Need advice for assembly line - Page 1
Forum section: electronics / general

author: pisoiu
author_rank: Regular Contributor
timestamp: March 07, 2019, 03:01:47 pm
content: Hi all,I have a small company which makes embedded designs in area of gps tracking, iot, sensors, etc. from 15 years or so.So far, we made just the designs and prototyping in house, the production assembly was made with various local assembly lines.Lately, due to some business specific reasons, externalizing pcb assembly became more and more problematic due to delays from order start to finish and high cost and mainly because of low volumes. We manufacture some products in 2k batches, maybe 1-2 batches per year, but other products may have much lower qty. For example we have some sensors which share the same pcb but the implanting recipe may differ because some customers require can communication, other want kline, other bluetooth and so on, and we end with 50-100 pcs from a specific recipe. Some sensors may have specific demands and I cannot tell the customer to wait 2-3 months until our partner with assembly line have a free slot for us. So we decided we need our production line to have more flexibility in production and we are prepared to spend around 20k for it. Smallest component is 0402 and we do not plan to use smaller, some designs are lead free, others not, almost all of them are with components on both sides. Most complex designs have around 70 different components categories, most in 8mm band but we have one in 56mm. Production line speed is not a concern, it will not work full time.Being involved only in prototyping, many aspects of manufacturing were foreign to me, but now I must learn them since this will be my responsibility. After some long readings of topics here, many of unknown things were cleared, but there are some more and I need to kindly ask them specifically to you, people with more experience.So far, my choices looks like this:-stencil printer YX3050:https://www.zjyingxing.com/products/semi-auto-printing-machine-yx3050-ID285.html-pick and place SMT660:https://www.zjyingxing.com/products/pick-and-place-machine-smt660-with-6-heads-64-feeders-ID259.html-reflow YX630:https://www.zjyingxing.com/products/reflow-oven-yx630-ID307.htmlMy question: that model of reflow oven is biggest I can use, it is at the limit of my power availability. I do not have 3 phase available, only 220v. It has 6 zones (as per documentation), 3 on top, 3 on bottom. Will this be suitable for leaded and lead free process also? And biggest problem: my boards are assembled on one face, then soldered, then assembled on the other face, then soldered again. Is this oven capable to perform correct soldering on top, without melting solder on bottom, causing bottom components to fall off?I understand technical aspects of all this but my practical experience is 0 so any advice would be much appreciated.Thank you.Best regards,

author: SMTech
author_rank: Frequent Contributor
timestamp: March 07, 2019, 07:06:13 pm
content: Quote from: pisoiu on March 07, 2019, 03:01:47 pmI'll ignore the question as to whether you might be better off finding another contractor who can offer better lead times or indeed if the machines suggested are a good choice or the budget sensible.. Plenty of chat about that in other threads.However on this point it is worth mentioning that the solder on the bottom side is allowed to melt, the devices stay held in place by the surface tension of the melted solder. If you had large or heavy devices you would try and make them all be on the 2nd side.You would need to develop profiles for both leaded and unleaded solder if the oven can do lead free it can do leaded, although how you manage to still have a leaded process in 2019 is another question, original leaded parts are not exactly common these days.No idea if the oven is any good, as a general rule I haven't heard many truly positive things about cheap Chinese ovens, they work, until they don't and then you're at their mercy for spares, assuming they even bother making them any more. The 9KW startup power is not exactly trivial and most likely exceeds the rating of many office circuits so you'd likely need some electrical work doing anyway. Well worth getting 3-phase if you can just to remove that limitation on choice

author: pisoiu
author_rank: Regular Contributor
timestamp: March 07, 2019, 07:58:39 pm
content: Thanks very much for your input.There are not that many contractors in our area. Indeed, some of them have better availability. But this comes with a higher price and some of them also have some requirements which forces us to higher expenses, one example is that they do not accept panels with X marked boards (failed at electrical test). They accept only 100% ok panels which forces us to use a more expensive supplier of pcbs. Using contractors far from us is also problematic due to shipping costs, especially for low volume batches.I already considered these alternatives and at this price range (~20k) is worth to have our line, so far I paid this amount in 2-3 years for assembly services. Of course, having our line will generate some expenses, but they are accounted for and the outcome still looks positive.

