The RepRapPro Mendel is set up with a Bowden cabled extruder running 1.75 PLA. My other printers use a direct drive MakerGear system and have extruded only 3mm ABS. Because of this my learning curve has been higher than it should be with this printer.
Using the PLA profile in Skeinforge and the supplied PLA filament, I was able to print the test.
It’s not a great print, but the printer moved in the proper directions, properly extruded PLA and didn't spew out blobs or jam up. A much better result than my first printing attempt on my Prusa Mendel reprap build.
The next test, I decided to print a replacement gear for the extruder. This is where it became difficult. I spent a lot of time tweaking and adjusting, trying to get a decent print. The extruder seemed not to be working well. After adjusting the extruder gears and the tension idler, changing the extruder temp and feedrate/ flowrate, and adjusting the stepper voltage driving the extruder , I started to get something working.
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| Cooling the PLA in delicate areas is very difficult without a fan. It's difficult not to end up with a melted blob. |
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| It's obvious that much tweaking in the slicer profile is needed to nicely print this model |
It seems most of my problems centered on one specific variable which I wasn't aware of. My other 2 printers use Sprinter firmware and this is my 1st time using Marlin. Marlin adds a M109 command in the gcode which specifies a set starting temperature. In this case, it's 200 degrees C. Even though the temperature was set higher in Ponterface during the start of the build the temperature would drop to 200 C. This was creating my extruder problems. I wasn't getting enough filament driven because it wasn't melting well enough. This command isn't given by Sprinter firmware, so it took me a long while to notice this initial drop in temperature. It's easily changed by changing the M109 temp setting in the command window or by editing the gcode.
After experiencing the problems inherent with PLA, I decided to switch to what I am more familiar with: ABS. For the first print, I decided to use the same profile that was used for my PLA print tests.
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| Using the PLA profile created many problems, the most obvious one is stringing. |
There’s a generic ABS profile included with Skeinforge, but it doesn't work. I added relevant changes that the PLA profile utilizes and did some minor tweaking using portions from my own ABS profiles that I use with my Prusa Mendel.
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Overall, I've made a good average ABS profile. Of all 3 of my printers, I think this printer is creating some of the best prints.
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Cool. Can you share your ABS profiles? I've been doing some really nice prints with PLA, but then I decided to switch to ABS and it is horrible now. First layer appears to be a lot thicker, than it should be, cause when it goes to second layer start point extruder scrapes away everything in its way. It's if I am using slic3r. SF gives me horrible results either - first layer is almost transparent, and a lot of strange blobs, like it extrudes in portions ):
ReplyDeleteGlad your PLA prints are working out. When I have time I plan to dial mine in better. I added a new blog entry covering my ABS profile. Hope it gets you better prints.
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