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High speed printing

Posted by calad 
High speed printing
March 01, 2014 08:55AM
Hi. Any tips how to do high speed printing?

I have managed to print on speeds: perimeter 80, infill 200 and travel 200 simply objects. Problem has been if I increase perimeter speed more sometimes pla won't stick on glass surface. Any tips here?

I am also concerned about firmware and motors. Does marlin firmware have inner limitations built and should I increase motors Vref to provide enough power? I have also oiled smooth rods.

Overall: any tips? Are there other print settings that affect success of high speed printing? Does hotend and bed temperature matter alot?
Re: High speed printing
March 01, 2014 06:00PM
You can slow the first layer right down in Slic3r to get better adhesion. For higher speeds, you would need to increase your hot-end temp. But your biggest challenge would probably be whether the extruder could keep up.


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Waitaki 3D Printer
Re: High speed printing
March 02, 2014 02:31AM
Do you mean e-motor aka filament feeding?
Re: High speed printing
March 02, 2014 03:40AM
I would also say that the extruder is the limiting factor for most printers.

It's not just how fast your extruder can spin/push filament, it's how fast it can push it out of the nozzle and how much of it will come out of the nozzle at that speed.

This is limited by a large number of factors:

1. Temperature of the hot end (mainly temp range).
2. Viscosity of the plastic at a suitable extrusion temperature (needs to be viscous enough to flow under suitable pressure from the extruder, but not too much to just flow out constantly under no pressure, also you don't want it to degrade/burn).
3. Size of the filament (usually filament diameter, but depends on how uniform the filament is).
4. Size of the nozzle orifice (just how much plastic do you get out of the nozzle).
5. Layer height (in combo with the nozzle orifice size, determines just how much plastic you are laying down each layer).
6. How well the plastic heats through (plastic in the middle of the filament not heating completely will plug the hot end if it can't heat it fast enough).
7. How big your hot end "hot zone" is (where the plastic itself melts).
8. The amount of pressure the extruder can apply before skipping or shredding filament (type of extruder, how much filament contact area it has, type of grip, type of stepper motor, what type of stepper driver is driving it, etc).
9. How much the plastic deforms between the extruder and said hot zone (depends on filament size, plastic type, type of hot end, type of extruder, is it a Bowden [whole new can of worms], how much pressure the extruder can apply, etc).


Note: This is just the things I can remember off the top of my head. There are probably even more things that would make a difference. Changing just one of these may improve things a little bit, but you really need to make improvements in many of these areas to get any significant increase how fast you can extrude plastic, and there are theoretical limits to many of these issues. Some of these also vary quite a lot between the different plastics, and even then there are variances in some of these within a single roll of plastic that makes it even more difficult. Also, if you use a finer (smaller) nozzle to get better feature sizes, you reduce how much plastic you can push out the nozzle, which will affect your top speed.
Re: High speed printing
March 04, 2014 04:36PM
So what kind of printing speed you guys have? I need to set goal to myself.
Re: High speed printing
March 04, 2014 07:28PM
With ABS and 0.3 mm nozzle, the fastest I can handle is about 35 mm/s at 230 degrees. More will lead to the extruder clogging.
Re: High speed printing
March 05, 2014 03:40AM
I normally print 50-70mm/s at 200 degrees with PLA. I can go up to 100mm/s at 215 degress, but then acceleration stretch my filament so 100% infill have small holes in the beginning of af layer. Have to play with advance in firmware to fix that.
I print ABS at 235 degrees and 50mm/s.
But acceleration have alot to say with speed. If you use ex. 1000mm/s acceleration it's no problem to print 100mm/s, but if you use 3000mm/s at 100mm/s print then you will shake your machine to much.
I use 2000mm/s acceleration on my Prusa i2 and Mendel90.
Re: High speed printing
March 05, 2014 08:34AM
I haven't understood yet a consept of acceleration. Can you elaborate it how it relates to printing and filament? And when speaking of speed do you speak of perimeter or infill value?
Re: High speed printing
March 07, 2014 12:43PM
The acceleration calculator on the bottom of Prusa's calculator page does a good job of showing what speed's you should be hitting based on accelration: [calculator.josefprusa.cz]
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