Author Topic: Complete Beginner Information ?  (Read 26707 times)

Tandy

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Complete Beginner Information ?
« on: January 14, 2014, 04:23:21 PM »
Hi

Just wondering where to start really, is there a guide somewhere explaining the steps to using a pick and place machine from scratch.

I.E I have a PCB design in eagle, what would the steps be to populate it?
Presumably I have to export a Gerber file from Eagle and then somehow tell the machine which part is in which feeder ?
Does the machine align the part automatically or is there are process required to teach the machine the orientation of the component?

Is there perhaps a beginners guide somewhere and maybe any manuals for the RV machines that might help me get started ?

Thanks
Darren

Gopher

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Re: Complete Beginner Information ?
« Reply #1 on: January 14, 2014, 05:20:12 PM »
http://electricstuff.co.uk/forum/index.php?topic=170 manual is linked in this thread. It does a fair job of covering all the steps without someone gong over it again in detail. Having said that you will probably find that on here too.
Orientation is defined in two places -
  • The component package type, which tells the machine how the part is stored in the tape
  • Against the component reference for a given product, which tells the machine how many 90deg step its needs to rotate from the its start position.
Because these two are linked, adjusting one messes with the other which can be frustrating and is worth bearing in mind.

If you are using Eagle some people on here may be able to provide you with ULP's they have written that skips some of the steps otherwise required, otherwise the machine works using Gerber data and a BOM. Essentially the process is automatic once you have supplied this data.
There is no "Manual Teach" mode as you might find on some other machines, you have to have some data to get started. Having said that the CD does include some software that purports to let you setup a PCB using a scan, I am unaware of anyone who knows how or even IF it works, it is not documented.

Mike

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Re: Complete Beginner Information ?
« Reply #2 on: January 14, 2014, 11:55:34 PM »
I'm not familiar with Eagle  - I think there is at least one user here that is.

What the machine needs as a minimum is a list of part type and name, position and rotation values. RV Gerber lets you import the silkscreen gerber to help creating the setup file (TFR) - I don't use it much so can't comment.

The part type refers to a type in the CDF file, which tells the machine the vision parameters (size, vision type, threshold offsets for body colour), height, tool type etc.

The value is used to select which feeder to take the part from.

Feeder allocation in RV setup maps values to feeders

It will save a lot of time if you set up your Eagle library so that all the rotations are consistent and match the RV's "natural" zero orientation, which is  is as parts sit in  the right-hand feeder bank, i.e. index towards you.

Make sure you define different part types for resistors and capacitors of the same size, as vision parameters may need to be set differently due to the darker body of capacitors

Gopher

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Re: Complete Beginner Information ?
« Reply #3 on: January 15, 2014, 10:20:54 AM »
Defining stuff in your CAD package the same as the machine is a good tip, something I have never had control over as a subby.
Not making your package definitions too generic is also a good tip, caps do indeed look quite different to the camera to resistors. Higher value caps can also be quite a bit taller, in 0805 they are as tall as they are wide, whereas pf values tend to be similar in size and colour to resistors. Getting the heights right helps ensure consistent placement pressure, getting the size and colour right helps ensure you get low vision failure rejects.

Mike

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Re: Complete Beginner Information ?
« Reply #4 on: January 15, 2014, 10:58:55 AM »
Component height is also affects vision as it's used to set distance to the camera for best focus.

Jason

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Re: Complete Beginner Information ?
« Reply #5 on: January 19, 2014, 10:22:53 AM »
So do people end up with multiple C0805 in the CDF, one
for each height? I'll have to see how I can capture the
height attribute in Eagle

Thanks for the tip on orientation. I'd already stumbled into
that one as there is no consistent orientation in the Eagle
part libraries which is a PITA.
I'm in no mood for modifying all the Eagle libraries so I'm
going to build a map so each automatic export from Eagle
uses the map to set the rotation rather than the fixed way
that I inherited from Mike's PCAD exporter.

Mike

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Re: Complete Beginner Information ?
« Reply #6 on: January 19, 2014, 11:19:53 AM »
So do people end up with multiple C0805 in the CDF, one
for each height? I'll have to see how I can capture the
height attribute in Eagle
I've not found it necessary to have more than just different CDFs for R's and C's (mostly for vision) , but the vast majority of the  cap values I use are the same for each footprint so YMMV. Worst case you can probably get away with just "fat" and "thin" variants.

phonoplug

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Re: Complete Beginner Information ?
« Reply #7 on: January 21, 2014, 12:37:26 AM »
I do have different CDFs for different height caps. The larger they get the more variety you have too.

