3D printed Hand: FA3D

The FA3D hand is a 3D printed Hand printed with a flexible filament. The fingers of the hand have multiple joints, allowing for adaptive gripping. The fingers have elastic joints and can be printed as one part. Therefore assembly of the finger phalanxes is not necessary.

FA3D Hand
FA3D Hand

Due to its adaptive gripping, the FA3D Hand can hold a broad range of objects.

FA3D Hand holding paper cup

The FA3D Hand consists of 8 3D-printed parts. The parts can be  connected with standard bolts and nuts. Steel cables are used to actuate the fingers.

Parts of the FA3D Hand
Parts of the FA3D Hand

The hand is body powered. It can be controlled by pulling the control cable, by using a shoulder strap.

User wearing the FA3D Hand
User wearing the FA3D Hand

 

Ovipositor Needle I – Self-Propelling through Tissue

Developed in 2014, thickness 2 mm.

Wasp ovipositors  are thin and flexible needle-like structures used for laying eggs inside wood or larvae.  Wasp ovipositors are composed out of  longitudinal segments, called “valves”, that can be actuated individually and independently of each other with musculature located in the abdomen of the insect. In this way the wasp can steer the ovipositor along curved trajectories inside different substrates without a need for rotatory motion or axial push.

Inspired by the anatomy of wasp ovipositors, we developed an Ovipositor Needle containing a 2 mm thick “needle” composed out of four sharp and polished stainless steel rods, representing four ovipositor valves. The four valves can be individually moved forward and backward by means of  electromechanical actuators mounted in a propulsion unit that is standing on four passive wheels. If the needle is inserted into a gel that represents tissue, and if the four valves are sequentially moved forward and backward, the friction behaviour around the valves in the gel will result in a net pulling motion that drives the needle forward through the gel. The ovipositor needle is therefore self-propelling, meaning that it does not need a net pushing motion for moving forward through tissue like normal needles do.

Ovipositor Needle I is part of the  WASP project that focuses on the development of steerable needles for localized therapeutic drug delivery or tissue sample removal (biopsy). In a new prototype that is currently under development, we aim to extend the self-propelled needle with steering capabilities at an outer diameter of just 1 mm.

 

Publications

Automatic design and manufacturing of upper limb prosthetic sockets for developing countries

Comfort and functionality of upper limb prosthetics is highly dependent on socket performance. Correct anatomical fit is therefore of paramount importance for prosthetic designs. We believe that the complex design process of prosthetic sockets can be achieved automatically using accurate anatomical models of the stump. With the increasing advance in smartphone technology it is possible to reconstruct digital models based on camera information. We plan to explore current technologies for generating 3D digital models from multiple 2D photos and assess such techniques to stablish a framework in which smartphone technology can be used to generate 3D computer models of upper limb stumps. Using precise geometry of the stump and current CAD technologies it is possible to create a socket design that fits accurately into the residual limb. We plan to adopt such process to build fully working prosthetic sockets using 3d printing technology for developing countries.

Contact: Juan Cuellar, J.S.CuellarLopez@tudelft.nl

Internship: Adhesive Microstructures from Additive Micro-Manufacturing

Tree frogs have impressive skills of sticking to all kind of substrates, even in wet or flooded circumstances. These adhesive properties origin from specific micrometer-sized pillars and grooves on the treefrog toepads. Mimicking these microstructures in artificial adhesives requires advanced fabrication methods, of which stereolithographic 3d-printing can be one option.

This internship contains the configuration of a stereolithographic instrument, which is subsequently used for the fabrication of artificial adhesive microstructures. Adhesive design and characterization are also an important part of the project, which will be carried out at TNO in Eindhoven.

Contact: Peter van Assenbergh, s.p.vanassenbergh@tudelft.nl

Designing an Adhesion-Based Medical Instrument

When it comes to the development of an adhesion-based gripper for wet, slippery tissue during surgical procedures (instead of pinching grippers), the main challenge is to stick to wet tissue. However, another great challenge is the design of the medical instrument itself. The existing designs of pinching-based grippers cannot be used for adhesion-based instruments, which demand a completely new way of manipulating tissue, and therefore a completely new ergonomical and mechanical instrument design.
In this assignment, the student will carry out an explorative  study to outline the functional requirements of an adhesion-based gripper, and based on that will design and construct a protoype to be used in feasibility studies.

Contact: Peter van Assenbergh, s.p.vanassenbergh@tudelft.nl

Hand-Held bio-inspired needle device (closed)

The wasp has a thin and flexible needle-like structure, called ovipositor, used for laying of eggs inside wood or larves. It is composed of three longitudinal segments, called valves, that can be actuated individually and independently of each other with musculature located in the abdomen of the insect. The sliding motion of the valves create an asymmetry at the tip which allows the ovipositor to move in a curve trajectory.

The goal of this project will be to design a hand-held needle device for biopsy or drug delivery procedures inspired by the ovipositor of the wasp.

Contact: Marta Scali (m.scali@tudelft.nl)