3D Printing Springs

Springs are elastic objects made of metals, most times, spring steel. A project that my team was working on needed a spring to create a compression and extension action. 

Unfortunately, when a cylindrical part meant to be used with the spring was designed, it had dimensions larger than the standard spring sizes available. We had already begun printing the cylindrical part, so there was no going back (as we were using a high-end 3D printer). So we decided to print a spring!

The spring design was made using Rhino, as it has a simple function that can make helical shapes and make them into solid pipes. And, if you think about it, a spring, is actually a solid helix shaped pipe.

Printing a spring would mean taking into account for its flexibility. Using regular materials like PLA or ABS will make the spring rigid. So we used a non-standard material which was flexible and strong: Thermoplastic Polyurethane, commonly known as TPU. A completely solid infill print on TPU with support structure will make the spring looks like this when it has finished printing:

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The only annoying thing about using this is the removal of the support material. Otherwise, the print comes out pretty good. It might look a bit messy, but it is good enough to be a low fidelity spring for prototyping. The final prototype kind of reminds me of a slinky 🙂

For the spring in action, check this video:

A maze of ABS

Acrylonitrile butadiene styrene (ABS) is a widely available thermoplastic. You can usually find them in legos.

While continuing my test of materials on OtherMill, this time, I decided to try ABS. The material is pretty soft, and can be milled easily. Unfortunately I could not find a block of ABS, so I printed one on a Mojo (much to the dismay of many).

I created a design for a Maze on Adobe illustrator, exported it into a DXF file, and extruded it into a 3D model, and made a GCODE file out of it.

Fixturing an object on the OtherMill can become tedious of the surfaces are not flat. Since my block of ABS was printed, it was quite flat and, only using double sided tape and a bracket with some fastners did the trick. The entire milling process took about 29 minutes (OtherPlan has a tendency to lie when it displays the milling time, because it said about 42 minutes).

I only have the video of how the milling ended (because a 30 minutes long video is what we want but not what we need)

Clearly, the machine can be very messy. But that’s why it needs to be closed while using.

Above is the final ABS maze. Below are images of the finished product.

      

More Clear Acrylic – Same things made using two kinds of machines

Got another chance to mill clear acrylic into a few  key chains. This time they are less bluer, but thinner than the previous ones (about 3.175 mm or 0.125 in thick). Milling gives away really clear surfaces rather than burnt ones.

On Laser cutters, the texts are engraved by, again,  burning the surface. The flat end mill can make the surface look more transparent than laser engraving. It is true that milling will make a transparent acrylic surface into translucent. But the finish is cleaner than the laser cut surface.

These images shows that it is not possible to deeply engrave acrylic using a laser cutter, but a CNC machine can do the job just fine! The key-chain on the top is made using the CNC macine, and the other two using the laser cutter.

The difference between Laser Cutting and CNC machining- Clear Acrylic 

Wouldn’t it be more appropriate to use a laser cutter to cut acrylic rather than using a small desktop CNC (Computer Numeric Control) machine to tediously mill it to a desired shape?

Well, the answer is not obvious to sometime who doesn’t care about having unfinished edges.

The difference becomes more obvious when using transparent acrylic. Using a laser cutter, melts the acrylic, leading to the “cut” sides to look more or less like melted plastic, and opaque. Using a CNC machine, on the other hand, gives it a smooth and nearly transparent (usually it’s translucent). Check the image below and you can see the finish.

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I decided to make a Jansen linkage model using clear acrylic, a piece of cardboard and some 3D printed parts.

I used Autodesk Fusion 360 to design the shapes and linkages, and also create a gcode file thought is CAM component. Finally, I used an OtherMill to mill them using a 1/16 inch flat end mill. The results were spectacular. The milled surfaces were smoother than any any piece of acrylic cut using a laser cutter.

The brown cardboard was etched and cut using a laser cutter. And the silver pins were 3D printed on an Ultimaker, using an STL file created using SolidWorks. The image of the final prototype is below:

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It doesn’t make sense to have a fixed Jansen Linkage model. The whole purpose of having it is to make it look like it is walking. Connecting two or more of these models can make it look like it is walking with more legs.

Here, check it out in the video:

 

A project from the past: ARTEMIS

High-altitude balloons are unmanned, filled with light gases (either hydrogen or helium), initially released from ground level. They can be used until they reach the stratosphere. Due to their comparatively low rate-of-ascent, these balloons are perfect candidates for precise measurements of sections of the atmosphere. High-altitude balloon experiments and activities in India are very rare. This project makes use of an alternative use for high altitude balloon. Imagine a situation where an area is struck with a disaster (natural or unnatural). Usually at such times, there are constant telecommunication problems. This is the main drawback of any such systems. A distress signal must be sent to rescue centers and ground stations to receive help. Data from the disaster struck area must be collected and sent for analysis. A possible solution is ARTEMISAirborne Remote Measurement and Information System.