For example I have I think two different heights for 0805, but 1206's I think I have 3, 1210's 3 too, and although I only use one 2220, you could end up with quite a few different heights anything from about 1.8mm upto 7 or 8mm for that footprint.

The pain is when you buy a new reel of, say, a 4u7 1210 cap from a different manufacturer and find their one has a different height! Ideally you need to change your BOM, then re-place them in the transfer file, save it and output to job again, though there are some quicker and dirtier ways of achieving the same result.

Tandy

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Re: Complete Beginner Information ?
« Reply #8 on: January 28, 2014, 06:15:43 PM »
Thanks for the suggestions but it all sounds a bit complicated. I don't think I'm going to bother after all when the cost of having things done by a contract manufacturer is not that high.

Gopher

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Re: Complete Beginner Information ?
« Reply #9 on: January 28, 2014, 09:47:03 PM »
I wouldn't say it was complicated, the basic day to day stuff is pretty straight-forwards and any special cases you only need react to when you encounter them, examples such as varying heights are things that I adjusted when I observed higher fail rates in terms of vision or poorer placement rates. The benefits of in house vs sub-con however will be different for each user, how they value their time, what availability they expect/require etc. As a sub contractor I can acknowledge there are things it is not easy to achieve in that capacity that one might conceivably be able to do in house especially where lead times are very tight.

I think if you were making lots of different little projects in small volumes, it's pretty hard to argue with the benefits of a small cheap pick and place of your own, what you don't know you will pick up fairly quickly and you may gain knowledge that helps with bigger projects you may then sub out. Beyond that it is probably more a question of do you want to be a manufacturer, do you want to expend the time and space a production line requires etc.

In our case I think our subcontract work was a very significant part of why we have surface mount capability, we would have found it much harder to justify solely for our own products. However, having it brings benefits to those products, what is possible and what they cost.

Looking back at your original question, were we too specific?
Breaking the process down to non RV steps would be:
Create Design in Eagle.
Get some PCB's made
Export Pick and Place data from eagle (or Gerbers if its an RV)
Generate a paste layer in Eagle and send that to a stencil manufacturer of some description (they can do this for you but they can and will miss things)
Import data to pick and place machine
Create any new packages required
(define how any new parts are packaged i.e reel/tube/tray)
Setup any panelling information
Put a blank PCB in the machine and setup/check your fiducial information information, on most machines you can also verify the placement co-odinates are correct. (not an RV)
Load your components into your feeders and tell the machine in what lanes these parts are loaded. For machines with dumb feeders, tell the machine where those feeders are on the machine. (on an RV this is where a job is created)
Setup the pick location and height for each feeder lane. (allows for variations in tape thickness and location of device vs index.
Paste your PCB's using your shiny stencil and ideally a stainless squeegee.
Load the board, load the job and run it.
Check the first PCB for any mistakes in loading/orientation/location (you cannot fully trust pick and place data)
Reflow the PCB, for prototypes this might be a toaster oven or small benchtop.
Inspect it, load your THT parts.

Things that can make your life easier :
Some form of printer with a frame or tensioning system for your stencil, and alignment adjustment. (even a DIY hack)
Fiducials on your PCB
Buying your parts in sensible volumes or use RS/Farnells "Production Packaging" option, little tiny strips can be quite annoying especially if you are going to use them more than once.
Put your PCBs in panels with routed or scored 10mm (or at least 5mm) borders, it gives you something to hold onto as well as machine it easier to secure the PCB in the machine. It also means the panel is ready for production in an inline process if needs be.
A proper convection oven or vapor phase batch oven. If you start using things like surface mount switches or large devices then simple reflow systems will start to let you down. The increased thermal mass and of such things means other parts of the board can overheat while you try to get others to solder. This is especially true with lead free where 217C is the melting point you need to reach which can be quite close to the maximum rated temp of certain devices. YMMV here however, some people will insist they are fine without.


Tandy

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Re: Complete Beginner Information ?
« Reply #10 on: January 30, 2014, 02:47:04 PM »
Thanks for the info.

I have the PCB and stencil production covered that is pretty straightforward in exporting Gerber files from Eagle. We also have a proper re-flow oven and as a component retailer a plentiful supply of components. Really the gap in knowledge is in setting-up and using a Pick and Place machine, having never used one.

Basically the situation is that many new IC's are understandably being produced in small pitch SMT packages because that is what the demand is for. The problem is that our customers who are mainly electronics enthusiasts building projects at home find them difficult to solder and obviously prototyping on a breadboard is not possible. So we were hoping to produce small breakout boards that have the main IC and any essential support components such as resonators, capacitors, pull-up resistors to make home experimenting easier for our custoemrs.

