Overview

The GSD has one Zünd cutter and ultrasonic welder available for welding heat-sealable materials. The machine is used for welding multiple layers of heat sealable fabrics such as TPU, Mylar, Nylon+TPU, and PVC fabrics. These tools are used within the school for model making, prototyping, and assisting with various forms of research.

Users can utilize the Zünd cutter with ultrasonic welder by both reserving a time slot through the Online Reservation App and sending an email to rvroman@gsd.harvard.edu.

Students' works form 2024 J-term course

Materials

Ultrasonic Welder (available in GSD)

Material link: https://www.amazon.com/gp/product/B08DV358X8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Fabrics

	TPU	Nylon + TPU	Mylar
Sealing	Easy	Easy	difficult
Elasticity	Somewhat	Rigid	Rigid

TPU (Thermoplastic Polyurethane)

Material link: Pneubots

0.1~0.3 thickness is ideal for small scale prototypes

0.3~0.7 thickness is ideal for large scale prototypes (furniture, facade)

Nylon + TPU

Material link: TBD

0.1 ~ 0.5 thickness is ideal

Mylar

Material link: Amazon.com: Plant Growth Mylar Films High Reflective Mylar Film Garden Greenhouse Covering Foil Sheets for First Aid Blanket Growth Room Camping Simple Tent,82.6 x 51.2 Inch(2 Pieces) : Patio, Lawn & Garden

Easy to break

Tube

Used for connecting inflatable prototypes to air pump

Material link: 3/16" ID Silicon Tubing, JoyTube Food Grade Silicon Tubing 3/16" ID x 5/16" OD 10 Feet High Temp Pure Silicone Hose Tube for Home Brewing Winemaking: Amazon.com: Industrial & Scientific

Air Pump

PnueVice : Used for inflation and vacuum.

Material Link: Home | Pneubots

BoxTech Aquarium Air Pump (only for inflation)

Material Link: Amazon.com : boxtech Upgrade Aquarium Air Pump, Ultra-Quiet Fish Tank Oxygen Pump with Adjustable Airflow, Powerful Air Pump with 2 Outlets to Pump Rich and Fine Air Bubbles : Pet Supplies

Valve

Used for connecting the tube from inflatable prototypes to air pump

Needs to be 3D-printed using Resin

valve 3d file : valve.STL

T-shape Connectors

Used for connecting inflatable prototypes

Material Link:

TPU Tape and Glue

Used for sealing holes (leaking region)

Tape Link: Amazon.com: TAMDESG Clear Repair Tape 2.75inch*9.8FT Waterproof High Elasticity TPU Repair Patch for Bathroom tub, Tent, Raincoat, Umbrella,Pool,Air Mattress, Bounce House, Swimming Ring, Awning Repair Tape : Sports & Outdoors

Glue Link: Amazon.com : Air Mattress Patch Kit, Salt, Hot Water and UV Resistant Pool Liner Patch Kit, Vinyl Pool Liner Repair Kit Repairs a Variety of Inflatables Including Hot Tubs, Inflatable Spa Pools : Patio, Lawn & Garden

Procedure

Set Up

Reserve a time slot through the Online Reservation App (minimum fabrication time is 1 hour) and send an email to Fablab.
Go to the Zünd cutter room. TA or Fablab facilities staff will assist students in implementing the ultrasonic welder to the Zünd cutter.
Place a 1/8-inch heat-resistant rubber sheet on the Zünd cutter. This will protect the Zünd cutter from melting due to the ultrasonic welder.
Place two layers of small pieces of heat-sealable fabric on top of the rubber sheet.
Place one layer of Teflon on top of the heat-sealable fabrics. This will prevent the welder from dragging and creating leakage on the fabric.

Welding

Turn on the power source of the welder and connect the cord from the welder to the power supply.
Run a test trial (1x1 inch rectangle) and check whether the two layers are sealed well.
- If it creates holes, it means the z-axis of the welder needs to be adjusted.
- If the welded lines have white bubbles, it means the power level of the welder is too high.
- If the lines are uneven, it means the cord connected to the power supply is too short.

Cleaning

Take out the welder from the Zünd cutter room.

Reference

PneuBots by Hye Jun Youn
1. PneuBots: Modular Inflatables for Playful Exploration of Soft Robotics | Extended Abstracts of the 2022 CHI Conference on Human Factors in Computing Systems (acm.org)
Aeromorph by Jifei
1. aeroMorph - Heat-sealing Inflatable Shape-change Materials for Interaction Design (youtube.com)
AuxeticBreath by Hye Jun Youn
1. Red Dot Design Award: AuxeticBreath (red-dot.org)
2. AuxeticBreath: Changing Perception of Respiration | Proceedings of the Fifteenth International Conference on Tangible, Embedded, and Embodied Interaction (acm.org)
Pneumatic Structures by Thomas Herzog
1. Inflatable Art, Architecture, and Design, the use of inflatables in design during the 60’s and ’70’s.
Inflatables Cookbook by Ant Farm
1. Combination of inflatables information and skills learned in process, easily accessible.
2. http://alumni.media.mit.edu/~bcroy/inflato-splitpages-small.pdf
The piper box
1. “The piper box was made with building wrap (probably Tyvek) and we melted the seams together with irons. This was easy and using irons was a convenient and effective way to bond the sheets together. I think it took only maybe four hours to assemble.”
2. https://www.flickr.com/photos/mwax/sets/72157626069094226/
ICE SHELTER INSTALLATION
1. http://www.archdaily.com/219734/fabricating-grounds-ice-shelter-installation-koepcke-prado
2. http://www.urbaindrc.com/portfolio - /digital-igloo/
MIMMI
1. http://www.urbaindrc.com/portfolio#/mimmi/
PERFORATED CLOUD
1. http://totallyepic.net/pp.html
LANDMARK CREATIONS Professional inflatable fabrication company, Minnesota
1. See their projects: https://vimeo.com/landmarkcreations
CLOUD CITY Tomas Saracenoe, Carpenter Center
1. http://www.archdaily.com/132706/video-cloud-city-by-tomas-saraceno

Archive Notes

✔ Iron + Wax paper+ Plastic tarp + Sleep deprivation

Awesome.

✔ Tyvek

Doesn't inflate so well.

✔ Mylar

Cool.

✔ Plastic

Fast, don't go too thick otherwise the weight of the material brings it down.

✔ Party plastic table cloths

✔ Tarp/Vinyl material (Heavy duty) + Seams

Professional inflatable manufacturer choice

Other things you might as well need

✔ Sticky Velcro

To enter inflatables or attach them to one another, etc.

✔ Vornado Fan

The cheap small kind is best for inflation.

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