author: jmelson
author_rank: Super Contributor
timestamp: March 07, 2019, 08:12:16 pm
content: First, a used high-end P&P machine may be a better way to go. These machines have very-well tested and refined software. Some users of these new Chinese machines report all sorts of issues with the software not working properly. Also, some of these machines are VERY slow.I have a very old Philips CSM84 (made by Yamaha) and it is built like an army tank and the software is very solid. No 3-phase power will limit your choice on the P&P machines, too.I use a batch oven made out of a toaster oven and a thermocouple controller. For your production level, you probably do want something faster, but you don't need a really big oven to produce that many boards/panels per hour. Some of the commercial ovens have insane power consumption to get up to temperature quickly.Jon

author: jmelson
author_rank: Super Contributor
timestamp: March 07, 2019, 08:16:15 pm
content: Quote from: pisoiu on March 07, 2019, 07:58:39 pmAnd, I suspect this is due to them using these cheap Chinese machines whose software does not support bad boards in a panel.As for double-sided, I run my boards through the solder stencil / P&P / reflow twice, first for bottom-side parts, then for top-side. NEVER, EVER, have I had a part fall off the bottom.Jon

author: pisoiu
author_rank: Regular Contributor
timestamp: March 07, 2019, 08:36:20 pm
content: Thanks, that gives me hope I won't break my neck with this deal. I'm a bit nervous spending 20k on something I've never work with, even if I perfectly understand what it does. I cannot spend less since a cheaper system won't fit my needs.About X marked boards, surprisingly, you're not entirely right. That contractor was Cicor/Systronics and they have top of the lines machines. I do not recall what types but definitely not chinese. And they are one of the few in Romania which have xray inspection machine and other fancy stuff. They said that x marked panels slows down their assembly lines and they run very tight schedules, it affects timing on other projects. I don't know exactly how, but that's what they told me.

author: jmelson
author_rank: Super Contributor
timestamp: March 07, 2019, 11:31:08 pm
content: Quote from: pisoiu on March 07, 2019, 08:36:20 pmOK, a random grease marker X is not the way to do it. What you need is a fiducial-style pad somewhere on the panel for each board instance. These could be on the actual board if there's a good spot, or on the border. The bad board's location can be marked on that bad mark spot, and then the P&P machine can scan that spot to detect which board instances should not be placed. If this is all done right, then there is no slowdown. On my CSM84, if you have individual fiducials for each board, then one of those can be made double-purpose as a bad mark. Not sure all makes of P&P can do that.But, I can see if the board house's method is a grease marker over the board, the contract assembler won't like it at all!Jon

author: mrpackethead
author_rank: Super Contributor
timestamp: March 07, 2019, 11:59:15 pm
content: Quote from: jmelson on March 07, 2019, 08:12:16 pm100% agree with this, and this is exactly what I did. You will be much much better of this way.QuoteI have some yamaha YS100-ii machines, and they ahve been awesome. Not looking back on that decision.

author: Reckless
author_rank: Frequent Contributor
timestamp: March 08, 2019, 04:56:00 pm
content: My recommendation is to stay away from anything from china. They are not reliable and will not work. I considered this first but bought used name brand equipment. I have some jukis for sale that are a good deal. I needed faster production so I upgraded. you can PM if interested.

author: pisoiu
author_rank: Regular Contributor
timestamp: March 08, 2019, 06:00:19 pm
content: Thanks, I will consider it.

author: IconicPCB
author_rank: Super Contributor
timestamp: March 09, 2019, 06:23:10 am
content: What You describe as six zone reflow oven is actually only three zones ( plus the cooling stage).

author: pisoiu
author_rank: Regular Contributor
timestamp: March 09, 2019, 08:36:52 am
content: Yes, that was my thought, different zones should be along the axis of movement, not total number of heaters. Just a marketing gimmick.I am also considering next model, but that one requires 3 phase power, which I may be able to install, but I don't know yet. It has 8 zones, but actually 4

author: IconicPCB
author_rank: Super Contributor
timestamp: March 09, 2019, 11:00:49 am
content: If you are to consider vapor phase soldering process with the view to evaluating throughput You might find it a better choice.

author: nisma
author_rank: Regular Contributor
timestamp: March 09, 2019, 12:50:45 pm
content: Generally 3 or 4 zone oven are not suited for the higher tech board you probably doing. Please tell us the max panel size and max PCB size, how many panels you need to do every batch run you want and what is the overall uniq component count of all boards.If you need make 1k PCB, for the oven and PNP it makes really a difference if this are 50 panels or 333.

author: mrpackethead
author_rank: Super Contributor
timestamp: March 09, 2019, 07:07:16 pm
content: Quote from: IconicPCB on March 09, 2019, 11:00:49 amI use Vapour Phase and its just a dream compared to ovens, as i have no issues with having to profile anything. The down shot is that its slow in comparsion, ( because of the system i have ).I bought a IEMS system, which i'd absolutely NOT recommend, as while the idea was good, its implemetnation was terrible. Electrically unsafe, contstruction was marginal. and the control system totally inadaquarte. I had to do qutie a lot of work on mine to get it to be safe, and ive improved its operation by putting new controls on it

author: pisoiu
author_rank: Regular Contributor
timestamp: March 09, 2019, 08:30:46 pm
content: The most complex board is 80x40mm and I usually assemble it in 5x2 panels. Panel is approx 100x200 with technological edge. Smallest is 0402, I have some QFN, biggest have 48 pin, I have some wireless modules from simcom and microfit connectors. For one PCB, approx. 75 unique components, around 30 on one side, the rest on the other. One batch can be anywhere between 100 and 2000 pcs (10 to 200 panels). But speed is not an issue. I know "slow" is not something good for smt assembly, but it can be acceptable in my case.

