet make them explain to you why the extra zones are necessity. Usually when they are faced with having to being technical you will get the "well that is what we were told by so and so" you then can tell them that this is reason why you build boards and they dont!!!

I have done this and no more discussion from anybody and yes it is a 5 zone oven!!! I used to do pbfree with a 3 and 4 zone as well.


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Jerry Butters


RoHS reflow ovens need more zones???? | 6 November, 2006

The "marketing geniuses" of the world are now touting lead free ovens, lead free irons, and even lead free smocks, heel straps, and even G-Strings!

Bottom line is - ya just gotta get it hotter, stupid! There's nothing "RoHS" about equipment besides the ability to get hotter.

Most modern reflow ovens can attain "RoHS" soldering temperatures - do the math... TAL for Sn/Pb = 183, and that for most Sn-Free is 220-ish, with peak temperatures 20-30 deg. more for lead free. It ain't that much more, mm'kay. ...not to mention, most "modern pastes" have very wide operating windows - as long as you attain sufficient TAL's and Peaks while still conforming to ramp up and ramp down rates.

If you are well versed in profiling and savvy with either manual or computer-assisted prediction, you can easily make a 5-zone oven do a RoHS song and dance through the right combinations of heater setpoints and conveyor speeds.

Obviously, with more zones you can do alot more with certain parts of your reflow profile - ramp, soak, and spike, and they're great for high-volume 'cause you can run them faster. A'd probably have to use a snail to calibrate your conveyor speed...BUWAHAHAHA.

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RoHS reflow ovens need more zones???? | 6 November, 2006


I have have to say Jerry's post here was one of the best I have read on the forum here. It has good accurate information combined with a very funny read.

I wish there was a top 10 best posts on this forum.


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RoHS reflow ovens need more zones???? | 6 November, 2006

G; Russ is spot on.

Butters; where can I get the Lead Free G-String? (no offense G)

Grant; get out more. (no offense Butters)

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RoHS reflow ovens need more zones???? | 10 November, 2006

What we've seen is more heated length gives you the ability to run the oven at a higher chain speed. Notice, heated length... not # of zones.

Needing to achieve higher temps at reflow can cause you to have to reduce your chain speed.

For lots of you, that might be a "big deal?" For me, it can be a big deal! We have several products where the oven is the slowest machine, right behind the printer. I think that sucks.

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RoHS reflow ovens need more zones???? | 10 November, 2006

Yep. If speed is not an issue a Heller 1500 will pretty well do you fine unless you are trying to process a brick. A Heller 1700 will not give you any more heated length, so don't get sucked in to that one. However, they are a little more fun to play with and are now cheaper than the 1500. Cooling rates are sometimes mentioned; as I have quoted several times before from a paste guru:

"The cool down rate is not as critical for Pb-free solder joints, as it was for SnPb. The grain sizes do not differ is size in the Pb-free bulk solder until you get to a cool down rate much greater than 6 degrees per second."

Not one oven purveyor has taken issue with that statement. Your paste metallurgist will agree. Go you good thing 1500.

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