SQUARE HOT END

Quite a lot of the extrusions require straight sides. Has anybody tried to make a square hot end hole, and if so, has it provided any better results?

Problem is that the extrusion width would change depending on the direction. I would also think that making a 0.4mm square hole would be quite difficult without using something like EDM.

Drilling a square hole is possible, but not at .4mm.

Hmm.. that's a very interesting idea.

If not square, how about a flat nozzle, like a slit or elongated oval shape.

At least in theory, we should be able to control the extrusion width by controlling the angle of this slit in relation to the movement of the nozzle (or the bed underneath, which is basically the same thing).

This means there will be another motor to rotate the nozzle head on XY plane.

For example, if the slit is perpendicular to the direction of the movement of the nozzle, then the extrusion width will be at its maximum. When it perfectly parallel to the movement, then the extrusion width will be at its minimum. These max and min width value will be constant for the physical size of the nozzle hole, but the angular orientation of the nozzle will allow us to have any extrusion width between the min and the max.

Determining proper angular orientation of this nozzle head in relation to nozzle head/bed movement, which often can be combination of both X and Y direction, will be helluva calculation for sure.

Oh yeah, not to mention the difficulty of making this flat nozzle hole in sub millimeter precision...

We may be surprised by what can be achieved today in sub-millimetre precision!
Those who watched this week's Dara O'Brien's Science Club on UK TV will have seen a short video of a little man - like a match-stick man, but made up of dots - stepping up on a small platform (also made of dots) and gracefully trampolining on it.

What was jaw-dropping about this was that it was an actual event, filmed under a very powerful microscope, and each of the dots in the scene was one discreet atom. Scientists were able to separate and arrange these atoms into a cartoon figure, and then make that figure move in co-ordinated animation! OK, they had to bring the temperature down to almost absolute zero to stop the atoms whizzing around uncontrollably, but - hey!

Seriously, Rolls Royce has been spark eroding miniscule holes through their jet turbine blades for decades (for cooling). I don't know what profiles the holes are, but I have been told that they take a curved path through the blade. If they can make sub-millimetre curved holes...

I predict the day will come when someone will think it advantageous to use a flat nozzle for some specific type of print job. It may or may not be sub millimetre. Surely, it must be possible to design a plastic that doesn't shrink and distort on cooling, and then huge 3d printers laying down 10mm thick filament will become available. A flat nozzle could then lay down strips of plastic next to each other to build a shell in one single layer! That's something to look forward to: Turn up to a lab, put money in one slot, your SD card in the other, and print your own canoe!

If you'll allow me to rabbit on a little longer...

The more I think about this idea of nozzles with different profiles, the more it dawns on me what a bullock-cart era we are passing through with our 3D printing! We've hardly begun to scratch the surface of its potential! As I see it, the next progression is to mount a print head on the end of a robot arm, and we immediately gain more axes of movement.

Nobody has said that we must print onto a flat surface! Why not begin with a 3D shape, and print onto its surface? Some simple shapes could be done even without a robot arm. For example, to print a cylindrical shape, we could rotate a cylindrical former on a turntable. Then, starting at the bottom, keeping the tip of our (probably flat) nozzle stationary on the x-y plane, and slowly spiralling it upwards in the Z, we could sort of 'paint' our plastic tube onto our cylindrical former. More complex shapes - statuettes - could be 'painted' like this using a robot arm. The software for doing the complex mathematics is already well developed in the robot world. The main challenge would be to make formers collapsible, or dissolvable, or - if cheap - they could be left inside.

Now.. as I read it, 3D cameras are being developed which also capture colour information. It's not a large leap then to think that since we already have our intended 3D model digitised for plastic printing, we could swap to an inkjet printer head on the end of our robot arm, and paint a photo-realistic image onto our bland coloured plastic model. Hey, presto! A photo-realistic model of your favourite big-breasted film star!

The difference between a robot and a CNC machine is that CNC's use g code and robots use a more complex program language. Even if you had a robot that ran on g code, you would need slicer to slice an object in a way that doesn't exist yet. It would take years to come up with that kind of program; that sliced an object so that a 6 degree of freedom articulated robot could print an object.

I have a mechanical mind and am a fabricator by nature and trade. This is an easy achievement and rather than do it my self to make money (laziness) I'll go on record here that I Perry D. none-of-biz thought of this method, and can there for, not be patented or stolen from the people to witch it was given.

so if one can mill a high-density metal (I suggest tungsten) to a square or rectangle shape linear rod, then made a crucible mold of an extrusion nozzle general shape with holes to guide and hold the square or rectangle shape linear rod down the center, then filled the mold with molten metal and waited for it to cool and removed the rod, they would then have an extrusion nozzle general shape with a square or rectangle hole down the middle, if you then drilled desired holes and milled and threaded you would have a square or rectangle extrusion nozzle.

As for slicing software: Ignore the fact that on the slicer screen the extrusion animation is round and make normal adjustments... figure it out

comments on the idea:
*It might be interesting to find a rectangular shape that when smashed between layers form a perfect square.
*I imagine it being hard to force the plastic not to gum up the corners and become a round extrusion anyway.

It's already been done