Manufacturing Bits: Dec. 21

Tiny electronic fountain pens
Karlsruhe Institute of Technology (KIT) and Taiyuan University of Technology have developed what resembles a tiny electronic fountain pen, a technology that can pattern and deposit small structures on surfaces.

The system from KIT and Taiyuan University is actually a high-precision tabletop microplotter, which is used to print or deposit materials for printed electronics applications. Resembling a tiny fountain pen, the microplotter can deposit conductive and biomaterial ink materials on surfaces at feature sizes from tens to hundreds of micrometers. It has demonstrated the ability to develop various structures, including circuits with gold line interconnects and traces.

3D printing is a growing business that involves several segments. For example, 3D printing or additive manufacturing makes use of a printer-like system, which can construct three-dimensional objects from a model.

3D printing of electronic circuits is also emerging. There are several methods to print various structures on surfaces, such as antennas, passive components, sensors and others. Inkjet printers, stereolithography and other systems are used here.

Microplotters is another system that can be used for this application. These systems are different than inject printers. These systems act like a pen plotter, which directly dispenses droplets on a true continuous fashion on surfaces, according to SonoPlot, a supplier of microplotters.

Using an ultrasonic pumping action, microplotters dispense or print novel nanomaterials on surfaces, such as carbon nanotubes, graphene and LEDs, according to SonoPlot. They can dispense nanometallic ink for use in developing conductive electronic traces.

Researchers from KIT and Taiyuan University developed a next-generation microplotter. The system consists of a printing stage with a USB webcam, a micromanipulator robotic arm, and a glass capillary stylus or pen. The micromanipulator is connected to a PC.

In operation, the capillary stylus is mounted on the micromanipulator. A handheld controller positions the capillary stylus over the sample. Ink is loaded in the inkwell of the stylus. A pattern is produced. The entire operation can be monitored in the webcam.

In one demonstration, researchers inserted a gold nanoparticle ink into the system. The system printed dots and line structures on glass and Kapton substrates. The system demonstrated the ability to print the macroscopic letters “INT” printed on a glass substrate. It also demonstrated the ability to print microdots on a glass substrate, as well as side-by-side printed dots with sub-10µm gap distances on a glass substrate.

The microplotter also showed the ability to print electrical circuits. Additionally, as an example of biomaterial inks, researchers also demonstrated the ability to print inks containing lipids, proteins, and small bioactive molecules.

Micro stereolithography
Using a 3D printer, Boston Micro Fabrication (BMF) and 4D Biomaterials have demonstrated a capability to print tiny bioresorbable or biodegradable materials for use in implantable medical devices.

This promises to revolutionize the way implantable medical devices are manufactured in the future. Aimed at creating biocompatible and bioresorbable micro-scale medical devices, the joint innovation has a variety of applications, such as micro-scale rigid orthopedic devices.

The partnership combines BMF’s projection micro stereolithography (PµSL) approach with 4D Biomaterials’ resin inks. A spin-out from the Universities of Birmingham and Warwick, 4D Biomaterials has developed 4Degra – a new class of bioresorbable 3D-printing resin inks for implantable medical device applications. The biocompatible shape memory photopolymers can be 3D-printed into flexible or rigid devices that promote tissue repair, then controllably degrade into benign, resorbable by-products.

BMF’s projection micro stereolithography, meanwhile, leverages customizable optics and a movement platform that produces accurate and precise 3D printing. “PµSL involves printing in the top-down direction of SLA (stereolithography),” according to BMF. “However rather than using a small spot laser, the entire image, or a section of the image is cured as done in DLP (Digital Light Processing). A thin plastic membrane is consistently stretching and leveling the uncured resin within the vat. This process fabricates micro-sized parts with resolution, at much faster speeds than traditional microfabrication techniques.”

BMF has a growing group of customers working to develop new micro-scale medical devices. “Our customers continue to seek out solutions to miniaturize, and now with bioresorbable material options, a whole new range of devices are possible,” said BMF CEO John Kawola. “Miniaturization in medical device development has been held back by the limitations of traditional manufacturing methods and the materials available. The BMF and 4D Biomaterials partnership is working towards eliminating those barriers.”

“We are enabling medical device companies to think about 3D printing micro-resorbable implants for the first time,” said Philip Smith, CEO of 4D Biomaterials. “We are already seeing the demand from this market growth as the range of applications continues to widen with the advancements in hardware, software and materials technology.”