TPU (thermoplastic polyurethane) is a flexible, elastic 3D printing material that combines the properties of plastic and rubber. Unlike rigid PLA or PETG, a part printed in TPU bends, stretches, absorbs impacts and returns to its original shape. That\u2019s why TPU for 3D printing<\/strong> is chosen when elasticity, cushioning or resistance to mechanical stress is needed.<\/p>\n Chemically, TPU belongs to the polyurethane family. Its molecular structure contains both hard and soft segments, which gives it a unique balance of flexibility and strength. In 3D printing this material<\/a> occupies a niche of its own \u2014 it\u2019s indispensable where a rigid plastic would simply crack.<\/p>\n The key property of any flexible material is its hardness on the Shore scale. Most TPU filaments for desktop 3D printers have a hardness of 95A<\/strong> \u2014 the standard that gives the best balance between flexibility and ease of printing. For comparison:<\/p>\n The lower the number, the softer the material \u2014 and the harder it is to print. For the vast majority of jobs, TPU 95A<\/strong> is the ideal choice: flexible enough for gaskets and cases, yet it feeds into the printer reliably.<\/p>\n TPU stands out with a whole set of properties that no rigid plastic can replace:<\/p>\n Printing with flexible filament is quite different from working with ordinary materials. TPU demands patience and the right settings, otherwise you\u2019ll get a tangle of strings instead of a part. Here are the main nuances:<\/p>\n TPU is printed slowly \u2014 a typical speed is 20\u201330 mm\/s<\/strong>, while PLA prints comfortably at 60\u201380 mm\/s. Trying to go faster makes the soft filament buckle in the extruder instead of being pushed through the nozzle.<\/p>\n The best results come from a Direct Drive<\/strong> extruder, where the motor sits right above the nozzle. In Bowden systems (with a long tube between the motor and the nozzle), soft TPU often jams or compresses in the tube. Printing on a Bowden is possible, but only with the hardest grades (98A+) and at minimum speed.<\/p>\n The main cosmetic problem when printing TPU is stringing<\/strong> (thin threads between features). The flexible material doesn\u2019t respond well to retraction, so it\u2019s hard to get rid of strings completely. Lowering the nozzle temperature by 5\u201310\u00b0C and using a minimal retraction distance (0.5\u20131 mm for Direct Drive) helps.<\/p>\n TPU is printed at a nozzle temperature of 220\u2013240\u00b0C<\/strong>, with the bed at 50\u201360\u00b0C. Bed adhesion is usually excellent, but removing the finished part can be tricky \u2014 the flexible base clings to the surface. A light coat of release agent on the bed or a removable build plate helps.<\/p>\n TPU\u2019s unique properties make it the ideal material for a whole class of items that can\u2019t be printed in rigid plastic:<\/p>\n There are alternatives to TPU on the market, but each has significant limitations. Let\u2019s look at the key differences:<\/p>\n Some manufacturers offer flexible PLA, but its elasticity is much lower \u2014 it\u2019s more \u201ca plastic that bends a bit\u201d than a true elastomer. Soft PLA is less abrasion-resistant, can become brittle over time and doesn\u2019t provide real cushioning. Its only advantage is easier printing, as it\u2019s less prone to stringing. It will do for decorative parts, but not for functional ones.<\/p>\n Real silicone can\u2019t be printed on ordinary FDM printers \u2014 it needs specialised equipment. Silicone parts are made by moulding, which is much more expensive for one-off items. TPU at 85A\u201395A hardness gives properties close to silicone but prints on a standard 3D printer, which makes it an affordable alternative for prototyping and small batches.<\/p>\nShore hardness: what the numbers mean<\/h2>\n
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Key properties of TPU<\/h2>\n
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Printing TPU: what you need to know<\/h2>\n
Print speed<\/h3>\n
Extruder type<\/h3>\n
Stringing<\/h3>\n
Adhesion and temperature<\/h3>\n
Where TPU is used: the best use cases<\/h2>\n
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TPU vs soft PLA and silicone<\/h2>\n
Soft PLA<\/h3>\n
Silicone<\/h3>\n