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Heller vs. Vitronics

Views: 1834

Mk

#45319

Heller vs. Vitronics | 21 November, 2006

I am having issues with parts falling off a double sided board in the Vitronics but not in Heller oven. The oven profiles are as close to each other as I can get them. Does the Vitronics have more air flow? The Heller is an older oven and the chain doesn't run as smooth. I am not sure where to go with this. Any suggestions? Thanks

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#45320

Heller vs. Vitronics | 21 November, 2006

These machines are very different. It falls under "there are no two machines alike" category. When you say the same profile, do you mean the same setpoints, or the same actual board profile that you get from running a profiler with TC's on the board? If it is the same profile, you could be loosing parts becuase of more airflow or board movement. They may be reflowing on the Heller, but not falling off.

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#45325

Heller vs. Vitronics | 21 November, 2006

Hi Bill, I have profiled the boards using a KIC. The temperature the board sees is close as I can get it. This is not the only difference I have seen between the two oven but it is the one I haven't been able to workout.

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JAX

#45328

Heller vs. Vitronics | 21 November, 2006

Depending on Zone Temperatures, Belt Speed, and Board Density... Some Convection Ovens will drop Zone Temperatures faster than others. They recover by increasing Air Circulation. This can make parts fall off the Bottom-Side that otherwise would not have any problems.

You can check this by verifying wether or not the Blowers engage when the board enters your problem Zones. You will probably need "Real Time" board tracking to do this.

Some Oven models allow you to adjust the Blowers...

If you still cannot get anything to work, change profiles.

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CK the Flip

#45329

Heller vs. Vitronics | 21 November, 2006

Lowering your bottom-side zone temperatures might help too.

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#45331

Heller vs. Vitronics | 21 November, 2006

I'll also make the same reccomendation, I always make. Call the OEM. Vitronics tech support is pretty good, and they should help you out. I don't think the blowers turn on and off as suggested earlier, but I do think they have multiple speeds than can be set to (low, medium, high), and this may help. Specifically, if you have your top side heats higher than your bottom side heats, you will want to reduce the amount of convection. Otherwise, you are circulating all of the heat, and the top and bottom side will see about the same timperatures.

Good Luck.

E mail me your actual profile as if you have a chance.

Bill

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#45341

Heller vs. Vitronics | 22 November, 2006

Try lowering your blower speeds on the bottom zones. Works as well and lowering temps but easier to control than balancing your delta T from zone to zone.

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Hussman

#45345

Heller vs. Vitronics | 22 November, 2006

Chunks is right. She's recommended this in the past and it does work.

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Reflow Oven

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