Joshua Pearce Archives - Perfect 3D Printing Filament

Michigan Tech Develops Open Source Smart Vision for 3D Printing Quality Control

Monitoring and quality control systems are becoming more widespread in additive manufacturing as a means of ensuring repeatability and aiming for first-time-right parts. A greater need for quality control are now trickling down to items that are more commonly made by the average consumer using FFF 3D printers, as detailed in “Open Source Computer Vision-based Layer-wise 3D Printing Analysis,” by Aliaksei L. Petsiuk and Joshua M. Pearce.

Dr. Joshua Pearce, an associate professor of materials science & engineering, and electrical & computer engineering at Michigan Technical University has performed extensive research into 3D printing, recyclability, and open-source platforms, along with protocrystallinity, photovoltaic technology, nanotechnology, and more.

As a proponent of 3D printing household items rather than purchasing them, Pearce foresees that the technology will infiltrate the mainstream and the average household much more deeply in the future. While there are many skeptics, this thinking is in line with many other tech visionaries who see great potential for 3D printing on all levels.

In a press release sent to 3DPrint.com, Pearce explains that quality control continues to be an issue at the household level—leading him to create a visual servoing platform for analysis in multi-stage image segmentation, preventing failure during AM, and tracking of errors both inside and out. In referring to previous research and development of quality control methods for “more mature areas of AM,” the authors realized that generally there is no “on-the-fly algorithm for compensating, correcting or eliminating manufacturing failures.

Analysis in Pearce’s program begins with side-view height validation, measuring both the external and internal structure. The approach is centered around repair-based actions, allowing users to enjoy all the benefits of 3D printing (speed, affordability, the ability to create and manufacture without a middleman, and more) without the headaches of wasted time and materials due to errors that could have been caught ahead of time. The overall goal is to “increase resiliency and quality” in FFF 3D printing.

3D printing parameters allowing failure correction

“The developed framework analyzes both global (deformation of overall dimensions) and local (deformation of filling) deviations of print modes, it restores the level of scale and displacement of the deformed layer and introduces a potential opportunity of repairing internal defects in printed layers,” explain Petsiuk and Pearce in their paper.

Parameters such as the following can be controlled:

Temperature
Feed rate
Extruder speed
Height of layers
Line thickness

While in most cases it may be impossible to compensate for mechanical or design errors, a suitable algorithm can cut down on the number of print failures significantly. In this study, the authors used a Michigan Tech Open Sustainability Technology (MOST) Delta RepRap FFF-based 3D printer for testing on a fixed surface improving synchronization between the printer and camera, based on a 1/2.9 inch Sony IMX322 CMOS Image Sensor and capturing 1280×720 pixel frames at a frequency of 30 Hz.

Visual Servoing Platform: working area (left), printer assembly (right): a – camera; b – 3-D printer frame; c – visual marker plate on top of the printing bed; d – extruder; e – movable lighting frame; f – printed part.

Projective transformation of the G-Code and STL model applied to the source image frame: a – camera position relative to the STL model; b– G-Code trajectories projected on the source image frame. This and the following slides illustrate the printing analysis for a low polygonal fox model [63].

The algorithm monitors for printing errors with the one camera situated at an angle, watching layers being printed—along with viewing the model from the side:

“Thus, one source frame can be divided into a virtual top view from above and a pseudo-view from the side.”

3D printing control algorithm

Currently, the study serves as a tool for optimizing efficiency in production via savings of time and material but should not be considered as a “full failure correction algorithm.”

Example of failure correction

Interested in finding out more about how to use this open-source analysis program? Click here.

[Source / Images: “Open Source Computer Vision-based Layer-wise 3D Printing Analysis”]

The post Michigan Tech Develops Open Source Smart Vision for 3D Printing Quality Control appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.

