lets all take a moment to marvel at this machine.
alls i know about it is that this photo was taken at Maker Faire Tokyo 2015.
So, I’ll ask, in my ignorance: what do you gain by having both the bed and the extruder independently positionable? Increased build area? Increased build speed?
I’m not sure, but I don’t think you would get extra degrees of freedom in that design.
I am intrigued…
3 stepper motors for extruder positioning, then another 3 for the build plate, plus the z axis height stepper. A total of 7 positioning motors!
Is there a video of this machine in action?
@John_Helmuth i guess it’s for speed … and for fun.
@Paul_Gross i’m pretty sure it’s just 6 for motion.
haven’t found a video yet, but i’ll let you know if i do.
@John_Helmuth It gets you close to five axis positioning so, with the correct slicing software, you no longer have any overhangs because the active build area is always oriented normal to the nozzle and as close to parallel to the ground as possible.
@John_Helmuth
This design makes me think of the many possibilities from having 7 positioning motors.
Maybe… if both the plate and the extruder were tilted at an angle while printing bridges, it is possible that bridging might be less droopy.
I would really like a see a video of how it actually moves during printing.
@william_foster
I see what you mean - there is no z-axis motor, so the height is controlled only by the 6 steppers.
Additionally, none of those 6 steppers can can move in the Z direction, and they are offset from each other in a 6-point star pattern… very, very intriguing.
I can see the utility of being able to tilt the bed (or the extruder) but I don’t THINK this design will do that… I think the parallel rods going to each corner would have to twist in relation to each other for that to work.
To my understanding, that’s why there’s six rods instead of three in most delta printer designs. I’m pretty new to this stuff, though, so I may be wrong on that.
@John_Helmuth it’s true. on the linear type at least, the head can only move in a parallel motion.
FWIW, the head and the bed are set up with a true delta robot configuration (at least as I first saw a delta robot, anyway). There is no more than 3 axis to this, that I can see. The bed can be placed anywhere in reachable 3D space and the head likewise. Clearly their reachable spaces overlap a bit so the first layers can be printed. My guess is that this only makes for a smaller machine space requirement.
@Jason_Doege
The plate and extruder could be arbitrarily tilted using the positioning motors, but how it has actually been programmed to move is an open question at the moment.
It is simplest to program this system as a pair of deltas, and is likely done that way, but there is no physical restriction to only 3 degrees of freedom.
But if I were forced to name this design (it isn’t a pure delta) the 6 motors are arranged in a 6-point star formation: 3 at the top, and 3 offset by 60 degrees at the bottom, so I would say a ‘star’ printer.
Maybe there is some advantage to designing a machine where none of the positioning motors are allowed to move in the z axis?
Is this a full metall hotend without a coolingfan to cool itself?
@Paul_Gross Actually. if you attach the head with the minimum amount of joints to fully define it’s motion. it’s impossible to get more that 3dof.
@william_foster
I think I see what you are getting at.
Those 6 rods and 6 contact points on the extruder head assembly prevent any tilting of the head - the extruder is mechanically constrained to move in the X-Y plane.
To allow the extruder to tilt - to allow more degrees of freedom - there would need to be less rods and joints: 3 rods instead of 6 connected to the head assembly.
@Paul_Gross but then it will rotate freely. and uncontrollably.
@william_foster
How could it rotate freely and uncontrollably?
It takes only 3 points to define a plane: the connector rods are rigid and the stepper motors won’t slip, thus the three points are defined, making any assigned plane stable too.
6 rods create a more rigid position, but 3 rods will still prevent any rotation. The extruder cannot rotate freely with 3 rods attached.
you only need 3 FIXED points.
however those points are pivoting in 2 different places.
i have a cad model simulation right in front of me. and a have have built a delta robot before. i’m pretty sure i know how they work.
@Paul_Gross
Sorry, but this is not true. You can make a simple experiment.
Just take a plate and place it on 3 pens. It will rotate around the z axis and sink down.
If you add parallel pens/rods to the existing 3 you’ll delete this movement.
The problem in this case is that the joints on each end of the rods are ball joint.
If you change them to ball bearings with only one degrees of freedom (for rotation) then you are right. But then the whole delta system doesn’t work anymore.
Only in a static system 3 points are enough to fix a plane 
@william_foster , @Sven_Eric_Nielsen , you are both right, and I stand corrected. Thank you both for explaining this to me. 
Three rods will not constrain the plane of the extruder by themselves, as you have described.
Having 3 rods is not enough because the angle of the rods is in no way constrained by the ball-joints, and there are any number of different planes, at all sorts of angles and positions, that will satisfy the requirement of fixed distance due to just 3 rods. There will be a minimum-energy (gravitational) extruder position, but the extruder will not be held there rigidly with just 3 rods.