3d-printed-mold

I bought a water bottle about two years ago after my old one was stolen (I know, who steals a water bottle!?) While the new bottle was much better, since it was insulated and could keep water cold for more than a day (with ice added in) one of the things I didn’t like about it was a small rubber ring used to seal the cap. The rubber ring had a split in it (maybe to assist with the seal?) and it was difficult to clean, and eventually it broke from attempts to vigorously clean it.

smooth-on

I replaced the sealing ring by 3D printing a small mold and then casting a replacement using Smooth-Sil™ 940 silicone. The silicone is a two part mold, with a volume of 100:1 for part B to part A, which is why you get a giant tub of silicone along with a small bottle of whatever the red stuff is.

ring-and-mold

This was my first silicone casting at home for a personal project. I’ve done casting at work for prop making, but this time I didn’t have a vacuum chamber, and I was doing a tiny part all by myself.

silicone-ring

So how did it turn out? Pretty good! I used a digital scale and filled a cup with 10 grams of part B, then added 1 gram of part A and mixed it all up with a popsicle stick and smeared it into the cavity of the 3D printed PLA mold. I let it sit overnight then used a sharp knife tip to pry it out. There was a thin skin around the piece but it peeled right off.

cap-with-ring

So how does it fit? It’s good but not perfect. If I make another one I may decrease both the inside diameter and outside diameter. It could fit a bit more snug, and it could have just a wee bit more clearance when inserting into the bottle. (I’m guessing between 0.1mm and 0.2mm, maybe)

I’ve got plenty more silicone, and it is food-safe, so I want to experiment with making some food molds, and yeah, I’ll probably 3D print the objects to create the molds from, taking a page from Anna Kaziunas France.

sifter-3d-printed

I needed a sifter to remove some small pebbles from concrete mix, so I designed and 3D printed one. Now, like many things that get 3D printed, you don’t always get it right the first time. After testing the sifter I decided it needed larger holes, so. I started on version 2.

inkscape-drawing

For version 1 I used Inkscape to quickly create a grid of circles (using the clone feature) and then differenced them from a circle. Once I had this done I exported as a DXF file and used that within OpenSCAD to create the bottom of the sifter. I added a ring and Bob’s your uncle. I use this Inkscape/DXF/OpenSCAD/extrude method sometimes, because it seems like the right way to do things, or because it’s pretty fast. But it’s not always the best.

The problem with the Inkscape/DXF/OpenSCAD/extrude method is that you have to go back to Inkscape and redo your DXF file if you want to make changes or tweak the design. This may not be an issue for many designs, but for some, I want the flexibility to easily change things.

openscad-holes

So for the next version I redid the holes portion of the design in OpenSCAD. The great advantage here is that you can very easily tweak things like the size of the holes, and the hole spacing, and automagically see how it looks. (Note: in the image above you’re seeing the positive “solids” of the holes. In the final file I differenced them from another solid object to make them “holes” in the design.)

While the method of doing in all right in OpenSCAD has advantages, the one way it suffers is when it comes to render time. I should note that in OpenSCAD you can choose how “smooth” circles are by applying a number between 1 and 200. It basically sets how many “sides” a circle has. You can typically use 100 and circles will look pretty circular, but you can also drop the number down to 6 for hexagons, 8 for octagons, etc. That said, at a setting of 100 rendering the sifter took nearly 15 minutes on my 6 year old MacBook Pro. Changing the circles to hexagons with just 6 sides took about one minute to render.

This is where The Cloud™ should save us, right? But while there are various versions of OpenSCAD running on public servers, no one is running a version that worked properly. And since OpenSCAD is a niche piece of open source software, I don’t know if this will change. But since there is a command line interface to OpenSCAD, maybe I can do complex renders on one of my more powerful computers. (Anyway, I’m getting off-topic, so let’s continue.)

openscad-sifter

Hey, it’s a sifter! Yes, I designed and 3D printed a sifter. I often design things and then print them overnight so I have them the next day. 3D printing is awesome, but it’s often not fast. I did consider trying to make a sifter plate with a drill press, and then I remembered I had a laser cutter, and considered using that, but ultimately I was not in a hurry and 3D printing one seemed like a good idea.

tinkercad

Speaking of good ideas, I’ve been looking at Tinkercad recently, and while I wanted to be convinced it wouldn’t be easy to do what I wanted, it actually was pretty easy to do what I wanted, so I redesigned my sifter using Tinkercad. The smart duplication feature made it fairly simple.

While I’m a bit more impressed with Tinkercad than I thought I would be, I still have the problem I had with Inkscape, that if I want to tweak some values, I need to redo work. In fact, I have to pretty much create a whole new model. For simple designs, this isn’t a huge deal, but it is a bit of a pain.

What’s a bigger pain is the fact that while I will always have copies of Inkscape and OpenSCAD to use, Tinkercad (and the files I create with it) may disappear. Tinkercad is own/run by Autodesk, and while it’s a great tool for beginners to get started with 3D modeling (without having to install any software) ultimately I’m concerned for its long-term existence (like any hosted/cloud service.)

I can easily edit the OpenSCAD files I created seven years ago, which is something that is important to me. That said, I do want to explore other software, because reasons, you know?

