Just over a decade ago came a great innovation in a staple design material. The kind you'll come into contact with during your first year at design school. And that is an air-cured, hand-formed rubber also known as Sugru - which is the Gaellic name for "play." It feels like modeling clay and you can mold it into any shape. We covered it when it first launched. After curing it is what you'd expect from a rubber-like material, flexible, grippy, sticky and waterproof. And it's very practical. It can repair everything from toasters to computer cables. And withstand extremes from the dishwasher to the Arctic ocean (temperature ranges from -50 to 180 degrees Celcius.) Check out all the creative uses featured on the sugru site site. It's pretty endless.
Its sticking power is best shown when it bonds to ABS (see video below.) It's sold in three, five and eight single use packs, in primary colors, or black and white. But it's going to stick to a lot: Aluminum, steel, ceramics, glass, wood, many plastics, leather, silicone, butyl rubber, and sugru itself. It is an electric insulator, so that is why you can safely use it to repair electrical cords under 24 volts. You typically have about 30 minutes to work with sugru once it is removed from its packaging and the cure time is 24 hours (per 3-5mm depth.) The cured material is resistant to UV light, oxidation, fire and water.
If you are a fresh industrial design student, you'll most likely have your first try at 3D printing this semester or this year. And while a lot of focus has been on the printers themselves, it's equally important and fascinating to look at the materials we can use.
There are surprisingly few limitations placed on the kinds of materials used to print 3D objects. As additive manufacturing develops into a widespread practice it's important to focus on the potential of the ingredients used. Here's a rundown of the popular and the strange.
The most commonly used materials today are the thermoplastics (polymers.) Typically the polymers are in the form of filament made from resins.
- Acrylonitile butadiene styrene (ABS) also known as lego plastic, is perhaps one of the most commonly used plastics in 3D printing.
- Polylactic acid (PLA) has the flexibility to be hard or soft and is starting to gain popularity. There is also a soft form of PLA that is rubbery and flexible.
- Polyvinyl alcohol (PVA) is a dissolvable material that is used as a support, that then gets washed away once the object is created.
- Polycarbonate requires high-temperature nozzle design and is in the proof-of-concept stage.
Plastics can be mixed with carbon fiber to make them stronger without adding weight.
There are also several metals that can be used for additive manufacturing:
Several types of processes work with metals and metal alloys. These are direct metal laser sintering (DMLS), electron-beam melting, selective laser melting (SLM). SLM can worth with plastics, ceramics abut also metal powders, and can produce metal objects that have strikingly similar properties as those of traditionally manufactured metals. (We previously posted videos of each of the methods listed above.)
If you're an industrial design student, now that school is back in swing you've probably got your hands on some foamcore or blue foam. Did you ever ask yourself what that stuff really is?
Let's start with the first one. The original foamcore was created and marketed in 1957 by the Monsanto Company. (Yes, that Monsanto, the leader in the genetically modified seed industry.) Their original brand name for the material was: Fome-Cor.
Foamcore, aka foamboard, is lightweight, easily cut, and surprisingly strong. In it's most basic form you'll find three layers: An inner layer of polystyrene foam, bookended by two sheets of clavcoated paper or simply kraft paper. The surface paper is slightly acidic but you can find acid-free versions for archival photography.
Junior and Senior ID majors already know this, but for you sophomores or first-year grads: One must be careful if using glue or paint with foamcore. Because glues, especially superglues, and paint cannot adhere to foam, it will actually melt and dissolve it. What you need to use are spray adhesives like 3M's Super77 or Loctite. Some might try using hot glue but do so with caution, as the heat can warp the board.
For those of you about to enter Industrial Design programs, you'll find epoxy resins are a staple studio adhesive. They're part of the class of super adhesives called structural or engineering adhesives, being a vital part of aircraft construction or on the smaller-scale, furniture design (see the wood fossil table below, made by Studio Nucleo), or even used in root canals, to bind the gutta-percha to the tooth.
Epoxy resins react with what are called polyfunctional amines, acids as well as phenols and alcohols - all commonly known as hardeners or curatives. Once mixed such epoxies transform from a liquid to a solid and become very strong, withstand high temperatures and have high chemical resistance. They are called thermosetting resins, because they cure by internally generating heat.
The important thing to note when one is mixing epoxy resins is the epoxide number which represents the amount of epoxide in 1 kg of resin. This number is used to measure how much hardener you'll need to cure the epoxy. However, the mix ratio can vary by as much as 10 times, from 10:1 to 1:1. Some epoxy resin / hardener combos will cure at room temperature but most need a lot of heat, from 150° C and up to 200° C. If the resin is not heated properly the material will lose its super adhesive properties.
Wind energy is gaining support in the U.S., both on ground and in the ocean. And the design specs for wind turbines are getting pretty sophisticated as they require exact performance requirements, including super lightweight material and a potential to operate for decades without maintenance. Meanwhile, the turbines are becoming longer, measuring as much as 75 meters, close to the wingspan of an Airbus jet. Most of the turbines in North America and Europe are made of balsa wood: It's durable, dense and yet lightweight... but it's expensive. So there is a new solution coming from materials scientists at Harvard.
Balsa's cellular structure has high strength per volume of space, as its cell walls carry the weight, but it has a lot of empty space which makes it extraordinarily lightweight. This new material is engineered with the same design (see photo above), so it can mimic the best qualities of balsa. But it is made from epoxy-based thermosetting resins and it's fabricated with 3D printers, which provide unprecedented precision.
Check out how they did it in the video here:
Typically 3D printing uses thermoplastics and resins, but these are not usually used in any sort of engineering solutions. This new material—based in epoxies—opens up another channel for 3D printing that has structural applications.