Friday, 23 September 2016 PLA Filament Brands comparison

3D Hubs Marvin in 4 brands of PLA from
     When I was restocking on filament a couple weeks ago, I noticed that had several other brands of PLA listed, some of which had very different colour ranges from the MG Chemicals PLA that I normally use, so I decided to get a spool of each to do a comparison with. The brands are (in order of Marvins): MG Chemicals BlueHATCHBOX PurpleAMZ3D Transparent Red, and 3D Solutech Apple Green. Benchmark prints are all done using the exact same files, 3D printer, and temperature settings so any variance is the result of the filament, not the print settings. Test prints are 3D Hubs' Marvin#3DBenchy, and a customized temperature calibration tower from Thingiverse. Both Marvin and 3D Benchy are printed at 220C on a 50C glass build plate with a light coating of glue stick.

MG Chemicals Label

765 grams of MG Chemicals PLA
     First up is the MG Chemicals PLA that I'm using as a reference point. Filament label is a bit basic, mostly just batch numbers and a brief description of the spool contents. Weight wise, the spool itself is about 190 grams of plastic, so the total weight is roughly 1,190 grams of material out of the box. Printing temperature range is 180C-220C, although it will print at up to 230C with some loss of detail.

HATCHBOX PLA spool being weighed out of the box
    Next up is the Hatchbox PLA, it comes a plain brown box, nothing special to look at on the outside. On opening it, I was surprised at the level of information included on the label, optimum temperature range, links to the brands social media pages, and the poorly advertized fact that the spool is a Pantone Colour (Purple C). That makes choosing a colour much less of a guessing game than some brands. Spool weight is on the heavier side with 311 grams of deadweight being used just to hold the filament.

AMZ3D filament label
AMZ3D spool being weighed
    For contrast, the AMZ3D is probably the most generic brand of the lot, colour is more of a fiery red/orange than pure red, and it's quite brittle to the touch, making handling a bit tricky. Spool weight is 228 grams with a temperature range of 180C-210C although it seems to work just fine up to 225C.

3D Solutech label
3D Solutech spool being weighed
3D printed Filament Clip

    And lastly is the surprise spool in the group, the 3D Solutech Apple Green PLA. The overall presentation of this filament is the nicest of the bunch, with both a decorated box and brand label on the spool. The real surprise though is the 3D printed filament clip that is used to lock the filament on the spool during packaging, not something you usually see. Spool weight is 180 grams, with a temperature range of 190C-220C, although it prints at 225C without complaints, the 190 is a hard floor, attempting to go below that just resulted in 'air printing' or zero material flow. Amazon's supply of this brand is a bit unstable, the selection of colours seems to vary from time to time.

3DBenchy in MG Chemicals Blue PLA at 220C
3DBenchy in HATCHBOX purple PLA at 220C
3DBenchy in AMZ3D Transparent Red PLA at 220C
3DBenchy in 3D Solutech Apple Green PLA at 220C
    As you can see, all 4 filaments print fairly similarly, with only minor variations due to slightly different temperature tolerances. The 3D Solutech PLA suffered a slight extrusion glitch around layer 6 due to the slight temperature drop caused by the below nozzle cooling fans coming online. As for the temperature towers, here's a 2 minute video showing them in sequence.

    Overall, I'd recommend the both the Hatchbox and MG Chemicals brands as best quality vs cost, and the 3D solutech as a good alternate if you don't mind a slightly random colour selection. I can't recommend the AMZ3D filament at all, since while I was writing this post, it snapped inside the filament tube on the Micro Kossel below the extruder motors' gearing!

Friday, 16 September 2016

Micro Kossel effector upgrade part 4

After about 2 months of heavy usage, the version 4 effector suffered the same bending damage that affected version 3, so I've redone the platform and moved the ducting to a screw-on skirt instead of inside the effector.

Version 5 assembled 
     Another issue that cropped up with version 4 was part of the upper fan mounts had a tendency to catch against the rod arms when printing near the outer edges of the printbed, so I've moved them upward by a couple of centimeters for version 5.

Version 5 being used to print 'Marvin'
    I've printed a few things with the version 5 effector so far, and it's much better than the old version 4. The STL's are available on Thingiverse (thing:1726397), and you'll need a couple of M3x10mm screws to attach the skirt after printing.

Friday, 9 September 2016

Fine Tuning the Mostly Printed CNC

After the last meetup at RPL, I decided to try and reduce the backlash issue that I'd been getting, about 3-4mm on the central junction. I eventually traced it to a combination of a fault in my Mini Kossel's calibration data and an offset in the STLs that made things a bit loose on one end of the brackets. My solution was to print some PLA tires for the 608 bearings and make up the gap that was causing the backlash.

608ZZ bearing and PLA tire/washer
     After installing the tires, the observable backlash is reduced to less than 1 mm, hopefully fixing the problem.
Bearings with tires installed on centre block
     The STL for the tire is here, it takes about 1 gram of filament, and 5 minutes to print one at 0.2mm layer height with a 0.4mm nozzle. As for installing them, you need to apply even pressure across the entire rim or the part will snap, so I'd recommend printing a few extras. Overall, probably one of the simplest fixes to a problem I've made so far.