A small box containing electronics, including measurement equipment like sensors and transceivers was attached to a set of 3 large high-altitude balloons (making it airborne). This was tethered to ground to make sure that it wouldn’t fly away. Multiple ground monitoring and control stations were set up to constantly monitor the transmitted data. Data presentation was available in these stations. A Cut-down altitude was set in the ground control station. When the balloon reached the cut-down altitude, i.e. the balloon was detached from its tether, a sub-system known as the Cut-down mechanism (made of heated nichrome wire) would separate the payload from the balloon. The cut-down mechanism was also an emergency Flight Termination Unit (FTU) in case of system faults. A parachute attached to the payload minimized the rate of descent and provided a safe landing. Since the test height was not in thousands of meters, a GPS system for recovery was not necessary. Finally, a recovery team could be dispatched to retrieve the payload. The payload could be serviced and reset for the next flight.

Doing a few tests, we determined that the payload was constrained to 300g. This forced us to use three baloons which could expand upto 3 meters in diameter, filled with hydrogen (since Helium was very expensive). A XBee Pro S2B was used as the communicating device at the airborne system, and at the ground stations. The FTU which  was a nichrome wire, was heated by a sudden surge of current provided through a Li-Po battery. The battery also powered the microcontroller used to control the FTU and Zigbees.

The main advantage of using a high altitude balloon is that it increases the range of communication. For instance, if the range is rated as 2 km line-of-sight on ground, then we observe that the same range increases if we consider one part of the system at an altitude.

Below is the launch sequence of the system:

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Graveyard Escape- The Game controlled using Wearable Tech

The term project of my Costumes as Game Controllers class had an awesome team of 4. There were two more teams. My team mates were Olivia, Samvid, and Yuan (White)

While our instructor had given us a task of watching a movie among a few choices (Our team chose The Fifth Element) to learn about how costumes impact emotions. After watching the movie, we were asked to write down a list of emotions. All students wrote down the emotions. We had to pick one emotion, based on which we had to build an entire game that used costumes as it’s game controllers. The emotion we got was:

Upset

Yes, were upset the we got that as our topic. We then had to do mind mapping, a way of generating words that somehow connect with “upset”

We came up with so many words that had even the slightest of connection with the word: sad, crying, suicide, murder, death, graveyards etc. There were also words that had nothing to do with the word: education, college, crows, gambling etc. The most tangential word we got was

 Happy

 How about making a game that begins sad and ends happy? No! That is too much of a cliche. Well, then there could be a factor of choice, begin with sad and end with sad or happy, deepening on the choice. That is what we did with our game:

 Graveyard Escape

 The entire game was made as a choice for one man who had to get out of the graveyard where he was trapped.

The story is pretty long and had to be divided into three acts. In the first act, the man was transformed into a cat, in the second, a crow.

The game began with a simple ritual of placing flowers in front of a gravestone, as in the image below. Conductive fabric was used to make this mechanism.

The game was played using a cat paw glove on one hand, and a black crow wing on another. The claw was used to attack the enemies on the ground, and the wing was used to fly. Below is an image of our instructor trying out the costume game controller.

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Finally, the images of a user testing the game while wearing the costume (the game was made using unity):

 

 

Utility Wrist Band

While working on the term project of my product design class (Design Strategies), we were randomly grouped into teams of 3. Each student had to come up with a product, and then decide which product is the most viable, and proceed with it.

After thinking of the feasibility of product development, we decided to go with a product called walk clean.

The concept was that a wrist band is only a fashion accessory, but has potential to be more. It is worn by many people; imagine a world, where it could be used as a utility device!

Walk clean is a utility wrist band that has a hollow compartment inside it. The compartment (for now) is used to store gloves, mostly meant to be used by a person who does not want his/her hands to be contaminated.

The wrist band was made using 3D printers with the material TPU.

Two iterations were made: In the first one, the band was supposed to be two different pieces, joined in the middle. However, the flaw with this one was that it would not create a circular shape around the wrist. Here are the images rendered using Rhino.

The following images show the first 3D printed prototype of the product. The glove could be easily placed inside the band, but the shape could not be kept. Also, there was space only for one glove.

The second prototype was designed as an incomplete hollow ring. This gave the band a circular shape. The hollow inside meant not just one, but two gloves could be placed inside. A simple piece of acrylic was used to join the ends together to make a complete ring.

Clearly, the size is larger than a regular wrist band, and the outer surface looks unpolished (unlike the previous one). However, for about 80% material infill, the prototype is very sturdy. The lesson from building this prototype is that TPU is very flexible, and it is very easy to make hollow objects with it. This means, that a “human” sized wrist band can be made with a little bit more effort while 3D modelling.

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Above is the image of all the things the prototype comprises of: the wrist band, a pair of gloves, two rubber bands, and an acrylic piece.
This video shows how the  second prototype of the utility wrist band works.