A Couple Questions from a 3D Printing Noob  

Re: A Couple Questions from a 3D Printing Noob

I do have a couple questions.
1) When a print finishes, there is always approx 1cm of filament dangling from the nozzle. Is this normal? Should I remove it before starting another print? Use my fingers (after the nozzle has cooled, of course) or a tool?
2) Right before the print starts, the 9-point leveling step happens, and it will often leave a small glob of filament behind, leaving a bump at (some of the) 9 points on my bed before the print starts. Is this normal?
3) I get the occasional really fine string of filament trailing behind the extruder, usually on the 1st layer. These are very small and fine and break off without (seemingly) affecting anything. Just wondering if that's just something that happens, or should I be concerned?

Welcome!

To answer your questions:

1) Yes, when your nozzle reaches temp the filament is soft / melted. This is completely normal and I normally remove the excess filament carefully with a pair of tweezers before the mesh bed leveling starts

2) Normal, see above. If there are any globs left over I quickly wipe them off the bed with a paper towel before the print starts.

3) No need to be concerned. There's always going to be wisps and you can carefully remove them as you're printing your first layer. I usually press the end of the wisp on the bed with a paper towel and pull it away from the print. Once again, be careful.

You should always supervise your print for the first layer.

Re: A Couple Questions from a 3D Printing Noob

1) Yes its normal. Use a tool to remove it hot. The Needle Nose Pliers will work. If you let it cool it will, of course, harden and be difficult to remove.

2) That's normal too. Just use a scraper to knock it off after calibration but before the print starts.

3) That's normal also.

It may be extruding more than needed. That is where your Extruder Multiplier comes in. If you want to check it is easy to do. From the top of the extruder (where the filament goes in) measure 100mm up on the filament and make a mark. Sharpie works good. Then above that mark another 100mm make another mark.

Tether the machine to your computer and favorite slicer or Pronterface. Preheat nozzle to the temp for the filament. Extrude 100mm of filament. For the longest time that confused me. Actually you will tell the printer to pull in 100mm of filament. Not actually put out 100mm.

Measure your marks new position from the top of the extruder. If the first is right on where you began your measurements, first mark moved 100mm to the extruder, then your Extruder Multiplier is 1.00. Let's say your first mark came up 10mm short of the extruder. Then you just do a bit of math. In this case 100mm (the length you wanted to extrude) divided by what you actually did extrude (100 -10 = 90). Then its 100/ 90 = 1.11 should be your new extruder multiplier. You will tell the machine by doing this to extrude MORE and by what percentage.

If only the second mark is showing again measure from the extruder to the mark. Let us say it is 80mm. So now you have to add 100mm to the extra you extruded. With 80mm left that means you extruded 20mm extra. Do the same math 100/ 120= 0.83.

So:

100mm/ X = EM

100mm- what you told it to extrude.
Divided By
X- what the machine actually extruded.
Equals
Extrusion Multiplier.

Once you get that down there is still speed and retraction settings to tweak it further. Bu those will be pretty much dependent on your particular circumstances. Type of filament, make of filament, your specific machine and the like.

Long winded and pedantic I know,

Neal

Re: A Couple Questions from a 3D Printing Noob

Thanks both of you.

I'll try out the extruder calibration when I have a bit more time on the weekend!