Pick and place build, openpnp

[pisoiu]

This one: https://www.aliexpress.com/item/32915353766.html , with a 6-60mm lens (*or 5-100, I have both and I don't know now which is installed). The lens however presents some problems, the aperture mechanism is moved inadvertently due to high accelerations, they can go as high as 5G. I have to find a better lens.
It uses a coaxial illuminator with a 50/50 mirror. Unfortunately, in order to see ok most of the items, I have to open the aperture to a point where shiny surfaces and the pads (in the video are ENIG pads) are overexposed and they don't look too nice. But it does not seem to affect fiducial recognition.

[Kjelt]

the aperture mechanism is moved inadvertently due to high accelerations, they can go as high as 5G. I have to find a better lens.

Do you mean it is broken or that the zoom, iris etc that you can lock with the screws goes loose all the time ? The latter you could add a drop of the right Loctite.

[pisoiu]

The rings for the zoom, focus and iris are locked with screws. Focus and zoom stays the same, but the luminosity of the image changes from time to time even if the ring is locked in position. I have to unlock it and re-adjust, then lock again. And after some time it changes again. At the beginning, with the screw unlocked, the iris adjustment was smooth but now when I turn it, it seem to move in steps.

[pisoiu]

Ok, so I begun to work on the firmware for the controller, the progress on mechanical system is not possible anymore without tons of io's.
Specs:
-usb interface
-rs485 bus for servos
-CAN bus for connecting to other boards
-60 physical ports, almost all of them can be outputs and digital inputs, 12 of them can be analog inputs
-80 logical ports which can be assigned either to physical port or to entities such as steppers, sensors, etc.
-configurable parameter system for io matrix assignment, motors parameters, etc
-the machine can use one controller board as master board, it takes data from openpnp to and from its ports, or it can route data to CAN bus. From there, any number of other controller boards, working as slaves, can take data from CAN and route it to their ports.

I also had to make a turn in the development. I badly need a working machine for my other designs, and is very important to have something that works, not necessary with the top performance. The heads designs is much slower than I expected and I suffered some setbacks. So I decided to quickly install 4 heads from aliexpress, to make it work, and in the mean time the work on my heads will continue.

[Kjelt]

So the interface of that I/O board to openpnp is USB ?
How does that work inside openpnp is that some old fashioned serial interface or can you do 10Mb/s as would ethernet ?
Nice sockets, what connectors are those, Molex ?

[pisoiu]

FT232RQ is the chip I use for USB interface. It presents a classic COM port to the OS, can be opened up to 921600. I have some restrictions with the crystals on that board and I can generate baud rate only up to 460800, but that's enough. I work with it at this speed. Since the data packets are not that large, it does not matter too much the speed increase once you are over 115200,  the communication is much more affected by turn around times and delays in communication.
Connectors are microfit 3.0 series, those are actually made by wurth, but molex also have them in identical footprint.

[olkipukki]

This one: https://www.aliexpress.com/item/32915353766.html , with a 6-60mm lens (*or 5-100, I have both and I don't know now which is installed).

Wow, "global shutter", "120fps", "1280X720", "with lens" for $85?! Hard to believe, but who knows...

Do you know what a sensor inside?
Does it come with any drivers or just works?

[pisoiu]

1280x720 it is, global shutter it is, the image does not twist when head is moving fast. About 120fps, I did not measured top value, but certainly openpnp reports much higher frame rate than other cameras. It does not come with drivers, it just works. Lens is a bit of a problem, is a low quality cctv lens, mine got damaged a bit due to high head accelerations, it can reach 5G. I don't know about the sensor, I can't see a part number in the description.

[MR]

Do you know which aperture this camera has?

[pisoiu]

Currently I am using this lens on it:
https://www.aliexpress.com/item/32972722509.html

It's a manual aperture, I think the mechanism is damaged because the image changes brightness from time to time and I need to readjust the aperture. Also, the adjustment does not seem to be smooth, it changes abruptly with the move of the ring.
On the other hand I need to look for another lens, made for this kind of applications. Do you know, by any chance, a manufacturer of such lenses?

[olkipukki]

On the other hand I need to look for another lens, made for this kind of applications. Do you know, by any chance, a manufacturer of such lenses?

Do you professional-made in well-know companies?
Well, prices starts from 300-400... and you relly need to know what you need to buy - so many variations there
In most cases, depends where you are to find a distributor, no many sell directly.

The budget option, I found on ali in range $100 in some specialized stores (search 'lens industrial camera machine vision' ) and still waiting 11.11 to pull a trigger for sake of a few bucks saving

Don't forget to check a mounting too, might need C-CS adapter as well 

[pisoiu]

Thanks for tips. I know they're not cheap but it's an expensive machine that needs to work so....

[olkipukki]

pisoiu, did you machine custom parts for your machine inhouse or outsource to somebody?

[pisoiu]

All parts are manufactured by me. Lathe and mill. Outsourcing at this level would be, at least in my case, impossible to work with. It is the first prototype and there are many uncertainties and unforeseen problems which changes  the design to the last second.

[olkipukki]

Thanks for tips. I know they're not cheap but it's an expensive machine that needs to work so....

Just give you an idea, not always you can find pricing available online w/o RFQ...

https://www.kowa-lenses.com/en/machine-vision-lenses-c-mount-cs-mount

[pisoiu]

A dry test with 2 heads. Pneumatics not installed yet and only 2 nozzles installed. Another 2 will join them soon.

https://youtu.be/CqVI0omaFPk

[Kjelt]

What is that cross axis chain contraption you have ?
Is that for mechanical synchronization of the two X axis ?
Do you need it with ball screw spindles and cl servos  or what is it for ?

