Bespoke and Repetitive: Converging Technologies in the Design of Custom Products
Zerong Yang | MDes Thesis | Research Phase | Fall 2021
The traditional ways to design customized products require a relatively larger amount of time and cost, but the potential growth in personalization is coming as the result of a set of advancing and potentially disruptive digital design tools that have been evolving over several decades. Specifically, the growth of 3D scanning, generative design, and digital fabrication has come to impact product design in different ways, and the intersection of these three technologies could trigger growth in designing for bespoke products.
To better understand the design of custom products, I conducted three interviews with experts who work with custom products. 3D scanning, generative design, and digital fabrication play important roles in the process. The intersection of the three technologies provides designers with a great opportunity to design custom products. Some categories of custom products are listed with examples, and gaming mouse within the repetitive use tools subcategory is selected for future ideation and design.
3D scanning, generative design, and digital fabrication have been in use in a long time. However, in recent years, the hardware development of 3D scanners and printers, the software improvement for generative tools, and further research about the three technologies have made them more accessible to industrial designers as well as the average end-user.
2.1. 3D Scanning
3D scanning is a way to capture a physical object’s exact size and shape into the computer world as a digital 3-dimensional representation. It has derived great opportunities for ergonomic product designs. There are two main ways to do an ergonomic design based on 3D scanning. The first one is made-to-measure products for specific users. Based on the 3D scans of the user’s body, a bespoke product may be made to custom fit the user. The second way is finding the most suitable design for a wide range of people based on a variety of 3D scans. A five-step process is created to design products with multiple body scans: (1) establishment of 3D human scan database, (2) analysis of anthropometric measurements, (3) development of sizing system, (4) development of representative models, and (5) design of size and shape of product. (D’Apuzzo 2017)
3D scanning devices are divided into two categories: contact and non-contact scanners. Contact devices use probes that follow the physical surface. Contact devices have high accuracy, but the scanning time is longer because points are registered sequentially at the probe. Besides, soft materials cannot be accurately measured due to the contact pressure. (Helle and Lemu 2021) Non-contact scanners capture geometry through lasers and optics, computer vision, photogrammetry, light detection and ranging (LiDAR), and imaged based techniques. These devices can capture large amounts of data in short time, but they have a relatively lower accuracy. Since light is used in scanning, non-contact devices have problems with shiny and black surfaces, resulting in a need for temporary coating. (Helle and Lemu 2021)
Once 3D scan images are gathered, the images are processed and analyzed for a certain design purpose. A raw 3D scan image generally has incomplete features such as uncaptured areas, noise, or nonoptimal mesh structure that need to be edited in order for the raw 3D image to become more useful for product design. (Lee et al. 2019) There are many image-editing software for different purposes such as Geomagic, Artec Studio, GOM Inspect, MeshLab, and MeshMixer. After applying functions like hole filling, noise reduction (or smoothing), and mesh optimization (or remesh), designers can analyze the size and shape of 3d scanned object and then make further adjustments.
2.2. Generative Design
Generative design is a technology in which 3D models are created and optimized by computer software. It has been an important tool since 1970’s and was adopted in computer science, architecture, engineering, and construction. In recent years, it has become popular in design disciplines. (Lobos, n.d.) When looking at applications closer to product design and fabrication, software company Autodesk (2018) proposes four types of generative systems: form synthesis, lattice and surface optimization, topology optimization, and trabecular structures. Generative design takes advantage of the computer’s power to help designers explore multiple alternatives and optimize the existing designs.
There is different generative design software in the market: Autodesk Fusion 360, Solidworks Topology Optimization, Grasshopper in Rhino, and nTopology. Coding is not required for the software, but it still requires intense mathematical knowledge and programming. Designers may need some basic programming skills to set the constraints. The creation of generative iterations offers solutions that work from a technical side, based on rules and goals, but not always take into account elements such as aesthetics, emotional attachment, and user experience. The designer’s intuition is a key tool for connecting all of these elements together in order to find engaging solutions that benefit from generative approaches. (Lobos, n.d.)
2.3. Digital Fabrication
Digital fabrication is a design and manufacturing workflow where digital data directly drives manufacturing equipment to form various part geometries. This data most often comes from CAD (computer-aided design), which is then transferred to CAM (computer-aided manufacturing) software. The output of CAM software is data that directs a specific additive and subtractive manufacturing tool, such as a 3D printer or CNC milling machine.(“Digital Fabrication 101” n.d.) Accessible digital fabrication tools bridge the gap between design and manufacturing. They provide efficient ways for engineers and product designers to produce anything from prototypes to final products.(“Digital Fabrication 101” n.d.)
