This week I have been focusing on getting the new printhead up and running, but without success. The HP45 is a fantastic little device from beginning of the last decade, yet it is delicate and hard to operate from my point of view. It has a 22 address lines and 14 primitive lines along with bunch of ground lines and a thermistor and reference resistor. Both the address lines and primitive lines form a 14*22 matrix, that yields 308 usable outputs of which 300 are used for nozzle heater resistors and 8 of them are not connected. All the inputs function at 12V, but the primitives also accept lower voltages to regulate the nozzle drop characteristics. The primitive lines need more current as they power the heater elements in the nozzle.
I am using the YTec3D hp45 controller. It has 2 subunits, where one is just a set of 4017s along with AND gates to increase their range. They are used to trigger between different address lines. The second unit consists of two TLC59213 latched led drivers. They supply current for the nozzle heating elements.
After numerous hours of bugfixing, troubleshooting, etc. I found that the problems I have encountered are caused by bricked TLC59213s. It is also interesting that both have 1 latch bricked. Furthermore the broken latches trigger the primitive line 12 and 13. These lines have neighbouring bins, so this indicates a problem on my side. Funnily enough both of bricked latches work alright with the CLK and RST pin but they just ignore the input pin.
I will order the new part from farnell, so I will be able to replace the chips on tuesday (hopefuly).
Few weeks ago Formlabs announced their Fuse 1 printer. Luckilly enough Tested (http://www.tested.com/) did a video on this printer. I have watched the video for couple of times just to get some ideas. Upon seeing and thorougly analysing the video and printer itself, I got some of the Ideas that I am going to include in my printer. The main feature I am going to add is a detachable bin (probably around 150mmX150mmX300mm) with a storaged powder deposition system. This way the loading and unloading of the printer are going to be much easier. Also it will be better for the system with any upcoming materials, as it will minimise the dust falling onto the rails.