Setting up  for in house small runs of pcb assembly - Page 1
Forum section: electronics / projects

author: senso
author_rank: Frequent Contributor
timestamp: May 01, 2016, 04:54:22 pm
content: Good evening, here I'am again with some strange doubts, hope you guys can help me a bit on this.So, my employer/boss wants to setup a small production line for in house production of pcb's and machining custom boxes.For the cnc part my boss is almost set in a Datron, probably the M8Cube and all the necessary tooling, the goal is mainly aluminium boxes and acrilic/lexan.For the pcb part, he saw a couple of those chinese pick and place machines in some eletronics fair in Europe recently and he asked me if there is something a bit better for small runs, if not, any small pick-and-place machine that you guys recomend?Solder paste can be applied manually but there are also those stands to facilitate that, like this one:http://www.alibaba.com/product-detail/T4030-solder-paste-screen-printer-PCB_1256664999.html?spm=a2700.7724857.29.10.w3ldLo&s=pRegarding the soldering oven I'm in a bit of a loss, a tunnel oven feels overkill, and small home made ovens are too small to throw in a full panel and expect even temperatures across all the pcb's/parts.Regarding the designs, for now its a couple projects that have 80x100mm pcb's more or less, and a small wireless module that measures 20x30mm.He is a bit against going for Chinese outsourcing for small runs, a bit of pride, a bit of being able to say made in Portugal.We have been doing all our pcb's at EuroCircuits, the delivery time as been around 3 days, the prices for a company are very competitive, I was even astonished at how low they make prototype runs and how fast we are getting them, send files at a friday, pcb's in my hand in wednesday, components we buy them from either Mouser or Farnell and RS.Around density/part count, ranging from 30 to 140 components, around 40 different components in the bigger pcb's, but that is one thing that I will have to start to optimize to reduce different reels/parts.I know that I have a lot to learn regrading all this.Best regards, and thanks for your patience.

author: nctnico
author_rank: Super Contributor
timestamp: May 01, 2016, 05:26:51 pm
content: I'd look for a local contractor for PCB assembly. You can have that done for competitive prices if you care to look around a bit and don't even think about going to China for less than 50000 pieces. Doing PCB assembly in house means training people who won't work on assembly full time and probably needing permits and training for handling toxic chemicals so it will be a waste of time and money in several ways. The same goes for milling boxes. Nowadays having plastic or metal lasercut costs peanuts so why bother with a CNC machine? This is one of my products:The housing is readily made but the face plates are lasercut. You can also have (color) stickers made to give a housing a neat finish.

author: uncle_bob
author_rank: Unknown
timestamp: May 01, 2016, 10:06:00 pm
content: HiOk, we do our own pcb assembly in house. We always have and probably always will. We do everything from prototypes to full 10K piece (boards not panels) per day runs. There is a lot of money tied up in equipment, training, parts, and inspection as a result. We do some very unique stuff in our assemblies so doing it outside is not at all easy. We have tried on many occasions. It has never worked out well.That said, for "production quality" parts, you need to put a lot into setting up a line. There are an infinite number of ways you can do it. The minimum I would suggest:1) Some sort of automated solder printer, possibly not a fancy one, but something past the basic manual ones. There is a lot of operator training / checking that goes on with manual solder print. It's much easier to get a machine wth basic automation going (fewer variables).2) Get a couple of *good* microscopes. You will need to inspect the boards after they are printed. That will go on for a bit longer than you might think.3) Pick and place machines are very much a "you get what you pay for" sort of thing. A lower cost machine likely will take more operator skill than a slightly more expensive one. Make sure that what you get will handle both your current parts and whatever you are likely to go to in the next few years. Feeders are something you need to look closely at.4) Go with a belt reflow oven. Get one that manly heats the boards by convection / moving air rather than IR heating. Again fewer variables. Your belt needs to be wide enough for a panel of your boards plus any holders / tooling you plan to use with them. Figure that the outside edges of the belt are not going to be uniform in temperature (don't plan on using the outside 10% on either side).5) Consider that if you have parts on both sides of the board, the complexity of the process goes up. You will find that placing parts on both sides and doing a single reflow is a very challenging thing to do. A pass on each side also presents issues, but it is often easier.Those are the very basic minimums. They don't get into number of feeders needed or feeder swap out approaches. They also don't get into the fact that parts now are inventoried as a reel of 10,000 rather than as a single piece. (Buying extra so you don't run out may mean buying 20,000 parts)Is this all a be scary? Yes, I'm being a bit overly dramatic at a few points there. The point is, you *really* have to be committed to doing this. You will have at least three well trained operators involved to keep things running. There are major rewards to doing it (2 hour quick turn is one), it is *not* something you will get done in a month or maybe even a year. If you only buy one piece of bad equipment, that's doing *very* well.Bob

author: nctnico
author_rank: Super Contributor
timestamp: May 01, 2016, 10:24:43 pm
content: One of my former employers had an in-house assembly line. After two years the production team was proud they went from 2 days to half a day to change the production line for a different product. Not to mention messing with different solder pastes, stencil thicknesses and PCB surface finishes. IMHO you should really do the math on going for an in house production line. Actually: regard a production line + operator team as an in-house company which needs to compete with an external assembler.

