• Two weeks in - plotting, upgrades and fun

    johnowhitaker • 07/22/2018 at 09:19 • 0 comments

    Two weeks down. 

    It's been good fun getting used to this machine - it is far and away my favourite tool. To illustrate this, a case study:

    I have always wanted a pen plotter, and built quite a few rough attempts. I measured the fan shroud on the ender, did 5 mins of CAD and started a print. Half an hour later I came back from a walk to find a part waiting. It fit, but was a bit wobbly. One small adjustment to the CAD file and another half hour wait, and I popped the part off the bed, clipped it in and smiled. I printed some different pen holders, clipped some paper to my bed and started plotting. Quick iteration, good results and it encouraged me to make something and to dig out my old generative art code. Winning!

    I've printed a few upgrades for the printer itself - a filament guide and new part cooling fan guide were recommended, but I have yet to notice much difference. Maybe when I try more miniatures I'll see it. I also added a tool draw and fan cover for the main board. 

  • Tolerances and ​some larger prints

    johnowhitaker • 07/22/2018 at 09:08 • 0 comments

    I started printing out one part of a larger system I'll be using for my thesis. It consists of an inner plate and an outer ring that can be spun independently by two stepper motors. I printed a few of the parts, then before printing the final large base *I made some test prints to check everything would fit*. If you haven't thought of doing this yet, it can save so much time. In this case, the most important test was what diameter should the center raised rod be to mate with the 15mm hole in the middle of the inner plate. 14.8 was a little too snug but could easily have been sanded down. 14.6mm was perfect, so I stopped testing and printed the main part. Here;s the full assembly:

    To attach the gears to my salvaged steppers, I heated up the gears that were already on the steppers (from an old printer) and pushed the hot metal into a slightly undersized hole. Seems to have worked well. Lesson for next time: bevel the hole to help keep things centered:

    I'll update on this project at a later date.

  • Heeeey ocarina, and recovering a failed print

    johnowhitaker • 07/13/2018 at 09:05 • 0 comments

    I found a neat design for a 12 hole ocarina on thingiverse - https://www.thingiverse.com/thing:2755765

    Printed it, but must have pulled out the SD card before it was done copying - the print stopped 3/4 of the way through and the rest of the gcode file was corrupted. Luckily, after a few false starts, I managed to re-start the print by editing out all the gcode that had already executed, clippin off the melted bit of plastic, adding a line of code to tell the extruder how much it had already pushed out and printing from there. The bond was weak but it held enough to finish the print, after which I could take it off, play it a bit and have some fun and then break it and glue it properly together. The glue is currently setting, and it needs some sanding and cleaning up, but I'm still very amazed at the quality coming off this printer!

  • Vase mode and speed settings

    johnowhitaker • 07/11/2018 at 08:12 • 0 comments

    I couldn't resist trying out vase mode. I used a very slow speed to start with, then kept cranking it up by turning the knob on the machine. It continued to work great up to 500% (40mm/sec * 5 = 200mm/sec) !!! Because the print head is so light, and the printer so rigid, it handles this with almost no perceptible drop in quality. However, around 600% it started having issues keeping up the plastic flow, and the layers stopped sticking so well. The lesson here is that I've been waiting too long for my prints!

  • Glass bed, producing parts

    johnowhitaker • 07/11/2018 at 05:10 • 0 comments

    I went to the hardware store for a R18 piece of mirror for the bed surface, and bought ~50x that in paint, glue, calipers, tape, supplies.... Ahhh the dangers of hardware stores. 

    The bed of my Ender 3 was a little warped, and I had to mess with the way it's attached to get it to slide right along the Y axis. Not terrible, but it made leveling hard and for large prints the level was varied enough that I got my first print failure when trying to make parts in a batch. The glass bed is much nicer. It works without adhesive, but spray adhesive makes it easier. 

    This is my first print on the bed - I got impatient and stopped it before the print was done - the rest was aesthetic and I was impatient to try other things! These parts get a paint job and some sanding, and will be used in an upcoming project. Some more pics of the parts being primed and painted, and of the final assembly with the giant base plate I printed. I'll laser cut future versions of the base, but when all you have is a 3d printer...... :)



    I get a nice interference fit with 0.1mm clearance. 

  • Assembly, first print and calibration

    johnowhitaker • 07/11/2018 at 05:02 • 0 comments

    Assembly was fun - took a couple of us about an hour, and then another 30 minutes of fine tuning on my part to get the frame all square try to level the bed. 

    First print (the test dog that came with the printer) looked great, and my family were suitably impressed:

    Next I tried a gear for a design I've been working on. It came out OK, but 210 was a little hot for my PLA by the looks of it. I printed some little calibration parts I made, and got a bit worried - they seemed off. Turns out they just had a bit of a bulge at the bottom (elephants foot) which was solved by lowering some temperatures. Didn't stop me spending ages trying to re-scale things in cura.

    The settings I've settled on for now, with my 0.4mm nozzle

    Layer Height 0.1 for fine detail, 0.2 for faster prints
    Initial Layer Height 0.15 for a better bed adhesion.
    Line width 0.35
    Wall Thickness 3 lines (1.2 mm)
    Top/Bottom layer thickness 5 layers if important, 2 if fast
    Top Bottom patterns Line
    Infill Density 20% and grid or line pattern
    Retraction 6.5mm at 25mm/sec
    Print speed 40mm/sec 

    Wall speed 20
    Infill Speed 80mm/sec
    initial Layer speed 20 mm/sec depending on the complexity of the model
    Adhesion Type Skirt and Line count 4 (gives time to adjust bed levelling if it looks off.

    I can speed things up quite a bit without loosing too much quality, but since a lot of my prints run overnight (he says, after three days) I tend to leave it on this most of the time.