david.z
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What print speeds do you use?

Jul 12, 2016 12:11 am

I was wondering what print speeds other MK2 users have tried. I stuck with the standard 40mm/s at first, but my printer has been running pretty well recently after tightening up all the screws, and I just did a 100um print at 80mm/s with a pretty good result, with the other speeds still at default.

How high have you gone successfully with your print speeds?

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PJR
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Re: What print speeds do you use?

Jul 12, 2016 8:35 am

David

It depends on what I am printing. There are also volumetric melt limits to the hot end to take into account (somewhere around 10mm^3 per second - I don't have time to get the exact figure).

At 0.2mm layers, my perimeter speeds range anything from 20 to 100 mm/sec and infill from 30 to 150mm/sec but those figures are quite meaningless unless you significantly increase the acceleration parameters.

Print speeds by themselves do not tell the whole story - in fact they are quite meaningless.

Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss.

david.z
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Re: What print speeds do you use?

Jul 12, 2016 11:58 pm

Interesting. By 'meaningless', do you mean they don't actually make much of a difference, due to acceleration being a large limiting factor? Do slicers like Cura not adjust those settings automatically when the speeds are changed?

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PJR
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Re: What print speeds do you use?

Jul 13, 2016 8:22 am

David

In my opinion, although some slicers do attempt to handle acceleration, it is still a function that is built into the firmware and best left to the printer to resolve. It is possible to change the printer's maximum acceleration rates via GCode.

The problem with talking about speed as a single entity is that it quite simply it is not something that can be discussed as a stand-alone parameter.

For example (with stupid values), what is the point in trying to print at 1000mm/second at a layer height and line width of 1mm when the extruder can only melt 1mm^3 of filament per second and the maximum acceleration is set to 50mms^-2

All these factors (and a few more) need to be considered as a whole.

I found the communication with E3D regarding the V6:
Printing with a V6 using pure MG94 ABS 1.75mm which we know the characteristics of very well and has a melt flow rate of 11.7g/10 min, running the HotEnd at the normal print temp for this material which is 240C we found the following:

11.5mm^3 per second is the max comfortable flow rate, you can go a little faster but extrusion is not as optimal.

This means an extruder feed rate of 4.8mm a second is easily achievable. These numbers are very conservative and are only a measure of max steady state flow.
Explanation:

Feeding 4.8mm of 1.75mm filament is 11.5mm^3 which will print a line (approximately) 143mm long at layer height of 0.2mm and width of 0.4mm, hence a maximum theoretical limit of 143mm/sec with that filament at those temps, subject to the possible acceleration and settings of the printer.

I hope this helps.

Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss.

jeff.w3
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Re: What print speeds do you use?

Jul 14, 2016 3:09 pm

Last night I have been printing the Marvin file over and over again trying out different parameters. When I turned the speed down to 20% and it printed really well. I didn't modify and of the other default parameters in that program.

A question though when I open the program .gcode I am assuming when I see F1000 that is 1000mm/s? Is that correct?

kevin.b2
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Re: What print speeds do you use?

Jul 14, 2016 3:38 pm

Did you have the cooling fan on full blast for all of those Marvin prints? I've found that has a ridiculously pronounced effect on their quality.

Also, i believe the F1000 is indeed a feedrate command as you suspect, but i think it is in units of mm/min instead of mm/sec as 1000 seems way too high for mm/s. So it would be like 16.67 mm/s, which should be the z-axis speed.

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Re: What print speeds do you use?

Jul 14, 2016 4:07 pm

Yes, the G0 and G1 commands specify the feed rate in mm/min: http://reprap.org/wiki/G-code#G0_.26_G1:_Move

The axis/axes to which this refers is/are determined by other parameters in the command.

If the command only contains Z or E, then the movement will be with that axis only at the specified speed.

If an X and/or Y parameter is specified, then the movement in the horizontal plane will be at the specified speed and the movement of the Z and/or E axis will be proportional such that all moves start and end at the same time.

The little processors controlling these printers really have to work extremely hard to earn their keep!

Peter

EDIT: Jeff - a word of caution here. There is a minimum speed at which material can be extruded. When printing at 100 microns at an already slow speed and reducing that speed by a factor of 5, you may be getting very close to the minimum and print quality can suffer.
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss.

jeff.w3
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Re: What print speeds do you use?

Jul 15, 2016 3:41 pm

"Did you have the cooling fan on full blast for all of those Marvin prints? I've found that has a ridiculously pronounced effect on their quality.

Also, i believe the F1000 is indeed a feedrate command as you suspect, but i think it is in units of mm/min instead of mm/sec as 1000 seems way too high for mm/s. So it would be like 16.67 mm/s, which should be the z-axis speed."

mm/min makes more sense. I didn't have the cooling fan on, I don't even know the M code to turn it on yet. I see faster cooling is a key to better printing. Thanks for the advice I have homework to do.

jeff.w3
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Re: What print speeds do you use?

Jul 15, 2016 3:43 pm

"EDIT: Jeff - a word of caution here. There is a minimum speed at which material can be extruded. When printing at 100 microns at an already slow speed and reducing that speed by a factor of 5, you may be getting very close to the minimum and print quality can suffer."

I appreciate the advice, so far in my very limited experience that has yielded the best result so far.

poorvesh.m
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Re: What print speeds do you use?

Jul 31, 2018 9:29 pm

Currently for PLA I am using 100mm/s print speed with 150% flow of filament, results are faster and quite similar to 50mm/s print speed with 100% flow. Nozzle is 0.4mm and layer height 0.2mm, just hoping that such fast action does not burn down electronics, I have added Mosfet to bed & nozzle.

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