[scsi]

It has been quiet here lately and I think I needed to post another video
This time it's a shaky teaser of the PPM software that I've been working on. It's almost ready for beta testing, just needs some user interface tweaks for better usability and a quick user manual to get things up and running.
[ame="http://www.youtube.com/watch?v=UI93vLnBAjU"]YouTube - PPM.[/ame]

To continue the discussion on this I welcome everybody interested into a new thread that I just created.

Also, since Tom Kerekes is here, he will probably like to know that I’m using his amazing KFlop motion controller for this project. The 3rd order interpolation is very nice at high speeds. Very smooth and accurate!

[neilw20]

Interesting.
What is machine doing on the gray bit in the bottom right hand corner?

[scsi]

I'm not sure I understand the question. What gray bit? which second?

[neilw20]

Oops, Sorry.
Got distracted by a youtube that followed at 1:45
[ame=http://www.youtube.com/watch?v=TT9AcIcbFPU&feature=related]Phoenix pick place controller preview - YouTube[/ame]

[crust]

That's awesome. I wouldnt have bat an eye at that price. Say at $3000 for 500 qty, 6$ board would have been an easy decision. I spent countless hours placing these things by hand to sell the first 200. It sucks. I had about 28 unique components per board, 3 QFNs, 1 0.5mm pitch SOIC, 1 atmel 48pin QFP. Should be pretty easy except maybe the QFNs.

Hi guru_florida, I am quiet on this forum (read it, but don't post often). I think for that assembly, you could easily have been in the sub $10 / board range. I design and build both custom products for others and my own designs (ps3toothfairy is one of them). I just took a look at one of mine that is roughly the same as yours, 30 unique components, 1 tqfp, 1 soic, sot23s 0603 r-packs, but also 8 through holes and one connector that must be press-fit. For 150 of those, I paid about $6.50/unit (after 400 nre). A few years ago (for this same assembly) another shop gave me a $50/unit quote. That board is simple enough and has high enough production yield that I do not do flying probe on it. I currently do them in 500 runs. My assembly is done in Austin, TX.

Ayman

[stewi]

Pick and place smt?
http://www.wimp.com/robotsfly/

[alphatroniqu]

HI

whit Business growing i was need better machine
so i got a Mydata machine ( 8 feet long / 2000 lbs)

so the good new for you i that i sold all my 4 zevatech machine
that machine was easy to hack and i sold it whit my own version
of controller running on XP , some one also make a open source version

all machine come will full service manual and documetation

you will probably never got a working pick place for a lower cost

and that machine also pass normal door way and was only ~300lbs
trust me it less more trouble that pass a 2000lbs 8 feet long machine on a stairway :drowning:

that video of machine take today [ame=http://www.youtube.com/watch?v=WicZKiOeGHI]Zevatech PM460 SN:453 Running Phoenix Software & Controller - YouTube[/ame]

it Item number: 261013110972 on ebay

once sold will list the next one and so on ....

[alphatroniqu]

HI

i read previous post about assembly cost

since i run myself a small assembly shop i may put my grain of salt ;-)

normally i charge ~150$ setup free , it take at least 3 hour to program machine
and load all feeder ... that fixed cost for small or big run

stencil was stencil shop price normally 200$ ...

ten i figure that machine run a 200$/ hour and it place ~3000 to 3600 part hour
that may seem high but a new commercial machine cost 100k and up
as example Mydata Qoute me 65K$ for a used re-manufactured machine
whit only 2 feeder box so 32 x 8mm reel ans for running we need much more

and you still need a good reflow and stencil printer and pcb wash station

the problem come from that it much more easy to make big batch
since one machine setup you only need to change empty reel and machine
will do money 24H/day 7/7

make small batch (<1000) require to stop and program ,setup etc etc
so shop increase price since it simply not what to make it

on my since i take profit of this job that other shop not want
i made my own software for program machine faster and make it painless
and i run on used machine that permit to lower my fie cost
but this require that i need to do all service by myself ...

i confirm that tom kflop board was well build i use it on my cnc
will surely used it for my zevatech if i have knot about before i start proejct

Best regard
Marc Lalonde

[mojalovaa]

Does someone can tell me why I can not get high speed with NEVA 17 engine, the driver is standard with the L297 and 298 half-steps, as soon as we cross the 300 mm per minute starts to lose a step, I want you to make a small pick and place machine, but no speed of the drive belt over and I saw that people here have very high-speed travel of the machine.
Regards

[Eclipze]

You can typically get around 4 to 5 revolutions per second with a stepper with a basic driver. To get faster, you need two things. The first... high voltage to overcome the inductance of the stepper windings, which is limiting the rate at which the winding can saturate. But you then need to PWM that power to avoid going over the rated power and burning the stepper up. The second is mid-band resonance. It's a big topic, but it will limit you speed if not handled.

There is where paying the bucks for a gecko driver will help.

[mojalovaa]

Do you have a scheme of such a basic driver to see things in ways that drive, if you send me a private post or to place a link to that address higher that's how it works.

My best speed is higher as in this video when you go slower, if you put a higher speed then we lose a step and if you set it to some 1200 mm / min engine can no longer even ones that run, the number of steps is 9.083 mm for a displacement.

