Category: Soft Robotics

 

 

 

 

 

For this week we were to design our own mold. Being newer to 3D printing I knew i wanted to dive straight in at least with a cardboard prototype to solidify my understanding of some of the mold making techniques introduced in class last week.

I just got trained on the 3d printers at Tandon and am excited for trying 3d printing in the future ❤ I decided to try the 3 part mold w/core, hoping to create a Starfish shaped grabber / inflatable actuator.  I included the slides from class I was inspired to try below from Kari’s Week 4 lecture Introduction to Silicone Mold Design Concepts and Approaches

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I ended up using more Silicone than I had hoped due to the cardboard walls leaning outwards and a leak in the center, maybe around 150 -180 vs 100, would definitely design a smaller mold for the next step.

Lessons Learned:

• Create thicker walls for part A + B, I had originally made them thinner to help maybe decrease the needed amount of silicone but overcompensated, and when removing from  mold some of the walls had some sizable tears to where I decided to hold off on part C until doing another model
• Start with a simple shape –  like a square to really understand the characteristics of silicone
• Use a sturdier material – my cardboard was too thin and so the sides began to warp / buckle. I was able to wrap 2 hair twist ties around the the frame while it cured but helping alleviate the warping.
• Be careful with overhangs –
  • I think some of my walls due to the warping created difficult overhangs for the test cast removal
• Design small –
  • while prototyping try designing / scaling down to the smallest size thats still helpful in order to conserve materials / & cure+ iterate faster
• Next test- 
  • Either a laser cutter one with small rectangles, gluing together with acrylic glue
    • could also do in sectional stacking to help avoid possible leaky edges
  • Test 3d rundown w/ Arnab
  • Or have Laguardia print @ cost

 

Thinking about a 3 part mold cast.  Slides are from our Week 4 class with Kari love. See slide here 

 

 

Week 4 Assignment

• #7 Silicone Casting Blog: Design Your Own Mold
  • Design an original/variation mold concept
  • Can be digitally designed or physically designed
    • 3D modeled/printed, Laser Cut, Cardboard
    • Simple or as complex as you like
    • Try to use less than 100g of silicone to conserve materials for classmates
  • Make a test cast
  • Photograph your finished mold and cast and write up a “lessons-learned” statement on your blog
  • Email your link and bring your physical prototype to class
• #8 Make Quad Chart of Final Project 1st Idea Proposal
• Optional Reading: Soft Robotics Commercialization: Jamming Grippers from Research to Product
  • http://bit.ly/softrobot-commercializationcasestudy
  • Rare technical Case-Study on hardware start-up (and ultimate closing)

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Hope to think about a HASEL actuator variation this week ❤ Still deciding what sounds fun for the final

• #7 Silicone Casting Blog: Design Your Own Mold
  • Design an original/variation mold concept
  • Can be digitally designed or physically designed
    • 3D modeled/printed, Laser Cut, Cardboard
    • Simple or as complex as you like
    • Try to use less than 100g of silicone to conserve materials for classmates
  • Make a test cast
  • Photograph your finished mold and cast and write up a “lessons-learned” statement on your blog
  • Email your link and bring your physical prototype to class
• #8 Make Quad Chart of Final Project 1st Idea Proposal
• Optional Reading: Soft Robotics Commercialization: Jamming Grippers from Research to Product
  • http://bit.ly/softrobot-commercializationcasestudy
  • Rare technical Case-Study on hardware start-up (and ultimate closing)

• Present: Explorations of simple flat-patterned inflatables from Assignment #4 & silicone cast actuators from Assignment #7
• Introduction to Silicone Mold Design for Soft Robotics
  • https://docs.google.com/presentation/d/1AXuOHncCWkDFcHJifK_cMs1xPDeh2sRB7-M_tjcxjyg/edit?usp=sharing
• Final Project Information: Heilmeier’s Catechism and Quad Charts
• Slide presentation about Final Project https://docs.google.com/presentation/d/1wZs8ry4IDExd-BUqYEyzQta-luVUa3-OQ3Bqtp2dqB0/edit?usp=sharing
• Heilmeier’s Catechism quick link- http://www.darpa.mil/work-with-us/heilmeier-catechism
• Cool Video of Magnetic Soft Actuator
  • http://harnettlab.org/2018/02/19/fabric-linear-motor/
• Demo: Programmable Air – Amitabh Shrivastava

 

 

Hw: Cast a Bibenda – Simple Pneumatic Bending Actuator

Image Credit: Image the Western Australian Herbarium, Department of Biodiversity, Conservation and Attractions (https://florabase.dpaw.wa.gov.au/help/copyright).

