Eclipze's SMD Pick'n'Place Build....

[Eclipze]

Thank RomanLini

I've machined the main platform now. Used corian

Also machined up an acrylic bar, which directs the tape underneath the board. I'm going to re-design that part, such that there will be a top and bottom piece. Together, they'll feed the tape back out to the same side.

[tataee1990]

Great job Eclipze
i found this forum on google searching about pick and place smt and i found it very interesting. i'm interested to build one too, but i don't know where to start.
i'm going to study this forum for more information's.
Reading all this thread, i got an idea, and i don't know exactly if's possible to achieve, maybe you guys can figure it out...

can you handle this p&p with your mouse? so the p&p follow the cursor movements helping you to pick and place smd and apply soldering paste to a specific place/pad. with the help of the camera you know what you are doing. this option it's useful for repairing damaged components on pcb's...

thanks!

[Eclipze]

Hi tataee1990, welcome to the forum

I could see using the mouse for teaching a p&p path would be very neat. Alternatively, if I had to place a part (ie.a QFN package), using the p&p would be ideal. Although I probably prefer to use keys to bump in small steps to get the alignment accurate in all axis before placing. Depending on the resolution of the paste dispension, it could possible paste the footprint, particularly given a macro for pasting different footprints.

[RomanLini]

I would use a trackball for the jog (or "train the machine" mode); hacking a mini-trackball! You can get them from old laptops or from many surplus re-sellers.

Eclipze- That's looking pretty pro!

If I was to pick something to niggle it would be that the tape pulling is on the wrong axis, it will cause skewing of the arm. Rotating the tapes 90' would make the geometry a lot better but of course that's probably secondary to other considerations of the build and the obvious performance speed of having all parts near the central PCB target.

[Eclipze]

Yes... I'd agree it would be nicer to tape pull the other direction. It was something I'd preferred, particularly because it opened up the possibility to have tape across the whole length of the front. However I didn't want to be leaning over the components to watch and work. I also wanted to keep that area clear for a rail or dolly wheel if it was needed. So I went for the horizontal movement and placed the index pin right on the side of the truck, very close. Seems like everything is a trade off.

[Robin Hewitt]

Hey, good thread

I've been getting big production delays getting stock out of China and I have a hankering to get back to making things in house. I've got the injection moulder and I've spent the last 6 weeks designing a pick and place machine and buying bits. I like to finish the design 100% before I cut metal, it goes together better that way.

I found you can get a reflow oven real cheap off that ghastly auction site, I already picked up 20 Fuji T6 nozzles in an assortment of 0.7, 1.0 and 1.3mm which will make life easier. I think they are designed to leak at the tip. If you allow them to leak Bennoulli says the air moving through the gaps will try to close those gaps so you can get more lifting/holding force with a leaky tip than one with a hermetic seal. Weird

The design should feed and peel 8mm tape straight from the reel, with a 'nipper' type alignment station because I don't do complicated. 3/4" pitch screws, linear rods, steppers throughout, 4 head autochanger. I'm aiming for 6 components a minute so I shouldn't be too cruelly disappointed when I turn it on.

You've been going for months, I haven't cut metal yet, wanna race?

best

Robin

[Eclipze]

HAHAHaaa... we will have to have two races then. One for getting the first functioning machine and the other for part placement speed

Unfortunately I struggle to find the time to work on the machine, and I prefer to get a stretch of a few days where I can make real progress. The work I'd done with setting up Mach3 was lost. Virus took my PC down, and because the Mach3 profiles sit in the programs directory (not on my files drive) it wasn't backed up - and the image restore wiped it I'II probably do a better job the second time around.

I tried to drill the shaft of tiny stepper for the component placement rotation. I managed a really neat hole down past 30mm. Then drilled from the other end, but when it reached the break through point the drill bit snapped (no chance it will come out). Had to get another stepper and now waiting to hook up with a friend that can drill it properly for me hahaa... Otherwise, I have re-designed the pickup head arrangement in CAD, but not machined the parts yet.

I've designed the PCBs for the back of the placement head carriage, the Y-axis and also the breakout PCB. This links all the wiring from the ribbon cable to the needed places. I should have them back from the manufacturer by the end of next week. Those, coupled with the modbus board I made and the gecko G540 should give me the basic electrical hardware.

If there is a race to be had, I'm the tortoise... you can be the hare

[Robin Hewitt]

The nozzle is a bit tricky because you have limited lift to clear it when it comes to change time.