author: uncle_bob
author_rank: Unknown
timestamp: May 01, 2016, 10:39:46 pm
content: Quote from: nctnico on May 01, 2016, 10:24:43 pmHiDon't forget to add the sheer panic when a main drive motor in a big P&P machine dies. *Everything* comes to a halt. We had that one hit for a day last week. Bottom line - you also need to add repair / maintenance guys to the mix or it takes a *lot* more than a few hours to get things back up and running.Does that sort of "back up and running" matter to everybody? Certainly not. If a few days of down time are ok, you might be able to contract some of the "repair it" stuff out. That's easier to do on some machines than others ( = something to check into as you shop).Bob

author: Spikee
author_rank: Frequent Contributor
timestamp: May 02, 2016, 12:47:44 am
content: All these replies are based on quite some volume. If OP only needs 5-10k boards a year than the requirements are quite different.A 750 euro vapor phase reflow oven, 400 euro stencil printer and a neoden 4 or even tvn802 setup can come quite far.Generally all the bigger machines are not really suited for changing setups regulary.

author: uncle_bob
author_rank: Unknown
timestamp: May 02, 2016, 01:05:00 am
content: Quote from: Spikee on May 02, 2016, 12:47:44 amHiAfter many decades of doing this, I can make a lot of things work. I already know (by making a *lot* of mistakes) what probably needs to be done here or there. That translates into a lower cost short line.The question is - would you give a novice a low cost line as their first exposure to doing this? There will be a *lot* of things come up. Any time you have an issue that is a combination of two things ... much harder to solve. Throw in a few where there are three mistakes in a row, the guy is now in really deep.If you are starting from scratch, the hours and hours of learning and setting up *will* cost you something. If you are smart, you will look at a number of machines running on a number of lines before you buy anything. That takes time, time costs money.Rather than teaming up a NeoDen 4 with a 750 euro oven, I'd match it up with one about twice as expensive. The screen printer would be about three times as expensive. The cost of the whole line would go up by less than 20%. Far less hassle, much higher likelihood of success. Indeed the recommendations I'm making here are the same ones made to me back in the 1980's. They are not some radical new approach to this. I have run lines that are smaller than the one being talked about here ...Bob

author: Apollyon25_
author_rank: Regular Contributor
timestamp: May 02, 2016, 02:26:16 am
content: Ditto everything Bob has said.You get what you pay for. Especially w.r.t. reliabilty, ease of setup/use/maintenance.Do you not have local contract manufacturers in Portugal?Rather than 'rush' into this, perhaps get several CM's to quote for a full turn key service.Its probably a more gradual way to sort your processes and systems around manufacturing.If you are looking for some Asian CM's, I have worked with In-Tech Electronics (HK-based, but factory in China), Hana Microelectronics (Thailand and China) and VS-Electronics in Malaysia.I'd use any of these again.

author: senso
author_rank: Frequent Contributor
timestamp: May 02, 2016, 09:22:31 am
content: Thanks for the real world experience responses!Yes, there is some assemblers, and one in Aveiro that is "near" us(1h drive), they are HFA:http://www.hfa.pt/They do some large scale projects and smaller scale as well, my university used them to assemble the dev board that we used in computer architecture(a pic32 because in CA1 we learned about MIPS), but these guys are a bit on the expensive side and they smallest run will be around 300-400 pcb's, and some things are designed to be used in house in lower quantities, and hand assembly of 30-40 pcb's would be a major pain for me, because around here I'am the only electronics person(the one man band "dream").I have also already tried to explain that in house will be expensive both in money an time wise, but money is not an object, and time, will just be my time, so you guys get the picture.The cnc machining part is due to a project that as a designer case, I have already sampled and test fitted a Takachi MXA extruded box with a milled(we have a diy cnc(its more of a router than a cnc) with 1000x1300 work table used to make some jigs and various bits and bobs) but design got into it and now the project "demands" for a full milled case, and because my boss likes to own fancy machinesIn a way it as its perks, having lots of fancy/quality machinery for all kinds of use and being able to use them at a whim.I fully understand that in house as lots of drawbacks, and can be very hard to justify going this way.Thanks again for your comments about this.Best regards.

