Posts Tagged M2

3D Printing Demo at the HV Boy Scout CamporALL: Image Processing

More than five hours of stand-up comedy condensed into two minutes of frenzied video showing activity like this:

3D Printing Demo - HV Scout CamporALL 2014

3D Printing Demo – HV Scout CamporALL 2014

The Sony HDR-AS30V perched atop a tripod behind the table, where only one errant Scout bumped it, recording one image every 5 seconds. The non-adjustable focus seems biased for selfies, but the compression definitely produces softer images in subdued lighting conditions, so it’s hard to say.

Each NP-BX1 battery lasts about 2.5 hr in that mode and I brought all three, but simply forgot to install the third one. As a result, we don’t get to see the last 2+ hours… it was a long day.

The “image processing” behind the movie went a little something like this, modulo a few edits to elide my blundering around:

sudo mount /dev/sdb1 /mnt/backup
sudo mount -o uid=ed /dev/sdd1 /mnt/part
mkdir /mnt/backup/Video/2014-05-17
rsync -au /mnt/part/DCIM/100MSDCF/ /mnt/backup/Video/2014-05-17
rsync -au /mnt/part/DCIM/101MSDCF/ /mnt/backup/Video/2014-05-17
cd /tmp
mkdir Video
cd Video
sn=1 ; for f in /mnt/backup/Video/2014-05-17/*JPG ; do printf -v dn 'dsc%05d.jpg' "$(( sn++ ))" ; cp -a $f $dn ; done
mkdir Shrink
for f in *jpg ; do convert $f -resize 50% Shrink/$f ; done
cd Shrink/
avconv -r 30 -i dsc%05d.jpg -q 5 3DPrinting-q5.mp4
mv 3DPrinting-q5.mp4 "3D Printing Demo - HV Scout CamporALL 2104.mp4"

One could, of course, do all that in fewer steps, if one knew the answers ahead of time, which should may apply when I refer back to this post.

Using rsync -au to copy the files from the camera to the 2 TB backup drive neatly solves the problems that occur when the camera’s USB port abruptly disconnects itself during the copy: rsync can recover without losing or trashing any files. Alas, after the camera disconnects, it requires a power cycle to recover its wits.

The USB camera connection reads data at 6 MB/s. Removing the MicroSD card and jamming it in the card-reader slot on my monitor runs at 18 MB/s. Apart from the fact that the MicroSD card seems so flimsy, I wonder how long the spring-detent latch inside the camera will continue working. On the other paw, when the USB port finally breaks, it’ll take the GPS assist data path along with it.

Not shown: the rename 'y/A-Z/a-z/' *JPG that converts the original filenames to lowercase, which I did after the fact. Because blundering around, OK?

The 3964 original 1920×1080 images, hot from the camera, weigh in at 2.2 GB and the half-size video emerged at 118 MB. The default avconv quality setting produces surprisingly crappy results, so I used -q 5. Some after-the-fact fiddling showed that -qscale 5 produces the same file size with about the same apparent quality.

None of that matters, because Youtube set the maximum resolution to 480 and applied ruthless compression. Now I know better…

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3D Printed Things I’ve Designed: Brag Sheets

The whole reason I got a 3D printer in the first place was to make things that would otherwise be too difficult or tedious by hand or on a CNC mill. Most of the things I make look like brackets and I don’t do sculptures … this stuff solves problems!

Being able to go from “I need a part shaped like that” to holding the thing in my hand a few hours (or, for complex designs, days) later is empowering. Being able to adjust a dimension by changing the source code and “recompiling” to get a new part is wonderful.

These five slides from the presentation show my answers to the question “Why would anyone want a 3D printer?” Clicky for more dots.

Things I Designed - 1

Things I Designed – 1

Things I Designed - 2

Things I Designed – 2

Things I Designed - 3

Things I Designed – 3

Things I Designed - 4

Things I Designed – 4

Things I Designed - 5

Things I Designed – 5

You can find those and more by searching for OpenSCAD source code.

They go along with the sheets of solid models.

