Monday, Mar 19 2018
New parts
The part cooling fang I added back in January seemed to do the job well, but the support that held it to the heat block above the hot end broke. Instead of printing the same fang over again I found a different design in two parts. One part is a heat-block fan housing that I printed in white PETG. The second part is the part cooling fang that attaches to the housing. I printed that in Orange PLA. The picture shows where I tapped holes for the 8-32 screws I used to attach the fang to the housing. Fang info: https://www.thingiverse.com/thing:2759439
Print test
Test piece on raft
I printed this test piece to test out the fang. It is designed to be hard to print and I found plenty of print failures in the small details. I don’t think any of the defects are related to part cooling. First and foremost is it appears my printer is not extruding filament with a consistant flow.
Tuesday, Mar 20 2018
Extrusion issues
bottom
top
This is a 50 mm x 50 mm x 0.60 mm test piece printed with a 0.20 mm layer height. The printed part is prety close (± .03mm) to the specified dimensions. The bottom layer shows an area where extrusion almost stopped. The top layer makes me think there is a pattern to the areas of under extrusion. Not sure.
This material is Hatchbox PLA printed at 215 °C 1st layer, 201 °C for 2nd and 3rd layer. Print speed is 40 mm/s with the first layer printed 50% under speed. The extruder is calibrated, e.g. ask for 100mm and I get exactly 100mm – however that was tested with the bowden tube disconnected so there is no back pressure from the hot end. I’m using a Capricorn bowden tube into the stock front end. The nozzle has been removed and cleaned. The hot end/heat block doesn’t seem to have any blockage. The filament comes out of the nozzle mostly straight.
Wednesday, Mar 21 2018
Not so clean
I explained my issue on the cr-10 subreddit and got a suggestion on a way to make sure the heat break and hot end were clean. I set the hot end to 230 °C and both removed the nozzle and the bowden tube. Then I dropped the heat to 180 °C and with the nozzle removed shoved the bowden tube through the heat break and the heater block. The pictures shows the junk that the bowden tube pushed out. I brought the hot end temperature back to 235 °C and installed a clean nozzle.
Top Layer of test print
A test print wasn’t perfect with some issues on the bottom layer. The top layer, howerver, was about as good as I could want. I’ll play a little more.
Note To Self: When using a shaved toothpick to clean the gunk out of a nozzle do not break the toothpick off inside. It is a pain to remove.