Solder Paste Dispenser/Extruder?
I have a BFB3000 I would like to use my free head space for alernative "print" heads, starting with a solder paste dispenser.
Is this possible at all with the existing firmware?
I saw that there are M codes for 2 aux channels, do these exist on the BFB3000, and if, where are they?
I could you an AUX channel to switch a valve to control paste dispension.
What would be the best solution to allign a PCB so that the dispenser hits the solder tabs?
Have a look in the 'build board' forum section under the 'paste extruder' thread.
Basically the firmware, looks at the resistance present on the connector to work out what type of head is present. Experiments are 'ongoing' with various extruder styles (with most people wanting something able to handle thicker pastes than yours, and build to greater heights), and with other things like milling. I'd have suspected that a basic 'paste' system, could possibly be done using the experiments in milling cutting aimed at PCB manufacture, with the drill on/off, being used to control the extruder, and with the extruder set to be a suitable height above the bed, when the mill, would be cutting.
The AUX commands, are M220, and M221. They are in appendix i of the BFB3000 manual, so should be available.
Best Wishes
will have a look at the paste extruder.
i found these liquid dispensers on ebay. they seem perfect for the task. the aux channel would trigger a shot.
i am just writing a tool to parse the gerber G*P files and create gcode for the printer. turned out to be quite easy, parsing is no problem. i can create a jpg image according the pads where solder paste should go. now starting the gcode generation. if i manage to stick a pen on the printer and successfully draw dots where solder mask should go, i will get one of these:
the AUX channel would replace the foot switch. they are not too expensive on ebay, search for "liquid dispenser".
ok, so I was able to hack a small program together that parses gerber paste screen files and creates gcode from them.
i strapped a pen to my printer and gave it a shot, here is the video: www.youtube.com/watch
works good. only issue i have is that I cannot get the G4 (dwell/wait) code working. its ignored, but I want a tiny pause to give the dispenser time to do its work. any hints?
Perhaps you should try to change the "tool type" resistor value which is soldered onto the 25 pin connector. The standard one is 4K7 which tells the controller it has attached standard extruder. 976 ohm (1K) it seems it is defined for "Pen" toole type. It is possible that firmware will ingnore G4 command if standard extruder is present but may work if it sensing a pen tool type. Not sure but give it a try.
For my paste extruder I soldered a 5K7 resistor in place of the thermistor input coresponding to some 122 deg. C. so I can cheat the controller and benefit the great options like reverse extruder, variable flow rate etc.
regards
Hi,
I have reached step two. I am now able to exaclty hit the solder tabs on a PCB. I am still using a pen, but the dispenser already arrived the other day, something to work on over the weekend.
here is a video that shows the steps to generate the gcode:
I wrote a little programme that calculates angular and linear offset of the PCB on the print bed and generates the g-code. All you need is the paste screen gerber files, all PCB design tools can output these as its the defacto industry standard. Because the programme does the allignment for you, you can just put the PCB anywhere on the print bed at any angle, so no need to precisely align it. You then switch the printer into manual move mode and move the head/dispenser/pen above two solder pads. any pads are fine. enter the coordinates of the two pads into the programme. Now, after the gerber file was loaded, the tool shows you a graphical representation of the solder pads. select the same two pads in the programme which you previously got the coordinates from.
The programme can now calculate 4 things:
* The absolute angle of the line AB on the print bed
* The relative angle of the line AB against the PCB
* the offset angle. this is the angle of the PCB on the print bed
* the scale. Comparing the length of the two vectors (one with coordinates from printer, one with coordinates from gerber file) the programme calculates the scale. In my case the gerber file was in milli inch, and the printer needs millimeters.
Once the stup is done, you can simulate the angle and double check if this seems to be correct, then you can generate the gcode.
I already got the paste dispenser unit. manual tests looked promising, I hope to set it up over the weekend.
Any way to get the software from you? What are you using to write it? I'd be happy to help you if I can.
i wrote it in Java.
Sure you can have it, but its not really a release candidate ;)
Its basically working, but I need to design a holder/bracket for the syringe. I was just clamped it in there but it was moving and my results were inconsistent (not repeatable) other than that its finished. once i have the syringe properly fixxed, I make another video of it.
edit: am at work, so will upload it somewhere later...
one solution to align a board on the bed i came up with so far:
* fix the PCB to the print bed (anywhere)
* manual move the dispenser needle to 2 solder pads. note pad and its coordinates.
* feed this info into the gcode generator, all other pad coordinates can be calulated.