Perfect 3D Printing Filament - Page 153 of 737 -

3D Printed mask strap reinforcements: Duck Boots #3Dprinting #COVID19 #MedTwitter

People are finding that sterilizing used masks and dealing with masks in general come with a common problem: Strap breakage. The materials are not designed for prolong or rough use. Christopher Van posts a neat solution on Twitter:

I’ve been developing a solution within @PanFabBoston for strap brackets on duck bill masks allowing them to be used longer with sterilization even if the straps break (they will). I fondly call them: Duck Boots! Rough draft, easy to 3D print and holds well. #MedTwitter #Covid_19

See the post here.

BeamIT and BERCELLA to develop R&D projects for additive manufacturing and carbon fiber parts

BeamIT, an Italian additive manufacturing service bureau, has announced a partnership with BERCELLA, a developer of composite materials, to undergo research and development projects within the aviation, space and defence markets. Utilizing both their expertise in additive manufacturing and composite materials respectively, the two companies will be developing joining methods between additive manufactured and carbon […]

Underwater ROV built with Farsoon 3D printers

Remote Operated Vehicle (ROV) manufacturer QYSEA is working with Chinese SLM and SLS 3D printer manufacturer Farsoon to produce protective covers for its FIFiSH V6 underwater ROV. These customized covers, used for protecting the ROV’s smart vector thrusters, are created using Farsoon’s Flight additive manufacturing technology. They provide the mechanical strength and durability necessary to […]

Monte Carlo Tree Search: Optimizing Toolpath Planning in FDM 3D Printing

Authors Chanyeol Yoo, Samuel Lensgraf, Samuel Lensgraf, Lee M. Clemon, and Ramgopal Mettu detail their research for improvements in FDM 3D printing, outlined in the recently published ‘Toward Optimal FDM Toolpath Planning with Monte Carlo Tree Search.’

Most toolpath planning in FDM 3D printing consists of input models sliced into layers; however, this can lead to a lack of efficiency in motion at times, especially when the extruder may still be moving but not actually printing. In this study, the researchers set out to compute an efficient and optimal toolpath via a new algorithm using the Monte Carlo Tree Search (MCTS).

“A powerful general-purpose method for navigating large search spaces that is guaranteed to converge to the optimal solution,” the MCTS was analyzed within this study regarding its ability to improve searches.

“To our knowledge, this is the first algorithm for toolpath planning with any guarantees on global optimality,” stated the researchers.

Example model of ‘four nuts’ (a) image, (b) labelled dependency graph, and (c) clustered dependency graph from (b)

Previously MCTS has been useful for solving problems in robotics applications, yielding the desired, greater efficiency in toolpath planning.

“Monte Carlo tree search algorithm is based on biased search algorithm for finding an optimal solution asymptotically. Starting at an initial condition, a tree grows at every iteration. The algorithm finds the next best node in a tree to expand using upper confidence bound (UCB), where UCB balances between exploitation and exploration. Intuitively, the node with higher likelihood of finding a better solution will be selected. Once a node is selected for expansion, one or a number of complete sequences is randomly generated from the node until reaching the end (e.g., end of time horizon),” explained the authors.

“In order to make our algorithm efficient, we also introduce a novel clustering algorithm on the dependency graph for the input model.”

An example illustrating clustering algorithm in Alg. 1. (1) 16 raw contours are clustered into three highly dependent subgraphs (HDS) as shown in (b).

With a dataset comprised of 75 models, use of the MCTS method did demonstrate ‘substantial reduction’ in wasted motion. The authors noted that MCTS performance was like that of their current local search toolpath planner, but overall made it easier for them to investigate difficult in planning with some models.

‘Four nuts’ model. Toolpath for building the part by (a)(d) typical layerwise planner, (b)(e) local search from [6], and (c)(f) proposed MCTS, with red indicating non-printing motion. The solution toolpath for each method is shown in red. Extrusionless distances (in mm) are 16737, 12220 and 11057, respectively.

‘Twisty’ model. Toolpath for building the part by (a) typical layerwise planner, (b) local search from [6], and (c) proposed MCTS, with red indicating
non-printing motion. Solution toolpath for each method is shown in red. Extrusionless distances (in mm) are 25021, 11423 and 11306, respectively.

“A natural question is why one would use MCTS over local search for a given model. Using our empirical studies, it appears that the output of the clustering step and subsequent composition of HDS components of the dependency graph provide guidance as to whether MCTS can achieve convergence,” concluded the researchers.

“As we saw in our empirical analysis if there enough HDS components with respect to the size of the dependency graph then it is highly likely that MCTS will converge to an optimal toolpath. If the number of HDS components is too large, or the average size is too small, then MCTS will have difficulty exploring the toolpath space and may perform worse than local search.”

