PCB assembly versus shared equipment

Chat about pick and place machines, reflow ovens, assembly techniques and other SMT tips & trix

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bootstrap
 
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Re: PCB assembly versus shared equipment

Post by bootstrap »

I found someone with the same pick-and-place machine I plan to buy (and similar but slightly cheaper stencil printer and reflow oven). I sent him my PCB photos, gerber files and BOM, and asked his opinion. The following is his response. Note quite as negative as you... but still warns "it isn't as easy as it looks".

For an entry system I now recommend people use Diptrace and I see from the files you sent that you use it.

Using modern components on old equipment is a recipe for frustration and horror stories. I don't see any reason why your boards can't be assembled on the equipment you listed. You will have a learning curve though because Pick and Place machines are not as simple as they may appear at first glance. Even things like threading the tapes through the feeders takes a bit of practice to get it right, specially Digireels or Mousereels that have splices in them. Then getting the tension right on the take up reel for the cover tape also takes a bit of practice. I thought I had mine perfectly set up and then found the tension a bit low as the take up reel got full. Another fun thing is learning how to remove a tape from a reel without scattering components all over the workplace and into the innards of the machine.

Before dropping a bunch of money on a set of equipment I sincerely suggest that you visit the manufacturer for a few days and see the machines in action. In a few months Novastar has an open house where they will demonstrate all their equipment and it would be good if you visited them.

In terms of equipment, I still think the LE40 is great value for money and it works really well. It is wonderfully accurate and the software is very good, second only to the MyData machines which cost more than $100k. Spending money on a good stencil printer is a really good idea. You live and die by the quality of the solder paste deposit on your PCB. Almost all my assembly problems trace back to solder paste issues and a few to the temperature profile in the oven. I have very few issues relating to the placement of the parts. There are a few components which are problem children; I designed a pot into one of my boards. I haven't used a pot in more than 10 years, I dislike 'tweaking' things. The first pot I chose wouldn't pick properly. The manufacturer chose to put a 3x3.5mm pot in an 8mm tape and there simply isn't enough room to clear the edge of the feeder. I just switched to another brand of pot. Another thing I learned is to avoid lead free HASL as a board finish for surface mount. I now use ENIG exclusively. Lead free HASL is not particularly flat but that is not nearly as important as the fact that it oxidizes during storage leading to solder issues. ENIG is flat and it solders really well even after extended storage.

Regarding the person with the horror stories of assembly problems I have this to say; Cell phones are assembled in the millions per day with really tiny components like 01005 with perfect yield (no rework) and tiny 0.4mm BGA parts that dissipate 1.5W of power without heatsinks. Assemblies similar to that is done every single day in Si Valley on much lower cost equipment than used in the phone factories with great results. Knowledge is an important part of the process and skimping on the wrong part of the process will drive you nuts.

Everything electronic is headed towards SMT, so learning how SMT assembly works is essential.

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alphatronique
 
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Re: PCB assembly versus shared equipment

Post by alphatronique »

Hi

whit better word it in essence said same as me ...

not forgot that in SI all shop do it board on big machine

i find nice video today that show extreme slow motion of a GSM machine feeder in operation
very nice http://www.youtube.com/watch?v=275BCu9lQJQ

and machine in operation ..
http://www.youtube.com/watch?v=6Ed0A7Sa8Os

i have room for this you may sure that it was part of the shop the one of the better money for the buck machine
available on used market ,mydata was good but to popular for short run so price keep bit high

not forgot that buy used machine was same process as new one , you ask to see it work first and that one whit supplied on site training , if seller not do that not touch it , and honestly if "BIG" machine made for 24/24 7/7 prod
have place 2-3 million part then still assemble perfect one of your board ,did you really think it will die just after this one ?
you said that you plant to use it very low usage ,so normally it will last you life time ,ok you will have some maintenance to
do but that true even on new machine ,and personally i see more issue on new machine that on used one (if you not buy boat anchor)

and last tip i may tell if you plant to do 0201 try buy machine that do 1005 that will keep mind in peace
like on my machine i use 0201 for all calibration ,and adjustment run ,then when yeil was good < 5% bad part ,miss pick , part missing etc etc .. i knot that will have 99.99% working on target 0402 and for make it will not pass the day to empty reel of part on testing ;-) my current test board have 1500 0201 on it so take <15 min to validate whole system healt

and keep in mind the extreme slow motion of the feeder ,you not knot now but it really amazing ... not vibration ,part cover
and perfect aligment under ~30 MS

ha and last ,never forgot that it i miss to pick a part and try to place the part , that start of big problem
since nozzle will touch past ,past make it sticky ,and reduce air flow end result was succession of more bad part
and more past on nozzel , that pain ... ( more part was small more it a issue) that was issue to any manufacturer
so i repeat it , feeder ,feeder ,feeder bad feeder design on the best machine = bad assembly ...
and ok aps gold feeder was not so bad for the kind of low end machine ,but it relfow was bad and it mechanical centering let me bit perplex as per it design ,you will Quily find that mechanical centering was a must and when work good it superior to vision on many aspect , honestly i almost never use vision ,but mydata have excellent mechanical centering system
it even use LCR METER for check part value and polarity ;-)

good luck and have fun ,and still cannot relive you not able to find a honest assembler and let you focus on your nice product .. ma-by time to open a us branch lol

Marc L.

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bcoggs
 
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Re: PCB assembly versus shared equipment

Post by bcoggs »

Hi, Bob here from smallbatchassembly -

It is correct that I do not do 0402 or 0201s because they require 2mm step feeders at $650 each and a new nozzle at $300. Eventually I might make the investment to upgrade, but right now I don't see the need to spend the money.

