PnP Machine for House Garage

[wilhe_jo]

Well it seems they are much better than one might expect...

That guy shows off some laser exposure tests of PCB material and some photos from a microscope:


In a different thread I mentioned, that I have in mind very cheap machines built for a specific design which is quite simple.

I was thinking of a PNP head which is not able to rotate.
Instead, I plan to let the machine pick the part and place it on a clear (for the vision of needed) acrylic plate which is rotated.
After rotating the part is repicked and placed.

So the head just needs to be lowered.
My vinyl cutter does this using a flexture and an electromagnet.
Would be very easy to replicate this... or just use the spare part...
No need for springs to accommodate variations in height, just adjust the down-pressure by setting the magnets current.

Should be much easier from the mechanics point of view but slow.

For my purpose that would be fine.
I'd just let the machine populate the next PCB while assembling, testing and packing a unit...

so XY is  cheap.
Pick/Place is simple.
Rotating without the need of rotating fittings, hollow steppers and such is fine.

The real problem are in my opinion the feeders.

I haven't found an economic solution for this yet.
Well, that's not totally true.. over in the openpnp group I found this one:
https://docs.mgrl.de/maschine:pickandplace:feeder:0816feeder

But i didn't had time so far to print and test one of these...

73

[Fire Doger]

In a different thread I mentioned, that I have in mind very cheap machines built for a specific design which is quite simple.

I was thinking of a PNP head which is not able to rotate.
Instead, I plan to let the machine pick the part and place it on a clear (for the vision of needed) acrylic plate which is rotated.
After rotating the part is repicked and placed.

So the head just needs to be lowered.
My vinyl cutter does this using a flexture and an electromagnet.
Would be very easy to replicate this... or just use the spare part...
No need for springs to accommodate variations in height, just adjust the down-pressure by setting the magnets current.

I don't think it will work, plus the changes in software...
Hollow shaft nema8 costs 9$ on ebay, a tmc stepper driver is more expensive....

[Harvs]

By all mean give it a go.  It may not be the most conventional, but building robots is interesting and can be fun if there's no looming deadline. OpenPNP looks pretty extensible and well writing from the small amount of looking I've done, so shouldn't be too hard to add your custom pick sequence of moves.

[spanner888]

hollow shaft nema8 9$ on ebay

....I want want want - been looking for cheap ones for years, but can't find, used several different model numbers and all sorts of search tricks. A search just now shows $A30 and up.

Can you share or PM any links please.

[wilhe_jo]

Well, you can find some...
https://m.de.aliexpress.com/item/32865075882.html

But making a low runout adapter to a nozzle which holds a sufficient vacuum is not too easy.

73

[Koen]

Send an email to 439291063@qq.com

He supplied all the specialized parts of my PNP like the head, hollow motors, nozzles, valves. He has his own 2 to 4 head designs or can make customs. Great guy, found him on Taobao in 2016.

And OpenPNP is great. It just works.

[mendez]

I've been busy with personal stuff but I was able to work on my PNP today. Please see below pictures. All I need now is to add the down camera, tape feeders and start placing parts. Everything seems to work fine (vacuum, rotation, repeatability ).

FYI: building the machine was not hard at all; but the cable management was key....prepare to have a lot of long wires.

[mrpackethead]

thats looking really good!  I'm really tempted to build one just for fun now.

[Harjit]

I've been busy with personal stuff but I was able to work on my PNP today. Please see below pictures. All I need now is to add the down camera, tape feeders and start placing parts. Everything seems to work fine (vacuum, rotation, repeatability ).

FYI: building the machine was not hard at all; but the cable management was key....prepare to have a lot of long wires.

Your machine seems very interesting. Can you elaborate on it, the build, performance, etc.?

[Harvs]

@mendez your machine's looking nice.

Here's where my build is at.  As you can see I've given up on cable management off the head, I think the number of cables going up to the head is a bit needlessly ridiculous.  I'm just going to make a custom control board for the head, so only USB, vac, power need to be transported up to it.  At the moment I have 7 cables and lines going to the head and it's in it's most simplest form. The capability to add extra widgets without trying to get things through the drag chains would be very useful in future.

Biggest issue for me at the moment appears to be the 40T pulleys I've used.  The machine in the HaD link used 52T, so I though 40T would be a safe bet, but I probably should have done the math as 40T is 0.4mm per full step! So I'm at 1/4 microsteps just to get 0.1mm, which is holding back it's accuracy (although it can move pretty fast.)  I have some 16T pulleys I might switch over to, but that does mean making new brackets and probably changing my idler guides somewhat.

