Advices for LQFP 144 placements

[villannm]

Hi everybody !
Ive tried several time to place a LQFP with 144 pins, but i always have a shift of like one pin each time. I tried to calibrate again and again the downlooking camera and the nozzle, but its still present. Do you have any idea/advice of how to increase the precision ?

[villannm]

I just changed the resolution of the DL camera (from 800/600 to 1280/1024) and now the component doesnt fit into the screen when "Show pixels" is on. And it doesnt see the component anymore, with the same algorythm than before. Do you have any suggestions ?

[JuKu]

I haven't modified the user interface from the old resolution. The show pixels mode shows the center of the full image in the window - sometimes you want to see the actual pixels, like when setting the box size. With show pixels off, the software scales the image to fit, but uses the full image. This is how you want set up your algorithms, when the target doesn't fit to the center and in some cases, to ensure that there are no false items in sight.

For the actual issue, is the performance fine with other parts? In other words, are you confident that the issue is with that part and not with the machine in general? For ideas, you could share some screenshots of the image with and without processing.

[villannm]

I did multiples tests to see where my calibration problems come from.

First, i set several positions on differents marks on my table, ans i made the placer travel between them. I saw that after some travels, there is a shift between the coordinates and the actual position: the first image is where the mark is set

Capture 2.PNG (458.59 KiB) Viewed 3321 times

, and the second is where the camera goes after some deplacements:

1.PNG (462.08 KiB) Viewed 3321 times

The coordinates are the same for the computer, i dont know where does this offset come from.

[villannm]

Another thing: for every component i had a little offset between the wanted placement position and the actual placement.
And just after recalibrating the nozzle/DL camera, i tried to aim the center of the target. There is a shift between whas aimed with the camera and where the nozzle goes:

Capture 3.PNG (652.85 KiB) Viewed 3321 times

IMG_20180525_112228.jpg (2.5 MiB) Viewed 3321 times

IMG_20180525_112327.jpg (2.49 MiB) Viewed 3321 times

Im sure my calibration is accurate, but this shift is always present...

[villannm]

I solved the proble with the nozzle calibration, my changing the nozzle nominal offset by hand until its okay. But i still have he deplacement shift. I think its a mechanical problem but i dont know where does it come from.