My experience placing my first board
Posted: Fri Oct 30, 2015 4:36 pm
I just placed 3 boards using liteplacer pnp and I'm writing my experiences here to help other people and improve the product.
These boards include DO214 Diode , 0603 resistors and caps, 20 pin 0.5mm pitch qfn and PWSON8 packages and some bigger caps that were placed manually.
--
I'm using altium thus I also generated the PNP files with it. But I came up with some issues:
Because of this most resistors (0603) were spot on but some had a pad length offset. So I needed to push them manually left or right a bit.
https://github.com/jkuusama/LitePlacer-DEV/issues/24
My parts were on the bottom of the pcb. This had two side-affects:
1. For some reason all parts were rotated by 180 degrees to much ( so if pnp file says 180 degrees it is actually 0 degrees)
https://github.com/jkuusama/LitePlacer-DEV/issues/26
2. Due to placing the bottom the x coordinate is inverted. To solve this I put a offset of 100 mm (x board size)
top:
bot:
https://github.com/jkuusama/LitePlacer-DEV/issues/25
Also measurement by fiducial seems off. Nominal placement was correct but the measured location was off.
It seemed not possible to place components without the fiducial compensation?
https://github.com/jkuusama/LitePlacer-DEV/issues/27
While most component were picked correctly once in a while there was one what did not. This is really annoying.
A good way to check if the component is picked just use vision. Go the location where you picked up the component.
See if there is something in the box (for example white tape look if there is some color or whatever in the box).
This would replace thereza vacuum sensor method.
https://github.com/jkuusama/LitePlacer-DEV/issues/23
While pickup works good enough for the DO214 diodes, qfn etc the detection is sometimes a bit of. It would be best to implement some kind of template matching to get the best result.
But most of the time is is good enough placement. Worst case you have to move the chip a mm to the right or left to align it properly.
Due to trays currently not being implemented you have to put the components in the pickup location which is annoying if you have to do 50 parts.
In the end the PNP did ok. Was it faster than placing by hand ? Yes , but not by much. When some of these issues are solved than this will be much faster.
I have used thereza's mod and it has many of the improvements that are needed. But it also has some significant bugs that make it unusable for my application.
Tapes only work in x+ location , the rest does not work etc...
These boards include DO214 Diode , 0603 resistors and caps, 20 pin 0.5mm pitch qfn and PWSON8 packages and some bigger caps that were placed manually.
--
I'm using altium thus I also generated the PNP files with it. But I came up with some issues:
Code: Select all
When using altium there are more than one XY coordinate.
It seems to use Ref X and Ref Y. Some footprints have these in pin 1.
That is why altium also includes Mid X and Mid y coordinate to combat that.
So it seems that Mid X and Mid Y need to be used for altium.
http://i.imgur.com/TFITsWP.pnghttps://github.com/jkuusama/LitePlacer-DEV/issues/24
My parts were on the bottom of the pcb. This had two side-affects:
1. For some reason all parts were rotated by 180 degrees to much ( so if pnp file says 180 degrees it is actually 0 degrees)
https://github.com/jkuusama/LitePlacer-DEV/issues/26
2. Due to placing the bottom the x coordinate is inverted. To solve this I put a offset of 100 mm (x board size)
top:
bot:
https://github.com/jkuusama/LitePlacer-DEV/issues/25
Also measurement by fiducial seems off. Nominal placement was correct but the measured location was off.
It seemed not possible to place components without the fiducial compensation?
https://github.com/jkuusama/LitePlacer-DEV/issues/27
While most component were picked correctly once in a while there was one what did not. This is really annoying.
A good way to check if the component is picked just use vision. Go the location where you picked up the component.
See if there is something in the box (for example white tape look if there is some color or whatever in the box).
This would replace thereza vacuum sensor method.
https://github.com/jkuusama/LitePlacer-DEV/issues/23
While pickup works good enough for the DO214 diodes, qfn etc the detection is sometimes a bit of. It would be best to implement some kind of template matching to get the best result.
But most of the time is is good enough placement. Worst case you have to move the chip a mm to the right or left to align it properly.
Due to trays currently not being implemented you have to put the components in the pickup location which is annoying if you have to do 50 parts.
In the end the PNP did ok. Was it faster than placing by hand ? Yes , but not by much. When some of these issues are solved than this will be much faster.
I have used thereza's mod and it has many of the improvements that are needed. But it also has some significant bugs that make it unusable for my application.
Tapes only work in x+ location , the rest does not work etc...