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Pre heat temperature in Solder wave

Kev

#26615

Pre heat temperature in Solder wave | 16 December, 2003

I am having problems achieving correct pre-heater temperatures with our Hollis solder wave. Our original "Verification Golden board" program uses a conveyor speed of 5ft per minute and pre-heat temps of 300, 350, 400 respectively. Our "golden Board" procedure states that it is possible to achieve betwen 105 & 125degC post pre-wave zone with these settings. I am unable to get near it though. The highest temp I can get to is ~ 85degC. This is with the tunnel fume extraction throttled back almost fully where I was loosing between 5 & 6 deg as a result of heat evacuation. I have checked all elements individually and none are dead. I also replaced the 3 thermocoupled pre-heater elements just in case they might be defective but this made little difference. Our problem is over the past, our operators have gradually raised the pre-heat temperatures and slowed conveyor speeds on a lot of programs to achieve good board heating. Our process is now out of control from an ISO point of view. To give you an example of one of the programs, The original settings were : 450, 500, 500, conv speed 4ft/min the settings are now at : 520, 545, 550, conv speed 3.65ft/min This is to achieve 90 -100deg C post pre-heat zone.

I am running out of ideas on how I might raise the temp to the specified 105 - 125 degC ?????

Any inputs?

Kev

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#26616

Pre heat temperature in Solder wave | 16 December, 2003

What model is your Hollis? Does it have the coil heater?

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#26617

Pre heat temperature in Solder wave | 16 December, 2003

Sounds like your preheat temperature controllers are out of adjustment. Check your operating manual for instructions.

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RDR

#26618

Pre heat temperature in Solder wave | 16 December, 2003

Has anyone possibly moved the location of your thermocouples? if not check the calibration of your temp controllers/ thermocouples.

Russ

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#26619

Pre heat temperature in Solder wave | 16 December, 2003

Kev,

I looked up records of various hollis machines with 3 preheat zones. and with progressive preheat temp. of 300 400 and 500 with a speed of 3.5ft/min the topside board temp was 120C before entering the wave. the preheat elements were infrared. Where and how do you measure the board temp. did you change flux type since you implemented your golden board procedure or did your board layout drastically change.

Best Regards, Patrick

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Peter

#26623

Pre heat temperature in Solder wave | 16 December, 2003

Maybe you fixture is too large for your product. If so, please redesign your fixture

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Kev

#26629

Pre heat temperature in Solder wave | 17 December, 2003

Hi Lads, Thanks for all of the replies. To answer a few of your questions..... My wave is a Hollis PT500N. It has 3 zones of pre-heater rod elements. Each individual element (601195-01) is 500 watts. There are 16 elements per zone so 8 Kw per zone. I use a datapac 9000 profiler to measure my board temp, with 3 thermocouples hard wired to specific locations (leading edge, middle, trailing) on the actual PCB. Theres not a huge temp range between the 3 thermocouples. The golden board design has not changed since its initial use, nor has the "golden board" program changed. The flux used has not changed (Alpha 857 flux & 425 thinners) The golden board was chosen when we first installed the machine to have it as a standard to verify the machine going forward. Our operating procedure doesn't have instructions for adjusting the preheat controllers. I have been "cover to cover" looking for it in both manuals several times over. Is it done by software or are there some vari-pot adjustors somewhere? Has anybody the info I require?

Kev

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ex maintain leader

#26630

Pre heat temperature in Solder wave | 17 December, 2003

140..155 degrees celsus the limit is your inserted component temp schock tolerance

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#26633

Pre heat temperature in Solder wave | 17 December, 2003

Kev,

It looks like you have a preheating powerplant and you still only get the board up to 85 Deg. This indicates that the preheating is out of calibration or the range settings might be very wide (Fex the preheat elements shut down at 500 and go back on @250) your program must have a range setting. If you can get hold of a calibration or service manual it will have the information you need to correct the problem.

Good luck Patrick

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Dean

#26650

Pre heat temperature in Solder wave | 17 December, 2003

How do you know your profiler is correct? Do you have a pyrometer you can verif the PCB temp with?

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Chandler

#26660

Pre heat temperature in Solder wave | 17 December, 2003

Kev, You seem to have a very good knowledge of your process and can convey it clearly and precisely. My advise to you is to dis-regard the BS most of these guys churn out and follow your own gut. They will ask a s**t load of irrelevant Q's in some futile attempt to impress each other. Knock on effect is they waste your time..... IMHO, C.

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RDR

#26681

Pre heat temperature in Solder wave | 19 December, 2003

What?

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Ron Herbert

#26685

Pre heat temperature in Solder wave | 19 December, 2003

Kev,

If I remember correctly, Hollis used calrod preheaters on that machine and they had a reflector under the elements to reflect the radiant waves back to the PCB.

You might want to clean the reflector. If it is too far gone, use some Reynolds Wrap.

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