Thermoplastic Polyurethane or TPU is referred to as the bridge between rubbers and plastics. The material appears rubber-like, which means it can be extremely flexible, durable and smooth to the touch. All these properties and compound versatility makes TPU widely used in many industries for coatings, components and customer goods.Order in TPU
|Tensile Strength||5076 psi *|
|Ultimate Elongation||750% *|
* Value for General Purpose TPU Resin (Shore 70A)
TPU material is a group of thermoplastic elastomers with good elasticity and resistance to stresses like abrasion and oil lubricants. Its structure consists of soft and hard segments linked together in the chain. The number and character of these segments can vary, resulting in a different material hardness of TPU from soft (Shore 30A) to very hard (Shore 100A), so the material is used both as soft engineering plastic and tough rubber. TPU is widely used as an additive for strengthening other materials. For example, composites of TPU and Polycarbonate or ABS have an improved flexural modulus up to 150,000 psi. In addition to hardness, TPUs can be manufactured with different base material components. There are three subgroups – polyester, polyether, and polycaprolactone:
Also, TPU can be mixed with specific agents or different proportion of compounds to achieve a certain appearance and features like fire-retardancy, biocompatibility, optical clarity and more.
TPU can be 3D printed with several technologies to achieve specific properties. FDM printers can melt and extrude TPU to create flexible parts like cases, seals, gloves and more. Being flexible, TPU filament can cause some difficulties while printing, including jamming, clogging the nozzle and deformation. However, with good calibration and settings, it opens the doors to a large variety of possibilities. SLS printers can use TPU based powders to sinter flexible parts as well. Sintered prints have 350% elastic elongation and long life cycle. There are wider dimensional and constructional possibilities compared to FDM technology, which makes it possible to 3D print bumpers, toys, seals, and footwear components.
Hard grades of TPU like polyamides can be easily machined using common metal and woodworking tools. Punching and thread cutting also works better for this group, however, 0.1 mm clearance for pre-drilled holes should be included into the design. While working with softer grades, the material’s flexibility and elasticity should also be taken into account. This requires using fast steel cutting tools, cooling systems and shavings removal.
TPU exhibits high-performance properties if processed correctly through injection molding. The material is non-abrasive, so a special coating on the tools aren’t necessary. Some manufacturers recommend pre-drying and post-treatment steps for imperfect parts. For molding TPU, the important factors are mold and nozzle temperature, pressure and plasticizing energy. If the molding process or an object’s design don’t suit the material, it may cause damage and shrinkage of parts. Despite special conditions required for molding, TPU components are extremely popular in various industries and can be processed with conventional thermoplastic manufacturing equipment.
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