Speaking of tubes, simply adding a roll of tube to a system like this is a "poor man's" way to add a reservoir.
Flow rate might be an issue if the tube is small.
It is offset with a belt drive, with about a 3:1 reduction for more accuracy in rotational angles.
That is very interesting. I presumed more or less the same design, wrongly.
I wonder if that is really necessary. Without the belt we have 200*8 steps. For a 10mm chip that translates into 0.04mm shift if the angle is off by one full step. But theoretically it should not be off by more than 1/2 step if visual system works 100% reliably. If it does not then higher resolution for angles does not really help anything at all.
I'm just wondering if that makes any difference in some circumstances.
I think the reasons for reduction are as follows:
#1, Camera can get a 20mm x 20mm chip in view, so with a larger chip, you have less resolution using a 200 step motor. Micro stepping without inertial load on stepper can be marginal at best.
#2, Run out. Steppers are not known for their shaft tolerances / run out. They are designed to be a driver, not a precision bearing assembly Hence the typical use of flexible couplings. Even a small amount of run out at the motor shaft translates into large problems once a nozzle coupling is added to the end.
#3, Compact assembly height. The TMV920 nozzle holder assembly is within (<5mm) of being vertically even with the front of the motor shaft, It shortens the length of the typical assembly by almost an 20 - 25mm. Shorter assembly translates to smaller run out errors if present.
#4, No need for hollow shaft steppers. Part of the problem with using small NEMA8 steppers for rotation is the limited torque produced, and the drag presented by the rotary coupling used for vacuum connection. This mitigates the problem by increasing output torque using the belt drive reducer, while increasing resolution as a byproduct.
Just my thoughts.
It is offset with a belt drive, with about a 3:1 reduction for more accuracy in rotational angles.
That is very interesting. I presumed more or less the same design, wrongly.
I wonder if that is really necessary. Without the belt we have 200*8 steps. For a 10mm chip that translates into 0.04mm shift if the angle is off by one full step. But theoretically it should not be off by more than 1/2 step if visual system works 100% reliably. If it does not then higher resolution for angles does not really help anything at all.
I'm just wondering if that makes any difference in some circumstances.
I looked into the TVM802 and found two pumps, I think there are two vac pumps, one for each nozzle.
Does anybody know how that works and are these pumps also use for blowing ?
To connect an external vac pump, which is the right tube ?
I don't remember about blowing, for the moment I left both pumps connected, but plugged their vacuum ends. Both of them can create positive pressure as well, I presume only one is used.
See the attached pic. I used whatever fittings I had at the moment, I guess it can be done in a neater way
thanks for the picture,
so you simply connected the vac to the two tubes going to the PnP-head.
I will try the same.
Regarding vibrations, I did some tests today and found that it works better with 100% speed.
Maximum vibrations are at about 70% speed.
I am now using 100% for R and C which works well.
The only thing which does not work with 100% (and not with 50%) are SOT23 cases. These parts
"jump" on the nozzle (No. 503) in any direction, even flipping upside down. I have to go down to 20% to get them stable.
I was hoping biddings were still going but it seems it sold for 2400€, crap.
Can anyone tell if the TVM802A can do double-sided boards? I could make a holder to fixate the board when populating the back side, but the board surface would move up by about 2cm. Can the TVM802A handle this, or would I have to modify the baseplate?
Max
@prpplague, @Koen: On the German forum, Axel stated he wanted to focus on SW development. There seems not to have been anything wrong with his TVM802A. I was among to ones who were too slow
You can, the board is held in place by the edges. If you don't place too close to the edges, you can do double sides.
Can confirm, no problem with double-sided population, as long as you don't have components near the edges or have a panel. We do 0402 and other components on both sides without issues.
Note the TVM802X placement becomes quite poor if the board is not sitting all the way down / is a few mm raised (even with the appropriate "board height" program setting).
How much edge distance is needed?
Unfortunately, Axel (the Servokit guy) has not only sold his TVM802A, but also removed his blog and his YouTube videos, which is a pity. Looking at another YouTube video (
https://youtu.be/g8IjoHn_oEg?t=38), I guess that the edge is about 3mm wide (for our non-EU friends: about 120 mil).
Does the TVM802A offer an arbitrary order of placement? I have some caps that are 7.7mm high. If they are placed last, I suppose that this should not be a problem, but even then, I need to set the proper placement order on the panel: the ones furthest to the front being placed first, the ones furthest to the back last. Is the SW capable of this?
Max
The software does not support arbitrary order, it always reorders as it pleases, and the logic is not clear.
What happened with Axel? That's unfortunate indeed.
Axel has stated (on the German forum) he wanted to focus on SW development. His company seems to be making money with barcode printing and/or scanning solutions, and his hardware excursion might have veered to far off course. Or maybe he simply realized that days are limited to 24h.
The height limit is a problem. Any suggestions how to get around it? Splitting the placement into several jobs?
Oh, and one more thing: the machine is stated to be L 980mm*W 655mm*H 285mm. Does this include the reels? I have rather limited space in my basement
Max
The only proper solution is s/w modification. I was placing 5mm switches, and even that is a problem. If it drops it for some reason over the feeder block it creates a huge mess as it tries to go to the discard location. It crushes the button and tapes in the process.
S/W modification would mean replacing the included S/W with something like OpenPNP (or some self-written stuff)? Not exactly my favourite. But the only alternative seems to be the SmallSMT, which has 10 mm.
Would it help to shorten the metal shield which is between the placement heads and the downward looking camera? This picture suggests so:
https://www.mikrocontroller.net/attachment/287193/tvm802a-max-part-height-6.jpg. Max
The lowest point is actually the transport needle, you can see sticking out just below the bolt.
does anybody know how to configure the TVM802 to make panels ?
it is sufficient to define multiple ficudials for each board in the panel, or is some
other configuration required ?
I'm not quite sure *why* DHL has so much fun with TVM802B's. Like others, mine spent a *lot* of time in limbo during the delivery process. I finally gave up on the delivery and drove over to the depot to pick it up. Yikes is this thing HEAVY !!!
Back to figuring out what goes where ....
does anybody know how to configure the TVM802 to make panels ?
it is sufficient to define multiple ficudials for each board in the panel, or is some
other configuration required ?
It is pretty simple. Board coordinates of fid are the same for each board, but phisical coords have to be defined separately for each board.
does anybody know how to configure the TVM802 to make panels ?
it is sufficient to define multiple ficudials for each board in the panel, or is some
other configuration required ?
It is pretty simple. Board coordinates of fid are the same for each board, but phisical coords have to be defined separately for each board.
thanks, I will try it tomorrow.
wow! anyone know what happened to axel and servokit? the website disappeared, and all the videos on youtube have been deleted!
dave
wow! anyone know what happened to axel and servokit? the website disappeared, and all the videos on youtube have been deleted!
dave
It seems that Axel has stated (on the German forum) he wanted to focus on SW development and sold the TVM802 machine. But why he deleted all the files and videos that were a good source of related information is something that only he can say
Has anyone already converted the nozzles from TVM802A to Juki using an adapter?
Paul.