author: pisoiu
author_rank: Regular Contributor
timestamp: March 10, 2019, 08:41:01 am
content: Quote from: nisma on March 09, 2019, 12:50:45 pmI'm not sure how to understand this statement. What means not suited? It means it won't be able to do the job at all or it means it will slow down the process? Because one scenario is acceptable, the other not. Thanks.

author: nisma
author_rank: Regular Contributor
timestamp: March 10, 2019, 09:52:48 am
content: Quote from: pisoiu on March 09, 2019, 08:30:46 pmWhat is the maximum Panel size and max pcb size of your products. What is the overall uniq components for all products. As example 10k resistor is probably used on many boards.Check this PDFhttp://avipre.com/products/smt&tht/juki//Juki%20-%20Nozzle%20Catalogue-Rev-C3.pdfand find out the nozzles you need for this most complex panel you have.Basically you get something like this for bottom and top.502 is used for 0402 only503 for 0603 to 1206 and some other stuff , 1206 needs lower speed as 504 is the correct nozzle.505 for SO IC packages, D Tantal, ...506 for bigger ICs , 5050, ...508 for modules like gps.This gives you a indication how many nozzles you need, or if you need a nozzle changer, or two machines.You can still do batch assembly as example first 2x 503, 1x502 and 1x505 then changing nozzles for the missing components,usually on this pcb dimension this is done on 20 panels. Maybe you should think or calculate takt time of panels,evaluate making more panelisation,and check the requirement for testing and the limits for the bogo pins chassy. Takt time is the overall time needed for the panel including loading and unloading time.As example if machine does 3300cph real and you need to place 120 component on one side, this is 131 seconds assembly, 20 seconds fiducial recognition and 25 second manual pcb handling. This sums to 176second, a bit less then 3 Minutes. One batch reflow need 420 seconds including load/unload, this are 7 minutes. If you decide to do batch reflowthen you need a oven that allows placing two panels at the same time and a machine that allows placing more panels at the same time for smaller boards or with conveyor.Conveyor have a bigger cost, but can save operator time if takt timing is wrong. Takt time of 4 Minutes lets you make 50 panels/day as example.Further you need to account at least 8k$ just for feeders excluding shipping and import duty.For bottom side component sticking, there exist a formula what components needs to be glued.If you dont make vapour phase, then you could use solder paste with different melting pointand you don't need glue the components, in case it's necessary.I don't know you boards, generally 3-4 zones oven are for led or diy boards, low tech requirement with relative uniform heat absorbtion.This could include a lot of boards with bga and qfn too, but if you have heavy connectors, or modules with rf shield, or just smd usb connector, pin in paste, ... , the soldering isinsufficient or you need to cook the other components increasing defects and field returns.For other than this, 6 zone is today the minimum (6 bottom + 6 top heater). I suggest to go with batch reflow instead of inline reflow.

author: HalFET
author_rank: Frequent Contributor
timestamp: March 10, 2019, 02:27:27 pm
content: Quote from: pisoiu on March 10, 2019, 08:41:01 amTo avoid getting into technicalities about heating and board deformation, more zones usually means better control over your temperature profile. A three zone oven might only be able to do pre-heat, solder temperature and then cooling down, that'll work but it isn't a great profile in terms of reliability and can break more sensitive components or melt certain connectors. Not to mention the fact that long-term stored components and boards which are sensitive to humidity might become a problem if you only have three zones, you wouldn't be able to do a good pre-bake. Ideally you want five or more zones to accurately reproduce most profiles.Also, in case you were thinking about it: avoid infrared ovens like the plague they are. Each time your supplier switches soldermask (and some do so frequently) you get to enjoy tuning the settings. Not to mention that some manufacturers (i.e. Avago) like to use weird materials which have different IR absorption profiles, making it hard to get a profile that works well for the entire board. Convection ovens are far more forgiving.

author: pisoiu
author_rank: Regular Contributor
timestamp: March 10, 2019, 04:46:02 pm
content: Quote from: nisma on March 10, 2019, 09:52:48 amSMT660 has 6 heads, I am also considering SMT880 which has 8 heads. I did not made an exact checkout but I am somehow sure I can place all the components using 6 nozzles, maybe 3 for 0402 and the other for bigger components. I should be able to avoid multiple passes of the panel inside the machine on the same side.I have attached 2 pictures with one of my designs. It is a bit older but has the same complexity as newer designs. It is detached from panel, but one panel has 5x2 of those.I know feeders will take some $ and machine comes without them. They are accounted.I would appreciate if you tell me about that formula for bottom components. I am not aware of it. No vapour phase, not IR, 100% hot air.Quote from: HalFET on March 10, 2019, 02:27:27 pmI have very bad memories with IR ovens and not baked components. A lot of rework hours and bad boards because my contractor ignored these problems and I was not aware of them at that time. I do not consider IR and I want to prebake pcbs and bigger components, modules, etc.Apparently the ovens need more attention than I initially thought. I know there are profiling devices used to check the accuracy of a thermal profile, and I intend to use one (buy one or build one if it's too expensive). In the past I designed and built some ovens for glass annealing and I am a bit familiar with high temperatures.