Ideally running our own machine would allow us to run small batches of perhaps 100 boards at a time that would be uneconomical for contract manufacturing. Most of the passive components would be the same for all boards and could stay in the machine, in most cases it would be just the main IC that would change.

Having investigated a bit further I am considering a slightly newer MyData machine that has quite a nice feeder arrangement, anyone have any experience of the MyData systems ?

Gopher

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Re: Complete Beginner Information ?
« Reply #11 on: January 30, 2014, 05:35:21 PM »
Sounds like a good idea, bit like these https://github.com/maugsburger featured on EEVBlog, but populated?

I am not familiar with them first hand but they were certainly on the cards when we were looking at machines, so I did look at them quite closely but only had a full in person demo of a MY100. I'm guessing you are looking at perhaps an MY9 and the feeder arrangement you are liking is 'Agilis' system? There are lots and lots of people out there with MyData's so there is probably one near you to have a look at if you ask someone nicely. ~2 years ago I could get an older TP11 series with a healthy complement of TM feeders for a little over £22k, so they are way more expensive than an RV.

IMHO
Pro's :
Agilis gives you great, low changeover times (which you don't need)
Built in Vacuum Pump so no need for noisy compressor and dryer
Lots of them out there ( I can see 22 listed for sale right now)
You can swap feeders on and off during a job if you need more than you can fit on your machine at a time
They seem to retain value better than many other brands
Easy to get more feeders (especially the pre Agilis 'TM' ones)
You can update a TP machine to take Agilis feeders (but it's £££)
Genuine MyData expertise available outside of MyData

Cons:
Agilis wastes parts because it uncovers more than one pocket (this is only bad if you do lots of changeovers and value those parts)
If you need a lot of feeders loaded at once you need a big model as all feeders are on one side.
Without a HYDRA head they are quite slow as the head has a long way up and down the machine to travel
Split axis - more to go grong?
Official support is expensive
Official support on 'TP' series is only available at a base level SLA
Agilis 'elements' are really quite expensive considering they are a piece of machined metal with a chip and some contacts.
Lots of different vision system options to choose between
There are mechanical centering ones out there which it is probably wise to avoid
Its not a shiny point and click windows world from start to finish.

From the type of work you describe you won't spend much time setting up and perhaps most of your setup time will be spend defining new IC packages, it also sounds like a job for the smallest machine you can find http://www.autotronik-smt.de/products/bs281.htm or a Dima ATOZ perhaps?

Plenty of us sub contractors are quite happy to do 100 PCB's, 4 panels of 25 small pcbs, or even one PCB. It doesn;t sound like complex or time consuming work I would certainly recommend getting a goodly number of quotes before spending a fortune. Those that want the work will probably quote similar numbers, the sums after all are all the same.

Tandy

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Re: Complete Beginner Information ?
« Reply #12 on: January 30, 2014, 07:11:11 PM »
Thanks for taking time to reply, much appreciated.

Regarding boards they are more like small ready made modules like these examples from Adafruit MCP4725 Breakout Board or this MPL115A2 Sensor. Most boards will just have a decoupling capacitor and pull-up resistors maybe the occasional LED or resonator. As the values will be pretty common across all boards most components can stay on the machine all the time.

Having said that once we get things up and running we would also like to offer our kits part assembled, take this for example http://www.tandyonline.co.uk/electronics/kits/multiface-kit.html it has quite a few through-hole resistors and capacitors and LEDs that we could replace with SMT versions so that the board comes part assembled and the end user then just needs to solder in IC sockets and pin headers for more instant gratification.

Gopher

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Re: Complete Beginner Information ?
« Reply #13 on: January 30, 2014, 07:53:53 PM »
Handy, a 10*10 matrix of either of the first two would fit in an RV quite nicely I would think and even that would finish placement in 30 mins or less.

Mike

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Re: Complete Beginner Information ?
« Reply #14 on: January 30, 2014, 09:52:03 PM »
You missed a bit...
Quote
Setup the pick location and height for each feeder lane. (allows for variations in tape thickness and location of device vs index.
Before pasting, do a dummy run on any newly defined parts to get the vision parameters right, and to check general alignment, using double-sided sticky tape on the bare PCB

Quote

Things that can make your life easier :
Some form of printer with a frame or tensioning system for your stencil, and alignment adjustment. (even a DIY hack)
Tensioning, yes. Adjustment - depends. I use the Eurocircuits printer that has fixed alignment pegs - works well enough that I've never found the need for adjustment