PP4 by VBsProjects - Page 1
Forum section: electronics / general

author: PixieDust
author_rank: Frequent Contributor
timestamp: February 10, 2019, 05:38:03 am
content: Searching these forums, I'm surprised I can't find any results of this machine:Here is the website for all the files for it:https://www.vbesmens.de/en/pick-and-place/downloads.html

author: JPortici
author_rank: Super Contributor
timestamp: February 15, 2019, 10:18:15 am
content: Quote from: Fromhttps://www.vbesmens.de/images/Downloads/PP4WordOfWarning.pdfQuoteThen i stopped reading the warning notes, not getting a good vibe

author: PixieDust
author_rank: Frequent Contributor
timestamp: February 15, 2019, 10:36:22 am
content: Reading everything else, you get the impression that he is mostly trying to offer this thing on an 'as is' basis. So I took that as meaning something more along the lines of 'I designed it, I'm happy with what it can do, I don't plan to improve it any time soon, I'm not interested in suggestions for further improvements'. He uses it for prototyping work for his consulting business.

author: jmelson
author_rank: Super Contributor
timestamp: February 17, 2019, 02:20:55 am
content: Quote from: JPortici on February 15, 2019, 10:18:15 amThen i stopped reading the warning notes, not getting a good vibeWell, my $100,000 Philips CSM84 can't handle MELF or domed LEDs without a custom nozzle.It has no vision, that cost extra. And, 6.5 mm is the max component height.Jon

author: PixieDust
author_rank: Frequent Contributor
timestamp: February 18, 2019, 06:06:19 am
content: The thing I don't understand about this PP machine and PP machines in general, is, how do they know the orientation of the parts that they pick up from the reels? They aren't exactly aligned perfectly in their little compartments.Only the chips are scanned with the vision system. The other components are picked up and placed right in their spot.

author: Kean
author_rank: Unknown
timestamp: February 18, 2019, 06:35:58 am
content: You can choose to have all parts go through the vision system, but it slows things down a lot and isn't really necessary.Many parts like 0603 and larger resistors and capacitors, SOT23 devices, and so forth don't need particularly accurate alignment because of the effect of surface tension when the solder melts.My Neoden TM240A doesn't have vision at all, and I even do 0402 parts on it occasionally. Although I always do inspection before reflow and sometimes have to nudge a few parts into place to try avoid tombstoning.

author: SMTech
author_rank: Frequent Contributor
timestamp: February 18, 2019, 12:00:23 pm
content: Careful with your terminology! In surface mount placement "chip" means a small two terminal device like a capacitor or resistor.Every modern machine will perform alignment correction on every part, skipping this process is the preserve of older or cheap machines. How much alignment slows down picking depends entirely on how it is done, if the system is mounted on the head the time added is basically zero. If its coming over a fixed camera then clearly there is some extra movement involved and the rate can drop, in some cases dramatically . Vision alignment dramatically reduces the chances for common placement issues to arise like tombstoning or two neighboring components hitting each other/soldering together when they shouldn't. The offsets corrected for in vision are also fed back into the system so the next pick on a given component is carried out where the device might reasonably be expected to be, there is much greater room for movement in the pockets holding many devices than you might think. As soon as you have any volume at all the cost of manually checking your placement and tweaking it with tweezers will become pretty apparent.You really shouldn't be counting on self correction, it is less reliable with modern solder & flux types than older ones & won't necessarily correct itself where you expect it to. How accurate your printing is, the shape of your pads, copper nearby, other components nearby all affect how a device heats up and moves in the oven. If you take a look at Jukis promo material for instance you will notice one of their features is that it can scan your solder printing and align the placement to match that, devices & solder will tend to move to their pads in the case of an offset, if the device (say a QFP) had been plonked down without that offset you could potentially end up with every single legs shorted out. However that kind of offset shouldn't really ever happen on the kind of line you might find a modern Juki in...This project has been around and mentioned in various places since it appeared but the fact remains the barrier to building open source l hardware of this type remains fairly high meaning most people wouldn't attempt it unless it was available as a kit for assembly. IIRC there was a website that was going to do just that it it never really happened.