author: HalFET
author_rank: Frequent Contributor
timestamp: March 10, 2019, 06:10:06 pm
content: Quote from: IconicPCB on March 09, 2019, 11:00:49 amVapour phase is expensive in terms of cost per board and has a rather long cycle time, keep that in mind. You also need to replenish that oil frequently and it costs a pretty penny. But it's ok with sensitive boards, doesn't ruin components nearly as often and can heat up massive components reliably. In short, it works with almost any board you throw at it. Also, I don't think we ever changed the profile on our vapour phase oven at work for general boards, I mean you could optimise it further by profiling with thermocouples, but the results were usually good enough that you really didn't have to bother when using SAC305 solder.And most decent industrial reflow ovens I've seen so far have some interface to attach thermocouples to the boards you run through them; as external readout (if necessary) the USB readers from picotech are quite nice.

author: nisma
author_rank: Regular Contributor
timestamp: March 10, 2019, 07:08:13 pm
content: This board is not recommended for vapour phase.

author: nisma
author_rank: Regular Contributor
timestamp: March 10, 2019, 09:28:14 pm
content: You confuse me a bit. Really you are evaluating buying PNP that cost 18k$ , 1.8-3k$ stencil printer , unknown reflow and at least 9k$ feeders with a budged of 20k$.This prices include shipping and customs costs. It seems that you need glue and dispenser and hand soldering.All three steps are doable using robots relative cheap, or can be done manually.Please answer this question.Are conveyor and ball screw really needed, you prefer to have it, just nice to have or it don't matter.Please check out used reflow oven near you including if you can afford the electric bills needed for that oven.Otherwise you need a decent batch oven that have not more as +-5degr temp diff over 25x30cm. If you need to stay with 25x17cm for price reason this slows down assembly .As example in the previous example of batch of 100 panels needing 2 days normally solder printing is done the first day only.If speed is cut down to half because of batch reflow that can do only one board at time, the production need 5.5 days.

author: pisoiu
author_rank: Regular Contributor
timestamp: March 10, 2019, 10:09:57 pm
content: I am sorry if I seed some confusion, this is sincerely not my intention.The amount of 20k$ is not fixed, just a rough initial estimation. It can be adjusted to a certain degree, let's say up to 25k or so, the most important thing being to be able to do my job. What I know for sure I can't afford are prices for 'big boys' machines: siemens, etc. I think they are at least 3x fold for same performances.Shipping costs and customs are not included in this amount. PNP is 11.5k for SMT660 (6 heads, 65 feeder spaces), ~15k for smt880 (8 heads, 80 feeder spaces), stencil printer is ~1500, oven is ~2100 with 8 zones (but actually 4top, 4bottom) or ~4100 with 12 zones (6+6). Feeders are not that much, I estimate around 4-5k for my needs. Example, one 8mm is 70$ and they offer as a promotion 20 pcs*8mm with the pnp machine. Pnp comes with juki nozzles.I hope I can avoid gluing, based on the fact that my designs were already produced on contractors and they were not using dispensing. So it can be done. I think they used 2 types of paste with different melting point.I prefer to have conveyor and ball screw. I don't really like belt because I have seen some placement problems toward 0402 and fine pitch qfn, which I use a lot.I do not like other suppliers (second hand or not) because I want to order everything from the same supplier. It will keep logistics more convenient and the shipping is not extremely expensive, I got ~400$ from china to my nearest port for the pnp machine. From there will be another ~1-200 on truck and ~20% VAT on import.Electric bills are also considered, in fact I have to install 3-phase into the office, I do not have it now, that's another story/expense.Those production figures are ok to me. And they are pretty close to what I had with previous contractors.I kept this design as a reference for what I need from this setup, but I want to leave some room for more complex designs, you don't know what future holds.

author: HalFET
author_rank: Frequent Contributor
timestamp: March 10, 2019, 10:17:22 pm
content: Quote from: nisma on March 10, 2019, 07:08:13 pmKind of curious, why is vapour phase not recommended? Are you planning to apply conformal coatings afterwards? Also, don't forget that you also need equipment to remove the flux residue after assembly.

author: mairo
author_rank: Unknown
timestamp: March 10, 2019, 10:40:14 pm
content: Have you also thought about PCB depaneling - will this be done manually, or will you require another machine for it.