author: Spikee
author_rank: Frequent Contributor
timestamp: May 02, 2016, 12:12:02 pm
content: Is OP does many small runs of different projects than low end equipment I mentioned is good enough. Manual labor is not as expensive as USA / AUS so spending some extra time instead of buying a machine that is 10x as expensive is probably not.I do many smaller runs of different projects. Most have 20-40 components or so, 10-30 boards. Takes to long to assembly by hand.Not using any stencil printer is a pain in the ass. The 750 euro vapor phase works fine even for bga.Never had any problems regarding that.Biggest pain for me at the moment is having no stencil printer (especially for BGA, 0402 it it quite easy),and a pnp with vision to at least place the passives. The few chips can be placed by hand if needed.It all depends on the amount of boards and quantity OP needs per year.Other than the neoden there are not that many well know machines until you are going for 30K and up.Automatic stencil printer is overkill if you do not need that many boards a year. Same for a conveyor oven (if you can actually find a decent one <5-10K).

author: Jeroen3
author_rank: Super Contributor
timestamp: May 02, 2016, 12:36:49 pm
content: Quote from: senso on May 02, 2016, 09:22:31 amWhat will happen if you leave the company? Do they end up with several k's in gear that nobody can use?Outsourcing is not that expensive, around €50 per board on <100 quantities (dual loaded). Initial setup is around 1k, then it's an increase with quantity, cost per board will decrease with quantity. Turnaround is about 3 months on average. Do some quick maths, call some assembly houses. Remember, you"re in europe, you can use assembly houses in Germany or somewhere cheaper, maybe Hungary.I doubt in-house will be cheaper.Try to find a manufacturing equipment dealer. They often have second hand europe-made pick&place and reflow ovens that cost the same as the chinese, but come with proper software and service.

author: Apollyon25_
author_rank: Regular Contributor
timestamp: May 02, 2016, 08:54:52 pm
content: Quote from: Jeroen3 on May 02, 2016, 12:36:49 pmThat's the idea! Convince the boss that you're fully behind setting up a cutting edge PnP assembly line, then once you are the systems' sole font of knowledge, threaten to resign if you don't get an extra '0' on your paycheck (trailing edge, pre-decimal point).

author: rx8pilot
author_rank: Super Contributor
timestamp: May 02, 2016, 10:19:12 pm
content: Quote from: Jeroen3 on May 02, 2016, 12:36:49 pmI recently setup an in-house line for low-med volume work. I live in a city with a LOT of assemblers and they are all much more expensive in the long run. The reason is because the process takes much longer than I have and the cost is not what they bill me - it's the cost of waiting. If everything is perfect it was not working for me and generally it even worse. First of all, I have to document and kit the project in a way that they cannot possibly mess it up - that is not a trivial task and it takes time. Then I get a quote and they put me on the schedule. They may start the next day or 2 weeks later which I cannot control. Almost all of my designs are odd shapes, double sided, and have something that is somewhat unconventional - that takes more time and adds cost. When I get 100 PCB's back that have a BOM cost of $150/ea and another $50 for the assembly I am sweating in fear of something being wrong. At that point, I have committed $20,000 for the run and waited a long time for them and put in significant labor to prep and supervise the project.In contrast - having my own in-house system....We never kit anything and only need the design data that already exists to build a board. We don't have to prepare anything special or explain any unconventional steps. I got a machine that can hold the majority of our commonly used parts so those just stay in the machine all the time. It takes 10-15 minutes to switch designs in general.When it is time to run - we can make a single pass - flip the pcb and place the other side. That single PCB gets inspected and tested which will reveal any out of place parts. After it is verified - we can run with confidence the amount we need right then. No waiting and no need for a huge overrun to build inventory. When I do a new design, we can turn that around very fast as well. While the PCB's are being fabbed I order the parts from DigiKey and prep the program in the machine. About 10 minutes after we receive the new PCB's, they are in the machine with parts on them in QTY of 1 or 2 without disturbing the setup of the normal production PCB's. I can literally do all of that with less labor than prepping and coordinating a fab house to do it for us.Now, if we needed a large volume it may be a different approach for sure but for the low-med volume specialty stuff - I cannot imagine dealing with an assembly house. The learning curve was steep and of course I had to buy a bunch of equipment, but I feel that it was easily worth the startup pains (major pains since I purchased used/broken equipment to overcome an empty bank account). Yes, in-house is cheaper in my case. FAR cheaper.