Oasis 3DP printer
Posted: Sun May 22, 2016 3:39 pm
I have gotten far enough with the HP45 that I can start with a new printer. I need something to test electronics and firmware with, and I might as well make it the functional printer I was planning to make. But first briefly what I have learned form the previous printers:
Focus: http://ytec3d.com/focus/
Was my first powder printer. It is cheap to build and can handle powder printing. That is basically all it does. It was designed as a cheap powder printing platform to test SLS and 3DP on. SLS never really worked on it, but the backup, 3DP did work good enough on it. (The fact that 3DP on focus was the backup is the reason Plan B is called Plan B).
The piston design jammed after a few hours of use and wobbled. The spreader design was novel, but also dead slow. Even the tiniest of prints took in the hour range (on a printer that jams every few hours). A good thing about Focus was that it was cheap and simple.
Plan B: http://ytec3d.com/plan-b/
Plan B was designed with speed in mind. The double feed piston and independently driven spreader were caused by this. On Plan B I used manufacturing techniques available to me at the time. The laser cut aluminium was easy for me to get, but difficult for others. Also the focus on speed made Plan B rather expensive.
The biggest issues with Plan B are that it only supports one printhead and everything is tied together. It is not tinker friendly at all. It is expensive and requires difficult to get parts. That said, Plan B ran way more reliable and a lot faster. At this point I found out that firmware is a lot bigger bottleneck than hardware on the speed. I never got good software to run for Plan B, something I hope to improve on the next printer.
Oasis:
I hope to make this printer a lot more hackable and easier to make. The laser cut aluminium frame has made way for a simpler wooden frame. The gantry and hoppers are (and should) not be connected to each other and can be changed independently. This is what the current design looks like.
The frame itself is a simple wooden box. The current itteration is designed to be cut from a single 122x61cm sheet of wood and has a size of roughly: 61x44x35cm. The design can quite easily be scaled to be made from different sheet sizes at this stage. On the top is a polycarbonate cover. This allows for a heated and/or draft free environment. I have 2 hinge designs, one requires more height to open, the other more space in the back.
The gantry is a very basic X-Y gantry with one motor for each axis. There are no complicated belt paths on this one. The gantry in it's current form can easily be scaled simply by using longer guide rods. At this moment the final axis is vertical, but I am still doubting about whether I should mount it vertical or horizontal. The spreader is going to be a Misumi rotary shaft. Misumi is an industrial supplier of everything mechanical, and a shaft is around 25 euros. I cannot design something cheaper and more accurate. The spreader in this design will be a rolling one.
The hoppers are more interesting on this design. There is no threaded rods and guide rods. I wanted Oasis to be tabletop, and any conventional piston design requires at least twice the stroke in space to work. The design is something I discussed with Ezrec here: http://ytec3d.com/forum/viewtopic.php?f=8&t=15
The basics are this. There is a piston that gets it's lateral guidance from the walls. The piston is suspended from 4 cables at the top and one cable from the bottom pulls it down. Elsewhere in the printer is a horizontal lead screw that actuates the cables of the piston. This way 1mm of lead screw gives 1mm of piston motion, every time. The cables run through 4mm bowden tubes to get to the pistons. The piston tubes are 120x120x5mm aluminium square tubes. Smaller tubes can be used to test a lot of small batches.
The design is still very fluid and can still be modified to suggestions by others. Want a feature, have a suggestion, have a question, please ask.
Focus: http://ytec3d.com/focus/
Was my first powder printer. It is cheap to build and can handle powder printing. That is basically all it does. It was designed as a cheap powder printing platform to test SLS and 3DP on. SLS never really worked on it, but the backup, 3DP did work good enough on it. (The fact that 3DP on focus was the backup is the reason Plan B is called Plan B).
The piston design jammed after a few hours of use and wobbled. The spreader design was novel, but also dead slow. Even the tiniest of prints took in the hour range (on a printer that jams every few hours). A good thing about Focus was that it was cheap and simple.
Plan B: http://ytec3d.com/plan-b/
Plan B was designed with speed in mind. The double feed piston and independently driven spreader were caused by this. On Plan B I used manufacturing techniques available to me at the time. The laser cut aluminium was easy for me to get, but difficult for others. Also the focus on speed made Plan B rather expensive.
The biggest issues with Plan B are that it only supports one printhead and everything is tied together. It is not tinker friendly at all. It is expensive and requires difficult to get parts. That said, Plan B ran way more reliable and a lot faster. At this point I found out that firmware is a lot bigger bottleneck than hardware on the speed. I never got good software to run for Plan B, something I hope to improve on the next printer.
Oasis:
I hope to make this printer a lot more hackable and easier to make. The laser cut aluminium frame has made way for a simpler wooden frame. The gantry and hoppers are (and should) not be connected to each other and can be changed independently. This is what the current design looks like.
The frame itself is a simple wooden box. The current itteration is designed to be cut from a single 122x61cm sheet of wood and has a size of roughly: 61x44x35cm. The design can quite easily be scaled to be made from different sheet sizes at this stage. On the top is a polycarbonate cover. This allows for a heated and/or draft free environment. I have 2 hinge designs, one requires more height to open, the other more space in the back.
The gantry is a very basic X-Y gantry with one motor for each axis. There are no complicated belt paths on this one. The gantry in it's current form can easily be scaled simply by using longer guide rods. At this moment the final axis is vertical, but I am still doubting about whether I should mount it vertical or horizontal. The spreader is going to be a Misumi rotary shaft. Misumi is an industrial supplier of everything mechanical, and a shaft is around 25 euros. I cannot design something cheaper and more accurate. The spreader in this design will be a rolling one.
The hoppers are more interesting on this design. There is no threaded rods and guide rods. I wanted Oasis to be tabletop, and any conventional piston design requires at least twice the stroke in space to work. The design is something I discussed with Ezrec here: http://ytec3d.com/forum/viewtopic.php?f=8&t=15
The basics are this. There is a piston that gets it's lateral guidance from the walls. The piston is suspended from 4 cables at the top and one cable from the bottom pulls it down. Elsewhere in the printer is a horizontal lead screw that actuates the cables of the piston. This way 1mm of lead screw gives 1mm of piston motion, every time. The cables run through 4mm bowden tubes to get to the pistons. The piston tubes are 120x120x5mm aluminium square tubes. Smaller tubes can be used to test a lot of small batches.
The design is still very fluid and can still be modified to suggestions by others. Want a feature, have a suggestion, have a question, please ask.