Tuning guide?

Hi guys,

Is there a guide anywhere on improving print quality?

I'm fairly confident that my bed is level, layer height and extrusion rate seem 'good', but seeing this 'crusting' on this calibration print (http://www.thingiverse.com/thing:8757) and when printing the cylindrical parts on the mendel90 spool holder brackets.

What would be causing this? insufficient retraction?

Thanks!
- Paul

On the legs?

They're probably wobbling since they're not supported, add support or slow your print speed... the M220 command is good for this so you're not waiting an age for the base to finish...

Yeah, the legs - thanks for the suggestions, I'll give them a go.

Can commands be sent while printing from the SD card? or is it a case of manually adding them to the gcode file?

add them via pronterface while printing although I advise ramping up the speed in 10% increments, sometimes go from 50% to 100% and it doesn't like it :p

You can also use this to test how fast you can print on the fly....

I am trying M220 for the first time. It's awesome! I had my machine ripping around at 102mm/sec. which is the fastest I've ever ran it. I don't know how fast I should try going? What can break?

The machine ran so smooth even at corners (I assume this is due too the 'look ahead' ability of Marlin). Layer alignment appears unaffected. I am impressed with the Mendel90!

I could have done with turning speed back down for the last layer. At this speed the surface is not shiny. It's duller.

Funnily, the octagonal infill and holes did not print any faster as I kept ramping up speeds. Hmmm? Perimeters and solid infill did speed up. Is this the way M220 is supposed to work?

I sliced with KISSlicer if that matters ...

OK, now to try it again!

The speed of octagonal infill is probably limited by the acceleration when you have the speed set high. I.e. it will only reach full speed on straight lines that are long enough. I.e. longer than v^2/a.

In terms of breaking anything I don't think there is a problem with the axes, the max speed is limited in the firmware and they will just start skipping steps if going too fast.

There is a maximum speed that the hot end can melt plastic at. When you exceed that it will put a lot of strain on the extruder parts. Particularly if you are using PLA, as the hobbed bolt has very strong grip. The firmware doesn't limit the speed because it needs to go fast during retract and restart.

Edited 2 time(s). Last edit at 06/24/2014 02:16PM by nophead.

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