If I understood well, the problem is that we stress long before reaching the maximum current value, but every engine should have a power supply with a constant current source, so that when the current reaches the maximum value that the power goes out.
I think the L298 and L297 are in constant current measurement itself but I do not know whether they work as PWM controllable.

[ame="http://www.youtube.com/watch?v=cSADe6YLlGg"]PnP_Y_Axis_Moves.wmv - YouTube[/ame]

[mojalovaa]

Come on people did not guess that my bass no one can help with advice on how to speed up stepper motor, I guess someone still had such a problem, please help me, thanks

[Eclipze]

Typically the higher the speed you run a stepper, the lower the torque. If run too high, it will stall. You can use a bigger stepper, higher voltage with current limiting or buy a good stepper driver, like those Gecko produce. If you want to make one yourself, you need to do a lot of reading. It's a big topic, not something a simple post on a forum is going to cover.

[mojalovaa]

Ok, you can tell whether you are using the driver for your machine, I see a very fast-moving head spade and place machine.
If GEKO can make the driver can and I just have to know that the problem troubles me, I so far I have not worked with the stepper so I do not know the problem, that you say to go with the higher voltage is not exactly a solution, because the engine will overheat in the long run, who stepper you use to run the head for pick and place.

[neilw20]

The new style current mode stepper drivers are effectively switch-mode driven and quite sophisticated.
The motors will not overheat.
The current is not exceeded.
When you apply voltage to an inductive device, the stepper winding, initially the current is zero and rises over time until the inductive effect is no longer significant.
At that point the winding resistance and supply voltage control the current.
These drivers run in constant current mode, so the current is not exceeded and the winding voltages drops back to a low enough voltage to satisfy the current programmed.
The high voltage is required so that the current rises to the programmed level in a shorter period of time, and this allows the motor to run faster.
As well as all this, the current mode is used to accurately control the ratio of the current between the windings and then you have microstepping.
And to top it off, the load reacting against the torque is like a spring, so that resonances can occur at certain speeds and loads.

More details... read on.
Stepper motor - Wikipedia, the free encyclopedia

[mojalovaa]

Not possible that anyone on this forum do not know that Stepp driver who will be able to run the engine at least 15 revolutions per second, on the internet I saw a bunch of videos on which engines cnc forced to 2400 mm / min and the homemade so I guess someone could articles to be used by controllers.

[stewi]

What is your point mojalovaa?
Some of the basic rules of this forum is to read other threads about motor basics first and then if you don't find the answer open a new thread on this subject. This thread from Eclipze was opened to demonstrate the progress he made with his P&P machine and your posts are off subject.
Second, you are mixing linear velocity with motor rev per seconds and may not even realize that 2400 mm per minute is actually only 40 mm per second, while fast machines do 2.4 m per seconds.
In order to increase linear speed with physical limitation of stepper motor steps per second, you'll have to get to a higher transmission ratio of the motor gear or pulley wheel. A higher gear ratio will require more motor torque. Initially you were inquiring about a NEMA 17 motor, with which you can likely do 40 mm per seconds with a low friction gantry and ultra light placement head.
Bottom line, there are very knowledgeable people on this forum, if you ask your question in the right format, at the right place and with enough technical expertise to understand the answer.

[Eclipze]

I use a Geckodrive G540

It has excellent performance for high speed stepper movement. I believe I have run a stepper up to 17 revolutions per second before with one.

[ImagineRobots]

Vision, it´s depends. Until yet i have used the usual basic algorithm, histogram and rotoation inside a ROI. Time for displacement and rotation detection is under 1-2ms.

Nisma,

Can you detail the algorithm for determining part rotation using histograms? I am new to vision processing. Access to sample code would be nice. I'm trying to use OpenCV to control my scratch built PNP. Is this Youtube video approach similiar?

[ame=http://www.youtube.com/watch?v=ACix9Oq69qA&feature=plcp]Part Rotation Detect for pick n place - YouTube[/ame]


thx

[guru_florida]

I'm not exactly sure what he is using, but that right B&W image is a high-pass version of the left one, high-pass gives basically gives you an edge detection image. I think I have seen this before, and after the high pass, he then calculates the line slope of each pixel. I.e. find the lightest pixels before, and the ones after, calculate a slope, and output. When the part is aligned the slopes should be 0 or infinity. (right angles) generally.

My PnP machine (Samsung CP20CV) uses laser aligners on the placement heads. These things are awesome!! The laser uses a lens that makes it a line (like barcode scanners) and a CCD on the opposite end reads the laser line. When a part is pulled in the path, the CCD detects the shadow. The part is raised up and down and the rotated so the whole part can basically be scanned in 3D. It detects alignment while in transit. It is also used to auto calculate the part L,W and Height, and it can detect a loose nozzle after pickup - it scans the nozzle position.

I also have a up facing camera, but I only need it for one part - and I could probably still use the laser aligners. The algorithms for the lasers should be simpler than a camera. You could probably find surplus laser aligner heads complete on ebay or something - then make your own modern digital interface. I cant find any now, but I did before. The ones I have come from "cyberoptics".

Nisma,

Can you detail the algorithm for determining part rotation using histograms? I am new to vision processing. Access to sample code would be nice. I'm trying to use OpenCV to control my scratch built PNP. Is this Youtube video approach similiar?

Part Rotation Detect for pick n place - YouTube


thx