Some testing last night without the bottom camera setup yet:
https://youtu.be/q1Wxt_wY1CY

[Harjit]

@Harvs, very impressive.

If you are going USB, why not go Bluetooth or Wifi? Then, you only have to send power over?

Can you elaborate on the pulley math? When you say one full step @ 40T is 0.4mm, this is based on some pulley pitch?

Will the head rotate to fix any angle error during component pick up?

Do you step the motors yourself? Or do you issue a high level command the there is a stepper motor controller board that does the motion profiling and stepping? Are you using pieces out of 3D printers? They have a similar need.

Can you share more details around the components and design? I'd like to learn more before jumping in and building one.

[Harvs]

@Harvs, very impressive.

If you are going USB, why not go Bluetooth or Wifi? Then, you only have to send power over?

Can you elaborate on the pulley math? When you say one full step @ 40T is 0.4mm, this is based on some pulley pitch?

Will the head rotate to fix any angle error during component pick up?

Do you step the motors yourself? Or do you issue a high level command the there is a stepper motor controller board that does the motion profiling and stepping? Are you using pieces out of 3D printers? They have a similar need.

Can you share more details around the components and design? I'd like to learn more before jumping in and building one.

Hi Harjit, there's nothing very impressive about it (other than the time investment), it's pretty much following the fairly well trodden route of building an OpenPNP build.

The machine I'm largely copying is this one https://hackaday.io/project/9319/logs

But head over to the OpenPNP project to see other examples.

But to answer your questions:

The USB is mainly for the camera, but may as well put a hub IC up there and run the control signals as well.  The OpenPNP folk don't recommend using a IP camera due to latency issues, never tried it myself but I'm pretty confident they've been down that rabbit hole.

The belts are GT2 size, which has a 2mm pitch, so it's simply 40 tooth*2mm for the circumference / 200 whole steps per rev for standard steppers. So 40*2/200=0.4mm.  I do get reasonably reliable 0.1mm moves, but it's not that great.

The vid I showed wasn't using the bottom camera, so it can only go off the feeder (tape) alignment and the rotation of the part on the board.  I've since got the bottom camera working, so now it takes the part over the bottom camera after pick and corrects for misalignment of both offset and rotation from the pick (in theory, it does seem to work pretty well in practice as well).  There's lots of videos on youtube of this if you search for OpenPNP.

OpenPNP generates G-code outputs which you direct to whatever controller you've got.  The "standard" route is pretty much using a smoothieboard (or compatible), as they have enough stepper drivers and IO to do everything from the one board.  So you can pretty much get one of those and the problems solved.

I really have nothing to add beyond what's on that HaD link above unless you want info on something specific.  There's a google docs spreadsheet in that link that has the BoM, which is very useful as there's a lot of parts to order.

Other than that, there's nothing particularly difficult about it, just it takes quite a time investment (both waiting for the 20odd aliexpress orders you'll make) and the careful build/setup.  There's lots of interesting problems in the setup and tuning, like I never thought to consider that the sensor on the USB "microscope" camera I used is actually a 10 or so degrees off being true to the body which causes all sorts of issues.

But overall it's only worth it really for the interest in doing it.  The difference in cost between the DIY route and the low end Chinese machines doesn't really make it worth it from a time perspective.

[Harjit]

Thanks for gently pointing out that there is USB camera data that needs to be transported. I didn't think about that but it makes perfect sense.

How are you handling the interface between the pick up motor and the vacuum line? Are you doing it the way the HackaDay article has it?

Several people had linked to stepper motors with a hollow shaft and I didn't follow why that was important but now I get it.

Have you come across a block diagram of the entire machine i.e. the controller, the motors, limit switches, wiring, vacuum circuits, etc.?

[GerardG]

Hello,

In some high schools in Europe they use the Neoden4 PnP machine.

http://neodentech.eu/

[Ribster]

Maybe something interesting on topic :

[mendez]

@Harvs; Your machine looks nice too!!

Here is an update of my PnP. I been busy with work but I finally finished. I must say....making this PnP took me a lot of time; because I had to modify a lot of parts.
-Autofeeder (up-to 24)
-Nozzle Tip changer (4 Max)
-Dual Cameras
-Dual Nozzles
~500CPH (this is for prototyping not for mass-production)

[Harjit]

@Mendez - super impressive!

I've got a similar build planned. Where did you get the brackets that connect the different rails and extrusions - essentially, the orange pieces?

Looks like you are driving the Y axis on one side. How has that worked out? I've read that it isn't a good idea and I've read it works fine.

