Author Topic: Solder paste machine  (Read 6018 times)

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Offline FreeThinkerTopic starter

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Solder paste machine
« on: April 17, 2011, 01:55:34 pm »
Hi Dave
What caused the miss registration? did the board move? (it looked like it was flexing a lot) or did the machine miss a few steps? For a machine of this cost going out of sync so quickly would be strange (and frustrating)
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Offline Rufus

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Re: Solder paste machine
« Reply #1 on: April 17, 2011, 02:56:25 pm »
I was surprised it was so slow. I imagined a paste printer would be more like an inkjet printing a raster at higher speed. How would the results compare with screening using a plastic stencil which you could cut at least as fast and with I guess a substantially cheaper machine? I imagined paste printers would be viable for runs of one off to a few tens off, hard to see this machine beating a stencil for more than a few off.

I was surprised it dispensed with air pressure (and the hassle of needing that huge regulator/filter box). Too many variables to be accurate compared to say a lead screw and plunger. But then I saw the nozzle was poking the board so I assume the nozzles have sort of cupped ends which seal against the board leaving a defined volume to be filled by the pressurized paste. The nozzle contacting the board would account for the minimum 'dot' pitch restriction which was mentioned.
 

Offline FreeThinkerTopic starter

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Re: Solder paste machine
« Reply #2 on: April 17, 2011, 06:50:02 pm »
I think that it is also aimed at rework of small batches. You could not screen print a board that was partially populated and needed (say) an fpga chip to be fitted or refitted.
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Offline vaneenbergen

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Re: Solder paste machine
« Reply #3 on: April 17, 2011, 06:52:55 pm »
there are highspeed dropjet past dispencers for production rns. but these set you back 320k.
we use stecil machine also for proto.
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Online mikeselectricstuff

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Re: Solder paste machine
« Reply #4 on: April 17, 2011, 09:51:31 pm »
I think it's aimed at low-volume and protos, although if you think about it,  for feeding one line it only needs to be slightly faster than the pick & place. Mydata do a solderpaste-jet printer for higher end users, although it looks similar in , this info suggests it can do up to 500 droplets per second.

I know the higher end dispenser systems use screw-augers instead of pneumatics for precision dispensing.
 
What surprised me was for an expensive bit of kit, why wasn't the software optimising the move path - it was flying back at the end of each BGA row instead of zig-zagging.
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Offline EEVblog

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Re: Solder paste machine
« Reply #5 on: April 17, 2011, 10:42:09 pm »
Hi Dave
What caused the miss registration? did the board move? (it looked like it was flexing a lot) or did the machine miss a few steps? For a machine of this cost going out of sync so quickly would be strange (and frustrating)

We just didn't take enough care in the registration, it was only for a quick demo.

Dave.
 

Offline Leo Bodnar

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Re: Solder paste machine
« Reply #6 on: April 18, 2011, 08:51:52 am »
What surprised me was for an expensive bit of kit, why wasn't the software optimising the move path - it was flying back at the end of each BGA row instead of zig-zagging.

Backlash avoidance?
 

Offline Andi

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Re: Solder paste machine
« Reply #7 on: April 21, 2011, 11:55:32 am »
Those machines really are for prototyping and small batches only. They work in a sequential manner, so every pad you add increases your production time. You don't want to wait for a board with a few thousand pads! But a good stencil costs way more than the time you put into this.
Misalignment is also a very common problem in solder paste printing, you have production offsets in every component (okay, here you only have a PCB...), further it's very important to choose reliable fiducials. After all, some fine tuning to eliminate the last offset usually doesn't hurt! But for a quick demo the result isn't bad at all.
Here at work (German University, research in electronics production) i'm sitting next to the exact same machine - the Martin Dot-Liner-06 - every day! Just haven't used it yet, i think after your video i might fire it up some day  ;)
 


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