This is a 4 inch long juggling club model with a pocket for a neodymium magnet which transmogrifies it into a fridge magnet with enough power to hold a sleeping baby to the freezer door.

I spent more time on the pocket than the rest of it. When printed in pleasantly flexible TPU a 25x10x3mm magnet slips easily into the pocket and then stays there. There is .75mm of TPU between the magnet and the outer edge to temper the pull and prevent damage to the magnet. I used N52 strength magnets as they are stronger than the lower numbered ones.

I doubt many people want this exact shape so I’ve included some files to work from to make your own thing. Along with the completed club file I’ve uploaded the file just for the magnet pocket. You can use this to cut the magnet pocket in anything you want for your fridge. STL & STEP formats included in this zip archive.

FridgeClubParts

If you open these parts in Fusion360 or other app of your choice it should be obvious how to make this work for other shapes. If it’s not just post on Slack and ask for guidance.

Last night, I went to my first 3D Printing 101 class at AMT.

It took me about a month to finally let go of all my excuses and commit to this intro class, but I’m glad I did. As a new member, I was sold on how much I could gain from the facilities and all the new things I could learn… but I knew there would be a HUGE learning curve with learning CAD/CAM design software and I wasn’t sure if I’d be patient enough to stick with it to be honest.

If you’re a new member, and have had the same doubts as I have, don’t fear, there are great people, instructors, and resources here every step of the way. This 3D Printing class was hosted by the amazing Volunstructor (Volunteer Instructor) Matt Keveney, and he definitely knows his stuff.

The class is about 2-hours long with the first half focused on the foundational concepts and printer settings, and the second half on the basics of Fusion 360 and a print project suggested by the class.

For this session, we decided to print out a Chop Stick Rest.

Our concept:

Our model:

It looks simple, but it took about 20 minutes to print out.

Matt even showed us one of the projects he’s been working on.

It’s an Eye Glass Holding Mount!

3D printing has been trending for a while now and I’ve always been fascinated with the creative possibilities, and now I know enough to get started.

After reading through this I hope you’re less intimidated and more inspired. Go out and make something– We are a Makers space after all. 🙂

Don’t forget to look at the calendar for all the new upcoming events:

I know what you’re thinking. I’m sure you think this all the time.

You’re thinking:

‘Gosh, I get so much out of Ace Monster Toys; I’d really love to give just a little back! After all, the membership agreement says I’m supposed to do one small thing a month, and one big thing a year. Boy, I don’t know though… what could a simple soul like me really accomplish?’

Then, you might think:

‘But, golly, I really don’t want to bother the officers or stewards with questions like this. They’re so busy already, I’d just be getting in their way.’

Have no fear! We’re never too busy to put you to work.

Here are a few ideas I’ve come up with in 3D printing. I’m sure any of the stewards will have other ideas if these don’t appeal.  The first three could be done while waiting for your next long print to finish!

Move the sign!

Now that we’ve stretched out along the west all, the sign is kind-of lost back there. Unscrew it and re-hang it. I’m thinking right over the Type-A printer would be a good place.

Wind some filament!

We have four loose spools of filament: two of natural PLA, one ‘wood fiber’, and another green ABS. Wind them onto spools so we can use them! You could do it by hand if you’re really bored, but I’d rig up a temporary axle with some clamps and sticks borrowed from the workshop. Something to do while waiting for your next long print!

Re-Hang Mario!

The Mario artwork is now hidden behind the Prusa. Move it up a few inches! That’ll require a hot glue gun and a bit of knot tying.

Make a new shelf!

Last year, Devon was good enough to build us this cool little shelf to hold 3D printing samples. Since then we moved upstairs and then rearranged again. But, now there’s no place to hang the shelf. (We’re not allowed to hang it on the nearby concrete wall.)

Instead, I’m thinking we ought to have a free-standing bookshelf-like-thing about the same size, to live atop the filament cabinet. Please talk to me before embarking on this one, so I know we’re on the same page! This would be a great candidate for your ‘one big thing’ for the year.

