I can only second thatWayOutWest wrote:Wow, Karl, that nozzle changer looks AWESOME.
![Smile :-)](./images/smilies/icon_e_smile.gif)
AFAIK, Karl is using Juki Nozzles and custom machined holder from China:
Nozzles:
http://www.ebay.com/itm/SMT-JUKI2050-20 ... 1783968281
Holder:
http://www.ebay.com/itm/Customized-SMT- ... 1826225528
The holder has a steel ball lock (similar to air compressor connectors) - thus the changer needs to have a angled surface to release the nozzle I suppose...
Options for new nozzles are also being discussed here:
http://liteplacer.com/phpBB/viewtopic.php?f=11&t=192
Some inspiration also came from OpenPNP google group discussion.
The Juki nozzles have a pin inside that moves up if nozzle touches something.WayOutWest wrote:How do you do z-min (i.e. hitting the table or PCB) detection? The original liteplacer depends on a "stiff" pickup rod to trigger the limit switch, but the Juki nozzles seem to have a built-in spring that would absorb the pressure. Do they have some kind of sensor switch in there?
Karl described his solution before - he is using a electric contact inside the nozzle holder in a true hacking style
![Razz :-P](./images/smilies/icon_razz.gif)
Check it out here:
http://liteplacer.com/phpBB/viewtopic.p ... t=10#p1292
Nozzle tip needs to be grounded. A slip ring (or electrically conductive ball bearing) could be used instead of steel wool to make reliable contact to the rotating contact pin - but then it should work fine.
Another option would be to put a longer plastic or metal pin inside the nozzle holder and us a piece of transparent tubing somewhere upstream. We could then use optical sensor to detect that pin's appearance / movement along Z-axis when nozzle spring is compressed.
A third option was introduced by jarekk - he uses 3D printed discs and a capacitive sensor:
http://liteplacer.com/phpBB/viewtopic.p ... =192#p1324
Personally, I will probably try the Juki nozzles and coupler with mechanical / optical detection. At the same time, I will change my LitePlacer's head design to use a hollow shaft stepper and get rid of tube + pulley + belt.
Regards
Malte