Open Source Orbital Shaker

Open Source Orbital Shaker
Open Source Orbital Shaker

Here is my entry for the Open Call for Open Science Equipment Contest.

I did this with help from Mike, Jack, Rob, Adam and others right here at Hive76. Thanks everyone!

Details and all source files for this project are available on Thingiverse.

The deadline for submission is December 15th, so if you have an idea for open source equipment you still have some time to submit your entry to the contest!

Open Source Orbital Shaker from jmil on Vimeo.

Join us for Open Art Studio this Weekend!

Chris building a BoomCase
Chris building a BoomCase

Our entire building at 915 Spring Garden is taking part in Open Art Studios this weekend, and we’ll be there too!

Almost 30 studios will be open to the public, including Hive76! There’s a ton of different medias people use, everything from textiles to clays to electronics.

Come join us on Saturday and Sunday, December 4th and 5th, from noon – 5 pm at Hive76. We’ll also be upgrading our MakerBot with a new MK5 Extruder so we’ll be printing in tip-top shape again soon!

Symmetry Design for 3D printing

Printed half-object. Print its mirror image (see instructions above), then glue together.

If you are designing objects for printing on MakerBot, the convention is to not try to print anything with overhangs. Well, what if you really want to? Simple… just cut your object in half, digitally. If you design with symmetry in mind, you can save yourself a whole lot of time and effort. Design and model half of your object. Print it out. Then invert your x or y axis, and print again. Bang, you get the exact mirror image of the first half-object. You won’t have to do any more modeling, processing, skeining, or converting to .s3g. bonus is that a single .s3g file on your SD card will be able to print both the left and right half-object. you will need to glue them together at the end, but this trick is most useful if your object has a lot of overhangs when trying to print it in one-shot. Just glue or epoxy them together to get a complete object.

This works really well for sphere-like (not quite spherical) objects, such as heads. See here: Symmetry Design — Blender Monkey Suzanne

Symmetric Monkey Head Print

Best of all, editing your hardware settings to flip either the X or Y axis means you can print the same .s3g file twice, once for each “half-face” of the object. Because the gcode is identical, this will always necessarily produce an exact mirror image.

Two Carbohydrates, an Alcohol, and an Acid Walk Into a Bar…

Making Bioplastic was just Boinged. What’s going on? Steph requested a bar story explanation, so here goes:

Two carbohydrates, an alcohol, and an acid walk into a bar. The carbohydrates are holding hands, but the acid wants none of it. She breaks them up with hot water in their face and a punch in the gut, then scrams. The skinny alcohol, seeing her chance, gets right between them before they can reconnect.

and there you have it — you’ve just created starch glass!

Starch Molecule, Adapted from Wikipedia

The starch is very very long chains of carbohydrate which normally crystallize to opaqueness. These can be broken (hydrolyzed) by strong acid, in this case white vinegar whose active ingredient is acetic acid. The heat really helps to get the molecules moving and so makes the acid work much faster than it would at room temperature. The heat can actually help water molecules to similarly break up the starch. The glycerol prevents the shortened starch molecules from just recrystallizing again after all the water and acid are boiled off. The glycerol gets physically entrapped between the starch molecules (intercalation). The broken-up starch chains can no longer organize into an opaque solid; they can no longer crystallize. This new highly disorganized, solid arrangement of moderately long molecules becomes translucent and is called a glass.

MakerBot Hotness Lives at Hive76

We love MakerBot, but we needed a better way to print larger objects (like parts for a Mendel). So I started experimenting in the lab at UPenn for how to get a heated platform up and working on 3D-PO.

The first design involved multiple layers of silicone fused together around a nichrome core. We told MakerBot about it, and they wanted more! Then Eberhard Rensch in Germany heard about it (go Internets!), and he went to town on a simplified software design. Awesome!

Of course the design is very simple, totally open (and transparent!). Hooray for Universities. So Mike and I bought a bunch of materials, refined the design a bit, and made a bunch more platforms. It was pretty risky but we trusted our gut and listened to all the awesome members right here at our favorite hackerspace. And we also made use of plenty of Hive resources to get the job done.

But we had gotten ahead of ourselves a bit… we don’t have the infrastructure to sell/invoice/ship/advertise this type of product. We could build that infrastructure, but we really love the core MakerBot community and don’t want to see market fragmentation. So we shipped them off to MakerBot to sell through their store. Check out this blog post and also the wiki page explaining how it works and how to use it.

It’s been an awesome experience: idea -> it works! -> invest in yourself -> Success!!

And about that Mendel… Fynflood’s assembling like gangbusters, check it out!!

“Handling” Hot Build Surfaces

photoSo when you use a silicone platform for the heated build stage, the heat doesn’t go all the way to the edges and corners of the stage (the material’s low conductivity which protects you from the 3 A electricity flowing is also the property that inhibits heat conduction laterally). This has a disadvantage in that effective build surface area is decreased, but a minor perk is that you can handle the stage with your hands by holding at the corners.

So tonight we realized that the 4″ putty knife we had been using to scrape off objects from the makerbot build platform was actually perfect for addressing BOTH of these problems. We put the putty knife between the heat and the build surface… The metal surface conducts the heat evenly to about 80% of the build surface now. So how do you pick up this hot stage? A huge bonus is that even though the stage is now too hot to hold at the edges, we have a sturdy handle that doesn’t interfere with printing!

heated build stage success!

our custom made heated build stage for our MakerBot CupCake CNC is working extremely well. here you can see 4 pulleys being printed at the same time. there’s no raft (saves time, plastic, and headache), and ZERO warping. excellent! the etched acrylic may stick a bit too well. we’ll have to try regular, unetched acrylic next (which will be less expensive anyway).

say hello to mass manufacturing.

MakerBot recommended Extrusion Temperatures for different materials

NopHead is a lead designer of the RepRap 3D printer, and designed theĀ Skyhook that we’re using all the time while printing at Hive. He’s worked out some good temperatures for extruding different materials in this RepRap guide for Newbies, which i’m reprinting here for posterity:

HDPE.raft_temp = 200
HDPE.first_layer_temp = 240
HDPE.layer_temp = 220

PCL.raft_temp = 0 // no raft
PCL.first_layer_temp = 130
PCL.layer_temp = 120

ABS.raft_temp = 200
ABS.first_layer_temp = 215
ABS.layer_temp = 230

PLA.raft_temp = 0
PLA.first_layer_temp = 180
PLA.layer_temp = 160

heated build platform for MakerBot

check out our work on making a heated build platform for MakerBot. The primary goal was to make it as light as possible since the stage is actively moving, so that means just some nichrome, a thermistor, and some silicone as a carrier. The silicone is also an insulator (very important!!) so no kapton tape is needed and we can see clearly what’s going on inside because the silicone is also clear. we currently use a reprap motherboard and extruder to drive the heat, looking at simpler electronic design soon (but this setup has the excellent PID in the extruder firmware 1.6!).