Messages

I would agree, unless they stumble on a cheap TWS/DDM these Chinese machines are getting there. I don't understand the people who were happy with the early versions ~5-6 years ago which appeared to be very poor and just expensive toys rather than useful tools. For in-house work in micro-businesses you likely only need the machine to do the donkey work and maybe a few of the complicated parts. Start scaling above that tho' and it is important to realize how quickly placement requirements can grow in both complexity and quantity, at that point always buy more than you think you need.

Who can say, I think quite a few of the RasPi support industry startups went ID, at least one of which went Europlacer after that, no idea what those people did with their ID machines - in a corner for NPI/Dev perhaps? The only existing Vivo customer I was put in contact with at the time, was having a less than stellar experience which I thought made them a somewhat interesting choice but there we go.

OK now I have to ask, what was the 'next machine'

We stayed non-conveyored and moved up to an Essemtec Paraquda  (for feeder capacity over the smaller models they had at the time), quite a significant step, skipping over machines from Autotronik/Novastar because we didn't like their machines or answers to what support and maintenance looked like. Also skipped over Dima which was a similar speed machine, however seeing as Dima later became part of Nordson and ditched placement entirely.. bullet dodged methinks. At the time however, had we discovered the Intelligent drives machine without Vivo written on it.. could have gone that way.

Currently lazily planning the next one... which way it will go depends a bit on the type of work we see coming out way, 6kcph is as fast as I would go without a conveyored line when doing any kind of volume. Current trends were seeing indicate a fondness among engineers for very high BOM line count requiring many feeders, which potentially pushes us towards 2 conventional machines from Yamaha/Samsung/etc or something vast like a europlacer iineo (which we almost chose last time).

From memory the least accurate area of our machine in later life was the top right corner where you would typically locate the PCB, which makes sense.

One thing you could check is the condition of the belts, if there is a worn area that could show up as inconsistent placement in some parts of the placement area. Probably not something you want to tinker with unless you have some scheduled not that busy time tho'.
Back in the days when we had an RV and it was still new, accuracy really wasn't all that bad, we build boards with biggish QFPs and lots of 0603 fairly reliably, you'd still need to inspect and possibly tweak the QFP before reflow but you could be pretty confident everything else was exactly where you wanted it to be. That was less true 10 years later when we encountered things like 0.5mm pitch 5mm QFNs (almost all needed tweaking), something the next machine found very easy, as indeed should any machine with linear encoders & decent drive control from the last 10 years.

Used to place similarly domed PLCC4 LEDs, to get as reliable operation as possible I countersunk the tip of a Nozzle and then adjusted the device height and Z pick offsets to compensate. I do much the same with our Essemtec machine except it has a Nozzle that shape by default, plus I suspect if I tried it a std one would work anyway. I can't recall the ID of the typical nozzles on the RV, maybe one of them fits quite nicely already?

https://london.craigslist.co.uk/bfd/d/aps-ddm-novastar-gold-l60-60/6577858709.html

Printer is surely worth it for the adjustment table alone, its a popular old model, I think 2 companies still refurb and up-spec them.

https://london.craigslist.co.uk/bfd/d/aps-ddm-novastar-gold-l60-60/6531632916.html theres this on craigslist...

Its been a while but I thought there was an option in RV Gerber to convert tracks to pads... Possibly in that modify layers menu.

That would be the idea certainly.
With other processes you would expect a longer profile with a higher temperature in the early zones to get energy into the board , then you need to carefully set the peak temperature so that it doesn't overshoot or stay above liquidous too long. At the end you might expect to need some additional cooling or make one of your final zones a cooling zone rather than a heating one. That's obviously tricky to replicate in an oven with no zones/conveyor and little control, boards with lots of metal or ceramic PCB's will prove tricky in many small ovens not least because the parameters will be be very different from some boring FR4.

I've seen more than one place, when building small batches literally just put the PCB on the table, put the stencil on top and paste it there and then, no fixtures, nothing to stop it slipping bar the weight of the frame (which were big and heavy as they all had proper printer(s) as well. Taking that one step further, put a large sheet (metal / acrylic /card)  on the table put your PCB on that, now fit your stencil either using sticky tape of perhaps a hinges and clamps if you have a frame, now you can tweak the PCB alignment by pushing and pulling the sheet around. the PCB can be held to the sheet with PCB offcuts and tape.

