How to win at 3D printing

The rest of the world moved on to steel, but the lion kingdom recently had good results with old fashioned glass.  The trick with glass is to wash 1 side with dishwashing soap & dry it with paper towels so no oil or wax is present. 

This one has a marker to indicate which side has been cleaned.

Clip it in the middle & it stays more level than the machine bed.   It has been level enough to not need auto leveling.  Heat it to 60C for PLA.  TPU doesn't require heating.

It adheres PLA better than TPU.  PLA parts can only be removed by dunking in cold water.  It's not known if cold water can shatter the glass.  The results are very shiny printouts. 

To avoid the hassle of dishwashing soap & drying, buildtak still has a role where shine isn't required.  The shine doesn't last, since PLA is very soft.  It's most long lived on cosmetic surfaces.

To apply hot glue, the opposite side must be on glass or it'll reflow to whatever surface it's on.

Game changer for a lot of problems.

Rails traditionally had to be triangles.

Rotating dials have edge overhangs.  The linear slicer can only print part of these.

Countersunk corners.

The answer is no, you can't clean the display with any kind of water.  It goes into the zebra strips & kills rows of pixels.  The zebra strips are held in by expendable metal tabs.  The lion kingdom managed to trade some bad rows for other bad rows.  The display would have to be covered in packing tape to try to keep water out.  The best long term solution is to get a better display.  It's so slow, it's not worth trying to save some bad rows.

The Ender 3 came in at 322W when starting up & 60W when printing PLA with a 50C bed & 230C nozzle.  The power supply was only rated for 300W.  When heating the bed & nozzle simultaneously, it dumps the full output & probably browns out.  

This brings up the question of how practical a 300x300mm bed is.  Even if the print is 10x10mm, the entire bed has to be heated.  So if you're paying for electricity instead of using solar panels, you'd need a smaller printer for smaller prints & a bigger printer for bigger prints.  If electricity is unlimited, you could use a bigger printer full time.

Printing TPU with a 260C nozzle & no bed heating burns 65W.  10 hours of printing burned 0.650kW hours.

The idle printer burns 7W.  With the motors on, it burns 22W.  Motors + 260C nozzle heating burns 65W.  Motors + 260C nozzle + 65C bed heating burns 330W as the worst case PETG setting.  Once at steady state, it oscillates between 65W & 300W with the worst case PETG temperature settings.  300W seems to happen when the bed is heating.  The nozzle heating seems to be proportional while the bed heating is binary & sucks most of the power.

The bowden extruder stopped extruding partway through a print.  The reason was 

scotch tape being used to keep the filament untangled.  It deposited adhesive on the filament which got in the bowden tube.  It pressed through the nozzle easily.  It pressed through the extruder easily.  It didn't press through the bowden tube anymore.  Retiring the bowden tube was believed to be the best strategy.  The lion kingdom has now spent as much in upgrades as a new printer.

Direct drive extruder: $40

EZR struder: $40

3D Touch bed leveling: $20

Copper heating block: $15

Metal hot end: $15

Glass bed: $15

Magnetic bed: $15

Nozzle assortment: $15

The latest replacement was the Creality direct drive

https://www.amazon.com/dp/B08J7N2LNL

It contained a completely new hot end, fans, cables.  It was a lot of work to install.  They say it can be easily swapped with the bowden extruder, but lions say fuggedaboutit.  The stock creality gear section was back.  The X axis then sagged to the right.  New parts had a slight tilt to the left but at least it printed again.  If right angles are really required, the easiest solution is to hack the G code rather than try to keep the X axis level.

The filament has to go in front & unroll sideways.  This is distinctly missing from the sales pitches for prusa MK III's & ball bearing filament rolls.

It successfully overcame the problem that killed the bowden tube, whether or not it really was friction in the tube.  The lion kingdom has now lived through the dual gear craze, the EZR struder craze, & the direct drive craze.  Will it print the unprintable Matterhackers PRO TPU from 2 years ago?

It did print the matterhackers Pro TPU even without a dual gear or a constrained path.  It still ran only at 20mm/s.  An important lesson is not throwing away filament that won't print. It might print in the future.  This filament was much softer than the tried & true filament, but it was twice the price & would require redesigning the tires.

The stock buildtak on FR4 bed had problems with air pockets between the buildtak & FR4 & not sticking flat on the aluminum.  The solution was seen as the mighty 

"Build Plate Ultra Flexible Removable Magnetic Build Surface Hot Bed Cover for Ender 3"

https://www.amazon.com/dp/B084YSZFXL

It's overall an improvement.  There are no more discernible air pockets.  There's much less warping.  The mane problem is sticking the adhesive magnet on the aluminum without creating air pockets.  The lion tried to stick down the back edge, then roll it forward but was off by 3mm.  

Taking it off & trying again would probably damage it or trap air bubbles.  It still managed to conduct enough heat.  The polarity of the magnets in bottom pad has to match the polarity of the magnets in the top pad.  

 There haven't been any air pockets when sticking down the buildtak magnet.  The 2 magnets create a uniform bond to the aluminum with minimal warping.

Having 2 magnet pads between the buildtak & aluminum means less heat gets through.  Fortunately, the magnetic buildtak is much stickier than the stock bed.  50C bed temperature was enough for PLA while the stock bed needed 65C.  0C with a 1st layer temperature of 220C is essential for TPU.  Higher layers for TPU can be 250C.

Combined with automatic bed leveling, the magnetic bed yielded gootuber quality 1st layers, all the way from edge to edge.  The mane problem was the magnetic bed caused the front row of probe points to always be .1mm lower, almost like a firmware bug more than a bed deformation.  It could be because the front row is 1st to be probed & there's a change in bed height in that motion.  

No-one really knows why the pogo probes have constant errors like this. They do provide manual tweeking in some firmware. The memory constrained Ender 3 could use some gcode commands, but only if the errors changed.  The easiest solution for a constant errors was hard coding the firmware & flashing.

The mane problem with the bed is it's very fragile.  Any nozzle crash leaves a hole.  Fold it sharply & it leaves a crease.  It tries to fold sharply & form creases when removing prints.  Waiting for the print to cool, using the spatula & xacto knife is essential for tough prints.

After stripping a heater, the lion kingdom got a copper heater for higher temperatures.

 https://www.amazon.com/dp/B09DS1P9VJ

Instead of what was pictured

The actual product had no holes for the studs which resist the torque during a nozzle change.

There was an experiment in resisting nozzle changes by grinding a flat & using a bigger set screw.

But tightening enough to resist nozzle changes stripped the heat sink.

The lion kingdom resigned itself to a future of grabbing the heater with pliers to resist torque while changing nozzles.

The most expensive consumable for lions has proven to be electricity rather than the filament.  

Many animals have exited a menu only to find their nozzle temperature was suddenly too cold or their probe Z offset was .1mm too high.  For animals who destroyed a print by trying to exit from a menu, the solution is to whack on a separate button instead of using the dial as a button.

The hardest part is drilling through the 2mm thick depleted uranium steel armor that is the front panel.