author: Kean
author_rank: Unknown
timestamp: February 18, 2019, 03:23:45 pm
content: Quote from: SMTech on February 18, 2019, 12:00:23 pmSure, you're certainly correct in relation to larger scale production on a "real" PnP. People considering a machine like the one discussed here (or my rather limited TM240A) are not really the target audience for a "modern" Juki.When I need a larger production run (>20 pcbs/panels and not a rush job), then I would outsource and let someone else deal with it. My TM240A is primarily for keeping some sanity when doing those small or urgent runs. And doing the manual inspection, re-alignment, and final rework correction isn't a concern if I haven't also had to manually place all those darn parts.I currently get pretty good results with GC10 paste and a semi-decent stencil printer, and the biggest variable is still the reflow process. It is hard to tune the profile & positioning in a crappy benchtop reflow oven for each design when you're only doing small batches and only running it once or twice a month.For me the biggest time waste is actually loading the reels/tape on the TM240A. The wide range of designs I work on mean very few common parts. If I ever upgrade then the feeders will be a bigger deciding factor for me than actual machine speed or vision capabilities.

author: SMTech
author_rank: Frequent Contributor
timestamp: February 18, 2019, 04:15:52 pm
content: OK... but to put that into context "modern machine" would include a ~2002 Versatronics RV4 that cost a whopping £24k new. A machine never designed to be volume (not that some people didn't try). Vision these days needn't cost a lot to add and you can get pretty close to "flying vision on some systems where the camera is mounted on the gantry. Prior to these Chinese machines every machine had some kind of centering systems be it laser, mechanical or optical, its the complete lack of anything like that on the TM240 et al that make them a laughable concept to many of us.Changeover is a huge issue to many people and a major focus even on "proper machines" aimed at something resembling volume. The key is to have lots of feeders and for it to be easy to switch between them. In the ideal world it helps if they are "smart" however the biggest focus (at the low end in particular) will be on cost. For the chinese machines this seems to mean copies of the very common Yamaha mechanical feeder. For bigger machines like Mycronic&Europlacer they separated the mechanical tape advance system from the part that holds the tape. So you buy many more holder bits than advancey bits and potentially keep many of your parts ready loaded in those holders. Mycronic went a step further and removed the need to peel off the cover tape and route/wind it anywhere. These systems are quite a bits cheaper than "gun feeders" but still much more expensive than those Yamaha clones.

author: PixieDust
author_rank: Frequent Contributor
timestamp: February 19, 2019, 04:50:29 am
content: Awesome info, learned a whole lot! Much appreciated. I wanted one of those Chinese TM240 machines. Now that I know the way things stand with the whole vision system, I'm happy I didn't pull the trigger. Makes me wonder if this PP4 machine can be configured to use vision every component. I think for small runs, this machine makes sense - if it can do position checking for every part in the software that is. I'm starting to think that the best alternative for hobbyists and small runs is one of those manual PP machines:Although this particular one seems way overpriced! At least now I think I understand why they exist.The only problem that I haven't solved in relation to these manual pick and place machines is the fact that you can't do very large boards with these. From what I know, solder paste has a working window beyond which it becomes unworkable. Learned that from one of Dave's EEV blogs. So basically, if you have a need for a very large board or one with hundreds and thousdands of components, you really don't have much choice but to go with a professional modern pick and place machine. The only solutions that I can come up with would be to break the large boards up into smaller ones and do them one after the other or apply solder paste in sections.Saw this the other day, couldn't help but provide a linkEDIT: I have also now realised that manual pick and place machines cost an arm and a leg, pretty much might as well go for something like this:http://openpnp.org/Supports up and down vision and there are open source hardware designs available. Looking further into this, looks very interesting!

author: SMTech
author_rank: Frequent Contributor
timestamp: February 19, 2019, 08:39:06 am
content: Manual Pick and place has its place but it soon becomes unworkable with lots of parts or with a large board or if there are lots of different parts. At that point something like a TM240 would still be a step up despite their limitations, however none of the Chinese machines cope well with large boards or lots of different parts as they all have quite low feeder counts and small footprints. I've never understood carousels on manual machines either, most parts have a right way up, as soon as you tip them out of tape they seem very determined to stay upside down. Maybe if you made all your parts melfs...What works for you depends entirely on what kinds of things you need to build, plenty of board types will come out OK on visionless machines with weird drag feeders provided you accept a bit of tweaking and component loss.On our production line we try to panelise boards to be at least 200mm square, and that typically results in panels with 200-400 parts on. A lot of what we build are industrial control interfaces, they have quite simple BOMs, and might only have 20-30 different parts on, you could build that on a Neoden no worries (feeder setup looks very sucky if you wanted to build something completely different after tho). However move into something a bit more exotic like drive control and you can end up with 100+line BOMs, nothing Chinese is really suited to that.