MTU’s Joshua Pearce develops open source, computer vision-based print correction algorithm

Two researchers from Michigan Technological University, Dr. Joshua Pearce and Aliaksei Petsiuk, have developed an open source, computer vision-based software algorithm capable of print failure detection and correction. Leveraging just a single camera pointed at the build plate, the code tracks – layer by layer – any printing errors that appear on the exterior or interior […]

Open Source Grinding Machine Cuts Cost of Pellet 3D Printing

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.

Michigan Tech researchers invent open-source grinding machine for compression screw 3D printing

Perennial 3D printing innovator and Professor at Michigan Technological University (MTU) Joshua Pearce, has teamed up with MTU colleague Jacob Franz, to create an open-source grinding machine for compression screw manufacturing. Dr Pearce, who has consistently championed the advancement of open-source 3D printing, led the project, which yielded a low-cost, easily replicable open-source machine. Reportedly […]

Michigan Tech scientists write recommendations for greener 3D printing

Fab Labs are forming a Green Fab Lab Network which will harness renewable resources and 3D printing to build sustainable and circular economies. In a paper titled, “Green Fab Lab Applications of Large-Area Waste Polymer-based Additive Manufacturing“, scientists from Michigan Technological University and Aalto University, Finland, studied how a Green Fab Lab Network can be economically […]

Michigan Tech’s Joshua Pearce launches free open-source 3D printing course

One of the most popular open-source 3D printing courses, taught by Dr. Joshua Pearce at the Michigan Technological University is now available online for free. Dr. Pearce, an open-source champion and professor of Materials Science & Engineering and the Electrical & Computer Engineering at Michigan Tech is the author of Open-Source Lab: How to Build […]

Researchers use industrial wood-waste to make FDM/FFF wood filament

Scientists at the Michigan Technology University, Houghton have successfully made 3D printable wood filament from furniture wood-waste. The success was published in a research paper co-authored by the open-source champion Joshua Pearce. The paper explored the possibility of upcycling furniture waste into wood filament to reduce the environmental impacts of wood waste. The wood filament […]

Michigan Tech Researchers Recycle Wood Furniture Waste into Composite 3D Printing Material

A) PLA during mechanical mixing with wood-waste powder, B) PLA and wood-waste powder-based WPC after mixing and cooling to room temperature, C) chipped WPC, and D) homogeneous WPC material after first pass through recyclebot.

From artwork, instruments, and boats to gear shift knobs, cell phone accessories, and even 3D printers, wood has been used often as a 3D printing material. It’s a valuable renewable resource that stores carbon and is easily recycled, so why wouldn’t we think to use it in 3D printing projects?

A trio of researchers from Michigan Technological University recently published a paper, titled “Wood Furniture Waste-Based Recycled 3-D Printing Filament,” that looks to see how viable a solution it is to use wood furniture waste, upcycled into a wood polymer composite (WPC) material, as a 3D printing feedstock for building furniture.

The abstract reads, “The Michigan furniture industry produces >150 tons/day of wood-based waste, which can be upcycled into a wood polymer composite (WPC). This study investigates the viability of using furniture waste as a feedstock for 3-D printer filament to produce furniture components. The process involves: grinding/milling board scraps made of both LDF/MDF/LDF and melamine/particleboard/paper impregnated with phenolic resins; pre-mixing wood-based powder with the biopolymer poly lactic acid (PLA), extruding twice through open-source recyclebots to fabricate homogeneous 3-D printable WPC filament, and printing with open source FFF-based 3-D printers. The results indicate there is a significant opportunity for waste-based composite WPCs to be used as 3-D printing filament.”

While a lot of wood is wasted by burning it, it may be better to upcycle it into WPCs, which contain a wood component in particle form inside a polymer matrix. These materials can help lower costs and environmental impact, as well as offer a greater performance.

A) 0.15 mm layer height drawer knob being 3D printed with a screw hole for attachment. B) Completed drawer knob fully attached on left of wood block with example pre-printed hole on right of block, 30wt% wood furniture waste.

“There is a wide range of modification techniques for wood either involving active modifications such as thermal or chemical treatments, or passive modification, which changes the physical properties but not the biochemical structure,” the researchers wrote. “However, WPCs still have limitations due to production methods, such as producing waste material or orientation reliant fabrication, which may be alleviated with alternative manufacturing techniques such as additive manufacturing.”