author: nisma
author_rank: Regular Contributor
timestamp: March 10, 2019, 10:53:20 pm
content: Vapour phase is not recomendet because the electrolytic capacitor and possible automobil usage.Ask cap producer about electrolytic capacitor degradation after vapour phase. Generally into datasheet there is mentioned "vp reflow not prefered" and "contact us if used outside soldered profile". The problem is the preheat temperature of max 200 degree and that from 150 to 200 degree, the time need to be 60-120 seconds.After that the high temperature types supports peak temperatur of 245 degrees max 3 times. The max ramp up rate should not exceed 3 degree and cool down rate not more the 6 degree. Both gives problem and damages the overpressure release valve and chemistry inside the package.

author: nisma
author_rank: Regular Contributor
timestamp: March 10, 2019, 11:00:21 pm
content: Dek and Erka stencil printer have integrated glue dispensers and solder paste dispensers that are applied after stencil printing for removing the need to have costly step stencilsand external dispensing for glue. more later today.

author: mrpackethead
author_rank: Super Contributor
timestamp: March 10, 2019, 11:20:06 pm
content: Quote from: HalFET on March 10, 2019, 06:10:06 pmOn cost That has not been my experience. I've run nearly 10,000 panels ( approx A4 page size as an average ) in teh last 18 months . The cycle time for our set up is 12 minutes.Which part do you think is expensive? the energy its using?QuoteI have replaced 1700ml of Galden in total, across all the panels i've made since we have been using it. Yes, it is expensive, But i've i've only used approx 1/3 of a bottle ( US$850 for a bottle ) since i've had it..QuoteAnd i dont' have to wait for it to heat up at the start of the day.QuoteI have one profile that i have used for everything. It just workes. Iv'e got some very large inductors on the same board as some fine pitched IC's ( .4mm ) and 0402.. I'm using CG10 paste. You do want to make sure your solder paste process is good. I think it might be slightly less forgiving than the convection process, for balling ad tombstones. However i have a good set of librarys that seem to work well for what we are doign. That being said, good solder paste stencil design, and applicaiton is critical for any process really. You can tolerate a bit of inaccuracy with yoru PNP often, but if the paste process is bad.. then its best just to go home.

author: SWR
author_rank: Regular Contributor
timestamp: March 10, 2019, 11:57:06 pm
content: Quote from: mrpackethead on March 10, 2019, 11:20:06 pmSounds like a low volume friendly choice - I'm gonna give it a shot.

author: SMTech
author_rank: Frequent Contributor
timestamp: March 11, 2019, 12:25:01 am
content: Well this thread is going silly quickly.Do electrolytics dislike vapor phase - Yes its right there in the datasheet but they also often suggest there may be solutions, talking to a VP manufacturer or the electrolytic manufacturer might help if its a technology you want to use.Vapor phase running costs, when I looked the oven in question used 1g/cycle.. so not really an issue.DOUBLE SIDED DOES NOT USE DIFFERENT MELTING POINT SOLDERS (except maybe in exceptional circumstances).The only vaguely awkward bit on your example PCB is the cluster of inductors and electrolytics, they are very close together so that section of the board will take more energy to reflow. Pure IR would probably fail miserably on shadowing alone, but most IR ovens will have a healthy dose of heat transfer by convection too, the trick would be finding a profile that reflowed that and didn't melt the plastic connector. You might find that a Chinese oven is actually IR even if its telling you it isn't.I don't know why it even gets mentioned in this thread but glue and extra paste can be added by dispensers in an automatic printer (which you clearly won't be buying), by a dedicated dispensing robot between the printer and the placement machine, or by dispensing heads in the pick and place.You never ever want to run the board through the machine twice to complete the placement on the same side so you need all your parts for that side to fit on the machine at once, it the machine only has 48/64 8mm slots, that may not be the case.Chinese machines are not equivalent to the established brands from Taiwan/Japan/"The West", but they do a job and they do it sufficiently well to please some people, they would be more likely to make you happy as someone building your own small range of designs than me building lots of designs form lots of people. That's because pretty much any situation or requirement in hardware or software has been fed back into the design of the machine I use. Real people and manufacturing experience have shaped it into what it is over the last 30 years, there are no weird tricks or workarounds, there doesn't need to be but it comes at a price.More zones = more control over the profile seen by the PCB as it travels through the oven. If you look at the datasheets for the components on the board, the paste you see all sorts of requirements you need to meet, e.g flux has to activate for 150s, this device must not exceed 240C peak, this one must not go above 235C for more than 50 seconds, this one can only be reflowed once (so it has to be on side 2). You have to balance all of that against the fact that this part is large and will need some time to get hot enough to reflow, this section of the board is almost empty and at the end of it the whole board has to cool down at 4C/second. Putting all that together is called a "process window" get particularly nerdy and you could measure it all and give it a score called a process window index. The more zones you have the more easily you can meet all these requirements by tweaking the speed the board moves through it and the temperature in each of those zones. Vapour phase in its most basic form can let you skip all that because the whole board never exceeds the temperature of the vapour which will typically be well below the max temp stated by any of your components. Electrolytics are a problem because the electrolyte inside isn't designed to get that hot, and in convection processes it usually doesn't, in VP it doesn't really get a choice.

