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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Hot Air Knife

Zvi Peretz

#1642

Hot Air Knife | 8 March, 2000

we are looking for any information that will help us do deside wether to implement that kind of system on our solder wave machine or not. Please advise equipment mfgr. and types.

Thanks, Zvi

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RDR

#1643

Re: Hot Air Knife | 8 March, 2000

So far, I have not been able to get any consistant or good results using one of these "problem solvers". I have managed however, to screw up some good processes. I believe that this technology can work though. I would reccomend contacting Speedline (electrovert)and have them review your needs. I have not used the Electrovert system and maybe they have some design enhancements that may sove some of the problems. I beleive that all of the HAK systems were once Hollis and each manufacturer has been tweaking on their original design. (Senbey, Electrovert, soltec, etc...). We purchased HAKs to try to eliminate shorting due to poor design of products that we receive. I would not use it as a band-aid for a poor process. As far as settings go we have tried 10-15 deg. angle at 700-800F with distances between .1 and .4 inches from board surface. Sometimes it works and sometimes it doesn't. So far it appears that each assembly requires a unique setup that can be difficult to have the operators perform consistantly.

Good luck

Russ

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#1644

Re: Hot Air Knife | 9 March, 2000

We used an air knife using foam fluxer and no clean flux to remove excessive flux from the boards for a better look afterwards. A secondary effect might be that the flux is forced into the vias giving you better results on the top. If you feel a need for such device you should check with the manufacturer of your wave, they have the thing you need and will set it up for you.

I don�t know if it�s still necessary with spray fluxer or other fluxes. I would consider measures like this only if there are some problems with soldering.

M2C

Wolfgang

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Boca

#1645

Re: Hot Air Knife | 13 March, 2000

By Hot Air Knife I assume (leave it alone Dave F.) that you mean a debridging knife located at the exit end of a wave solder machine.

Russ is right, they are not a good substitute for a good process, but once the process (w/o HAK) is developed, it is a good substitute for good PCB design! It is difficult to get set up right and consistantly, but by developing the setup, they can be of tremendous help. We typically run 4 to 10 degrees of angle, 800 to 850 F, as close to the pcb as possible, and about an inch from the trailing edge of the lambda nozzle. We found the distance from the wave to be a biggie (apologies to Wendys). We have had varied results depending on PCB design, sometimes we can completely eliminate solder bridges, sometimes only reduce them. Sometimes we can not use it due to features like large plated holes in the fab.... (can blow solder all over the top side of the assmembly)

- There is no substitute for good design for manufacturing -

Ours is factory installed on Electrovert equipment.

Boca

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Boca

#1646

Re: Hot Air Knife | 13 March, 2000

By Hot Air Knife I assume (leave it alone Dave F.) that you mean a debridging knife located at the exit end of a wave solder machine.

Russ is right, they are not a good substitute for a good process, but once the process (w/o HAK) is developed, it is a good substitute for good PCB design! It is difficult to get set up right and consistantly, but by developing the setup, they can be of tremendous help. We typically run 4 to 10 degrees of angle, 800 to 850 F, as close to the pcb as possible, and about an inch from the trailing edge of the lambda nozzle. We found the distance from the wave to be a biggie (apologies to Wendys). We have had varied results depending on PCB design, sometimes we can completely eliminate solder bridges, sometimes only reduce them. Sometimes we can not use it due to features like large plated holes in the fab.... (can blow solder all over the top side of the assmembly)

- There is no substitute for good design for manufacturing -

Ours is factory installed on Electrovert equipment.

Boca

reply »

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