My folks just moved here from out-of-state. Naturally a few things got broken in transit, including the cabinet door handles for a simple storage unit.

There was nothing appropriate in the right size at the local hardware stores. These have holes 5″ apart, which seems to be larger than average.

This is a great example of a simple and practical use of 3D printing. It didn’t take long to design or print, and looks great!

The originals were of circular section, which can be difficult to print. I designed a slightly different section that would print on its side without any support material. Note the use of a ‘driven’ dimension, just to manually ensure that the angle with the build surface will be at least 45°.

The body is generated with a single sweep operation.

The threads were too fine to print, so I modeled holes and tapped them afterward. Tapping plastic is a tedious process. You must withdraw the tap and clear the chips about every 3mm. While I’m always skeptical of plastic threads, these seem to be holding up quite well so far.

Further proof that 3D printing is not just for cereal box toys anymore!

In the last article, I shared a few photos of the numbered ‘billiard peas’ I recently made. Traditionally, these are selected from a pea bottle. This was a great opportunity to try the sample PETG material as well as the ‘spiral vase’ mode available in Slic3r.

When printing anything with a single-thickness wall, there is always a small flaw where the printer advances to the next layer. By default this point will land at nearly the same XY position, yielding an unsightly ‘scar’ running up the side of the piece. This scar is also a weak point of the print.

For this reason, most slicers feature a spiral mode. The printer moves continuously around the perimeter, advancing very slowly and evenly in the Z direction. This gives a superb, continuous surface finish.

When activating this mode, Slic3r PE automatically sets related settings accordingly; No top layer is allowed, perimeter thickness must be just one filament wide, etc. You can still control the with somewhat by adjusting the extrusion width in the ‘Advanced’ menu. I changed perimeters from .45 to .6 to get a slightly stronger bottle.

The model should be defined as a solid; otherwise Slic3r will try (and fail) to create both inside and outside surfaces. Model the outside dimensions only.

Since I wanted a stronger lip for my bottle, I designed a separate piece to be glued on later. I also made a snap-on cap, with a retaining ring, just to see how well this works with PETG.

I’m happy to say it worked perfectly on the first try. The PETG material is easy to work with on our Prusa, and noticeably more flexible than PLA when printing such a thin section.

Give it a try!

with just one extruder!

A couple weeks ago, Rachel asked me for a 3D printed AMT Robot similar to this one:

She wanted it to be done in our official logo colors, and was okay with a thinner version. This was a perfect opportunity to make good on my year-old promise to document my multi-color printing trick on the Prusa MK2.

Prusa-research offers a free utility which allows you to insert a filament-change-pause command at any layer in the print job. The new color will be used for the entire layer, until the next color change is encountered.

This can be useful for certain effects, like this little AMT robot plaque I made last year.

But true multi-color printing can be done the same way, if you have the patience to change filament manually at every color change. This eliminates the more complex multi-color models, but with a little planning, the filament changes can be kept to a minimum and yield surprisingly nice effects!

The basic steps are:

• Prepare your model
• Configure the slicer for multiple-extruders
• Load the STLs and slice
• manually edit the gcode, replacing extruder changes with filament-change-pause commands
• print as usual; change filament when prompted

These instructions assume Slic3r and our Prusa i3 MK2. Your printer must support a working filament change pause command. Unfortunately, this command is not universally implemented. If you’re unsure, you might want to try a small-scale experiment or two.

Prepare the model

I made a new model in Fusion 360. There are three colors: Black, white, and orange. I modeled the different colored sections as separate bodies like so:

Note that there’s a white section just behind the orange eyes. That’s because the orange I have available is a translucent color which did not show well when printed over the black main color.

By changing visibility and exporting the model three times, I ended up with one STL for each color, even though the white and orange sections have multiple bodies.

Configure the slicer

Note: Please don’t save these configuration changes on our 3D print computer. Make temporary changes only, or use your own laptop.

Under printer settings/general, set extruders to 3 (for three colors). The additional extruders will be copies of the first, which is what we want.