Colored clusters for example parts

Researchers around the world continue to study ways to refine and use FDM 3D printing, from experimenting with new materials to fabricating innovative medical devices. 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 / Image: ‘Toward Optimal FDM Toolpath Planning with Monte Carlo Tree Search’]

The post Monte Carlo Tree Search: Optimizing Toolpath Planning in FDM 3D Printing appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.

Improving Foundry Production of Metal Sand Molds via 3D Printing

Saptarshee Mitra has recently published a doctoral thesis, ‘Experimental and numerical characterization of functional properties of sand molds produced by additive manufacturing (3D printing by jet binding) in a fast foundry.’ Delving into hybrid casting and improved methods for creating metal molds, Mitra analyzes varied printing parameters and their effects on mechanical properties.

Centered around improving production in foundries, the author investigates ways to create molds in a completely automated manner, taking advantage of some of the most classic benefits in 3D printing—from greater affordability and faster production time, to better quality in prototypes and parts.

“Besides, the absence of tooling costs makes this process particularly economical, and much complex geometry that cannot be manufactured using traditional sand casting can be reconsidered,” states Mitra. 3D printers are generally faster, easier to use and cheaper than other add-on technologies. It is also possible to make foundry sand molds of extremely small dimensions and very thin parts. Modern foundry industries gradually use this Hybrid Casting technology because they provide ease of sand molding with good surface finish.”

The goal of Mitra’s thesis is to create molds for metal casting with greater stiffness and permeability—ultimately, for use in both the aerospace and automotive industries—applications we have seen significantly impacted by AM processes from car parts to rocket engines, to the qualification of important end-use parts.

(a) Ancient Greece; bronze statue casting circa 450BC, (b) Iron works in early Europe: cast-iron cannons from England circa 1543 [4]

“Sand casting is the most widely used metal casting process in manufacturing, and almost all casting metals can casted in sand molds,” explained Mitra. “Sand castings can range in size from very small to extremely large. Some notable examples of items manufactured in modern industry by sand casting processes are engine blocks, machine tool bases, cylinder heads, pump housings, and valves.”

Metal casting requires:

Proper design
Suitable choice in material
Production of patterns for molds and cores
Selection of the casting process
Post-processing
Quality control

“Three-dimensional printing (3DP) of sand molds using binder jetting technology overcomes challenges faced in the traditional production method, e.g., limitations in terms of part complexity and size, production time and cost (which depends on the quantity and the part complexity, optimization in part design/design freedom for any castable alloys,” states Mitra.

Schematic representation of particle binder bonding and resin

Powder binder jetting process

A series of chemically bonded 3D printed samples were examined. While binder amounts were evaluated by Loss on ignition (LOI) experiments, mechanical strength was measured via standard 3-point bending tests. Permeability was measured by the air flow rate through the ‘samples at a given pressure.’

Mitra learned that molds could be stored extensively at room temperature, but permeability of samples did decrease as temperature was raised.

Printing recipe on ExOne 3D printer

3D printed 3PB test bars and permeability specimens

The author also noted that strength of the molds was ‘profoundly influenced’ by binder content, with increased amounts consequently increased mechanical strength.

“X-ray µ-CT images were used to compute the porosity, pore size, throat size and the permeability of the 3D printed specimens for different binder contents and grain sizes, using analytical and numerical methods,” concluded Mitra. “The permeability predicted in the steady-state was compared with experimental and analytical measurements for layered silica grain arrangement. A major advantage of using X-ray CT characterization is the nondestructive nature of the tests. The computed permeability can be used as input to numerical simulations of metal casting allowing the prediction of macroscopic defects.”

“The present findings represent a step forward towards improved prediction of mass transport properties of the 3DP sand molds. However, further characterization of permeability of such additively processed sand mold should be performed with varying average grain diameter, to check the convergence of the present model. Also, samples printed with other printing process parameters should be studied.”

Steps involved, (a) 3D printing of sand mold, (b) melting iron, (c) casting process
and (d) eroded molded with the respective positioning of thermocouples.

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: ‘Experimental and numerical characterization of functional properties of sand molds produced by additive manufacturing (3D printing by jet binding) in a fast foundry’]

The post Improving Foundry Production of Metal Sand Molds via 3D Printing appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.

Turntable #3DPrinting #3DThursday

FreshPrince3d shared this project on Thingiverse! Learn more and download files here: https://www.thingiverse.com/thing:4252227

Every Thursday is #3dthursday here at Adafruit! The DIY 3D printing community has passion and dedication for making solid objects from digital models. Recently, we have noticed electronics projects integrated with 3D printed enclosures, brackets, and sculptures, so each Thursday we celebrate and highlight these bold pioneers!

