open source designs Archives - Perfect 3D Printing Filament

In pursuing the Distributed Recycling and Additive Manufacturing (DRAM) approach to open-source hardware development, a significant challenge lies in addressing the high cost of the compression screw component for alternative 3D printers, such as Fused Particle Fabrication (FPF) or Fused Granular Fabrication (FGF).

Platform solutions such as RepRap and Arduino, have allowed users and professionals worldwide to access or manufacture products or scientific tools themselves, cheaper and more effectively than commercial hardware products. Yet, as Dr. Joshua Pearce, of Michigan Technological University (MTU), notes in his study on the topic, open hardware lags the success of the open software community by about fifteen years. It is initiatives such as Dr Pearce’s Open Lab that are helping to bridge this gap—and in this case, with open hardware solutions that make FPF and FGF cheaper, more accessible, and more efficient than they are at present. The details of the lab’s work on the subject are described in a recent study, “Open Source Grinding Machine for Compression Screw Manufacturing.”

FPF or FGF are more effective than the traditional Fused Filament Fabrication (FFF) for DRAM, since they use raw plastic particles or granules which are more easily available and cheaper, instead of filament, to 3D print objects. Although it is has proven much cheaper and technically viable to produce filament from a variety of waste polymers, using an open-source waste plastic extruder (or recyclebot) – the process degrades the mechanical properties of the filament material over time, and limits its recyclability. In addition, commercially 3D printing filament is more expensive, at $20 per kg, than raw plastic pellets which are priced at $1-5 per kg.

This is why FPF and FGF printers are seen as a more effective alternative for the DRAM approach, and are already being used by academia, maker communities and businesses—the best example for the latter being GigabotX, an open-source industrial 3D printer than can use a range of materials from Polylactic Acid (PLA) to polycarbonate (PC). However, FPF/FGF 3D printers are more expensive, primarily due to the high cost of the precision compression screw, compared to FFF printers, and commercially available screws are not only very expensive (over $700 for the filabot screw) but also limited in handling larger pellets due to their small scale and size.

Image courtesy of MDPI

This is where Dr. Pearce’s open source hardware solves the problem: by providing a low-cost open-source grinding machine, so users of FPF/FGF can fabricate a precision compression screw for about the cost of the bar stock. Users will no longer be limited to commercial designs, and will be able to customize or optimize the screw to suit their requirements in terms of channel depth, screw diameter or length, pitch, abrasive disk thickness, handedness, and materials (three types of steel, 1045 steel, 1144 steel, and 416 stainless steel).

Image courtesy of MDPI

These compression screws will make recycling polymer particles/granules cheaper, more efficient, and flexible for FPF/FGF users, thus strengthening the case for DRAM as it pushes towards a circular economy.

Image courtesy of MDPI

The grinding machine is made using an off-the-shelf cut-off grinder (approximate cost $130, ideally suited only for steel or stainless steel) and less than $155 in parts. It is classified as an outside diameter cylindrical grinding machine. All the 3D printed parts can be made using any desktop printer using PLA (in this case a Lulzbot Taz 6), and the plywood parts were prepared using a CNC wood router.

Dr Pearce has long been an advocate of open source, distributed manufacturing, and DIY solutions for students, businesses, and, in particular, for scientists and researchers. To help accelerate innovation, empower scientists and users dependent on or limited by expensive commercial equipment and supply chains, and to reduce the cost of scientific tools, Dr.Pearce has led the way with his open source software or hardware solutions and initiatives. He has helped develop the Recyclbot, respirators, ventilators, specialized 3D printers, scientific or medical device components, and more.

Among other work, he has also worked to show how DIY 3D printing could impact the toys and game market (reducing costs of simple and complex toys or games by 40-90%), how to develop open-source, affordable metal 3D printing solutions using GMAW, and to 3D print slot die cast parts, that cost thousands of dollars, for just cents. He is also the author of Open-Source Lab: How to Build your Own Hardware and Reduce Research Costs and teaches a renowned open source introductory course in additive manufacturing at MTU, which is now online and free.

This latest work shows just how far his lab is going to make manufacturing technology accessible, even down to the compression screw needed for FPF/FGF 3D printing. The design, instructions and files for the device are free, and available here.

The post Open Source Grinding Machine Cuts Cost of Pellet 3D Printing appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.

While there is always the question of whether life imitates art, or vice versa, science and innovation today often imitate nature—and we humans seem to be getting better at it. A recent case and point involve a new e-NABLE prosthetic called the Frog Arm, developed by e-NABLE designer and volunteer, Peter Binkley.

Most of us take the ability to open our hands and flex our fingers completely for granted. For kids with severe epilepsy who have undergone difficult treatments, however, this can be impossible.

Upon discovering the enormous challenges kids with epilepsy face, Binkley began working with the Brain Recovery Project to create a functional limb replacement for children dealing with life after hemispherectomies—a surgery removing a portion of the brain’s hemisphere to help prevent dangerous seizures.

“In early 2016, I was approached by the Brain Recovery Project. They wanted me to pick up on Elizabeth Jackson’s amazing Airy Arm project. Elizabeth created a wearable arm that allowed a user to open his paralyzed fingers. They wanted something with a similar action. That is, a wearable device that opens the fingers via an extension of the elbow. The BRP wanted me to design a more low-profile, easy-to-wear solution. In September, I began sketching ideas for the Frog Arm,” states Binkley.

“Frog Hand (Frog Arm 0.1) would have been too difficult to manufacture. And I hadn’t even met a test pilot for the device yet, so I had a lot to learn.”

He met with his ‘test subject’ Cameron a few times, noting her exceptional social and academic skills despite the extreme medical treatments she had to endure. Soon after taking measurements and considering the level of functionality required in the prosthetic, Binkley created a 3D printed prototype accentuated with leather, screws, and a variety of cables:

“I was trying to make a device that could give users control of the wrist. With paralyzed tendons, flexing the wrist extends the fingers and extending the wrist flexes the fingers. I was trying to use that biomechanical fact to advantage. Large hair elastics hold the wrist in extension, so the normal position of the hand is closed. When the user extends the elbow, it pulls a cable that flexes the wrist, thereby opening the fingers.”

Numerous iterations were required for version 0.2, so Binkley moved on to the Frog Arm 0.3, using a 3D model and 3D printed forming blocks for better hinge design. He was forced to keep on editing his designs though, moving from 0.3 to 0.4 quickly also:

“The leap from version 0.3 to 0.4 was a big one. I had to attach directly to the fingers somehow. It seemed to me that Cameron’s only needed to be able to actively open her fingers, since they close on their own and remain closed at rest,” said Binkley.

Binkley used an elbow hinge for manipulating the cable, along with nylon tubing to serve as a braking system—allowing the fingers to move ‘relative to the carpals but not bound to the forearm.’ Leather cots made of distressed goat hide were placed around the fingers also. The forearm was not a good fit, however, and Binkley forged ahead to version 0.5.

While Cameron continued to have issues with finger extension due to such long-term paralysis, Binkley decided to discourage regular wear of the device for her due to fear of physical damage. He is continuing to work with another test pilot though, and his experimental open-source design has been released for the Frog Arm on Thingiverse.

e-NABLE has made a huge impact around the world in creating prosthetics for individuals of all ages in need of limb replacement. While these medical devices are meant to add to the quality of life for patients, many of the designs are spectacular—from those meant to help kids play violi n to integrating complex features like parametrics, and even adding to veterinary medicine with bird prosthetics.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: Enabling the Future]

The post Enabling the Future: 3D Printed Frog Arm Prosthetic for Epilepsy Patients appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.