author: mrpackethead
author_rank: Super Contributor
timestamp: March 11, 2019, 01:55:04 am
content: Quote from: SWR on March 10, 2019, 11:57:06 pmI have up to three tanks running, It does depend a little bit on the boards, if they are sparcely populated the reflow becomes the bottle neck.. on some of the panels they are dense so PNP takes longer.. Worst case i've had all three going and can't keep up.. Mostly i use two. I've actually made my own, and its something i must get around to documenting, becuase its very easy to replicate.

author: mrpackethead
author_rank: Super Contributor
timestamp: March 11, 2019, 02:12:20 am
content: Quote from: SMTech on March 11, 2019, 12:25:01 amYes, some do, but as you suggest, check i out. and see what they ahve to say. I've placed reels of 100uF/6.3V panasonic electroyltics with no issues. In the main however most of what i do, doe'st have them.. the ramp up period can be accelerated by havingt enough heating.. My orginal IEMS Vapour Phase, simply did'tn have enough heating power to do a decent job of the ramp up. It also did'tn cool things fast enough.QuoteMy reality is that its been considerably less than that, less than .2g/cycle. I have heard of people loosing lots, so i think it might be related to your process.QuoteI have one board, that has a large inductor on it, that has a tendancy to want to walk. I use some 'red glue' which i manually apply.. I also actuallyk hand place those inductors, as they are problematic for automatic placement ( they are 24x24x13mm ) and weigh about 40g. On this point.. in your line, always have a place between your PNP and ovens where you can inspect the PCB's and do any manual work.. You'd be suprised at how many times this comes in hand.Quoteit sounds like a lot of slots, but you'll rapidlly find its not enough. I have two machines end on end, that gives me 150 slots + a big tray space. It means that i only rarely need to swap out feeders.QuoteI'd say 'some'. There are 'some' machines from china that are now really very good. But they dont' come at the 10k mark, they are more like 40-60% of yamaha/juki price point. China has some great stuff and some not so great stuff. Your job is to be able to identify which is which. Slapping a generic 'made in china' judgement often means you will miss out on some very high quality products. But you have to do your homework.M Electrolytics are a problem because the electrolyte inside isn't designed to get that hot, and in convection processes it usually doesn't, in VP it doesn't really get a choice.Im using Galden LS230, so its max temp is always 230C.QUoting Panasonic.."(6) VPS (Vapor Phase Soldering) reflow can cause significant characteristics change and/ or mounting failure due todeformation by acute temperature rise.VPS is acceptable provided that the process does not exceed recommended reflow profile and temperature riseis less than 3degC/secMy profiles are not quite classic 'oven' profiles but they don't exceed it, in terms of overall energy, and the temps things get to are definately lower.

author: HalFET
author_rank: Frequent Contributor
timestamp: March 11, 2019, 10:07:16 pm
content: Quote from: mrpackethead on March 10, 2019, 11:20:06 pmThat's a significantly higher volume than we ran, that would most likely offset the cost significantly.Quote from: mrpackethead on March 10, 2019, 11:20:06 pmThe consumption really depends on the boards you run through and what they're mounted in. If it's for flat rigid PCBs with nothing special, then your consumption will be minimal. Run flex and flex rigids on a smt carrier and you're in for some expensive fun we've noticed. The liquid tends to pool in the clamped areas.Quote from: mrpackethead on March 10, 2019, 11:20:06 pmI'd say that's even more important with infrared!

author: pisoiu
author_rank: Regular Contributor
timestamp: May 09, 2019, 06:22:21 am
content: I have a choice between 2 convection ovens, both have 6 zones top and 6 bottom. I'm pretty sure they will be enough for leaded processes and I hope will be enough for lead free. But this manufacturer does not have anything bigger. My designs are however mostly leaded, for automotive.https://www.zjyingxing.com/products/reflow-oven-yx1230-ID279.htmlhttps://www.zjyingxing.com/products/reflow-oven-with-the-chain-yx1230r-ID314.htmlHowever, the difference between them is the transport system. One uses net belt, the other chain rail+mesh belt. Which one is better and why?Thanks.

author: SMTech
author_rank: Frequent Contributor
timestamp: May 09, 2019, 09:25:11 am
content: Quote from: pisoiu on May 09, 2019, 06:22:21 amChain + Mesh is better. Mesh only really handles single sided, but its also helpful if you forgot to put "tooling strip" "panel border" or other free space between the edge of your boards and any components. It can also help with oddly shaped boards or ones that need support during reflow (as your cheap oven won't have a centre support rail).Chain or pin edge conveyor holds your PCBs by the edges so it can handle double sided boards without the need for any silly jigs to hold the bottom side off the mesh.