While lots of PLA composite manufacturers are already in the market to make virgin, wood-based 3D printing filaments, the Michigan Tech study investigated using wood furniture waste as a 3D printing feedstock for WPC filament, which could then be used to make new furniture components.

“The process uses grinding and milling of two furniture waste materials – boards scraps made of both LDF/MDF/LDF (where LDF is light density fill and MDF is medium density fill) and melamine/particleboard/paper impregnated with phenolic resins. A pre-mixing process is used for the resultant wood-based powder with PLA pellets,” the researchers wrote. “This material is extruded twice through an open source recyclebot to fabricate homogeneous 3-D printable filament in volume fractions of wood:PLA from 10:100 to 40:100. The filament is tested in an open source FFF-based industrial 3-D printer. The results are presented and discussed to analyze the opportunity for waste based composite filament production.”

Surface contours of a personalized drawer handle with the Herman Miller emblem. A coloration change from the outside to the center is shown due to induced temperature changes during printing to provide a tree ring.

The team received wood-based waste material, in both sawdust and bulk form, from several furniture manufacturing companies, and completed some important steps to turn the wood waste into WPCs for 3D printing filament:

Size reduction from macro- and meso-scale to micro-scale
Mix fine wood-based filler material with matrix polymer
Extrude feed material into filament of homogeneous thickness and density

Then, the material was loaded into a delta RepRap 3D printer, as well as an open source Re:3D Gigabot 3D printer, to make a high-resolution drawer knob that was “attached to a printed wood block using a wood screw threaded through a pre-printed hole.”

“The wood screw was easily twisted through both objects with a Phillips screwdriver and the resulting connection withstood normal forces expected in everyday use. Additionally due to the flexibility of 3-D printing orientations a unique or personalized surfaces may be printed onto objects,” the researchers wrote.

“This is shown through the particular geometries or print directions which may be modified directly by altering gcode, or more conveniently by changing parameters in slicer programs. This enables mass-scale personalization of not only furniture components with wood, but any 3D printed part using recycled waste-based plastic composites.”

Once an optimized 3D printing profile was obtained, the recycled wood furniture waste-based WPC filament was able to produce parts without too many errors. However, there was a greater frequency of filament blockages and nozzle clogging with this material, when compared to pure PLA.

Five desk cable feedthrough parts 3D printed consecutively, 30wt% wood furniture-based waste.

“This study has demonstrated a technically viable methodology of upcycling furniture wood waste into usable 3-D printable parts for the furniture industry,” the researchers concluded. “By mixing PLA pellets and recycled wood waste material filament was produced with a diameter size of 1.65±0.10 mm and used to print a small variety of test parts. This method while developed in the lab may be scaled up to meet industry needs as the process steps are uncomplicated. Small batches of 40wt% wood were created, but showed reduced repeatability, while batches of 30wt% wood showed the most promise with ease of use.”

The researchers wrote that further work on creating waste-based WPC filament should include quantifying the material’s mechanical properties after the first cycle, and then comparing it to other materials, such as pure PLA and modified wood fiber powder. Additionally, industrial equipment and grouped 3D printing nozzles should be evaluated in terms of scaling up the process.

Co-authors of the paper are Adam M. Pringle, Mark Rudnicki, and Joshua Pearce.

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Desktop 3D Printing and Functional Replacement Parts

3D printing is seeing increasing use in the manufacture of components for bikes, and sometimes even the bikes themselves. Bikes with 3D printed parts don’t just look cool, either – they perform just as well as, and sometimes even better than, regular bikes.

Open source advocate and 3D printing educator at Michigan Tech Dr. Joshua Pearce recently published an Ultimaker blog post about how to use your desktop 3D printer to create functional, inexpensive replacement parts for complex machines that require mechanical integrity – like bicycles.

