The Make Something Every Week Contest

[JoeP]

You can print candy?

[Corona688]

Actually -- you can. Someone made a 3d printer that extruded sugar a while ago.

That's just a container for candy, though.

[Corona688]

Candy Twist 2.0.

[Corona688]

I am finding that printing large overhangs requires large amounts of cooling. Not to be outdone, this fist-sized noisemaker rated in 2/3 cubic feet per second resides where a puny 40mm used to be:



....It is far too much. My hotend can't heat past 205 any more. I'll need to use the fan channel to slow it down after all.

And yes, it does aim at the bed, after it goes past the heatsink.

[Corona688]

Running the fan at 10%, and giving this sort of "nose", has it working just right.

[ceptimus]

I made this POV kit I bought from Banggood.com - it's only $11 including shipping



The real value to me turned out to be the the complete lack of instructions or program. I wrote my own program for it to make it work as a clock, and then I also had to write a programmer tool to upload the resulting hex file to the microcontroller. It uses an STC89C52RC microcontroller, which is a Chinese version of a 90s-era 8051 chip. The problem is that it's very difficult to find any English documentation on the kit or the chip or the necessary programming tools.

I took it as a challenge and so I've had many hours of 'fun' figuring out how to make it work. I've put a couple of posts on my blog about it in case anyone else wants to build on what I've done.

[Janet]

Inspired by a comment my mother made during a game of gin rummy, I flexed parody song-writing muscles I have sadly neglected for some time. Here's my cheery, seasonal offering.

The Twelve Days of Revolution


On the first day of revolution my comrades killed for me
A Bad King sitting on a Throne

On the second day of revolution my comrades killed for me
Two Evil Queens
and a Bad King sitting on a Throne

On the third day of revolution my comrades killed for me
Three Doltish Dukes
Two Evil Queens
and a Bad King sitting on a Throne

On the fourth day of revolution my comrades killed for me
Four Ugly Earls
Three Doltish Dukes
Two Evil Queens
and a Bad King sitting on a Throne

On the fifth day of revolution my comrades killed for me
Five Mad Marquis
Four Ugly Earls
Three Doltish Dukes
Two Evil Queens
and a Bad King sitting on a Throne

On the sixth day of revolution my comrades killed for me
Six Counts Betraying
Five Mad Marquis
Four Ugly Earls
Three Doltish Dukes
Two Evil Queens
and a Bad King sitting on a Throne

On the seventh day of revolution my comrades killed for me
Seven Squires Seducing
Six Counts Betraying
Five Mad Marquis
Four Ugly Earls
Three Doltish Dukes
Two Evil Queens
and a Bad King sitting on a Throne


On the eighth day of revolution my comrades killed for me
Eight Dames Condemning
Seven Squires Seducing
Six Counts Betraying
Five Mad Marquis
Four Ugly Earls
Three Doltish Dukes
Two Evil Queens
and a Bad King sitting on a Throne

On the ninth day of revolution my comrades killed for me
Nine Ladies Slapping
Eight Dames Condemning
Seven Squires Seducing
Six Counts Betraying
Five Mad Marquis
Four Ugly Earls
Three Doltish Dukes
Two Evil Queens
and a Bad King sitting on a Throne

On the tenth day of revolution my comrades killed for me
Ten Lords Accosting
Nine Ladies Slapping
Eight Dames Condemning
Seven Squires Seducing
Six Counts Betraying
Five Mad Marquis
Four Ugly Earls
Three Doltish Dukes
Two Evil Queens
and a Bad King sitting on a Throne

On the eleventh day of revolution my comrades killed for me
Eleven Proud Princesses
Ten Lords Accosting
Nine Ladies Slapping
Eight Dames Condemning
Seven Squires Seducing
Six Counts Betraying
Five Mad Marquis
Four Ugly Earls
Three Doltish Dukes
Two Evil Queens
and a Bad King sitting on a Throne

On the twelfth day of revolution my comrades killed for me
Twelve Princes Plund’ring
Eleven Proud Princesses
Ten Lords Accosting
Nine Ladies Slapping
Eight Dames Condemning
Seven Squires Seducing
Six Counts Betraying
Five Mad Marquis
Four Ugly Earls
Three Doltish Dukes
Two Evil Queens
and a Bad King sitting on a Throne

[S.Vashti]

Originally Posted by Corona688

Actually -- you can. Someone made a 3d printer that extruded sugar a while ago.

That's just a container for candy, though.

That would be the CandyFab 4000 from Evil Mad Scientist Laboratories.

[specious_reasons]

Got a new, large spool of filament over the holidays, but I needed a mount for the spool... Enter my son's Erector set:

IMG_0443.JPG

[Corona688]

The new 2016 "light" extruder, with 50% less extruder than other extruders.