Choose extruder 1 and scroll to the bottom of the panel on the right. Click the ‘extruder color’ settings and choose black. Set Extruder 2 to white and extruder 3 to orange.

Slice the model

Click ‘add’ and load the main (black) STL file. Then click ‘Settings’ and use the ‘load part’ command to load the white and orange STL files.

Select each part in turn and choose the appropriate extruder: For the main black part, use extruder 1; for White use extruder 2; for Orange, extruder 3.

Adjust the rest of the settings as desired. I’m using default settings for the .020mm Normal profile.

Click ‘Slice now’ if necessary, and choose ‘preview’ on the ‘plater’ tab. Check ‘tool’ to activate the tool-specific preview colors. Your preview should look like this:

Export to gcode and save to a local file.

Edit the gcode

Open the .gcode file with a text editor and find all the lines containing t0, t1, and t2. These ‘tool change’ commands correspond to extruders 1, 2, and 3 respectively. A few of them will appear in a ‘preamble’ near the beginning of the file. In the body of the file a Tx command appears for each nozzle change. The idea is to delete the ones that don’t matter, and replace the rest with M600 commands. Your slicer may give slightly different results than shown here, so a basic understanding of gcode is assumed.

In my case the first was a lone T0 command that selects the first extruder to use. I left this one intact.

.
 .
 .
 G90 ; use absolute coordinates
 M83 ; use relative distances for extrusion
 T0  ; leave this one alone!
 ;BEFORE_LAYER_CHANGE
 ;0.2
 .
 .
 .

Slightly further down, three M104 commands appeared for setting nozzle temperature. I deleted the t1 and t2 versions.

.
 .
 .
 ;AFTER_LAYER_CHANGE
 ;0.4
 M104 S210 T0 ; set temperature
 M104 S210 T1 ; set temperature ; delete these
 M104 S210 T2 ; set temperature ; two lines
 G1 X116.894 Y125.880 F7200.000
 .
 .
 .

Then the actual printing starts using the T0 (black) nozzle already selected. The next one encountered is T1.

.
 .
 .
 G1 E-0.15000 F2100.00000
 G1 Z1.400 F7200.000
 T1  ; change to M600
 G1 E-0.80000 F2100.00000
 G1 X128.346 Y108.791 F7200.000
 .
 .
 .

Change this and all remaining Tx commands to M600. While you’re at it, make a list of which extruder numbers were selected. Check them off as you go, so you know you’re loading the correct color. In my case, this list looked like this:

0 -start with black-
 1 white
 0 black
 2 orange
 0 black
 2 orange
 0 black
 1 white
 0 black
 1 white
 0 black ..for remainder of job

Print

At each M600 command, the printer will pause, prompting you to load the next color.

Results? Hm…

My results with the robot were a bit disappointing. Since these colors are very high contrast (black and white) the slightest little blob will noticeably mar the finish.

Also, I learned that translucent colors over a black layer need a lot of layers, or a white layer or two behind them to keep them from looking too dark. I was not satisfied with the eyes in any of these models.

One last issue is that the Prusa seems to extrude a bit of extra plastic just after resuming the print, but before the nozzle gets into position. This almost guarantees the aforementioned ‘blob’ of plastic, which invariably lands in the wrong place. With a bit of practice, I was able to quickly grab this extra blob with tweezers, but clearly there’s room for improvement! Maybe there’s a setting I missed somewhere.

Still, I think it’s a worthwhile technique to know, especially if combined with other effects.

I’m an avid pool player and have recently taken an interest in games that require each player to randomly choose a ‘game ball.’ The traditional way to do this is via a set of ‘peas’ and a shaker bottle.

My peas are spheres with a flat spot on on side; the flat part faces down when printing. The numbers are recessed into this surface. These might work fine as-is, or a bit of paint could carefully be applied in the recess. I decided to try embedding a disc of contrasting color just behind the recess. I printed in white with green highlight, and got good results by turning the speed down to just 40% for the first few layers. Those finely detailed numbers are tricky! (I’ll save the bottle for another post!)