Dr. Pearce’s team partnered up with the research group of John Gershenson. Dr. Pearce, Gershenson, Nagendra Tanikella, and Ben Savonen completed a study on the use of open source 3D printers for making components for the popular Black Mamba bicycle.

Dr. Pearce wrote, “Specifically, we chose to start tests with pedals that fail often and have clear standards namely the CEN (European Committee for Standardization) standards for racing bicycles for 1) static strength, 2) impact, and 3) dynamic durability.”

First, the teams used parametric open source FreeCAD to design a custom CAD model of a replacement pedal; the model and STL files are available for download from Youmagine. The pedal was made using the most common 3D printing material – biodegradable, inexpensive PLA.

Static strength test

The pedal was first subjected to a 1,500 N vertical downward force under the CEN static strength test, which found no fractures. Then, the pedal was tested to a 3,000 N compression load applied pedal uniformly – this is actually twice the required amount, which meant that the pedal well exceeded the standard, and, as Dr. Pearce put it, was able to “clear the first hurdle!”

A mass of 15 kg was dropped onto the pedal from 400 mm up, 60 mm from the mounting face, for the CEN bicycle pedal impact resistance test. While the test resulted in a minor dent, there weren’t any fractures – another test passed.

In order to simulate a real-world bicycle, with a person on the pedals, the CEN developed its dynamic durability test for bike pedals. For this test, the research groups had to spin the spindle at 100 rev/min for 100,000 revolutions; at the same time, the pedal also had a mass of 65 kg suspended only by a string. Just like with the static strength test, the pedal’s dynamic durability was designed to exceed the CEN standard under normal conditions.

Impact resistance

Rather than using a rig, the team attached the 3D printed pedal to a bicycle for direct testing, and went 200,000 revolutions with a person’s 75 kg weight being carried solely by the pedals. Again, this was twice the CEN standard, and passed again – I’m sensing a theme here.

Dr. Pearce wrote, “Our humble 3D printed pedal is now good enough for European [racing] bikes…but wait it is actually better!”

The 3D printed pedals are nearly a third of the moss of the Black Mamba stock pedals, which is performance-enhancing as well as cost-effective…if raw PLA pellets or recycled materials, like ABS, nylon, or PET, are used, that is.

Dr. Pearce also provided some easy, DIY guidelines to achieve lab-worthy results for the 3D printed pedals, so you won’t have to redo any bike part experiments.

First, look into expertise already available through a study that researched the parts you were interested in, such as this one regarding the viability of distributed manufacturing of 3D printed PLA bike pedals. Then, determine the material’s mechanical requirements – check out this study for a handy open access list of most of the commonly available tensile strengths of the more common 3D printing materials.

Sub-optimal layers

Print the component in the right material, and with required infills, to achieve your application’s desired mechanical properties. Then, make sure to check out the print’s exterior for any sub-optimal layers from under-extrusion – if the part is under-extruded, fix your 3D printer and try it again.

Finally, weigh the part to make sure there isn’t any under-extrusion inside that you’re not able to see; Dr. Pearce explained that a digital food scale has “acceptable precision and accuracy” for most prints done on extrusion-based 3D printers.

“This mass is compared to the theoretical value using the densities from this table for the material and the volume of the object,” Dr. Pearce said.

The previously mentioned study with the list of tensile strengths was able to find a linear relationship between a 3D printed part’s ideal mass and the maximum stress able to be undertaken by samples. You can just check the study to see how far off from the ideal your part is, and then determine if it needs to be reprinted before figuring out the high probability of your needed properties.

According to mechanical studies completed on many extrusion 3D printers, open source machines produce stronger prints than proprietary systems, mostly thanks to the setting limitations of the latter.

“But be aware that there is a range and the properties of your parts will depend a lot on your machine and the settings you use,” Dr. Pearce warns. “In general printing at the high end of the extruder temperature range for your material will result in a higher strength.”

Just use that weighing technique, and compare your part’s mass to the ideal, to find out where it will most likely lie on the strength range.

You can read Dr. Pearce’s full rundown at Ultimaker.

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