Ultimaker 2 mm/s discussion

[morgan_ebc 0]

does anyone know how to convert the mm/s speeds to the percentages on the read out on the machine?

the ultimaker 2 software shows that you are able to go from 0.02mm/s to 300mm/s speed. but when you go to the actual machine it shows it from 0-1000% not in mm/s.

i was wondering if anyone knew how to convert it to percentage. i've looked around the internet and also here but couldn't find anything

 

[IRobertI 520]

The percentage setting on the machine is a percentage of the setting in cura. So say you set a print speed of 50mm/s in cura and 50% on the machine, then the actual print speed will become 25mm/s.

 

[morgan_ebc 0]

So hypothetically if I set setting to 300mm/s in Cuba and bump it to 300% that means it's running at 150mm/s in actuality. Is there any reason to set the machin past 100%.? Also is there any reason to run any print at 1000%?

[IRobertI 520]

It's cura, not "Cuba" Sorry, it's Friday and late, and I'm tired, that made me giggle

No, if you bump it to 300% with a setting of 300mm/s in cura, the printer would try (and fail) to print at 900mm/s. You can't really print at any of those speeds though.

Normally there wouldn't be any reason to change this setting. It can be used if you notice that what you're printing is having trouble at the speed you selected. You can then simply lower the speed a bit and let it continue instead of aborting a starting a new print. Or if you're in a hurry for a print to finish you could bump the speed up a bit.

 

[morgan_ebc 0]

Haha. I'm typing on my phone and it auto corrected to that. But I understand. Haha. Thanks for your help. Mind if I have further questions about the machine run speeds, or anything else like material flow speeds or what not.?

[IRobertI 520]

Ah, that explains it

Not at all. Answering and asking questions is what this place is for.

 

[gr5 2,173]

The "feedrate %" affects all 4 axes equally X,Y,Z,E but realize that each axis also has a max velocity. So if Cura requests a move at 300mm/sec and you choose 200% feedrate then it will print at the XY max speed which I believe is still 300mm/sec. The problem with going faster is the Uno chip can't go much faster than that. I'm quite sure the hardware can go faster.

I usually print at 100% because after 2 years I am more patient and just let it print at 35mm/sec. Plus I have 2 printers. But there was a time when I *always* printed at 100mm/sec and that way I could mess with feedrate and the % equaled the mm/sec. Nice trick, eh?

 

[gr5 2,173]

Also note that messing with feedrate will override the "minimal layer time". Say your minimal layer time is 10 seconds and you are on a small layer or printing a very small part that normally only takes 5 seconds. Cura will tell the printer to print at half the normal speed to spread that 5 seconds out to 10 seconds so that the layer has time to cool before the next layer.

But if you set feedrate to 200% then it will only print that layer in 5 seconds and you have defeated the feature.

 

[ultiarjan 1,223]

Hmm just checking. Will it always override minimal layer time? So also when printing at 105% the 10 will become 5 (+ 5%) ???

[pm_dude 27]

From what I understand Cura just create a gcode that will give that result. If the speed is changed it still just read the gcode but at a different speed.

[gr5 2,173]

Right. Cura puts a feedrate into the gcode file that satisfies the "minimum layer time" condition.

Then when you tell the printer to print at a faster speed, Marlin doesn't know anything about minimum layer time. It just knows the requested speed in gcode and multiplies by the feed rate %.