By Akitha Ekanayaka
3D printing, also known as three-dimensional printing, is an additive manufacturing technology that is not an uncommon word to the present world. There are three different classes of 3D printing which are hobbyist, engineering, and high-temperature printing. Hobbyist 3D printing is used to make simple decorations or architectural models. Engineering and high-temperature 3D printing is used as industrial 3D printing. Industrial 3D printing is widely used in high tech industries like research and development, automotive, soft sensors, and actuators. In Sri Lanka, none of the 3D printing companies offers industrial 3D printing as a service.
Hobbyist 3D printing uses around 250 degrees Celsius of nozzle temperature with 120 degrees Celsius bed temperature. There is no requirement for a heated chamber for this type of 3D printing. Although in engineering type of 3D printing, nozzle temperature goes up to 320 degrees Celsius while bed temperature increases to 160 degrees Celsius. In this method they use heated chambers or closed chambers. Build quality and chamber temperature are the two main differences between engineering and high-temperature printers. Industrial 3D printers (both engineering and high temperature working printers) must work 24 hours per day in the high-temperature mode consistently. Hence the build quality should be higher than the hobbyist printing.
For industrial 3D printing, common 3D printing materials like Polylactic acid (PLA+), ABS+ (Acrylonitrile Butadiene Styrene), PETG (Polyethylene terephthalate glycol) are rarely used. This is because these materials do not have enough strength to build rigid prototypes and their tendency to melt at low temperatures (direct sunlight can melt PLA). Although they are easy to print and have good accuracy, they are not suitable for industrial prototypes and consumer products.
CF Nylon, ULTEM 9085, Flex TPU/TPE and PP are known as the best materials for industrial 3D printing. Carbon Fiber Nylon (CF Nylon) has the highest tensile strength of all 3D printing materials. It is also known as black aluminum because the tensile strength of carbon fiber nylon is almost closer to aluminum. In the United States, carbon fiber nylon has the highest demand, and this material is used to make machine parts like jigs and fixtures for its similarity with aluminum. An aluminum machined part that will take about 2-6 weeks to make can be 3D printed overnight using carbon fiber nylon. Advantages like lightweight compared to metals, impact resistance and self-lubricating properties create a huge demand for this material in the automotive industry. Usually, nylon tends to warp during printing, but reinforced carbon fiber has decreased the warping effect of this composite material.
ULTEM 9085 is an outcome of an expensive military grade research project. Airplane interiors are made using this material. ULTEM 9085 has been researched and evaluated for 15-20 years, therefore it is a certified industrially applicable material. Also, ULTEM 9085 is the only material that FAA (Federal Aviation Administration of USA) has approved. This is an expensive material that is hard to print and requires a high-temperature printer. It can be autoclaved and make radiation resistive. It is one of the highest demanding 3D printing materials because of its certifications.
TPU means thermoplastic urethane and TPE means thermoplastic elastomer. These two are impact absorbing, ultra-flexible materials. TPU is good at heat absorption, and it can be used as a heat sink. Hence TPU is used for making flexible heat sinks for LED lamps. Also, this material is used in dual extruding 3D printers to make bending parts by printing flexible material layer between two hard material layers. Polypropylene, also known as PP, is another flexible 3D printing material that can self-heal. Polypropylene can be used to make hinges, but it is hard to print. Specific adhesives and packing tapes of heat beds are required to print this material. This material has a huge demand because PP is recyclable. Extremely chemical, weather and UV resistance are other advantages of polypropylene.
Industrial 3D printers use dual, triple, quadruple extruders and can print support materials. Support materials are a different material than the primary printing material and most of support materials are water soluble. When the printing process is finished, supports can be removed easily by soaking in water.
Metal 3D printing is trending nowadays given the consideration on minimizing difficulties in machining metal parts. Few additional steps are added in metal 3D printing compared to general 3D printing. Specific metal powder-based filament that binds with wax polymer is used for metal 3D printing. This wax polymer can keep the metal material in its raw form. Once the metal part is being printed, it should be put into a wash station. Combination of two chemicals which is a solvent-based material is going to remove 95% of polymer from metal part. Then the left part has higher brittle properties. After that, part should be put into sintering furnace. In here, part is going to shrink back to normal dimensions.
In conclusion, 3D printing technologies are trying to dominate the additive manufacturing world. Currently, 10% of parts manufacturing are done by 3D printing and machining has limited to 90%. Technologies of 3D printing are constantly updating, and researchers are expanding this area.
Information and image courtesy – https://visionminer.com/