I just changed from 0.4 to 0.5 nozzle and layer height from 0.24 to 0.4mm for a larger printed part where quality is not an issue.

Using Arduino 2560 and Ramps board.

eSteps is 450, and filament is 1.75mm

My extruder is a Charlstruder with a gear ratio of about 1:3 ( can't count it now as the printer is running )

Trying to run at 80mm/s print speed and the extruder stepper is clicking. If I slow down to 60mm/s then the noise stops and prints are great.

I know the max speed of a printer using the Arduino is supposed to be 200mm/s, but I suspect that this is being limited to even slower because of the extruder gearing.

How can I calculate if the Arduino is able to process the instructions for the extruder stepper ?

Would the effect change if I changed the microstepping for the extruder from 16 to 8 ? ( I assume then that the eSteps would change from 450 to 225 )

You need to first understand the process as a whole before assuming that the problem is in the software or the steps or even in the gear ratio of the extruder.

Non of those things you mentioned are slowing your printer down, it's all in the hotend. Your hotend cannot keep up with the amount of filament your extruder is pushing in.

The faster you print the higher the temperature and melt zone of your hotend needs to be to keep up with extrusion, take a look at the e3d volcano as reference of what i'm saying.

You need to fine tune your extruder, stepper drivers and firmware to get the best quality prints at high speeds, but first you need to get your hotend ready for those speeds.

Thanks. That is what I have just learnt from a different discussion.

So here's my calculation, assuming that the vRef for the stepper driver is correct, as are the mechanics if the gears, etc.

Using a standard e3dv6 all metal hotend, I believe the max output is around 15mm^3/second.

So :
0.4 nozzle = 0.1257mm^2 x 0.32 layer height = 0.0402 mm^3. Max 15mm^3 / 0.0402 = ~370mm/s print speed

0.5 nozzle = 0.1964mm^2 x 0.40 layer height = 0.0786 mm^3. Max 15mm^3 / 0.0786 = ~190mm/s print speed

with the volcano hotend :
0.6 nozzle = 0.2527mm^2 x 0.48 layer height = 0.1357 mm^3. Max 40mm^3 / 0.1357 = ~290mm/s print speed

This does not make sense to me as I was experiencing problems with the e3dv6 0.5 nozzle at 80mm/s, but all printing good at 60mm/s

Unless there was a problem with the heating unit of the hot end, I should not have been having problems at 80mm/s

Yes the problem is in the "heating unit" but not what you think, yes the thermistor might no giving you the right temperature, yes the heating resistor might be underpowered, but most important are three things: heat dissipation, heat transfer and melt zone.

Lets say you are printing with PLA, heat up your hotend to 190 degrees and then extrude 10mm of filament, wait a minute and then retract all the filament as fast as possible. Cut the filament just above the swollen section and measure it, now do the same with 195, 200 and 210 degrees and observe the differences, one last test do all again but this time leave it for about 3 to 5 minutes.

What it is stopping you from printing fast is the amount of filament that is already in a glass transition stage (swollen section) the bigger that section is the faster you can print (e3d volcano have a large heater block to allow for a large melting zone) if you have a small block more heat will dissipate, less heat will be transferred to both nozzle and pipe and the melt zone will be of small size.

Now, without having to change your hotend configuration you can improve it to allow faster printing, first insulate the heater block with either silicone tape, fiberglass cloth, ceramic cloth or any other insulation material suitable for the application, then PID your thermistor so it can stay within range and if you have a probe measure the nozzle temperature and adjust the thermistor table in the firmware so the temperature readings match the nozzle temperature, and last test the temperature related to speed so using an starting point of 190 degrees increase your printing speed until you find the limit for that temperature, then increase it 5 degrees each time until you find a temperature that with allow you to print at 80mm/sec once you find it adjust your jerk and acceleration setting to get the best results at those speeds.

Quote
ggherbaz
Yes the problem is in the "heating unit" ..............

Thank You very much for your feedback and ideas / suggestions.

I am going to follow your advice carefully and trust my print speed will increase.

Regards