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Personal 3D Printing: 2014 Status Report

Herewith, the MHVLUG – 3D Printing Status 2104 slides (remember slides?) I’ll be using for my talk this evening at the MHVLUG meeting; you don’t get the audio track in the PDF, but the pictures may be informative.

If you believe everything you read, you might think personal 3D printing will go like this:

3D Printing 2014 - What They Say

3D Printing 2014 – What They Say

But it requires entirely too much of this:

3D Printing 2014 - What They Dont Say

3D Printing 2014 – What They Dont Say

Personal 3D printing requires that you take full control:

3D Printing 2014 - Personal 3D Printing

3D Printing 2014 – Personal 3D Printing

Not knowing the answers, I’ll still make some guesses about what lies ahead:

3D Printing 2014 - The Future

3D Printing 2014 – The Future

And I found the best tchotchkes ever:

3D Printing 2014 - Tchotchkes

3D Printing 2014 – Tchotchkes

See you there…

(The PDF has clickable links for those images, plus the 60-some-odd other slides. The plan: talk like an auctioneer for an hour!)



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A Pleasant Morning, With Chocolate

With a bit more attention to detail, I now have about 125 Tux chocolate tchotchkes for my LUG presentation tomorrow evening:

Tux in PLA - Dark - Milk Chocolate

Tux in PLA – Dark – Milk Chocolate

Seeing as how the Tux chocolates were produced in a facility containing a big nut, some folks may prefer an (inedible, at least by humans, but correspondingly more permanent) Tux tchotchke in PLA. I plan to have the M2 running off more of them, so there should be enough to go around.

For what it’s worth, you can actually buy a 3D chocolate printer that seems rather overpriced for what’s basically a desktop CNC gantry mill with a heated syringe. The site seems dead, so maybe other folks came to that conclusion, too.


Slicing Anomaly: Resolved, With Cross-Check

Some pix that serve as a stick in the ground showing that my current Slic3r configuration constellation doesn’t produce thin infill

All of the layers in the 20 mm calibration cube look just like this:

Solid cube - Slic3r normal infill

Solid cube – Slic3r normal infill

The bottom layer of the Tux mold comes out solid:

Tux thread fill - bottom

Tux thread fill – bottom

As does the top:

Tux thread fill - top

Tux thread fill – top

The Gcode Analyzer algorithm that assigns colors to numeric values tends to produce many aliases, although most of the time you can figure out what’s going on. If somebody wants to dive into the code, I’d like to have unique colors and get the color table sorted in ascending order.

The current Slic3r configuration:

# generated by Slic3r 1.1.1 on Sat May  3 10:31:36 2014
avoid_crossing_perimeters = 0
bed_size = 190,250
bed_temperature = 70
bottom_solid_layers = 3
bridge_acceleration = 0
bridge_fan_speed = 100
bridge_flow_ratio = 1
bridge_speed = 150
brim_width = 0
complete_objects = 0
cooling = 1
default_acceleration = 0
disable_fan_first_layers = 1
duplicate_distance = 6
end_gcode = ;-- Slic3r End G-Code for M2 starts --\n;  Ed Nisley KE4NZU - 15 November 2013\nM104 S0		; drop extruder temperature\nM140 S0		; drop bed temperature\nM106 S0		; bed fan off\nG1 Z180 F2000	; lower bed\nG1 X130 Y125 F30000	; nozzle to right, bed front\nM84     	; disable motors\n;-- Slic3r End G-Code ends --
external_perimeter_speed = 25
external_perimeters_first = 0
extra_perimeters = 1
extruder_clearance_height = 25
extruder_clearance_radius = 15
extruder_offset = 0x0
extrusion_axis = E
extrusion_multiplier = 1.07
extrusion_width = 0.4
fan_always_on = 0
fan_below_layer_time = 30
filament_diameter = 1.79
fill_angle = 45
fill_density = 100%
fill_pattern = rectilinear
first_layer_acceleration = 0
first_layer_bed_temperature = 70
first_layer_extrusion_width = 0.4
first_layer_height = 100%
first_layer_speed = 25
first_layer_temperature = 175
g0 = 0
gap_fill_speed = 50
gcode_arcs = 0
gcode_comments = 0
gcode_flavor = reprap
infill_acceleration = 0
infill_every_layers = 3
infill_extruder = 1
infill_extrusion_width = 0
infill_first = 1
infill_only_where_needed = 0
infill_speed = 150
interface_shells = 0
layer_gcode = 
layer_height = 0.2
max_fan_speed = 100
min_fan_speed = 75
min_print_speed = 4
min_skirt_length = 15
notes = 
nozzle_diameter = 0.35
only_retract_when_crossing_perimeters = 1
ooze_prevention = 0
output_filename_format = [input_filename_base].gcode
overhangs = 1
perimeter_acceleration = 0
perimeter_extruder = 1
perimeter_extrusion_width = 0.4
perimeter_speed = 150
perimeters = 2
post_process = 
print_center = 0,0
raft_layers = 0
randomize_start = 1
resolution = 0.05
retract_before_travel = 1
retract_layer_change = 0
retract_length = 1
retract_length_toolchange = 5
retract_lift = 0
retract_restart_extra = 0
retract_restart_extra_toolchange = 0
retract_speed = 60
skirt_distance = 3
skirt_height = 1
skirts = 3
slowdown_below_layer_time = 20
small_perimeter_speed = 25
solid_fill_pattern = rectilinear
solid_infill_below_area = 5
solid_infill_every_layers = 0
solid_infill_extrusion_width = 0
solid_infill_speed = 150
spiral_vase = 0
standby_temperature_delta = -5
start_gcode = ;-- Slic3r Start G-Code for M2 starts --\n;  Ed Nisley KE4NZU - 15 Nov 2013\n;  28 Feb 2014 - 6 Mar 2014 - tweak Z offset\n; Z-min switch at platform, must move nozzle to X=130 to clear\nM140 S[first_layer_bed_temperature]	; start bed heating\nG90				; absolute coordinates\nG21				; millimeters\nM83				; relative extrusion distance\nG92 Z0			; set Z to zero, wherever it might be now\nG1 Z10 F1000	; move platform downward to clear nozzle; may crash at bottom\nG28 Y0			; home Y to be sure of clearing probe point\nG92 Y-127 		; set origin so 0 = center of plate\nG28 X0			; home X\nG92 X-95		; set origin so 0 = center of plate\nG1 X130 Y0 F30000	; move off platform to right side, center Y\nG28 Z0			; home Z with switch near center of platform\nG92 Z-4.40		; set origin to measured z offset\nG0 Z2.0			; get air under switch\nG0 Y-127 F10000	; set up for priming, zig around corner\nG0 X0			;  center X\nM109 S[first_layer_temperature]	; set extruder temperature and wait\nM190 S[first_layer_bed_temperature]	; wait for bed to finish heating\nG1 Z0.0 F500	; put extruder near plate \nG1 E25 F300		; prime to get pressure, generate blob\nG1 Z5 F2000		; rise above blob\nG1 X15 Y-125 F20000	; jerk away from blob, move over surface\nG1 Z0.0 F1000	; dab nozzle to attach outer snot to platform\nG4 P1			; pause to attach\nG1 X35 F500		; slowly smear snot to clear nozzle\nG1 Z1.0 F2000	; clear bed for travel\n;-- Slic3r Start G-Code ends --
start_perimeters_at_concave_points = 1
start_perimeters_at_non_overhang = 1
support_material = 0
support_material_angle = 0
support_material_enforce_layers = 0
support_material_extruder = 1
support_material_extrusion_width = 0
support_material_interface_extruder = 1
support_material_interface_layers = 0
support_material_interface_spacing = 0
support_material_pattern = honeycomb
support_material_spacing = 2.5
support_material_speed = 150
support_material_threshold = 0
temperature = 175
thin_walls = 1
threads = 2
toolchange_gcode = 
top_infill_extrusion_width = 0.4
top_solid_infill_speed = 25
top_solid_layers = 3
travel_speed = 250
use_firmware_retraction = 0
use_relative_e_distances = 0
vibration_limit = 0
wipe = 0
z_offset = 0