author: Kean
author_rank: Unknown
timestamp: February 19, 2019, 08:43:41 am
content: I got a very good deal on my used TM240A & stencil printer, otherwise I would have waited and bought something like a Neoden 4. Apart from the poor feeder arrangement and lack of vision, the firmware is also pretty poor and not upgradable. It is really aimed at only the most basic assembly jobs, like LED panels, but it has been useful for me both for small runs and as a learning experience. A bit like the manual air-powered solder paste dispenser - I rarely use it now and order a stencil with most new designs, but that is largely a factor of the massive drop in stencil prices.I looked at OpenPnP and the LitePlacer, but that was a couple of year ago. Because of its limitations, it didn't strike me as being much better than the manual placement I was already doing. Hopefully more PnP machine manufacturers (especially the Chinese) start to offer native compatiblity with OpenPnP, as many of the software packages are dated or just horrid to use.I lusted after one of those manual placement systems, but they really are not necessary except for the most demanding R&D jobs. They cost an arm and a leg because there is such little demand for them, but some like the Fritsch are very nice pieces of engineering.Regarding paste, the maximum working time between printing/dispensing and final placement/reflow varies. Some pastes start to dry out/deteriorate in just a few hours, but many newer ones (like GC10) can sit for a day or even two, and are much less fuss to work with because they are room temperature stable.

author: PixieDust
author_rank: Frequent Contributor
timestamp: February 20, 2019, 05:18:26 am
content: Quote from: SMTech on February 19, 2019, 08:39:06 amYep large boards or high unique component counts = not ideal.Quote from: SMTech on February 19, 2019, 08:39:06 amThat was the other thing turning me off from the Chinese machines, so much money for like 5 reels at a time.Quote from: SMTech on February 19, 2019, 08:39:06 amI noted that in the videos, was wondering how they got around that.Quote from: SMTech on February 19, 2019, 08:39:06 amPersonally I'm looking for the most universal design for the least money. Aren't we all? But you're right, part of the problems lies in carefully defined requirements. At the moment, my definition is fuzzy.Quote from: SMTech on February 19, 2019, 08:39:06 amExotics cost a lot in all walks of life. I think it goes without saying that something that complex can't be fixed with a home made or cheap solution.Quote from: Kean on February 19, 2019, 08:43:41 amI've got my CNC machine to thank for my experience. I've got some basic grounding on what is go and what is no go but certainly not perfectly versed to avoid all pitfalls. Bottom of the range Chinese solutions I think can only really be used for what you described - a learning experience.Quote from: Kean on February 19, 2019, 08:43:41 amI've only just found out about these, so doing research on their capabilities.EDIT: Would love to hear what limitations you encountered in your reading!Quote from: Kean on February 19, 2019, 08:43:41 amYep, certainly aimed at professional markets.Quote from: Kean on February 19, 2019, 08:43:41 amThat's what I was hoping for. Will look into these newer pastes, thanks.

author: SMTech
author_rank: Frequent Contributor
timestamp: February 20, 2019, 09:24:20 am
content: Pastes usually have a number of times in the datasheet that they are rated to be OK for (terminology may differ).Shelf Time - needs no explanationStencil Time - the amount of time the paste can be out and in use. Solder paste is made up of tiny balls of solder alloy suspended in flux, while in active use it is constantly being mixed with air, the air can cause those balls to oxidise reducing your pastes effectiveness. Many people will almost certainly continue using paste long after the manufacturer suggests but at some level their paste is degrading. Proper paste management would mean you had a 2nd tub that any used pate went into, if at some point you decide your paste "in-use" is no good anymore, the master pot is then not contaminated.Slump time - how long a print will maintain its definition after printing, lots of pastes will manage hours, many manage days. The paste I use is rated to 72 hours but is notably not as sticky if you leave it that long so isn't a great idea.

author: jmelson
author_rank: Super Contributor
timestamp: February 20, 2019, 11:25:30 pm
content: Quote from: PixieDust on February 18, 2019, 06:06:19 amMy Philips CSM84 has chuck jaws that center and align the smaller parts while the nozzle is in the up position. Works pretty well, and is "instant", as you have to raise the part anyway. But, it needs two sizes of jaws to accommodate from 0603 to SOIC-16 parts. Anything larger than SOIC-16 uses the mechanical alignment station, that takes about 5 seconds to align the part.Alignment of the passives in the tape is probably good enough for them - the solder surface tension will probably fix alignment, but might not completely fix the centering. And, some machines DO optically align all passives, but that slows the machine down.Jon