Mosaic Manufacturing's New Single Extruder/Multiple Color 3D Printing Technique

[truly_bent]

Call me a noob, but i don't understand what's to calibrate. It looks, from the vids, that the Mosaic box doesn't replace the extruder feed mechanism, so all they have to worry about is being able to stay one step ahead of that. Well, that's not all they have to worry about. They also have to be sure that the colours synchronize with the printer movements, but i'm sure they have that figured out.

What else is there to calibrate?

[Feign]

What else is there to calibrate?

Well, the Mosaic machine needs to know exactly how far the hot end (more accurately the nozzle output) is from where it is splicing the filaments to know how far ahead in the G-Code it needs to look for the material change. They can have a tube that keeps the filament at an exact length from the device to the printer, but the distance from the printer intake to the hot end is pretty variable, even on a direct drive extruder. If this distance is off, then the distance the output color is wrong is magnified by the difference in the filament and nozzle areas.

For instance, say you are using 3mm filament (actually 2.98mm) and you have a 0.4mm output (about as far a difference as one would reasonably find). The filament's cross sectional area is just under 14 times that of the output area. So if there is an error in the distance between the Mosaic machine and the nozzle is off by 0.1mm, the output would have a offset error of around 1.4mm every time the color changes.

Most professional printers hold pretty tight standards, but home printers are pretty likely to have a tolerance of around 0.1mm in places, much more for a Bowden tube setup. So it is absolutely essential to calibrate the distance for each individual printer, not even just for each model. Though getting the intended dimensions of as many printers as possible is a good idea for making a general range for calibration for each printer model.

[mitchfrommosaic]

I signed up for those updates as well. It's definitely a clever solution though i do have to wonder just how adjustable the thing is going to end up being. Given the HUGE array of printers out there there is simply no way they will be able to calibrate this thing to work with every possible machine. In order to not limit their market then, they will need to allow for adjustments to whatever parameters determine when to cut and fuse the different pieces. Documentation and support are going to be key here to make sure that people don't end up with an expensive piece of equipment that they can't get to work properly.

@soofle616 Hi I'm Mitch one of the founders of the Mosaic Palette. You have a great point and I want to explain how we went about making the Palette work with a huge number of printers, while keeping the calibration process streamlined and simple.

The Palette outputs 1.75mm filament just like most printers are designed to use which is what allows it to be such a universal solution. It also requires no modification (firmware or hardware) to the printer. The only thing you need to do to your printer is stick on a piece of Velcro (included with Palette) to which the scroll wheel will attach. The scroll wheel is a small measuring device that the filament passes through before entering the printer. It precisely measured the filament used by the printer and relays this information back to The Palette. This allows the Palette to keep track of the print job and even to make compensations if your printer's extruder skips steps, or is over/under extruding. The closed loop feedback system is what allows The Palette and your printer to stay in tune.

There are only 3 calibration constants required for any given printer to be used with The Palette. They are the extrusion constant (similar to extrusion multiplier), hot end transition volume constant, and Bowden distance constant. We have designed simple exercises that the Palette's on board LCD screen can guide you through to get each of these constants. We also plan to provide plenty of documentation to ensure this process goes smoothly for everyone. If you use The Palette with more then one of your printers, you will need to do this sequence for each of them once and then you will be set.

There are some more schematics and descriptions on the Kickstarter campaign here: https://www.kickstarter.com/projects...ed/description

[mitchfrommosaic]

Hi @Feign, I'm sorry I'm replying to your comment so late but yes knowing the exact position of the nozzle is critical. We have overcome this by implementing a closed loop feedback system that measured the filament consumption by the printer. There is a diagram in our Kickstarter campaign in the "staying in sync" section here:

https://www.kickstarter.com/projects...ed/description

With this set up, knowing the distance between the nozzle and the scroll wheel is critical. We have developed a very simple calibration sequence that uses the scroll wheel to determine this distance. Yes your correct the cross sectional area reduction will magnify any error but through the insertion of a transition buffer we have been able to mitigate this. The high precision scroll wheel keeps the print right on track and in sync allowing for fantastic quality output.

If you have any more questions, I'll be around.

[curious aardvark]

well you're looking $849 + post and import tax just for the earlybird kickstarter price.

So final retail - what somewhere north of $1000 ?

Yes it's clever - but at that price, just don't see it taking off commercially.