Is it possible to print with rubber?
The answer is simple: no. Rubber is a type of sticky material that is pressed hot into a mold in which it cools and vulcanizes. When rubber vulcanizes, it becomes solid and holds its shape. However, after vulcanizing, rubber will never become liquid again. If rubber is heated again, it will burn. For 3D printing, you need a material that liquefies in a controlled way. This is not possible with rubber, so rubber is not suitable for printing.
What is possible, though?
Synthetic materials such as Thermoplastic Elastomers (TPEs) are good replacements for rubber. TPEs are suitable for printing. TPU filament is such a TPE, it has the same flexibility as rubber but it already melts at 60°C. Rubber is an organic material: the properties of rubber cannot be influenced. However, with TPU we can determine, for example, hardness, heat resistance and wear resistance. We imitate the organic material, but we ensure that we get the desired and most optimal properties.
TPEs, including TPU, are used for various applications in industry. You can think of shoe soles, but industrial applications such as sealing rings are also a good example.
What do I need to consider when printing with TPU?
Printing with TPU is difficult. Therefore, it is necessary to practice with PLA first before printing with TPU. TPU needs more time to melt and flow. If you print too fast, the material will collapse. Therefore, it is important to reduce the printing speed. The type of printer you use is also relevant to printing TPU. If the drive motor is at the back of the printer, the material is pushed through the extruder to eventually melt into the print head. With direct-drive printers, where the motor is located in the print head, the filament does not have to be pushed through the entire extruder. It only has to travel a short distance until it is melted. Imagine pushing a rubber band through a pipe, the rubber band will accumulate: the greater the distance, the harder it gets. If the drive motor is in the print head, the filament has to travel a shorter distance. So you need a printer with a direct drive to print well with TPU filament.
How do you affect flexibility?
There are different TPEs available: the ones that are really stiff and others that are really elastic. However, the elasticity of the final product is not only influenced by the filament used. The printing technique also affects the elasticity. The thinner you print, the more elastic your product becomes. For example: printing a honeycomb structure creates thin layers with air in between. In this way you can determine which part is more flexible than the other. Thanks to the printing technique, you can achieve different levels of flexibility. When rubber is vulcanized, the end product is always solid. So it is not possible to play with the elasticity of rubber.
Can I combine support material with TPU?
When you use support material, you have to pay attention to the print and bed temperatures. These should be about the same temperature as the filament being used. PVA needs about the same temperature as TPU and therefore PVA is the best option to combine with this filament. Is it possible to combine TPU with a material other than the carrier material? Yes, but in this case both must also have the same print and bed temperature. ABS needs a higher temperature than TPU. Therefore, this would not be a good combination because the TPU filament will melt on the print bed. We also recommend that when printing with two materials, the parts should be mechanically joined. That way, the parts will stick together even if the print adhesion does not. More information on printing with support materials can be found here.
Would you like to print flexible 3D models?
Our dddrop RAPID ONE features a direct drive, so it’s suitable for printing TPU. Furthermore, for optimum print quality, we offer our own dddrop TPU filament. In case you have any questions, please feel free to contact us: email@example.com. We would love to help you.