There is a wide variety of digital fabrication tools, and 3D printers and CNC tools are the two major types. 3D printing (additive manufacturing) is the process of creating parts by successively adding material layer by layer. The categories of 3D printers include fused deposition modeling (FDM), stereolithography (SLA), and selective laser sintering (SLS). Computer numerical control (subtractive manufacturing) is the process of removing material to a specific shape through cutting, boring, drilling, and grinding. CNC tools include CNC machining, laser cutters, and water jet cutters. (“Digital Fabrication 101” n.d.)
3. Research — Custom Products
For my primary research, I conducted three interviews with two professionals in the industry and one expert at the University of Washington. They are all using 3D scanning in their workflow to create custom products through digital fabrication.
3.1. Animal Prosthetics
I interviewed Adam Hecht, who is co-founder & director of Additive Manufacturing DiveDesign. The company simplified the process of making animal prosthetics through digital tools. They partnered with Chris Landau, who has been working with Grasshopper for 15 years. After 2 months of incrementally modifying the algorithm, they successfully developed an algorithm for generating prosthetic models from 3D scans.
The traditional way to create a single full-limb prosthetic takes a minimum of 15 hours to complete. The process began by sealing the patient mold to prevent leaks and then mixing plaster to create the positive. Sheets of plastic were heated and wrapped over the plaster positive, then trimmed and shaped further. Finally, foam was added along with hardware and the leg. (“Bionic Pets” n.d.)
For the new process, they send a casting kit to the client, and the client wraps the patient with fiberglass casting tape. The molds are sent back to the company when the tape is hardened. Then, they use an iPhone medical-grade 3d scanning app called Comb Scan to scan the molds and clean up the scans in MeshMixer. It takes 10 minutes for setting up the scans in Grasshopper and 2 minutes for processing. Through this algorithm, the finalized 3D printable models of the prosthetics are generated in 12 minutes. At last, they 3D print the prosthetic in TPU (Thermoplastic polyurethane), which is a type of flexible and elastic 3D printing filament. The custom design allows the prosthetic to be optimized for comfort, breathability, and flexibility.
3.2. Custom Fit Earphone
I conducted an interview with Andrew Tenney, who is a quality assurance manager at Ultimate Ears Pro. Ultimate Ears produces custom in-ear monitor (IEM) for the world’s top touring musicians for over 20 years. Each pair of the earphone is molded to custom fit the unique contours of the ear.
For the Professional IEMs series, there are two ways to get the digital impression of ears from the customer. Traditionally, custom in-ear monitors are created by taking a mold of the inside of the ear. The mold uses a fast-drying silicone from Westone, and it is injected into the ear cavity by an audiologist. Then the impression is scanned by a 3D scanner. The other way is digital ear scanning. The UE 3D Ear Scanner from Ultimate Ears is the only digital scanner on the market that offers the necessary precision to create custom in-ear monitors.
The next step is detailing the ear impression. They use a software called 3Shape to eliminate all the unnecessary parts of the model and then use an SLA 3d printer to fabricate the part with acrylic or resin.
3.3. Human Prosthetics
I went to Sanders’ UW Research Lab and met Conor Lanahan, who is a PhD Candidate in Bioengineering at the University of Washington. The Sanders’ Lab is creating the next generation of prosthetic scientists and researchers that will further advance the field and enhance the quality of life of people with limb loss.
At the lab, Conor showed me the process of how they duplicate a prosthetics socket for their research project. First, they use a contact scanner to scan the inside of the existing socket, and it takes about one hour to finish, because enough points have to be collected in order to create a mesh.
Next, they will use a software called Geomagic Design to turn the point cloud into a surface model. A STL file will be used to create a foam positive through CNC. Then, they will use carbon fiber, nylon, and resin to make the new socket by vacuum sealing them onto the foam positive. At last, a software called OMEGA Tracer is used to convert the STL file to an AOP format, which is a standardized format for prosthetics device building. The AOP file could be sent to manufactures for making prosthetics.
4. Findings and Opportunities
By interviewing with professionals and researching 3D scanning, generative design, and digital fabrication, I can see the potentials for making custom design products at the intersection of the three technologies. There is a loop among these technologies. The first step is to 3D scan a part of the human body or the impression of the human body. The second step is to generate a custom-fit model based on the necessary information from the 3D scans. An algorithm could be developed to save time and effort in designing custom-fit products for more users. The third step is to digitally fabricate the design through CNC tools or 3D printers. They are perfect tools to use for small-scale and customized production. If the final product does not fit or has any problems, it could be 3D scanned again for modification.
By examining how the intersection of these technologies is currently being leveraged by designers for bespoke solutions, I categorized custom products into three groups: industrial parts, repetitive use tools, and decorative objects. After interviewing three people in the industry who are doing animal prosthetics, human prosthetics, and custom fit earphones, I found the growing opportunities and attributes that make the design of customized repetitive use products a strong candidate for the adoption of the three technologies. Repetitive use tools could then be classified into three categories: wearable, hand-manipulated, and body-interactive.