My last mold making experiment was a good experiment, and if I learned one thing, it’s that the mold should be flexible to allow for the removal of the piece you are casting without destroying the mold or the casting. (Duh!) Instead of ABS I decided to print a mold using flexible filament. Now, to print flexible filament I had to do a small modification to my extruder lever to allow the insertion of a piece of PTFE tubing so that the filament wouldn’t bend over before it fed into the feed gear. Once I did that, I was printing flexible filament (very slowly.)

path-01

I decided to start with something less complex, and used a 2.5D object instead of a 3D object. I had an illustration of a hammer, which seemed to be a simple shape, with no weird inside parts or sharp corners. I started by opening the vector file in Inkscape.

path-02

Once I had the file open I used Inkscape’s dynamic offset feature to extend the shape into a larger piece so I’d have “walls” for my mold.

path-03

I did a Boolean difference between the original and the scaled part to get the wall piece, with the wall pieces being approximately 4mm wide.

path-04

I also created a bottom plate that the wall piece would attach to. I did not make it fit with pins or any other alignment method, I just ended up using tape to hold the pieces together.

piece-outside

piece-bottom

Here are the modeled pieces. The wall piece was easy enough to flex around, but seemed strong enough to hold up for the casting.

hammer-mold-1832

And here are the printed pieces. The flexible filament did not print as well as PLA does, and there were some rough parts on the top of the walls, but it wasn’t going to matter for these purposes.

hammer-mold-1833

hammer-mold-1834

I put the two pieces together and applied some masking tape to hold them. Since I was going to use plaster I knew that it didn’t have to be too water-tight to hold the plaster in place.

hammer-mold-1840

I then filled the vessel with the plaster. (Yeah, I have a big bag of plaster on hand for weird reasons, so I occasionally use it, though eventually I want to use concrete for these experiments.)

hammer-mold-1882

After letting the plaster dry for a few days I removed the tape and then pulled off the bottom…

hammer-mold-1885

…and then was able to flex the wall piece enough to get the plaster out of the mold, so that worked pretty well. Again, this was not a complex shape, which really helped as I just had to push the piece straight down through the mold.

hammer-mold-1890

And here’s my (tiny) plaster hammer. I like how it turned out. The edges are not perfect, but then, what is, Right?

hammer-mold-1852

I ended up making two of them, and with one I found that it was fairly easy to shape the edges using tools, so my 2.5D hammer (sort of) became a 3D hammer.

make-sign

Yes, I know it’s July, but it’s time for the May update because summer is so busy that’s just how it works.

In May I went to the Madison Mini Maker Faire and we ran out Design & Build Derby (formerly known as “Nerdy Derby”) and kids and adults had fun. It was not as busy as previous years, which was good, because the number of volunteers was down, but as always, Adrian from Milwaukee Makerspace did an amazing job! If you missed it, check it out at Maker Faire Milwaukee.

Right after Madison it was time for Maker Faire Bay Area. I was able to join the Power Racing Series gang and assist with running the races. I think I can now say that straw bales may be worse than tires. The straw is very irritating. The race was fun, and I got to see a good amount of the Faire (but not everything, I mean, there’s a lot to see!) I also got to attend the Bring a Hack event, and if you don’t already know that Drew is awesome, you should know that now.

Also in May, I went to an event that shared the findings from the State of Urban Manufacturing Report. It was interesting how it relates to the “Maker Economy” and individuals and small businesses making and selling products.

I also went to the Meet the Meetups and it was interesting but difficult due to the crowded venue. I still got to see some old friends and talk to a few people about the Milwaukee tech scene, so that was good. Hopefully it can be a bit more spacious next time. We offered to do another Meet the Meetups at Maker Faire Milwaukee, but I don’t think there is enough interest in it…

I also did a tour of Milwaukee Blacksmith with BLK SHP Milwaukee. Ken is a great speaker as well as a great blacksmith, and it was cool to see what he’s built over the years for his family and the community. If you haven’t checked them out yet, add it to your list.

Besides all that I worked on a lot of components for a new museum exhibit, 3D printed a lot of parts for a giant sculpture, and a few other things, but we’ll cover that in future posts… As always, if you want to see a glimpse of things I’m working on, check out Instagram.

beexcellent

Milwaukee Makerspace has a weekly meeting every Tuesday at 7pm. We go over upcoming events, new stuff happening at the space, and we show off projects and welcome guests. And there’s one more thing we do… we recognize awesomeness.

In an effort to make members aware of the fact that nothing happens at the space without a member doing it, we typically have a segment of the meeting where any member (or guest) can stand up and publicly thank another member for doing something awesome, or being awesome. Sometimes this might happen if a member sees another member take out the trash, or empty a vacuum cleaner, or it might happen if someone takes the time to help someone with their project, or to train them on a piece of equipment.

Milwaukee Makerspace has no employees, and no staff, and everyone who is a member is expected to volunteer in some way. Seven of the members volunteer to be on the Board of Directors. and they pay the same dues everyone else does, and besides helping to run the space, they help when and where they can. Some members serve as Area Champions, and are in charge of a specific area of the space, and get to make the rules there, and also get a budget and yet others don’t want any official responsibility, but are more than willing to pitch in when cleaning is needed on Space Improvement Day.

It’s common to hear someone stand up at a meeting and say “I want to thank Harvey for emptying all the trash cans today.” or “Thanks to Tom for getting us [insert name of tool he got on auction for super-cheap]!” And after a few meetings you start to see who the people are that are regular contributors to the space, and you come to value those people.

Members are always free to call out others on the mailing list when they are excellent, but there is something special about being recognized at a meeting, in person. Typically there’s some applause for the person being recogznied, and hopefully it makes them feel good about their contributions.

In the end, it’s one more way we’ve tried to help build a community of makers, and not just be a building full of tools and weird stuff.

abeexcellent

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