author: joaomatos
author_rank: Newbie
timestamp: May 09, 2019, 02:03:22 pm
content: Does anyone have any experience or feedback on the smaller ovens with less zones (for low volume production)?Reflow Oven YX630 (3 zones top / bottom)https://www.zjyingxing.com/products/reflow-oven-yx630-ID307.htmlReflow Oven YX830 (4 zones top / bottom)https://www.zjyingxing.com/products/reflow-oven-yx830-ID278.htmlWhat will I be missing by going with these? Harder time following the reflow profile?Should I go for the bigger 12-zone linked by @pisoiu previously?

author: pisoiu
author_rank: Regular Contributor
timestamp: May 09, 2019, 03:45:51 pm
content: I obviously have no experience, only advice from others more experienced and from various articles over the net.If I'm not mistaking, it is almost impossible to setup a correct lead free profile (with soaking phase) with less than 6 zones, specifically in the initial heating and final cooling temperature gradients (heating and cooling rates). Violating those parameters may lead to component cracks, poor solder joints, etc.Assuming that you will setup a profile without soaking, maybe you can make it work with fewer zones, but skipping soaking will cause troubles with bigger components.Almost all my designs are currently for automotive market and are made with leaded paste, so maybe I can do it with 3-4 zones, but at this level of investment (for me is quite big), I also have to think about the future and be prepared for it, meaning rohs. This is why I picked the 6 zones oven (they call it 12 zones, actually 6 zones top+ 6 bottom). I would have picked a bigger one, but this one is the biggest they have, and due to logistical reasons, I do not want to work with 2 suppliers.

author: SMTech
author_rank: Frequent Contributor
timestamp: May 09, 2019, 11:12:23 pm
content: In our shopping round days one of the sites we visited had an Ersa 3 zone oven reflowing lead-free boards for something pretty niche (it was either space or the hadron collider) they seemingly had no issue getting a profile that worked for them.We run our lead free process through a "5-zone" oven about the size of these, and that was a distinct improvement on "4-zones". The key difference was flattening out the soak section of the profile, which helped with larger devices and made things a little bit more predictable. The more zones you have the more control, but I wouldn't pay too much attention to SMTnet gurus insistence that anything less than 12 vertical zones is a waste of space; 6-8 zones is perfectly standard fare for low volume production and such an oven is normally 3.5-4metres long much like this one. As chinese reflow goes this I guess is kinda entry level, one like thishttp://www.folungwin.com/product/showproduct.php?lang=en&id=42more high-end (there is or was a 660). Models like the Folungwin come in a little bit cheaper than an entry level Heller but with the features of a more expensive one, maybe cheaper again if you cut out the middleman.

author: Reckless
author_rank: Frequent Contributor
timestamp: May 10, 2019, 03:41:12 am
content: I don't trust chinese ovens, neotech released a new smart oven 3 zone a month ago. Only issue its missing SMEMA connectors and edge rail. A bit pricey at $2k + 1k shipping. Looks consumer grade not industrial grade. 10" width.I use a 3 zone Essemtec RO300fc-c which I love. 3 phase 28A means easy to plug anywhere. It only uses 5kwh when running. I have only done ~2,500 lead free boards and its been perfect. My current profile is 6 minutes, we haven't tried optimizing yet, just using stock profile. It's tiny compared to 7 zone oven but sometimes I wish it was even smaller. Essemtec is a swiss company so temperature is very precise. I think thats the secret to sucess, very precise temperature control. For some reason chinese ovens are not as repeatable long term.

author: IconicPCB
author_rank: Super Contributor
timestamp: May 10, 2019, 03:49:31 am
content: Reckles,Can You specify Your six minute profile namely zone length, zone temperature setpoint and conveyor speed for each zone.

author: Reckless
author_rank: Frequent Contributor
timestamp: May 10, 2019, 05:42:43 am
content: I'm out of town right now. See link for 4 zone oven manual from essemtec:http://www.murraypercival.com/files/pdf/RF400FCUM.pdf&ved=2ahUKEwjIgN2XnpDiAhVCRa0KHb_BB6YQFjAAegQIBRAB&usg=AOvVaw2jsnnvjq_VGpItgtcMNk9D

author: pisoiu
author_rank: Regular Contributor
timestamp: May 13, 2019, 05:49:38 pm
content: Has anyone thought to use reflow oven as a component baking oven? Just to put reels inside, all zones to 70-80 degrees, transport belt stopped and keep it on for whatever period is required.I will not be a contract manufacturer, so, my production line will work with big pauses between production batches. When I want to produce some boards, I can make some preparations one day before, bring all room at a controlled temperature, baking all high MSL components, etc.I am just trying to cut some costs with another oven for component baking.