5. Next Step
Although the three technologies provide growth opportunities in product design, there are also challenges in integrating and adapting these to an existing design workflow. I want to develop a method or framework for designing customized repetitive use tools and start a design project as an example to show the process.
5.1. Problem Space
For decades, mouse has been a key component of how people interact with computers. Most people spend a considerable amount of time with a mouse in their hands. Heavy use of a mouse can result in a repetitive strain injury to the wrist/s. The target people will be pc gamers who have a relatively larger chance to hurt their wrist due to the heavy use of the mouse. Esports pro players are training in front of the computers 12–18 hours per day, and many of them retired because of wrist injuries. However, there is no bespoke mouse in the market. Even pro esports players use the mass-produced gaming mouses.
To further explore how gamers use their mouse, I created a gaming mouse survey and sent it out to different gaming communities. I received effective 108 responses: 56% percent of them play games almost every day, and 36% of them play games for more than 4 hours each time. More than one-third of them indicate that they have forearm and wrist pain (muscle fatigue) or numbness and tingling to fingers (carpal tunnel syndrome). These two problems are the common injuries of heavy mouse use.
Too much compression to the carpal tunnel area combined with a lot of repetitive motions can lead to carpal tunnel syndrome, and it can be permanent damage if left untreated. For muscle fatigue, if the mouse user holds the hand in an extended position and keeps the same position for a long time, the activated muscles in the forearm will get tiring and even painful.
For the design project, I would like to design a custom-fit mouse with bespoke wrist protection to prevent or relieve carpal tunnel syndrome and forearm muscle fatigue.
When it comes to choosing the right gaming mouse, people usually consider the shape, size, weight, and other attributes of the mouse, but one of the most important factors to be considered is the grip type. There are three main grip types that have been identified: palm grip, claw grip, and fingertip grip. There has not been one mouse that could satisfy all the needs, so the difference among the three grip types is crucial to make any designs. From the survey, 28% of people use the palm grip, 54.2% of people use the claw grip, and 15.9% of them use the fingertip grip.
Palm grip is probably the most common type for non-gamers. The user rests the entire hand on the surface of the mouse. With this natural and relaxed position, the user has maximum support and a more comfortable gaming experience. Claw grip is more useful for speed and quick reactions. The user’s palm rests on the edge rather than the whole hand. By placing less weight on the mouse, the user will have much faster movements. Fingertip grip provides the fastest reaction times. Only the fingertips are touching the mouse. With such minimum contact with the mouse, the user can make movements as fast as possible.
From the survey, most gamers have not done any customization to their mouse. A few people did some custom paint and attached non-slipped grip stickers. A few people changed the paracord and mouse skates. Three people reduced the mouse weight, and one person added some weight. Although most people do not customize their mouse, there are still needs for customization on the weight and components of the mouse. It might not be easy for normal users to customize the shape of the mouse. A lot of gamers have trouble choosing the right mouse, and it is hard to find a suitable mouse without testing it in hand. More than 70% of people changed their mouses within two years, one of the reasons may be the discomfort of the mouse, so there is potential to create a custom fit mouse based on the user’s hand shape.
I explored some current “solutions” of carpal tunnel and forearm muscle fatigue that do not work for gamers: ergonomic mouse and wrist rest. Using an ergonomic mouse requires a learning curve, because the user needs to move the arm with a totally different axis. Besides, it cannot be used for gaming. The user will have less control because the mouse is clicked sideways. Wrist rest helps with muscle fatigue, but it makes carpal tunnel syndrome worse. According to Ergo Canada, wrist rests do not provide any significant ergonomic benefit and in fact will usually increase the number of risk factors for injury in the computer workstation. From the survey, only 10% of people use wrist rest. It blocks the users and prevents them from moving their hands.
5.3. Design Direction
For the solution, I plan to 3d scan the user’s hand or a manipulated object (the impression of the hand) based on the user’s grip style. The next step will be cleaning up the 3d models using image editing software (MeshMixer) and then importing the 3d models into generative software (grasshopper or nTopology) to generate a custom fit mouse and wrist support. The wrist support is attachable or wearable, and it has a constant slope from the mouse to the desk and does not end right at the carpal tunnel area.
In order to have the best user experience and 3d scan quality, I still need to try out different materials for the impression (different types of clay, silicone, plaster). I have to study the software and develop an algorithm from the generative software. A lot of testing needs to be done includes comparison and disassembly of different mouses (gaming mouse, ergonomic mouse, modular mouse) and other current products (computer gloves, palm rest) for carpal tunnel syndrome and muscle fatigue. I may also need to test different materials (resin, metal, carbon fiber, different types of plastics) and different digital fabrication methods (3D print, CNC) to make the outcome durable and stable.
“Bionic Pets.” n.d. Accessed December 14, 2021. https://www.divedesignco.com/works/bionic-pets.
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