To my mind with that machine and some cut to size aluminum plate, maybe some extrusion and some fittings you could make a pretty convincing one. Maybe steal the tensioning concept from something like this http://blundell.co.uk/product/sd-360u-screen-printer-with-drape-table-effect/ and the alignment on SAM1515 is not exactly revolutionary

Most printers (that one included) require your PCB to be in a frame, typically a frame is quite a bit bigger than your printable area to allow for whatever fixes it to the frame plus somewhere for the paste to go when you print. There are reusable frame systems from Tecan and Dek etc but they cost quite a bit and the stencils for them will cost you £150+, fixed frame stencil from major suppliers like Alpha,Tecan & others can cost ~£250. The most common frame sizes are 23 and 29" square
If you're buying PCB's from China, PCBWay they often have the option to make you a framed stencil at the same time, they are nowhere near as good as proper ones and if you go large they are also often warped but they are like $40. However they are certainly good enough for low volume production as long as you make sure your stencil layer is everything it needs to be. A UK stencil house will look at your data, perhaps apply some special requests like aperture reduction or "homebase apertures" & give some advice on stencil thickness or other design elements, the Chinese just shove it through the laser cutter without a second look.

Mike I believe has the (fairly expensive) protoype stencil printer that takes frameless foils...

The "printer" in your image is about as basic as it can get, alignment seems to be push-pull between some bolts (tedious?), there's nothing in the way of a pcb fixture and then you have a clamp on a hinge. Its probably a reasonable match to the small cheap chinese framed stencils, but it would also be pretty easy to knock up in the garage too. If you move up to the £500 ones on eBay they look a touch more convincing, PCB support (helps with double sided as well as holding in place), the base plate looks more solid (is the cheap one perhaps hollow?) and it still looks a decent match for chinese framed stencils.

We have one of these https://www.pmtech.co.uk/sam-manual-screen-printer.html and use it with a 430mm self tensioning Tecan reusable frame, you really miss the lack of PCB fixtures at times. With manual printing I would say 0402 and 0.5mm pitch is about as far as you want to go, I do print a few things this way that have 0.4mm pitch QFPs on but that does require frequent stencil cleaning and of checking the alignment for each and every print very carefully followed by a very careful pass with the squeegee.

Beyond this tho' I think the market gets really blurred at ~£2.5k you can get over engineered manual printers, mechanically assisted printers and possibly even things like the TWS SR2700.

I don't think they're all that common, even the small vapor phase units seems to default to 3-phase. Blundell  & PMTech sell the Mistral 260 which is single phase so tracking down one of those could be a plan- @£8k new that's about the same money as often seems to be asked for 2nd user VP reflow. Turner Electronics http://www.turnerelectronics.co.uk/products/surface-mount/reflow-solderin/ have a bunch of small ovens of which the tabletop DDM seems to single phase at the very least.

I don't think I've ever seen any of these crop up on eBay or Grove for instance, but maybe if you had a chat they might be able to hook you up with a unit as someone upgrades or an ex-demo...

3 zones does work for many people, but combine that with a short process length and low power and you'll struggle to get a "good" profile on some board types. What those issues will be will depend on the type of oven, and the components used. IR for instance has shadowing issues with tall parts as well as some degree of colour sensitivity , VP is not electrolytic friendly (personally I question the value of surface mount electrolytics in small batch manufacturing) and small convection ovens may simply not be able to deliver the requisite heat for a dense PCB. 5-6 zones and 2.5m+ process length is where you can start to be pretty confident of being able to come up with a nice profile for just about anything, extra length and zones after that is all about delivering a decent profile while also improving throughput.

Not reachable means for whatever reason the machine believes the pick position for that lane cannot be reached by the place head. This could be because the feeder has moved and needs re-seating and then resetting ref1&2. However it could also be because the machine has used its pick position correction algorithm to move the pick position outside of pick area, that can happen form a poorly designed component definition or you might need to run through the known calibration routine.

I'm pretty sure Ed was in fact David Clements, I can't imagine there were ever many calibration kits in existence and VSMT who took on the servicing was only ever a 2-3 man outfit, David, Darren and I remember one other but not their name.

I would have thought David was well shot of any kit, at the time of that offer RV machines were apparently owned by two types of customer, small OEMs who didn't have the cash to move on, and hobbyist/single person outfits. One group was confident  in their ability to work things out themselves and the other weren't going to invest in a dead platform or perhaps had already gained the knowledge required.