The Culprit

After much consternation the last few days, I have finally solved the riddle of my extrusion problems.  The culprit...

The K-Extruder that I am using, is slipping AND chewing, which is causing barely any filament to be extruded.

While I have been raising the temperature higher and higher, the lower viscosity of the PLA was not helping it extrude any more than above.

Again, I found the solution to the problem when the "rocker arm" actually broke.  While I had to fix the arm to print, I used a small clamp to keep the bearing pressed against the filament.  That's when I realized my problem.  The extrusion problem immediately went away and I was printing at 205 C instead of 230 C.  Eureka!

I of course, immediately printed a replacement arm, and here it is, working better than the original...

I have printed an extra, just in case (or when) this one breaks.  So far, it has been strong enough to keep adequate pressure on the filament for the printer to work.   I am not sure how long this will last, but at least I know the source of my issue.

I have been considering another extruder option, and that is a "bowden extruder".  It's a simple and inexpensive change that may give me better extrustion AND better printing quality.  For now, I will see how well I can keep the K-Extruder working.

New Hot End

Well out of frustration with the hot end I was dealing with, I ordered another one... but with a 0.4mm nozzle.  Unfortunately though, they shipped the wrong one.

The vendor was quite splendid in handling the issue though, and a correct one should be in the mailbox when I get home this evening.  I was told that I could keep the all metal h-head to "tinker" with.

Well having the whole weekend, I decided to try an use the all metal version in my printer.  The results are fantastic... but it was quite an ordeal getting it going.

My first mistake was over-handling the hot end and breaking a lead to the thermistor.  The wires are very delicate... and too much flexing and stretching will definitely weaken or break them.  So how do I fix this?

First I tried the thermistor in my old hot end... but it was permanently cemented into the block.  So that was a no go.  Was I finished? No.  Let me look at the broken lead again...

Well it was about half an inch long.

I can't solder a new wire to extend it.  My only choice is to physically tie the wire to the short, incredibly fragile lead.  Needles to say, I managed it... and actually managed to secure the full signal wire to match the other lead.  Test it with the multimeter... 9.9Kohms... great... it still works and the connections are holding.

So I then installed the hot end and fired up the printer.  The temp worked fine... but it would not heat!  Check the voltage.... 12V... good.  Check the connections... good.   It was a bad heater cartridge.  Great!

I thought... wait I can use the old one!  I disassemble the hot end, try to remove the bad cartridge... and bingo... one of the grub screws holding it in is stripped!  I can't win for losing.  Was I finished now?  No.  Let's get the drill out.

And I drilled the damn grub screw into non-existence!  With that, I was able to install the old cartridge and assemble the whole thing again.

This time it worked!

I had an even more fun time learning how to use the new metal hot end, must the printing has improved greatly.  Maybe, I will complain about that later.

Parting shot...

Well No One Said It Would Be Easy

Here I am again, basically having printing issues with my new Heacent 3DP03 Printer. The main issue it seems to be is that I just cannot get consistent, long-term flow though my 0.2mm nozzle.  Either there is heat creep up the heat break that is softening the filament too early... or the inability for the hot end to maintain a stable temperature.

I usually need to run at higher temperatures to get sufficient flow of PLA to print.  But eventually the extrusion "peters out" and pretty soon I am air printing.

The answer of course is to actively cool the heat break.  And this is what I have done... but there are some issues...

• Space
  There is VERY little room to fit a fan and duct
• Directional flow.
  The hot end is so close that it will be hard to cool one, but heat the other

I have designed a small duct/bracket that I hope will work.  The intent is to cool the heat break, but keep the hot end hot.

I will post some pictures when I have it printed and installed.

Overheating Melzi Board

Although it has never happened before, Alfred just froze in mid-print.  This happened twice and it really seemed to be an issue with the CPU board components overheating.  They already run insanely hot in ambient air, but the have never just stopped operating.

As a temporary solution, I rigged up a old CPU fan to constantly blow on the board.  It definitely cooled the component, and the printer did not halt.

I think it may be wise to rig a permanent cooling solution for the motherboard.  Perhaps an enclosed case with with a 40mmx40mm fan.

Melted Bed Screw Terminal Block Connector

I notice that I had a melted terminal block where the bed heating wires are connected to the motherboard.

At first I thought I had possibly shorted the heater, but after some research it seems to be a common problem.  The apparent cause is loose wiring.

So, I have new screw connector and everything I need to fix the board.  The only thing is to be careful not to lift the pads on the PCB.

And Unknown Nozzle Width

I was so frustrated with my 0.2mm nozzle that when it clogged, I decided to try and drill out a larger size orifice.  While the task was easy, the result were a little off.  The extrusion amount was now much more pronounced.

My original problem was solved... as I expected, 0.2mm is too small.  It takes too high a pressure and temperature to be able to extrude effectively.

SO for no, I am experimenting with various nozzle sizes to get the best prints.

I will keep you posted.

More Fun To Be Had

While I continue to print bigger and better things on my Heacent 3DP02, I have learned quite a bit about 3D printing in general.

Temperature Is Important

Take for instance the temperature setting for the extruder hot end.  If it is set 5 degrees too low, the extruder will not put out enough material and you will get gaps and weak bonding between layers.

Just 5 degrees higher and the same model comes out like this...

By the same token, I had alot of trouble printing with the translucent PLA, because apparently it needs a much higher temperature.

Another problem I seem to have is temperature consistency.  The hot end temperature does oscillate by several degrees, so I will probably have to tune the PID values.  Again, because I do not know what "normal" is, I think something is fine... but it really isn't.

New Firmware

If I have to consider tuning my temperature PIDs, I may look again at upgrading the firmware on my printer.  The latest Marlin firmware has auto-tuning commands built right in to the firmware... as well as a bunch of other nice features.

The issue I have is whether I should (or can) upgrade any of the other software.  I have already upgraded to the latest version of Slic3r within the Repetier Host... I'm just not sure I can upgrade the Repetier host app.


Some parting shots of items I have printed...