“Newly-classified in 2007, Tecticornia Bibenda is a unique succulent native to Western Australia, and has been recognized as a plant particularly worthy of conservation and continued research. Its segmented stem frequently prompts comparison to the Michelin Man. The Bibenda Actuator’s relationship to this plant extends beyond the nod to the segmented bulbous shape, finding bio-inspiration from the mobility of plants, which move via hydraulic manipulation while most animals use muscle contraction. Usually plant hydraulic motion occurs as tissue-level adjustments of fluid (primarily water): for example, with the inside of a curve having less fluid, and the outside more. ” [chapter 10 Make:Soft Robotics ]

 

 

This weekend a few of us that were on the floor at the same time decided to join forces when we couldn’t find the right PVC size reserved from class (and after trying a local hardware store <3). Rachel, Madison, Gabriella & I went through the Bibenda pneumatic actuator tutorial round robin style, taking turns with each step / making sure we each understood & tried out all the tools. Matt was also in the area and reminded us how the Vacuum worked. Arnab who was in the room working on another project mentioned how he was excited to see the vacuum and that he had actually tried to make one himself one time. He mentioned that cellophane could be a good alternative as a material to help with future Silicone mold experiences.

Lessons Learned:

1. make sure the core print legs sit super snuggly on the PVC pipe. This could mean for us adding more tape along the rim to increase pipe material thickness.  We realized after the last degassing w/ the entire mold setup that the core had started to float a little out of the silicone, fortunately our actuator still worked for this round but would definitely fix for next time.
2. When cutting the restraint slits in the tubing, we realized after applying silicone that our initial slit closest to the tip of the core was a little too close/large and wanted to slip off. Next time we would maybe start 18mm out from where we tied to increase stability.
3. Making sure to be safe when cutting the styrene into 2×2 squares – When trying to snap after scoring it actually went through Rachel’s glove cutting her arm. Fortunately there’s first aid items in the shop! And also a reminder for all of us to keep on scoring if it doesn’t feel like a easy break ❤
4. Apply PVC primer & cement in spray booth. I think we for some reason thought the degreaser was the item that needed the most ventilation so went straight for the pvc primer/cement in the room w/ windows open. In case you or others in the room have a more acute sense of smell / or are prone to headaches definitely apply in spray booth or w/ a window that can open more than NYC 4in standard 🙂
5. This week Kari was super kind and provided a couple cores for us to use. If we were to print the core ourselves, we’ve realized its a good idea to go ahead and complete  the Tandon Maker space training for their shop / 3d printers, due to it being thesis & many wanting to use the printers. It can be good to have 2 potential places to print to allow schedule / sign up flexibility

 

 

(pictures throughout process with Rachel, Madison & Gabriella – & a thank you to Matt for reminding us how to use the vacuum! We ended up using the remaining PVC from Matt & Ashley’s endeavors.  We think either the class had already used the amount designated for the exercise, or maybe it had accidentally been placed into the junk shelf area after a previous group <3)

 

 

(Gabriella showing pix post removing from mold)

 

 

( learning how to use the Vacuum for the degassing stages)

 

 

(Madison pouring the A+B mixed Eco-Silicone mix into our mold from a distance to help with air bubbles)

 

(Rachel weighing & pouring the A+B mixture)

 

“This pneumatic bending actuator doesn’t have a specific job, but it’s a very good demonstration of how you can create a complex system with a minimal number of simple parts. It also serves as an on-ramp for working with cast silicone for robotics. The Bibenda can be cast in an afternoon, and its size and shape allow for bubbles to easily escape to the top for a clean casting. Another feature is the ease of demolding, which can serve as some early practice as you proceed to the more elaborate projects later in the book. This project can also be hooked up to the air power supply to be controlled digitally, or with a jumbo syringe filled with water to evoke the hydraulic motion of its namesake.

 

This design highlights the capabilities of using fabric to vary the amount of elasticity. By embedding fabric into the silicone to limit the stretch, we create zones of greater and lesser inflation. You can check out this concept as applied in RBO Hand’s PneuFlex actuators, where this kind of constrained area is referred to as the “passive layer” and includes embedded porous fabric. The PnueNet actuator developed by the Whitesides Research Group at Harvard takes advantage of what they call the “differential strain” effect to help achieve motions such as bending and twisting by using a paper layer to cause more rigidity. Similarly, a collaboration between UPenn and Cornell yielded an octopus-like skin by including fiber-mesh rings to make dynamic multidimensional motion.” – Chapter 10 Make:Soft Robotics

 

