Where can I find info about the details of printer design
June 04, 2017 03:33PM
I have been unable to find anywhere that explains the detail design requirements for a 3D printer. I understand the general way in which they are constructed and the general way in which they work.

But I am curious to know, for example ...
  • What determines the speed at which a line can be printed; what happens if the motion is too slow or too fast?
  • What determines the minimum width of a printed line - is it thinner if the head moves faster?
  • What is the relationship between nozzle diameter and the Z movement between different layers of a print?

Maybe someone has a link to some document where that sort of thing is discussed?


Re: Where can I find info about the details of printer design
June 04, 2017 10:08PM
I don't relly have any documentation, in general, most of that stuff comes from you when you are messing around or designing your printer. however, I can answer so of your questions

the speed at which you run your printer is quite variable, but certain factors do come into play, how fast you can melt plastic how fast your steppers move, and to a lesser extent your printer design. having had experience with many different types of extruders I can say a single hot end with one filament can usually run faster than a large mixing head but this come down to your design. there is definitely a max speed where your printer just won't be able to get the filament out and you will be missing a lot of bits, most printers are right around 150mm/s I have run my printer at 10mm/s when printing super complex things with a .15mm nozzle but it takes forever.

the width of a printed line is a combo of the nozzle diameter, the speed, the layer height, and how fast your printer extrudes filament, in general, its best to have the right amount of filament, too much and you get over extrusion to little and you may be missing layer or parts may have holes in them, realistically when you make your printer you do a few test prints and figure it all out.genraly you printer will limit is top speed by how fast it can extrude plastic. much of this has to do with your design and the firmware, with a good printer and some firmware changes I have seen people get their printers to 300mm/s but usually with less than perfect resalts.

the relationship between nozzle and layer height is important, basically as the nozzle moves it lays down plastic, the higher your layer the more visible your layers, and the nozzle will lay down more of a cylindrical extrusion, the smaller your layer height the less visible, and in general the nozzle lays down more of a patty of plastic
something like this;

(the picture rotated I don't know why?) but you get the idea
Re: Where can I find info about the details of printer design
June 05, 2017 03:01AM
Thanks. That certainly helps.

From your drawing it looks like the width between lines should be a little wider when the height between layers is smaller.

Re: Where can I find info about the details of printer design
June 05, 2017 04:24PM
the width of the extrusion is based a lot on how much you extrude, that picture is just about layer height, if you have too much extrusion you will knock the head as your printer tries to print the next layer if there is too little plastic you will get gaps.
Re: Where can I find info about the details of printer design
June 09, 2017 09:37AM
Imagine squeezing toothpaste out of a tube. . .

Slow is better, can draw quite accurately. Fast it starts to drag what you have just laid down, especially in corners

A thin line is about the width of the nozzle, you can draw quite a thicker line - more toothpaste/ slower motion.

Z - see above

. . . sticky toothpaste than goes from gooey to solid quite quickly
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