square shaped nozzles - why doesn't anyone make them ?

Was having a discussion about why 3d printed canoes would sink yesterday.
It occurred to me that the main reason 3d prints are not know for being watertight is simply that we extrude a round bead and place it on top of another round bead.
It's also why transparent filaments don't print all that transparent.

If you had a square nozzle - you would then be laying a flat bead directly ontop of another flat bead. Both increasing the layer adhesion and watertightness and improve the transparency.

It would also give you sharper corners.

Not sure what effect it would have on curved shapes.
But used for the right model it would improve some models immensely.

I suppose they'd be quite hard to make - but I'd definitely be prepared to pay a premium for a set of square holed nozzles.

Seems obvious when you think about it.

I expect a large portion of the reasoning is manufacturing costs. It's far easier to generate a cylindrical hole in a mass than it is to create a precision square hole. Broaching is one method of making square holes but to get to 0.25 mm would be amazing with a broach. EDM, electrical discharge machining, can make holes as small as 0.0015 inches (0.038 mm) but this was in an experimental environment, not a production one.

I suppose it's possible to contract with an EDM facility and ask how much to create a rectangular/square hole in an un-drilled nozzle. I'm confident the "premium" aspect of that would come into play.

Another thought, most printers use a 0.40 mm nozzle and have a seventy-five percent recommended limit on layer height. This means that the round nozzle puts out a flattened cylinder, mostly flat. I suspect there will not be as great of an advantage as you suggest by using a square hole in the nozzle.

At first, I thought you were suggesting a square wrench surface in place of the hex. (grin)

Better contact would only occur with the print head moving in the X or Y direction. Moving in any other direction would have the material laid down on the edge, and not the face.
Assuming that you could install the nozzle square with the XY axis, of course.

Petercat, your observation is a good one. With a non-orthogonal move, the width of the layer would be something other than the dimension of the square's width. That's the best reason yet for a cylindrical nozzle opening. A circle is going to have the same diameter in all directions and the layer will be the same width.

Imagine the assembly instructions for a hot end with a square opening! "Examine the nozzle with a microscope, ensuring that the edge is parallel to the heater block. When placing the heater block, ensure that the edge is parallel to the bed." Yikes.

Quote:

---

Assuming that you could install the nozzle square with the XY axis, of course.

---

had not thought of that !
:-)

Okay so there are reasons for not having it on desktop 3d printers. Could work on extruded concrete buildings though :-)

Thank you. Makes me feel good about my first post, especially since I've never 3D printed anything! (Waiting on a Photon S to be delivered now.)
I suppose you could index the nozzle and add another stepper motor to rotate the extruder assembly. Should be a simple mod, right?
Right?

Another place an unusual nozzle shape might work is on the 6 axis robotic arm type 3d printers. The wrist typically can rotate through 360?.

Quote:

---

Originally Posted by Petercat

Thank you. Makes me feel good about my first post, especially since I've never 3D printed anything! (Waiting on a Photon S to be delivered now.)
I suppose you could index the nozzle and add another stepper motor to rotate the extruder assembly. Should be a simple mod, right?
Right?

---

Thinking logically - no experience required :-)

So you're jumping right in with resin eh ?

don't forget the gloves, active ventilation, alcohol washing stations and some kind of stain proof table covering.

Yes, it seemed best for my needs. I want to build small items with high detail, like Z-scale buildings, cars, people and stuff.
If I have a good experience with it and Anycube's customer service, I'll probably go for the 4Max Pro next.
Also looking into photogrammetry.
This forum is going to get sick of me asking questions, since I've never done any of this before.