5-Axis CNC and die casting
CNC machined components of LTS headphones are to be made out of 6061 or 7075 „aerospace" grade aluminium, as well as 316L Stainless steel, on 5-axis CNC machines. Aluminium components can later be finished using a more commonly known Type II anodizing process in combination with a brushed or finely textured surface finish in various colors, as well as the more expensive Type III anodizing process, also known as Hardcoating, commonly used on firearms due to durability, longevity and a non-reflective surface. It is more limited in terms of color choices, and looks best in black or grey tones with a finely textured matte surface, which are also my personal favorites. Other surface finish options such as ceramic coatings, automotive grade paints, powder coating, chrome plating, as well as just raw polished or sanded aluminium are possible. Stainless steel can be used for decorative components such as the LTS logo, or components that will be polished to a mirror finish. Because of the higher surface hardness of stainless steel compared to aluminium, it will retain the polished finish for a longer time.
These materials are relatively light, but very strong and durable, and not only improve the objective characteristics of the headphones, but also improve the subjective ones and increase the perceived level of quality. There is just something in the cold and solid feel of metal that can't be replaced by plastic, no matter how high-tech it is. For that reason, certain components on the headphones that could be manufactured using plastic materials in order to slightly reduce the cost, will be manufactured using metals in favor of quality and longevity, unless otherwise required.
In case of higher volume production in the future (200+ units of a single component), replacing CNC machining with die casting methods for production of metal components is a possibility and would be ideal. Because die casting requires a sizeable investment at the beginning of the production process in order to have complex and expensive steel molds produced, it is not the best choice in low volume manufacturing.
These materials are relatively light, but very strong and durable, and not only improve the objective characteristics of the headphones, but also improve the subjective ones and increase the perceived level of quality. There is just something in the cold and solid feel of metal that can't be replaced by plastic, no matter how high-tech it is. For that reason, certain components on the headphones that could be manufactured using plastic materials in order to slightly reduce the cost, will be manufactured using metals in favor of quality and longevity, unless otherwise required.
In case of higher volume production in the future (200+ units of a single component), replacing CNC machining with die casting methods for production of metal components is a possibility and would be ideal. Because die casting requires a sizeable investment at the beginning of the production process in order to have complex and expensive steel molds produced, it is not the best choice in low volume manufacturing.
Carbon Fiber & Graphite SLS
The use of carbon fiber and graphite reinforced polyamides produced using Selective Laser Sintering technology is at the core of LTS headphones. These are technologies and materials that, just a few years ago, were used only by a handful of aerospace and automotive companies, and are another example of pushing the quality to the highest level and doing something unique and not seen before in the headphone world, as well as keeping up with the most modern technologies available. They enable the production of very geometrically complex and detailed 3D shapes that are often impossible to create using CNC machining or injection molding. Materials and manufacturing methods mentioned here are not to be confused with regular FDM 3D printers that most people are familiar with. These methods use professional industrial additive manufacturing machines, costing upwards of €100000 each, just to put comparisons with common 3D printers into perspective. The mechanical properties of these parts are vastly superior to those produced even using professional FDM 3D printers and their dimensional accuracy and tolerance levels, as well as freedom of design, are on entirely different levels, to such an extent that none of the LTS headphone components can be produced using FDM 3D printers at anywhere near an acceptable level of structural and dimensional characteristics. In order to produce the parts using FDM printers, all of the tolerances and dimensions would need to be reworked in the designs, and even then a high percentage of FDM produced components would be unusable due to manufacturing inconsistencies. For that reason FDM is avoided and SLS is the obvious choice. We could say that anything above 0.1 mm of a dimensional error per 100 mm is already unacceptable, but generally better than those tolerances are achieved with no issues using SLS technology. Many of LTS headphone components are designed with assembly tolerances as small as 0.05 mm, while still fitting together perfectly, and can be disassembled with ease, which is a testament to their quality.
On top of being incredibly dimensionally accurate and stable, carbon fiber reinforced polyamide used in production of key structural components has the highest stiffness to weight ratio of any 3D printing plastic material currently available on the market, and is approximately 7 times stiffer and 7 times stronger than ABS plastic per weight, as well as thermally stable up to 170°C. High relative stiffness of this material, as well as good noise and vibration damping properties, make it especially well suited for headphone purposes, because it enables the creation of extremely rigid and acoustically inert components, while still keeping their weight relatively low. Graphite reinforced polyamide is used as well, and is very similar to the carbon fiber reinforced one, with slightly lower stiffness and strength to weight ratios, but more flexibility and higher elongation at break, for applications where those properties are more welcome. Both materials represent the pinnacle of additive manufacturing plastics. The biggest downside of the graphite and carbon fiber SLS produced parts is the surface finish, which is dark grey, slightly rough, sometimes with typical 3D printing stepping lines visible on surfaces with small angles relative to the horizontal plane, so they are generally not used for components that are aesthetic in nature without further post-processing. However, as can be seen on the proof of concept headphone, an absolutely flawless surface finish is achievable on such components when proper post-processing methods are used. Find out more about achieving the best possible finish in the LEARN MORE page. In the motorsport industry components produced out of these materials are sometimes covered with a decorative carbon fiber sheet and clear resin, and then finished in a glossy or matte look. Of course, some people perhaps like the industrial, raw look of the components produced using these methods, and they will be made available in such form upon request.