This past Monday we had the great experience of visiting Material ConneXion!  and their sustainable materials library . It was such a great experience and perfect complement to our Wearables W9 class (Manufacturing + Crafting) that night as well where Loomia came in to talk us through their process. I was attracted to so many materials, and really after signing up for the student account got lost in their Material Library archive for a handful of hours. What a mindblowing resource! Around 8000 material items to learn from in their digital archive. I found myself tending to be attracted to materials that:

 

• Natural category / thinking about biodegradable and renewable resources
• Hard materials becoming Soft – normally hard things that through various processes or additive materials had become soft
• conductive or electronic materials as explained in Material ConneXion’s Live Materials Review:Structural Electronics

 

 

 

Thinking about knitting soft sensors : Belkinox VN + Wool & the Gang 

Soft Robotics & Wearables class have been complementing eachother in really nice ways. After our Wearables make up class on Friday covering various soft sensor crafting techniques, felt excited about reaching out to sources through Material ConneXion’s database for samples for knitting soft sensors:

• Material: Bekinox VN [steel yarn]
• Manufacturer: Bekintex N.V [Belgium]
• Manufacturer Site: https://www.bekaert.com/
• Link to Material ConneXion Database
• Sustainability: Easily Recyclable, Single or Mono-materials
• Material: Continuous filament steel yarn with filament diameters of 0.48 mil (12 micrometers) for 275 filaments, and 0.56 mil (14 micrometers) for 90 filaments
• Usage: can be processed with textile fibers to fabricate electrically conductive textiles that prevent the build-up of static electricity
• Applications: include protective clothing, floor coverings, anti-static brushes, filters, electrodes for medical devices

 

 

 

• Material: Billie Jean Yarn
• Manufacturer: Wool and the Gang [UK]
• Manufacturer Site: https://www.woolandthegang.com/
• Link to Material ConneXion Database
• Sustainability: Easily Recyclable, Single or Mono-materials
• Material: Upcycled, pre-consumer denim waste. It has been developed in collaboration with The New Denim Project, a project within a 3rd generation family textile factory promoting conscious consumption and investment in sustainable materials.
• Process:after jeans are made, denim scraps and offcuts are gathered, ground back down into fibers, then respun into yarn. It comes in three different compositions and colors: 100% upcycled denim (Raw Denim), 60% upcycled denim and 40% upcycled raw cotton (Dirty Denim), and 20% upcycled denim and 80% upcycled raw cotton (Washed Out Denim). As the yarn is upcycled from denim production, it ends up saving 20,000 liters of water per kg compared to ‘fresh’ cotton production. It is lightweight, dye- and harsh-chemical-free and has excellent drape. Unlike some ‘denim yarn’ that is dyed soft cotton, this has the texture and feel of actual denim.
• Usage / applications: It is used for crocheting and hand knitting sweaters, tops, or year-round wardrobe staples, as well as accessories.

 

 

 

 

 

 

Thinking about Material Categories

The Material ConneXion library  is broken down into 8 different material categories:

1. carbon
2. cement
3. ceramic
4. glass
5. metal
6. natural
7. polymer
8. process

 

 

More soon!

 Water storage & the Desert Kangaroo Rat 

• How could we use a counter-current exchange system to help minimize the amount of water lost from the respiratory system process for humans in arid climates? Or if it could apply to cooling mechanisms / systems for machines? 

Originally for the assignment I started thinking about jellyfish both their phosphorescence and self-healing abilities. However, there’s a lot of current existing technology and applications centered around those qualities so tried to think a little more on another animal and came across the kangaroo rat ❤ It has an increased ability for water storage, having adapted to its desert climate. According to its wiki page there are a few qualities that play into its superwater storage ability are its kidneys, its back legs that allow it to bounce around large areas for high carb seeds that yield it water, and its skull anatomy.

I wonder if there’s a way to incorporate the structural understanding or its longer nasal cavities into housing for tech to keep it cooler or more moist. Thinking about the potential benefits of a counter- current exchange system.

“Desert kangaroo rats have the longest nasal cavity of all the kangaroo rats, which allows for better water conservation. Hot, dry air can remove water from the body. The long nasal cavities reduce this water loss by cooling the air leaving the lungs. Cooling air releases moisture for reabsorption to the body so its loss can be avoided in a situation where water is a precious resource.^[5]” 

 

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Skull Anatomy[edit]

Desert kangaroo rats have the longest nasal cavity of all the kangaroo rats, which allows for better water conservation. Hot, dry air can remove water from the body. The long nasal cavities reduce this water loss by cooling the air leaving the lungs. Cooling air releases moisture for reabsorption to the body so its loss can be avoided in a situation where water is a precious resource.^[5]” 

(slide from powerpoint presentation Illinois University )

 

 

https://www.pbs.org/wgbh/nova/article/evolution-of-bioinspired-robots/