3D Printing for Robotics

Published on April 19, 2017

3D Printing for Robotics

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  • 3D printing is used extensively to prototype, manufacture and customize robots.
  • The technology is used by researchers, companies and home users.
  • Small, unique and custom 3D printed parts match the low volumes of custom or new robots best.

Robots are often customized for particular applications. In applications such as customizing robot grippers or improving a robot on a production line, 3D printing can provide fast low cost solutions. When prototyping new robots or making small series of robots 3D printing can be used as a manufacturing technology. Exciting new applications such as 3D printing soft robotics or making integrated robots through 3D printing are frontiers that are beginning to be explored.

Best Materials for 3D printing robot parts

Generally surface quality of parts will be the main issue when wanting to 3D print robot parts. While desktop 3D printer users often use PLA as a material we would recommend ASA, ABS, PC or PETG as a 3D printing material for this application. ABS is a well known material with good strength and toughness. ASA is an alternative to ABS with similar performance but better wear in conditions in the long run. For robotics specifically ASA would in most cases outperform ABS. PETG is an alternative and can be sterilized which could make it ideal for certain robotics applications. PC (polycarbonate) has excellent impact strength and if the part will need to perform under high impact situations. On the whole based upon our testing ASA or PETG will meet most users needs and outperform other materials for this particular application. Higher strength and specifically higher wear characteristics mean that these materials will be much more suited for this application than PLA.

We recommend high degrees of infill for robot parts as well. In most cases desktop 3D printer users will fill their parts 30 to 40% but for robotics infill percentages such as 80% could improve part stability and wear characteristics. It is important to consider that layer adhesion and part directionality do affect 3D printed part’s performance significantly. The orientation of a part on the printer will have to be optimized to perform the best for the specific load under which the 3D printer is to be placed.

3D Printing for prototypes

3D printing excels at low volume parts and prototypes. For people creating all manner of robots 3D printing has been used to do initial production runs. This has been the case for small consumer robots, research robots and even some commercial robotics solutions.

3D Printing for open source robotics

One of the areas where 3D printing has seen the broadest adoption in robotics is in creating open source robotics. For hobbyists the idea of contributing to and improving an open source robot is an exciting one. Many are exploring robotics for the first time and 3D printing is an inexpensive way for them to prototype parts or to manufacture robots. 3D printed robot files are exchanged and this accelerates the spread of the robot. Open source projects using 3D printing can simply exchange files and each member can print them out locally. Files and parts can then be improved upon and these improvements can also be shared. This quickens the pace of the development of the open source robot and one reason why open source robotics and 3D printing play so well together. Another reason is that the individual robot parts are generally low cost and fit inside the build volumes of desktop 3D printers. A gripper part can be made for around $10 to $40. This is a very low cost part, especially considering that it is unique. Yet another reason why there is so much happening in 3D printed robotics is that there is a high degree of overlap between the skills and people in both fields. Both robotics and 3D printing use a lot of mechatronics skills combining engineering and software to make machines. Often robotics researchers are very interested in 3D printing and very able in operating the machines.

Kickstarters and start ups

A number of Kickstarters and robot start ups also use 3D printing for prototypes and later on production. 3D printing for them is a very cost effective way to produce prototype parts and iteratively develop these parts. Many of them then realized that they could take these parts into production. Fused Deposition Modeling (material extrusion) and powder bed fusion (laser sintering) are the technologies most used in open source robotics production. When a robot is being developed by home users FDM is the most used technology by far. In some cases people order parts from services and these are then often laser sintered. In terms of performance FDM parts are cheaper, tougher, have a closed surface texture and have higher dimensional accuracy. Laser sintered parts have finer details and smoother surfaces.

InMoov

One of the most talked about open source robotics projects is InMoov (pictured below). InMoov is a life sized open source robot conceived by Gael Langevin. This French designer came up with the idea to make a complete and working robot whose body was entirely capable of being made on desktop FDM 3D printers in 2012. Each of the parts were designed in such a way that they were printable without supports and fit inside the build volumes of the printers. Robot builders from all over the world joined the project and jointly develop the robot. The robot has articulated fingers as well as movable biceps, back, shoulders and arms. Eyes can be independently moved and sensors abound. The robot is built using off the shelf electronics components and inexpensive to build. By connecting 3D printers to open source and robotics InMoov is a fast developing project that blazes a path in making robotics more affordable and easy to develop.

 

3D Printing robot grippers

In industrial and smaller scale robots one thing that is happening is the 3D printing of grippers or other robot attachments. Often these grippers have to be customized for certain applications or parts. Depending on how a robot is to be used a custom gripper can reduce failure rates in the operation the robot has to carry out. With 3D printing one can customize the textures of “fingertips” or other contact surfaces for robots. Files can easily be adapted to add and optimize unique textures to improve gripping. The flexibility of parts can also be adjusted through changing infill percentages, wall thicknesses and infill patterns. In this way a gripper can be designed through which the shape, texture and part qualities can be optimized for one particular application. In an affordable way companies can improve the performance of industrial robots and cobots through customizing their grippers using 3D printing.

3D Printing soft robotics

A new field is soft robotics. In soft robotics, soft materials which can be deformed, shaped and changed are used in place of the more traditional rigid materials usually used in robots. On the one hand it is more challenging to manufacture, simulate and control soft materials when compared to rigid ones. On the other hand soft robotics open up new areas for robotics research and may lead to novel gripping and motion systems. In many cases soft robotics takes its design information from nature and natural systems. Soft robotics present a completely new way of thinking about robots. A robot becomes a dynamic deformable system that can use pneumatic muscles to in a disorganized seeming but very resilient way navigate through the world. Chemical reactions, phase changes and biomaterials may be used to power robots, a remarkable difference from the way robots are traditionally made.

3D Printing integrated functionality in soft robots

In 3D printing novel soft structures can be made using a wide array of materials. Integrated pneumatic muscles, actuators and phase change structures can be manufactured in place also. By creating a part in which all of the functionality is printed in place in one manufacturing step 3D printing can make integrated mechanical elements for robots. A complete actuator can be made just on the 3D printer and this points to a world where robots will be produced that consist of far fewer parts. Production steps can be minimized and the costs eventually may also be minimized.

Researchers are experimenting with a wide array of materials for 3D printed soft robotics including TPE/TPU type materials and silicones. Fused Deposition Modeling, Stereolithography, Objet Polyjet and other 3D printing processes are used for making robotics. 3D printing is also used to cast parts for soft robots.

With soft robotics actuators, pneumatic channels, printed circuits and microfluidic logic boards are being made. In essence the field is trying to make all of the constituent parts of the robot soft. In Harvard’s  soft robot the Octobot (pictured above) all of the structural components are 3D printed and it moves through a chemical reaction activating pneumatic muscles.