Unanswered A couple of questions from a Newbie

Changing the default 723.38 to the new calculation in the firmware is best. I think he talks about if using 2.85 mm filament the speed is 30 p/min and 1.75 is 90 p/min. So if you did the test with G1E100F90 and got 90 out of 100 mm extracted, then you take (728.23*100)/90 and your new value for e steps should be 803.76. 90 in that formula is the actual length extruded. Make sure to do an M503 after flashing the firmware to make sure it took. If not, do an M502 and then an M500 to reset the EEPROM with the firmware values. I always do that after a firmware update just as a sanity check to make sure nothing old is sitting in the EEPROM. No need to change anything in the actual slicer for this.

 

Ok - thanks Geof! Man you guys are quick! The method got me in the ballpark, but using the straight math as he did, had me overextruding now by a bit. So I used trial and error until I got a number with consistent results. Think I am now at 788.85 (which I know is arbitrary to anyone else) - and that is consistently extruding between 99 and 99.5 out of 100mm. I think that's about as good as I am going to get it. Headed to MicroCenter for a few things and then back to retest and see how it works.

Also - I changed the value for the E-step in the eeprom via MC. Is that the correct way or do I now need to go in and do something with the firmware in Arduino?

 

Thanks! Didn't see this one before my last post. I turned off the printer and restarted MC to make sure the values took.Also did the M503 after each iteration while I was searching for the perfect value.

 

So to do a more permanent change, you can look at doing the firmware update. I always keep a working copy so that if needing to reflash, i don't use any of my custom changes. Always a good idea to comment your custom changes in the firnware as well for reference. So to do this in the firmware, open the configuration.h tab and search for DEFAULT_AXIS_STEPS_PER_UNIT. Change the 4th parameter and that will take care of you e-step. Doing it the way you did it is a good way to experiment until you get the final value. Changing your firmware is just a way to make sure you don't loose it. Sounds like you have this pretty well buttoned up. Hopefully this helps. If nothing else, it removes one more variable from the equation.

#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,800,723.38} // default steps per unit for RoBo 3D R1

 

Just a quick note, that the off switch doesn't kill power to the arduino if you are still hooked up via USB. I normally turn off and unplug both power cable and usb to make sure everything is reset.

 

Excellent point Danzca - Thanks!

Last thing I want to figure out before I try another test print is the Z-offset. As we've discussed, the manual and MatterControl seem to be different than what is understood with respect to the firmware. As if MC switches the sign value for you to make it more intuitive.

That said,I currently have Z-offset at -.2 and I really want to know if I have it correct. I imagine now that the extrusion issues are fixed, that should be more easy to notice when I try different values. I assume there is a way I can slice the file with MC and then go into the file and see what value the software provided for Z-offset.

Also - I have been using the PLA default of 50 degrees for the bed. Is that sufficient or should I use something higher. The MatterHacker website seems to indicate I should be using 70 but that seems high to me. Thoughts?

 

have you saved the sliced gcode to a file from MC so that you can do a search for the M565 command and confirm?

50 is more than fine for PLA for the bed. I did 70 once and it doesn't seem to allow the PLA from cooling. You can actually use no heat in the bed for PLA, but a bit helps with it sticking to the bed.

 

Not yet but I plan to do that tonight. Once I save the Gcode to a fIle, however, where do I open it to search for the command m565?

 

Thanks Geof!
Well I think I am getting there as far as setup goes. I am not experienced enough to be able to tell yet, but it looks better than it has been looking now that the extruder is calibrated. Are there any other calibrations I should do at this point. Below is the first layer. it was printed at 195/50 with Z offset of 0. I purposely set the z offset to 0 because I am still not sure at this point which value I should be trying to put in there. Here are the pictures. I know it's black but is there any advice or thoughts you guys have after seeing this first layer?

 

Also - do you guys know of a good first layer test print? I have seen a few on thingiverse but they all seem to be fairly small. I was hoping for something similar to this one: http://community.robo3d.com/index.php?threads/a-couple-of-questions-from-a-newbie.8881/page-3

 

Thanks Mark. Any feedback on the prints above as to what might need to be tweaked?

 

Thanks Mark. I actually posted this last night before I had the z offset figured out for this. I might just reprint this first layer again with the offset now and see if it is flatter. Thanks again!

 

Question with resepct to stringy condition. I have slight - and it is slight - stringing on my current print. If I understand correctly, two primary ways to correct this are lower temp and increase retraction. I am printing PLA right now and my temp is at 195 and my retraction is set to 3mm Length on Move.

Which should I try and adjust first? Lower the temp, or increase the retraction? Does it matter?

 

Thanks Geof. I assume I should just start with a couple of degrees? And am I starting to get too low? I ask because the preset in MC for PLA is 210 - which seems very high. I am already down to 195, but have heard of others printing PLA at 185. Thoughts?