Motor is 1.5 oz-in with a roughly 200:1 differential cyclodial gearbox.

[JoeP]

Originally Posted by Corona688

The new 2016 "light" extruder

When you turn it on a beam of light shoots out?

[Corona688]

Originally Posted by JoeP

When you turn it on a beam of light shoots out?

It's lightweight -- the motor, gearbox, extruder, hotend, and everything holding them together weigh less (160 grams) than one ordinary NEMA-17 motor alone (220 grams). Just weighed them this morning.

It's another widget to push filament for a 3d printer.

[Corona688]

I'd been working on my latest project, a mechanical timer, until I got sick of it... I took a break and made this animation instead. You can't see it, though. The upload tool turned it into a jpg for being slightly above the upload limit. Sorry. I'll see if a gifv will fit.

[Corona688]

Here we go, reduced to 64 colors.

[ceptimus]

So it looks like 13 rotations of the input shaft cause the two gears to index one tooth relative to each other - so the two gears take about 157 revolutions of the input shaft to make one revolution with respect to each other - but how do you get any output from the thing?

[Corona688]

It took a great deal of squint-eye to make a properly working equation to predict the motion in a better than phrenological manner -- i.e. correctly predict based on the number of teeth, rather than punching in ratios until it works right.

The lower ring, a1, is 14 teeth. Its inner gear, a2, is 13 teeth. The upper ring, b1, is 13 teeth. Its inner gear, b2, is 12.

The gear ratio here is:



Which works out to exactly 169:1.

In the actual gearbox, the teal gear is tall and thick enough to hold a bolt, and restrained inside a tube so the inner cycloid always meshes with it.

[Janet]

Did my first 3D print yesterday. I wanted something we could make fast for a demonstration, so I started with a guitar pick. I put the meme hazard symbol Mick designed for <i>Dangerous Magical Noise</i> on it. I didn't use the finest setting, so it's a bit rough. All my attempts today stuck to the nozzle instead of the plate, which was disappointing. I know I glued the plate all over, so I'm not sure why that happens.

[ceptimus]

The plate has to be clean and level and made of (or covered with) the correct material, and, if heated, at the correct temperature.

When you've satisfied all those basics, the biggest problem is the gap between the nozzle and the plate for the first layer. You've probably got the gap too big. With my simple printer I command the z-axis to zero (with the printer empty and cold) and check that a piece of paper can just be slid under the nozzle and that the nozzle 'grips' the paper lightly: I adjust the z-axis zero sensing switch till I get it right. This also lets me check the plate is level - by testing at different x and y positions.

More advanced printers 'probe' the plate with the print head to allow them to auto-zero the first layer height (and maybe auto-level). If your printer has these abilities then setting the first layer height is done by editing some numbers in the printing software.

[Janet]

I am certain they told us it auto levels, but there may be a button for it. They are coming today to try to figure out why our second color cartridge won't work and we're going to ask about the failures. But already I can tell you they did not tell us to clean it after every print, only when the glue had built up a bit, so that's probably part of the problem.

[ceptimus]

You don't need to clean it every time.

What are you printing on? I print on that high temperature (Kapton) tape stuck to an aluminium plate - it works well with PLA and ABS. I used to spray a bit of hairspray onto it at one time to make the prints stick better, but once I got the temperatures and first layer height right I found it works better without any glue. I clean it with some solvent cleaner occasionally.

I keep meaning to experiment with printing on some glass plates - you clip these to the bed and just print straight onto the clean glass - you have at least two plates so that once a print is complete you can remove the glass with the print while it cools down and fit another piece of glass if you want to print something else straight away.

[Janet]

It's got a big glass plate. They gave us glue but told us we could use hairspray to make it stick. I've had failures with both. This is what we have.

[ceptimus]

[Janet]

Well, I think we solved it and it was stupid. Today I went down with my colleague and said I wanted to watch her put the glue on to see if it was different. It was very different. The glue bottle I was using didn't actually have any glue coming out of it. I don't know why, since both were working today. Since I hadn't seen the glue go on, I'd just assumed it wasn't very visible, like a glue stick. I'm relieved it was that simple.

[Corona688]

The Emperor's New Gluestick?

[Corona688]

An airlift pump is a method for raising water using an air source, such as a fish bubbler you can get at any pet store. They deliver water slowly+steadily, many small greenhouse setups use them.




OK, my airlift pump isn't exactly new. I designed it a year+some months ago. But it just got a big improvement.

On the outlet side, a foot or so above it, if you put a tiny loop in the tubing it works much better. Without it, sometimes the water only makes it halfway before falling back into the water bottle. With the loop, it just falls into the loop, and builds up there. Once there's enough to block the tube, it all gets forced upwards in one try.

It went from "a drip every 12 seconds or so" to "I had to put a cup on top of the output to stop it splashing all over".