author: Smallsmt
author_rank: Frequent Contributor
timestamp: May 13, 2019, 06:24:34 pm
content: Take care if you use shipping by sea.First of all the machine need a good sealing to protect against rust when traveling 6 weeks over sea.Next problem ask shipping company for complete costs you need to pay until machine arrived in your company.i compared shipping costs for our biggest machines by air is 1300usd and 900usd by sea.You need to pay port fee to release goods and transportation costs plus sometimes shipping compensation.First offer from China always looks cheap!

author: mrpackethead
author_rank: Super Contributor
timestamp: May 13, 2019, 07:03:05 pm
content: Quote from: Reckless on May 10, 2019, 03:41:12 amProfiling somethign by race or blanket origin is just insane. I bought a 'german' vapour phase machine that was just absolute junk. I've got a japenese PNP line, its great. I've got chinese stencil printers that are fantastic, i've bought chinese PNP that are meh, very middle of the road.. 'chinese' as a broad term is really being rather simplistic.

author: jmelson
author_rank: Super Contributor
timestamp: May 13, 2019, 08:34:50 pm
content: Quote from: pisoiu on May 13, 2019, 05:49:38 pmI bake all bare boards that have sat around a while in the toaster oven I use for reflow. My system is, half hour at 50 C, half hour at 60 C and then 1-2 hours at 70 - 75 C. I would occasionally get a board that blistered when reflowed, if it had been here for 6 months or more. Never had that problem after the bake out.I have not done components, as I have never had any issues with them. But, I usually do not keep big FPGAs and whatever in stock for a long time for them to absorb moisture.So, I can't see any reason why using it for baking won't work. Some reels and waffle packs have temperature limits on them.Jon

author: SMTech
author_rank: Frequent Contributor
timestamp: May 13, 2019, 10:24:38 pm
content: Quote from: jmelson on May 13, 2019, 08:34:50 pmBaking times according to IPC standards are way way longer than you might think hence not done with a conveyor, check them out. Rather than baking stuff on the offchance before using it you could instead store the parts in climate controlled storage like one of thesehttp://www.mekko.co.uk/dry-storage-cabinets/

author: Reckless
author_rank: Frequent Contributor
timestamp: May 14, 2019, 05:42:40 am
content: Quote from: mrpackethead on May 13, 2019, 07:03:05 pmI agree with not stereo typing based on race BUT I think origin might be ok. I should have said ovens made in china by Chinese corporations (Heller and other companies make ovens there too). They each manufacture to different standards. What interests me is a quality, precision, industrial grade machine from anywhere in the world. Fyi my favorite car is a toyota land cruiser from japan because of its industrial grade quality. My admiration for producing engineering marvels.

author: mrpackethead
author_rank: Super Contributor
timestamp: May 14, 2019, 05:57:38 am
content: I have to say that the worst two bits of equipment I bought have both come from Germany. I got lulled into a sense of security thinking it’s German it will be fine!! Now I know that doing proper due dilligence is really important! But the Siemens gear I have is the very best you can buy anywhere ( also German ). Just need to be smart and do your homework.

author: pisoiu
author_rank: Regular Contributor
timestamp: May 14, 2019, 06:00:48 am
content: Quote from: SMTech on May 13, 2019, 10:24:38 pmYes, I know they are long (tens of hours) but I need to be creative here since I'm on very tight budget. Of course climate controlled storage space would be ideal, but for me these are dreams at this moment.

author: mrpackethead
author_rank: Super Contributor
timestamp: May 14, 2019, 07:53:33 am
content: Quote from: pisoiu on May 14, 2019, 06:00:48 amYou can rebake your parts at 70C for about 24-48hours and it will dry them out pretty well. Get a bag of damp rip, and then put your parts ( in their static bag ) in a sealed container. If you can get one of those humidity cards, even better. :-) It works. I've also used a food vacumn sealer, wiht antistatic b bags and it works pretty well.

author: pisoiu
author_rank: Regular Contributor
timestamp: May 19, 2019, 08:07:48 am
content: Well..damn. I spent last week with $ calculation because that is important too. Otherwise, on the long run, I may just end up with a very expensive toy.My main business works well at the moment, and taking into consideration current volume of sales and income, that will justify investment in a production line, even if my requirements are around 10-15% of its capacity. But some aspects of my business makes it quite unpredictable for a period of over 1-2 years.For that reason I must take into consideration to use assembly line for PCBA in the prototyping and low volumes market. Initially I tried to avoid that, but apparently that's not wise. I know that's a different beast with its own quirks and for that I must deal among others with the optimization of the pnp machine setup, because (from what I understand from opinion of experienced people) that is the most time consuming part and is problematic because it keeps the machine stopped.For the physical part, I will try to keep as many standard parts on feeders but for the machine programming part (teaching locations, etc) I really cannot evaluate anything because I only have seen in pictures/movies the software used by the machine.Has anyone been able to obtain a copy of the software used by (chinese) machine manufacturers before actual buying the machine? These software have anything like 'demo' or 'offline' mode? I asked my contact person but this question was ignored. I will insist if there is any chance of success.