The aim is to create a proof of concept full color 3D printer from just a few household scraps and use readily available materials. If it works it could be the bases of a low cost full color 3D printer.
The idea behind this printer is to use layers of plaster and print ink onto it. This should hopefully set the plaster as well as color it.
Finally found some time to work on the printer. The main addition has been the spreader beam and recipe for print material which I'm testing from the reprap wiki. The beam is an old printer axle held in with some wire. An optical encoder has been added to the bed drive motor. And all the electronics have been redone to use a dsPIC30F3012. Next thing to do is finish the control loops and the state machine to run the whole system and then fiddle with material and binder fluids.
Finally managed to complete a new compact Z-axis. It's not very impressive with only 15mm of movement. But it is capable of extremely fine increments. It is essentially a wedge design with a lead screw moving the wedge. It might have been more productive to use multiple vertical lead screws but it was too mechanically challenging to spin all the lead screws at once.
I have also tested multiple variation of the print material. The base is still plaster of paris. The main additive that I found that reduced binder and improved strength was talc powder (baby powder). I also tried to add glycerine to the water binder and no effect was observed on the plaster mixture. The glycerine is now used as a viscosity control for the ink as I have noticed pure water based ink was too runny and had issues with the printhead.
Managed to break a nice 6 row epson printhead as I was trying to unclog it. Found a few HP printers which are well under way to being fooled into printing on to flat surfaces. I have to print sequence worked out and is in the process of replacing encoders and switches with a uC. I'm not able to remove the scanner head as it stops the printer from working. So untill there is more time there is just a stray scanner attached to the printer. The good thing about cheap HP printers are that they use minimal sensors making it much easier to fool. Currently I only have 3 pins I have to emulate and a motor drive input.
The current idea for the powet bed is two identical square chambers with moving floor. One chamber starts full and one empty, as one is lowered the other is rised and the powder is shifted across. This should create fine layers to work on. This is not a new idea so I hope I can get it to work with plaster. Drawings and photos are to come soon.
Also currently trying to hack various printers to print onto a rigid flat surface but having a lot more trouble with the printheads clogging. It is also looking to be a bit of effort fooling a mid-range Epson Photo printer to think that it is printing to paper. There seems to be light-sensor on the printhead that will not allow a print unless the paper is there. Also there is an army of switches that need to be activated at the right time to trigger the print. It is almost looking easier to replace the printer electronics with a custom inkjet driver.