I decided to put the magnet on the nozzle rather than the head. A non-magnetic penny washer underneath to give me something to pull against. A stumpy brass cone above to guide it in to the head and all held together with Loctite 638. With the magnet in the nozzle I can add a small amount of iron behind the aluminium nozzle rack so they can't vibrate out.

I need 5N to lift the head, 13N max to break free of the magnet and I get 22N from the motor with the cam horizontal. I'm in the ballpark, reckon that if I avoid horizontal on the cam, maybe limit the amount of iron the magnet has to stick to, it should be fine and dandy. It's all a bit suck it and see

best

Robin

[RomanLini]

Sorry to hear about the drill bit incident Eclipze. And the virus too I guess.

You must be close now with the PCBs on the way. I'm looking forward to the pictures (and you too Robin, are you going to make your own build thread?)

[Robin Hewitt]

Design complete, metal cutting begun. Trouble is, with 24 slots to fill with reel feeds and IC dispensers there's a LOT of metal that needs cutting. This isn't going to be quick as I first thought

[dandumit]

Nice design Robin ! however I am a little reluctant with those ball recirculating bearings.
I think that at very appropriated positions when the bearings turns the balls the effort for movement it's much higher and may lead to inappropriate positioning.
By the way from where did you bought the leading screw ?

Daniel

[daedalus]

Eclipze: cool machine, nice to see things are coming together. Any chance you could share where you found the rotary pneumatic coupler you are using above the stepper shaft in your design? have been looking for one of these, but dont know what they are called.

With regard to drilling stepper shafts, if you are buying a new stepper anyway, why not get a hollow shaft stepper? Are the ones you are using a particularly good deal or something?

Robin: any chance you are going to do a build log here for us all to follow?

[Eclipze]

I haven't seen any small steppers with the shaft drilled through, and I want this particular stepper. It's quite light weight and small, and still has the need 1.8 degree step - not too expensive. Standard NEMA size too. The shaft drilling is no longer a problem. A friend has drilled another motor for me - just haven't picked it up yet.

The pneumatic rotary fitting hasn't worked for me. The combination of the turning friction for this part and the reduction gear set was too high for the motor. This is why I've gone for the drilled shaft, as I'm going to remove those components and run the placement head directly from the steppers shaft. This should save some weight too!

I've taken a step backwards with the design. I am no longer happen with the main rail. It's simply not suitable and it's being replaced. The issue is the tolerance vs friction. If I dial in to remove carriage skew, the friction increases. In addition, when the head is at the extent, the torsional stress on the main carriage causes an increase in it's friction... which limits the travel speed.

I'm hoping to obtain some THK rails by the weekend... may be looking to upgrade the y-axis too. I'm also going to consider a rod rail for additional support on the X axis, however I'II probably put this right at the back. I'm told the THK rails won't need the this support, but probably going to put it with the re-design anyway. It will help support further weight on the head carriage... which will make it easier to accommodate a more elaborate paste dispension system.

[RomanLini]

...
I'm also going to consider a rod rail for additional support on the X axis, ...

[Eclipze]

BHAHAHAaaa....

[atlab]

...Any chance you could share where you found the rotary pneumatic coupler you are using above the stepper shaft in your design? have been looking for one of these, but dont know what they are called...

SMC Pneumatics: KX, High Speed, Rotary, One-touch Fitting
SMC

[RomanLini]

All that weight hanging off the end of a 250mm long arm adds up hey?

Do you really need to replace that main X rail? I would just try adding the support bar like you said, with some slippery material there (like a PETP self lube plastic). I think once you have dealt with the vertical skew load it should work pretty well as your drive belt is quite close to the rail and your rail bearing handles horizontal skew much better than vertical.

You don't need huge accelerations and actually you want to keep the accelerations low anyway to reduce the chance of component drift on the pickup head. It's only the accelerations that cause the horizontal skew.

[Eclipze]

I've considered the options with the main X-rail, and I'm just not happy with the amount of friction needed to obtain good tolerance. It's one step too cheap and it doesn't hold up as good as I'd expected. Counter balancing it more helps, and I even got a slightly bigger stepper for the Y-Axis. It's a problem I really don't want to patch. The disappointment with the rail/carriage has been annoying me and I just haven't put more time into it... so it's got to go!

[RomanLini]

Fair enough.

What length is it and did you want to sell it? I'm not sure what those style rails cost, I've only used the low profile Drylin rails, which I like and haven;t had binding problems with but they do look like different rail/anodising surfaces.

[Robin Hewitt]

HAHAHaaa... we will have to have two races then. One for getting the first functioning machine and the other for part placement speed

Have you finished it yet? If not, I'm catching up