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Rheopump vs. squeegee

vance

#6848

Rheopump vs. squeegee | 13 June, 2001

What kind of quality improvements could be expected by implementing MPM's Rheopump instead of using squeegee blades on a stencil printer?

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Dave G

#6851

Rheopump vs. squeegee | 13 June, 2001

I don't have any actual "hard" data to give on improvements but, I can share some experiences with you. What we noticed when we implemented the Rheo pump was: No more solder "skips" on our boards, Improved print quality on our BGA's & 16mil fine pitch (Using both Laser & Nickel Additive Stencils), Better throughput due to less operator interaction, Less wasted paste, Better printing on "large aperatures (Less Scoop-out). Some negatives were: Pump cleaning can be "painful" if you don't run 24/7, (Noticed that Rheo pumps that were not used for several days needed cleaning to remove "old" paste) Same goes for changing between Pastes if you don't have more than one Pump, PCB Support Tooling is absolutely critical (Can't Swag it with Pins or generic tooling to get by anymore - A big issue for quick NPI) Careful handling is requiired when servicing/cleaning to avoid damage to the pump sensors & blades.

Our experience has been very positive to this point. I wouldn't go back to blades for most of our products.

Hope this helps.

DG

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vance

#6853

Rheopump vs. squeegee | 13 June, 2001

Any solder paste reccommendations?

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Dave G

#6856

Rheopump vs. squeegee | 13 June, 2001

The only ones we've tried so far are Indium SMQ92 & AIM NC251 + one from Sinju (SP ?) that I can't remember the Part # for. They all printed fairly well. The pump seems to be a bit more forgiving than traditonal blades. The Rheo pump may mask some paste problems that could come out in an emergency switch back to blades. (We saw this with the Sinju paste when they accidentally shipped it in jars instead of tubes for a qualification run.)

Hope this is what you were looking for. Dave G

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dougk

#6866

Rheopump vs. squeegee | 13 June, 2001

We've tried the MPM rheo., with excellent results. We saw a decrease in fine-pitch pad coverage rejects from ~20% to bacicially ~0%. Print speeds went from 1-2 in/sec (metal blade) to 4-5 in/sec (rheo.). Could probably go faster. Great throughput. Little to no stencil cleanup after production (if using wet-vac underwipe system for finepitch). Currently using Alpha no-clean. Problems: Can't use OA chemistries yet, cleaning unit is a pain, and unit is somewhat fragile. Has anyone tried the "PastePuck" product. It's sort of the bargain-basement version of a rheopump. Have older machines we would like to retrofit to use this technology.

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vance

#6885

Rheopump vs. squeegee | 14 June, 2001

Could you guys comment on changing heads? We may have to change heads 6-7 times a day. What would be the negatives with this?

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Dave G

#6886

Rheopump vs. squeegee | 14 June, 2001

Are you changing heads because of pastes or just changing widths ?

Changing the head w/o cleaning is fairly straight forward. (Actually it's Pretty easy.) We have two widths - 8" & 12". We switch twice a day with very few problems but, we don't have to clean either very often because we use the same paste for all our boards and run 6-7 days a week.

Dave G

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vance66

#6888

Rheopump vs. squeegee | 14 June, 2001

We will be using the same paste for all boards. We would need to change head because of board widths.

Is the amount of time changing heads comparable to the time changing squeegee blades?

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Dave G

#6889

Rheopump vs. squeegee | 14 June, 2001

Change times for the Rheo pump are probably a little slower than just swapping blades. You have to hook up the sensors & air lines,remove the bottom cover + charge the pump to get it to operating pressure before you can print. I would guess that if you added up the time it takes to install & level a new set of blades you would be a bit faster than the time it takes to change pumps. (Probably only by a minute or Two) However, I haven't actually timed how long it takes to switch pumps.

One thing to consider is all the time you save vs blades while you're running. (Faster print speed, less operator interaction, fewer misprints) Not to mention the potential quality improvements. That's how I justified the purchase of the four pumps I have in house.

I'll see if I can time a switch today and I'll post it this afternoon.

Dave G

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vance66

#6892

Rheopump vs. squeegee | 14 June, 2001

Thanks, I'd appreciate an actual time.

How long was your downtime per rheopump install? I heard about 1 1/2 weeks per head. That included training as well.

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vance66

#6893

Rheopump vs. squeegee | 14 June, 2001

How long was your downtime on the install?

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pr

#6895

Rheopump vs. squeegee | 14 June, 2001

I have found all the advantages (that others have spoken about) are true. One thing to look at is the quick disconnect system that MPM offers which will reduce changeover times to almost the same as blades. It's well designed and so far, for us, has worked great.

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rpereira

#6904

| 14 June, 2001

Dave G

#6918

Rheopump vs. squeegee | 15 June, 2001

Timed an actual Change today.

It took about 6 min to actually change the head and then about a 2 minutes to start printing again after installing the new stencil & loading the program for the next PCB. The whole thing including stencil swap out & program load took about 12 minutes total. When I timed this everything was close by & ready to go. My operators say they can do it in in 15-20 min total under more "normal" conditions.

Our installs took about 7-8 hrs each. A lot of time was spent loading SW @ our site. Not including reprogramming afterwards. The field guy that did ours had done several before ours and was pretty familiar with the whole process. He had said some of the early installs took quite a bit longer.

Dave G

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Carl Evans

#6921

Rheopump vs. squeegee | 18 June, 2001

If you require several changeovers per shift the quick connect closed loop pump option would be your best bet.You can change between pump and blades within minutes. Hoever if you have several different size pumps a simple pump switch over would be perfect. You also may need to look at your board size range and investigate further into the pump size or sizes that would minimalise Change over. Example: If you have 6" 7" 8" 9" and 10" boards you may well be able to use the ten inch pump head with the correct suppport for all the boards of the above sizes.

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Carl Evans

#6923

Rheopump vs. squeegee | 18 June, 2001

The install of the new closed loop system is totally dependant on which m/c and levell of software you have. the maximum time it should take for a older m/c that has to have new wiring run in the m/c should take no longer than five days including training. Carl Evans: Speedline FSE If you have a newer m/c this can be achieved within three days with the m/c being able to run inbetween installation.

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Carl Evans

#6924

Rheopump vs. squeegee | 18 June, 2001

If you visit the Cookson web site you will find a detailed list of trials of pastes and how they performed within the pump.

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Brian W.

#7123

Rheopump vs. squeegee | 29 June, 2001

I have had some conversations with MPM about the Rheo pump. They have some data to support the change from an ROI standpoint. One of their customers has seen a dramatic decline in the amount of wasted paste, resulting in a very large cost savings. You can also run blades or the Rheo pump on the machine. The largest Rheo pump head is 16". Anything over that size has to use blades. You also cannot use the Rheo pump with stepped stencils. Overall, from the data I have seen, it is worth it to change to the Rheo pump.

Brian W.

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