[pisoiu]

It is for Y axis. It is driven asimetrically by ballscrew and the other end vibrates badly if left unconnected. The chain is mounted in such a way that is connected to both ends of the X rail and when Y motor pushes one end, the other one is pushed through the chain.

LE: pulled instead of pushed, it sounds better for chains

[pisoiu]

These are the first placement tests.
0402 with juki 501 nozzle placed on test board from a strip feeder. At this point there is no nozzle calibration and parts are placed without vision. Some parts have wrong rotation, still working on that.

And a bouncing problem which I need to solve:

https://youtu.be/99QcyA9aAJI


LE: 10xSOT23, full speed

https://youtu.be/5jwegV7XlWE

[olkipukki]

LE: 10xSOT23, full speed

https://youtu.be/5jwegV7XlWE

Are you planning to add an conveyor eventually to feed PCB into? or... place all PCBs on custom fixtures (as per video) for production run?

[pisoiu]

Hi,
The goal of this machine is to perform small and prototyping production batches. It will be used mainly for in house production , <10k boards/year and if all goes well, I will also offer PCBA for prototyping/low volumes.
The machine is designed to be loaded fast with components, this is the key to lower setup costs. It has large x-y (~1x1m) usable space to allow as many strips as possible. Most of the components must be loaded as strips and as few as possible on pneumatic feeders, loading and preparing them takes too much time. Maybe only common components will always stay on pneumatic feeders, such as 100nf, etc.
The other steps in production (paste deposition, soldering) are also not inline. Soldering is with vapour phase.
That being said, it does not make sense to spend effort adding conveyor. It adds little benefit in my setup. Maybe I will change the corner holders with some sort of pcb bracket, but will be manual load for sure.

[Kjelt]

If you can handle panelized pcbs a conveyor without pneumatic feeders makes little sense IMO. You have to replace the strips anyways

[olkipukki]

The goal of this machine is to perform small and prototyping production batches.

Yes, make sense, I'm more interested how you will keep up with this machine, especially if you have optimized for XY movement in advance.
I guess if you will place just one board per time, you basically babysitting this machine and no time to boil a water to make a coffee.

Thought you either place as many PCB as possible and let it go while doing something else, no?

Are your boards high-density with 100++ parts?

[pisoiu]

Hi,

Imho, prototyping and low volumes involves babysitting, this is why I did not bothered with an inline process.
Before considering designing this machine, I was looking to buy one ready made, chinese, something like SMT880, Kayo A4, etc. but none suited to my needs.
My most complex design have around 180 parts (total) or 65 parts (unique) on a 75x35mm 4 layer board . It is my main product, a GPS tracking device. The problem is that with my current design there are a lot of variations for my customers, depending on which part of the world are they and what interfaces they require. There are variations in cellular modem type (2G, 3G, LTE), some have internal simchip, some needs CAN interface, there are RS485, RS232, Kline interfaces, etc. Currently I use external PCBA services but it is economically unwise to manufacture and keep on stock all possible variations between these options. I can produce 2-3 variations of products and then hope that the next order will be the right combination of options I have in stock. If I do not have it on stock, then in some cases I can manually change an existing board in something suited for the client, but for me it is an extra cost in labor and thrown components. And it only can be done with 10-20 pcs, not more. What I take out from that board becomes unusable for production. Many times I also had to refuse orders because they were too low on quantity and producing 10-20 pcs with a specific recipe would turn a 50$ product into a 500$ one and the client will not absorb such price difference.
So, for me it makes sense to keep on my machine as many common components as possible loaded in pneumatic feeders, others can be quickly loaded on trays and if I need to produce 10-20 custom assemblies for a customer, no problem, it is done in a couple of hours. This is why my machine have big x-y space.
I actually do not need from it very high speed. Current speed with what is visible in videos is around 2500cph and will drop once I start to use vision and components placed farther away from the PCB. What I need is to be able to load it fast, and fastest way is using tapes and trays.
I used best technologies I could afford because I need precision and repetability over the entire working area, down to 0402. I do agree to babysit it to change boards and load components but I cannot agree to babysit it by always correcting misplaced components.
If process works well and if I can find a way to allocate resources to create a PCBA service for prototyping volumes, that will be available as well.

[pisoiu]

Hi,
I need a bit of advice, since my knowledge in optic fiber components is minimalistic to say the least.
My machine design is progressing slowly. Now I am running reliability tests and I have some communication problems between main board and head board. After ~ 1000 components since job start something happens and machine stops, waiting indefinitely after some command. Somewhere between openpnp, serial port, main board, can interface, head board, something is lost. I tried to debug this by putting logic analyzer on the relevant signals but it is impossible. The electrical noise coming from the servos makes any low voltage signal completely unreadable if routed with long wires. On the logic analyzer all I see is noise from servos, nothing readable from wanted signals. So, the only choice I see is to use optical coupling for debugging signals. I want to use fiber optic emitters to be wired on the relevant signals, or to be wired on the CPUS and sending test codes, and those coupled with optic fiber to a receiver in the logic analyzer. But I am not sure what to use, I am unfamiliar with various optic fiber types, connectors, systems, etc. Test signals are in the microsecond range. What optic fiber transceiver/receiver/cable can be suited to this task? I am looking for low cost and ease of use. I want to use ready made cables, not raw fiber, splicers, etc.
Thanks.