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Marco/DIY3D mentioned the LeFabShop Elephant on the Makergear Google Group (defunct, now that MG started their own forum) and I had to print one for an upcoming presentation:

Elephant - on platform

Elephant – on platform

The leg shafts broke free after a bit of struggle and it now prowls my desk in search of handouts:

Elephant - standing

Elephant – standing

I like the semi-transparent crystalline effect of natural PLA, even if it’s not appropriate for an elephant…

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Slicing Anomaly: Thin Fill

Having discovering that the chocolate mold positives suffered from sparse top infill, to the extent that silicone rubber would flow right though the surface…

Tux Gradient - PLA positive detail

Tux Gradient – PLA positive detail

… I ran off a few variations of the classic 20 mm calibration “cube” (which is 10 mm tall):

Solid cube - thin top infill - on platform

Solid cube – thin top infill – on platform

Not only were the infilled surfaces porous, I could see right through the block! That’s impossible to photograph, but here’s a laser beam shining through the entire 10 mm stack, showing how precisely the M2 aligns 50 under-filled thread layers:

Solid cube - laser transmission

Solid cube – laser transmission

The yellow spot in the middle marks the overexposed laser beam. There’s a distinct beam passing through the block that, with the proper orientation, can create a spot on the cutting mat atop my desk.

In fact, I can blow air through the blocks; one could use them as (rather coarse) air filters.

Normally, underfill happens when a mechanical problem prevents the printer from feeding enough filament to keep up with demand, but that’s not the case here: the perimeter threads came out exactly 0.4 mm wide for the entire height of the cube, as you can see if you click the picture for more dots. The top and bottom infill, plus all the interior threads, seem to be about half the nominal width and don’t touch their neighbors on the same XY plane at all.

Alex Ustyantsev’s incomparable G-Code Analyzer shows that Slic3r baked the problem right into the G-Code, so the M2 is cranking out exactly the right amount of filament:

Solid cube - Slic3r thin infill

Solid cube – Slic3r thin infill

The colors show the length of extruder filament per millimeter of XY motion, not the usual XY speed, with the two perimeter threads at 0.033 mm/mm and the interior at 0.18 mm/mm. In round numbers, the G-Code starves the infill by a factor of 1.8, which is close enough to the factor of two I’d guessed going into this mess.

Being that type of guy, I set the exact extrusion thickness and width (0.20 x 0.40 mm), rather than let Slic3r pick them. The extruded thread has a fixed cross-section of (roughly) 0.080 mm2 and a millimeter of XY motion thus requires 0.080 mm3 of filament.

The PLA filament measures 1.79 mm diameter, for a cross-section of 2.5 mm2. Getting 0.080 mm3 from the incoming filament requires feeding 0.032 mm into the extruder, which is almost exactly what you see for the perimeter threads.

After restoring Slic3r’s default configuration, the problem Went Away, which suggests that I backed the algorithms into a corner with some perverse combination of settings. Rebuilding my usual configuration from the defaults also worked fine, so it’s obviously not Slic3r’s problem.

Which one is not like the other ones?

Solid cube tests

Solid cube tests

You can see the thin infill on three of those cubes, with the solid one in the lower right showing how it should look.

The solid cube weighs 4.4 g and the thin-fill variations weigh 2.7 to 2.9 g. Assuming PLA density = 1.25 g/cm3 and “cube” volume = 4 cm3, a completely solid cube should weigh 5.0 g. I think 4.4 g is close enough; the top surface came out flat with nice adjacent-thread fusion. Working backwards, the average fill = 88%; the perimeter is fused-glass solid, so the actual infill will be a bit under that.

I generally run Slic3r from my desktop box, with ~/.Slic3r symlinked to the actual config directory and its files on the NFS server downstairs. Perhaps running different versions of Slic3r on two or three different boxes, all using the same config files, wrecked something that didn’t show up in the UI and produced bad slices. I probably ran two different versions of Slic3r at the same time against the same files, although I wasn’t simultaneously typing at both keyboards.

Moral of the story: check the G-Code before assuming a hardware failure!