bmw330i wrote:Ok, I get it. I do remember you mentioning it but do not remember a diagram or image. Which belt? There are belts all over this thing.
It's not in the manual, I mentioned it *above* (here on the forums) like I posted.
there's only one belt and one motor involved in the Z axis / head. See directly with MDC to check / fix that. Basically you just need to check that the tensioner isn't loose and ensure it won't move anymore. MDC will send you a picture.
bmw330i wrote:I have RTFM and I got to page 39 now. Thank you. I now know what Posi2 is...I think. I was able to go there and yes it was not centered. I fixed that. I'm not sure about stroke though.
I'm not sure the stroke you set in Posi2 teaching is usable. Like explained in the calibration section, I would only use the teaching mode to put the head in focus, note the stroke, and set the value manually in the scrub constant, either in the quick settings or the constant itself.
You definitely want to read the whole thing IMO, as there are cross references everywhere despite the fact I attempted to split things into chapters. The calibration section is quite coherent though, and it's at the end of the document.
I believe your focus/scrub WAS already at 280 or so (read previous discussion about your screen captures). Check that you're in focus, note the value and change the scrub accordingly.
[addon] reading your next post.
bmw330i wrote:Eureka! I found it. Page 154 at the top.
check also page 1, *wave hand* "this is the index table you're looking for"
So, in the end it seems my K6#1 and K6#2 were no longer working from factory.
normally, the head is meant to apply "excessive" pressure on the PCB without harming anything because the head is spring loaded ; the motor can keep turning the timing belt even if the head is stuck on a part or PCB, thanks to a spring.
However, if the timing belt is loose or the tensioner isn't tight enough, the belt might have a bit of backlash and at the first obstacle, the excessive pressure can change the offset a bit. Double check this, ensure that the mechanical link between the head and the belt has no backlash, and use eventually epoxy or thread locking fluid to ensure you won't have the problem again.
I also suggest you calibration the nozzle changer depth (see section about the nozzle changer), mine was WAY too high and it was really shocking the head when changing nozzles. Again the spring loaded mechanism is supposed to compensate BUT it's not meant to absorb shocks during high speed moves.
Then head is capable however of applying pressure on purpose, and like explained in the manual, the proper definition of the the PCB stroke AND part thickness is important and mandatory, as the head usually applies a "half thickness" pressure to force the part to penetrate the solder paste and stick properly. Get the thickness wrong (or the PCB stroke) and you'll either have the chip floating on the paste or it will crash on the PCB.
See my § about setting the proper PCB stroke to have this done with accuracy.
overall, it's never a problem to apply a slight pressure at the end of the movement when the head is slowing down, but it's really a problem when the machine believe that the stop point is 3 mm later and that it's still at high speed when it's touching the obstacle. This is probably what caused your machine to lose its calibration.
In the meantime I did go through the manual and did the other calibrations. Focus, nozzle changes etc. So hopefully the placement will be more accurate now. Before the parts were off a bit. I didn't know if it was the sticky tape or what the issue was. I'll do some assemblies tomorrow (hopefully).
you get A- for not reading the index table first place
lack of accuracy is usually wrong offsets for side vision / bottom vision placement, the double sided tape has nothing to do with this. The nozzle to top camera offset might need to be calibrated a couple of times as it's not always easy to see / find the center of the stamped circle on the DS tape, I usually do it with a medium sized nozzle then with a bigger one to check.
I see indeed your nozzle height is better now for the side vision, almost there (not 100% aligned with the horizontal ref, try with no part to better see the nozzle tip). Your vertical axis is still off though. You need to correct this before you run the general placement offset calibration (again) cause the lack of concentricity in the side vision will induce more offset as it's adding a momentum.
glad it work. Did you find it difficult ? it's really like a set of instruction to follow BUT you need to be familiar with several other things before. That's why I put the calibration at the end of the handbook, so that people read as much as possible about the machine before calibrating (you must master the teaching mode first, for instance).