On top of being incredibly dimensionally accurate and stable, carbon fiber reinforced polyamide used in production of key structural components has the highest stiffness to weight ratio of any 3D printing plastic material currently available on the market, and is approximately 7 times stiffer and 7 times stronger than ABS plastic per weight, as well as thermally stable up to 170°C. High relative stiffness of this material, as well as good noise and vibration damping properties, make it especially well suited for headphone purposes, because it enables the creation of extremely rigid and acoustically inert components, while still keeping their weight relatively low. Graphite reinforced polyamide is used as well, and is very similar to the carbon fiber reinforced one, with slightly lower stiffness and strength to weight ratios, but more flexibility and higher elongation at break, for applications where those properties are more welcome. Both materials represent the pinnacle of additive manufacturing plastics. The biggest downside of the graphite and carbon fiber SLS produced parts is the surface finish, which is dark grey, slightly rough, sometimes with typical 3D printing stepping lines visible on surfaces with small angles relative to the horizontal plane, so they are generally not used for components that are aesthetic in nature without further post-processing. However, as can be seen on the proof of concept headphone, an absolutely flawless surface finish is achievable on such components when proper post-processing methods are used. Find out more about achieving the best possible finish in the LEARN MORE page. In the motorsport industry components produced out of these materials are sometimes covered with a decorative carbon fiber sheet and clear resin, and then finished in a glossy or matte look. Of course, some people perhaps like the industrial, raw look of the components produced using these methods, and they will be made available in such form upon request.
Multi-Jet Fusion PA12
Another plastic material that will be used on LTS headphones is PA12 polyamide, which is very similar to the base material in carbon fiber and graphite reinforced materials, except it's not reinforced by any additional material added to it in the basic version. A glass reinforced version of this material is available as well, with an increased level of rigidity and strength, but reduced elasticity. The technology used to produce parts out of these materials is one of the newest additive manufacturing processes on the market, called Multi Jet Fusion or MJF. This is a unique technology developed by HP that became publicly available in 2016 and which excels at quickly producing components with a high quality surface finish that require no post-processing and can be used as end products in their raw form. Of course, the material possesses all mechanical properties that PA12 is known for, such as high strength, toughness, high elongation at break, thermal stability, UV stability, high chemical resistance, vibration damping properties, etc. It is available in grey and black colors. Components produced using this technology have a very finely and uniformly textured surface that is very pleasant to look at and nothing about it suggests that it's a result of additive manufacturing. The surface finish is very similar to that found on most injection molded plastic components with a fine bead-blasted texture, and for that reason it can be used for production of components on which the visual aspect is of a high priority. That being said, it's still a mechanically excellent material and vastly superior to ABS most commonly used in headphone manufacturing, especially the glass reinforced version. Another advantage of this, as well as the previously mentioned SLS materials, is the fact that they don't squeak, crackle or rattle like most plastic materials do, so tightly assembled components manufactured out of these materials give off an even higher sense of quality and solidity, because they never make any unwanted sounds. Of course, the components don't have to be used in their raw form, and can be post-processed to a desired finish, including various automatic polishing methods, glass bead blasting, sanding, painting, etc. All of the guidelines for post-processing available in the post-processing guide section apply to this material as well. One disadvantage of this technology is a relatively high cost of production compared to injection molding in larger production runs, but that is understandable when we take into consideration the fact that MJF machines range up to €300000 in cost and they can produce components with incredibly complex and detailed 3D geometries that are impossible to produce with injection molding. However, it is still a considerably cheaper material than the Carbon Fiber and Graphite reinforced polyamides. MJF PA12 will be selectively used on LTS headphones, primarily for production of components visible on fully assembled products, or for the production of components in more affordable versions of DIY kits.
More details on use of materials are available in the sections describing individual headphone models and their components.
More details on use of materials are available in the sections describing individual headphone models and their components.
DMLS Metal 3D Printing
Future LTS headphone models, including some that I'm already very actively working on, and should become available in the second half of 2020, will rely on metal 3D printing as well. This is a technology very similar to the previously mentioned SLS plastic 3D printing technology, except it uses high-powered lasers to melt and solidify metal powder into complex, solid 3D objects. It represents the absolute cutting-edge of additive manufacturing technologies, being almost exclusively reserved for use in aerospace, medical and high-end automotive industries at the moment. I plan to utilize them for production of the world's first headphones featuring 3D printed metal components, and a highly efficient, bio-mechanical design. Various metal materials are available for use, such as Aluminium, Stainless Steel and Titanium. This technology can produce incredibly intricate and complex 3-dimensional metal components, which can't be produced using CNC machines or die casting. It offers great dimensional accuracy, unparalleled mechanical properties and very few design rules, enabling the creation of incredibly strong, stiff and efficient components, using as little material as possible to achieve more than ever before with older manufacturing methods.