It seems like if you use linear rails, driving on one side is okay but if you use wheels on V-style rails, maybe not?

What width belts are you using? 6mm? 9mm?

[Kjelt]

The orange pieces look 3D printed. If so which material did you use and is it sturdy enough?

Looks like you are driving the Y axis on one side. How has that worked out? I've read that it isn't a good idea and I've read it works fine.

I also shared this worry in the past.
It depends on the application. For P&P where there are literally zero counterforces it should be fine.
For a CNC mill it would be a big nono.

Actually what could happen is that the bridge that is fixed on the belt in this case could be less than 90 degrees straight. Since the bridge is a sturdy fixed connection this can only be a small offset.
And could vary with the position of the head.
You can try this by feeling it by hand, if your linear rails are not pretensioned or have slack this could become worse. A solution would be to use double wagons with some space in between on both sides fixed with the bridge, at that point it will be very hard for the bridge to stay out of line.

If you read in the SmallSMT topic their $20k P&P machine also use a single sided ballscrew with servo motor and they can place 0201 parts so it looks like it is feasible.

[Harjit]

@Harvs; Your machine looks nice too!!

Here is an update of my PnP. I been busy with work but I finally finished. I must say....making this PnP took me a lot of time; because I had to modify a lot of parts.
-Autofeeder (up-to 24)
-Nozzle Tip changer (4 Max)
-Dual Cameras
-Dual Nozzles
~500CPH (this is for prototyping not for mass-production)

Any chance you can post your design, STL and bill of material files? Thanks.

[Fire Doger]

Any chance you can post your design, STL and bill of material files? Thanks.

https://docs.mgrl.de/maschine:pickandplace
http://www.betztechnik.ca/store/p34/Pick_and_Place_head_-_dual_nozzle_-_OpenPnP_compatible.html
I identified some parts from these 2
And some parts can be replaced from ebay common parts like motor mount.
I would guess on 800-1k € I don't know if he is selling the head but I don't like it. I would choose something similar to these https://www.aliexpress.com/popular/pick-and-place-heads.html
3D printed nema8 shaft to fitting coupler is a joke and very cheap to skip cost...
*I wouldn't recommend building it if you need a machine.
It would be cool though if more PnP experienced users contributed to make a nice open source machine (designed to work, not all 3D printed craps).
https://www.ebay.com/itm/for-NEMA-17-Stepper-Motor-Mount-Plate-Fixed-Bracket-Holders-For-3D-Printer/352650307456?hash=item521b98a780:g:8wEAAOSwPT5cwtwM

[stoyanoff]

I have question! Can you share what are the tiniest parts which your home made machines can place correctly? For example have you tried with TQFP64? I am talking about machines with top and bottom cameras?
I am building one and I am waiting for my control pcb and drivers and I am not sure if have much bigger expections then really achievabled!
Thanks!

[jmelson]

Looks like you are driving the Y axis on one side. How has that worked out? I've read that it isn't a good idea and I've read it works fine.

My $100K Philips CSM84 works the same way.  It has two parallel linear slides, and a coarse-pitch ballscrew on only one slide.  Works fine.  But, these are pretty big THK linear slideways, and on the driven end, the gantry spans quite a distance between the two slider blocks.

Jon

[Harjit]

@Fire Doger - thank you for the links, especially the eBay ones. I'll check if those will work for me.

@mendez's design seems interesting because he seems to have made the pulley mounts more robust and the 3D printed pieces look really good. I'd love to get the design files, 3D print material information, and info. on how well they are working.

[wilhe_jo]

FYI there's currently an EleksDraw XY deal on bangood... 136€ delivered... couldn't step back from ordering such a toy.

At this price point I'll give it a try for a weekend or so to see if this could actually be a plattform for a single-prototype-board pnp-machine.

Just to repeat it for the new folks: For a single prototype, you're typically dealing with small 5-pcs strips from digikey and such odds. So feeders are not the main problem.

If you could manage the toolschain in such way, that the placement is a 1-click operation, this machine would/could be helpfull.

73

[mendez]

@Harvs; Your machine looks nice too!!

Here is an update of my PnP. I been busy with work but I finally finished. I must say....making this PnP took me a lot of time; because I had to modify a lot of parts.
-Autofeeder (up-to 24)
-Nozzle Tip changer (4 Max)
-Dual Cameras
-Dual Nozzles
~500CPH (this is for prototyping not for mass-production)

Any chance you can post your design, STL and bill of material files? Thanks.

I honestly build it by trial and error; I don't have an assembled 3d model or bom. I do have the 3d parts if you need anything specific. As soon I get some relax time I put a model together with bom to share.