I do have double-sided capability now, but I have not upgraded the web site to handle it.

If you have any questions don't hesitate to ask me - [email protected]

Cheers
..c

bootstrap
 
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Re: PCB assembly versus shared equipment

Post by bootstrap »

Maybe if I do buy this equipment, I'll offer my own "small batch prototype assembly" service... and call it "0201 assembly corp". That would seem appropriate given how many small assembly companies want to keep us in the dark ages (avoid smaller components). Just kidding... I suspect. But it remains annoying to go through so much hassle on this issue.
Last edited by bootstrap on Fri Jul 18, 2014 3:02 pm, edited 2 times in total.

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alphatronique
 
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Re: PCB assembly versus shared equipment

Post by alphatronique »

Hi

it all Mather of price , got machine that do "production" on 0201 cost 4 - 5 more of what i have now
so need to refill the bill to all customer since same machine do all ,also now i have nice profit margin
on nice as easy to assemble board ,wly what to lower the profit and got more trouble .. money rule ..

and honestly here i have only 1-2 Jod a year that have 0201 ,that forward to my competitor that charge 2 time my cost
customer later come back and more that happy to deal whit me at lower cost and much better personalized service
so probably all the industrial company in canada was stone age ;-) but that perfect fit my nice market

and yes will repeat it marketing will tell machine do 0201 and 1005
but do real production and lo defect rate on short run was another stories ,so test it in deep before put check on the table
it a good idea to make a board whit something like 2000 0201 part on it for test it and test it whit past not double side tape and finally reflow then cont how was bad (on my version it put all 100 string in series whit TP
so if use 10ohm resistor it easy to spot open or short on the string ..


and i greatly suspect that it same for most of small to medium shop

bootstrap
 
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Re: PCB assembly versus shared equipment

Post by bootstrap »

All I can say is, I've now talked to 3 people with novastar LE40V pick-and-place machines, and they all reliably place 0201 discretes and 0.40mm BGA/QFN components. They said the pick-and-place is very precise, and what is necessary to get reliable placement of 0201s and fine-pitch components is... good solder-paste application (which requires good equipment and care). Plus a proper heat cycle in the reflow oven to make sure all the solder paste melts everywhere on the PCB.

It is good and fine to have separate services for people who don't have 0201s [or 0402s], or other fine-pitch components. Why not? Many people have plenty of room on their PCBs for larger components, and don't need any fine pitch components.

However, some of us make devices that need to pack a lot of components into a small volume, and design with components that aren't even available in coarser-pitch packages. Frankly, I don't design or prototype devices even remotely as simple as some companies, and so I can't live with the same constraints and restrictions. And I'm not alone.

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richardlawson1489
 
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Re: PCB assembly versus shared equipment

Post by richardlawson1489 »

If You need Quality PCB Assembly Service in California Then 4 PCB assembly is one of the best place for PCB Assembly and the Company best competitive to other and also price is in your beget

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juku
 
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Re: PCB assembly versus shared equipment

Post by juku »

[My apologies if talking about your own business is prohibited here. If so, moderators please remove this post.]

Old thread, but talking about prototyping SMDs: Not even close to the league of the machines mentioned here, but not even close to the costs either, my project is aimed to exactly the problem of assembling SMD designs for prototype verification: http://www.liteplacer.com, a vision assisted SMD prototyping pick and place machine capable of doing 0402s and up. The DIY kit costs 1199€ / $1349.

AdHoc
 
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Re: PCB assembly versus shared equipment

Post by AdHoc »

I've recently upgraded from an LE40V to a Europlacer XPiiT (a very big upgrade!) partly because the APS machine struggled with 0402. I'd recommend sticking with 0603 or larger with that class of machine. The Europlacer can handle 0201 (and smaller) but it needs a special set of nozzels to manage them (feeders are the same though).

One of the problems of the non-production machines is the amount of baby-sitting they need, it's very time consuming.

For a lot of machines the set-up time for a new design is also an issue and it can make short run jobs relatively expensive, this was also one of the deciding factors in my upgrades as I do a high mix of board designs.

bootstrap
 
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Re: PCB assembly versus shared equipment

Post by bootstrap »

Have you contacted them to make sure something didn't get out of whack with your LE40V, because they are supposed to be easily capable of 0201 components, and I know two people personally who regularly place 0201s with their LE40V.

Hey, would you like to give your LE40V away to me? :-) Or sell it cheap?

AdHoc
 
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Re: PCB assembly versus shared equipment

Post by AdHoc »

Sold it as soon as I had the new machine I'm afraid ;-) It may have been a local setup problem, I can't completely rule it out. However I doubt it as there are obvious issues that would prevent it from being reliable for any parts 0402 or smaller. Even if it could be made to work with those sizes I suspect that effort to do more than a couple of boards would drive you crazy in short order ;-(

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SDMI
 
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Re: PCB assembly versus shared equipment

Post by SDMI »

Bootsrap, I have a Qsp2 assembly machine in Chico, California. perhaps I could be of service for your needs. I am usually able to offer better rates than most other assembly houses.

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Funman1
 
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Re: PCB assembly versus shared equipment

Post by Funman1 »

Hooo.. I may be interested in your services...
I'm here in Roseville, CA and might need someone to do PnP for me soonish....

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SDMI
 
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Re: PCB assembly versus shared equipment

Post by SDMI »

Hello, Is there a message function on this forum? How can I give you my contact info?

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adafruit_support_mike
 
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Re: PCB assembly versus shared equipment

Post by adafruit_support_mike »

There's an email icon under the user image/stats. You can use that for off-forum conversations.

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