Have you considered building a 3D project around an Arduino or other microcontroller? How about printing a bracket to mount your Raspberry Pi to the back of your HD monitor? And don’t forget the countless LED projects that are possible when you are modeling your projects in 3D!

Spiral Art Fidget Spinner #3DThursday #3DPrinting

This project makes the fidget spinner slightly more practical.

Shared by JON-A-TRON on Instructables:

The fidget spinner is a missed opportunity- you can do so many things with spinning motion! Follow along and learn how to 3D-model and print your on fidget spinner that doubles as a clever device for making unique art.

Learn more

Winch Hook Isolator – for Synthetic Line Fairlead #3DThursday #3DPrinting

Handy winch accessory if you need it. Shared by dirty_travel on Thingiverse:

Winch Hook Isolator for a synthetic line Fairlead.

Keeps my anodized aluminum fairlead nice and shiny and subsequently stops my line from chafing on burrs.

Enjoy

Download the files and learn more

Morse-Vail Telegraph Key #3Dprinting #3DThursday

OldManJohnson shared this project on Thingiverse!

Alfred Vail made this key in 1844, believed to be from the first Baltimore-Washington telegraph line, as an improvement on Samuel Morse’s original transmitter.

My model is based on a 3D scan of the original key from the Smithsonian 3D Digitization web site. It can be seen and downloaded here :

https://3d.si.edu/object/3d/morse-vail-telegraph-key:ed99f44d-3c60-4111-b666-e2908e1b64ef

Download files: https://www.thingiverse.com/thing:4207626

DMG Mori Announces LASERTEC 400 Shape Laser Ablation System

The hybrid manufacturing market continues to grow at a steady pace, as an increasing number of machine manufacturers look to combine additive manufacturing and machining capabilities. The latest comes from CNC machine and 3D printer manufacturer DMG Mori.

DMG Mori has announced the release of a new five-axis CNC machine designed specifically for performing laser texturing on 3D freeform surfaces of molds and tools. The LASERTEC 400 Shape is the largest of the company’s four laser ablation machines, capable of working with parts weighing up to 20 tons and measuring up to 3,350 x 1,350 x 1,000 mm. In addition to the large LASERTEC 400 Shape, the machine manufacturer is aiming to release a more mid-range system with a 2,000 mm X-axis, the LASERTEC 200 Shape.

Using a newly developed additive manufacturing laser head, the purpose of the LASERTEC 400 Shape is to apply defined surface structures to existing plastic injection molds and press tools which improve the form and/or function of parts that they produce, such as scratch resistance or water repellence.

The laser scanning head of the LASERTEC 400 Shape.

The laser features 100W of power with a switchable pulse length and frequency up to 1 kHz. An F-Theta scanning lens provides the system with 3D processing optics that allow the system to apply features onto existing 3D surfaces. The print head has two degrees of movement with ± 200 degrees rotation and a swivel range of -100 to +135 degrees, allowing it to process undercuts.

DMG Mori suggests that laser machining is more ecologically sustainable than conventional etching, while offering greater freedom of design and repeatability. The system is marketed as being able to reach seemingly inaccessible portions of a part, including deep and narrow features, saying that even filigree cavities can be filled with the ablation process.

As discussed in a previous profile on the Japanese conglomerate, DMG Mori is one of the largest machine builders globally. This most recent addition to its systems portfolio builds off of the company’s more recent entry into additive manufacturing. DMG Mori offers a variety of hybrid manufacturing systems that incorporate DED laser systems into milling machines. With the acquisition of a majority stake in metal powder bed fusion system maker Realizer, the company began offering its own laser PBF printers in 2017.

Two different technical surface structures ablated onto the surface of a mould.

DMG Mori has yet to combine PBF and machining processes the way that its competitor Matsurra has, but this Shaper line does operate similarly to Trumpf’s laser-based machining. Meanwhile, a hidden player with a huge stake in all manner of AM is Siemens, which produces hardware and software for managing systems like these. In the case of the LASERTEC 400 Shape, a Siemens 840 D solutionline provides control.

Mould applications for the LASERTEC 400 Shape.

Hybrid manufacturing has huge potential for the manufacturing of molds and dies. In addition to the ability to repair existing tools, it is possible that functionally graded materials can be used to create unique molds that take advantage of the properties of multiple materials. For instance, copper could be used as a heat sink in order to more quickly cool down the part after an injection molding cycle, while steel can be used to maintain the overall durability of the part. When complex features are possible (not often the case with directed energy deposition-based systems), conformal cooling channels can be added, which can also reduce cooling time.

To read more about the state of hybrid manufacturing, look for our series here. To read more about tools and dies, see this series.

The post DMG Mori Announces LASERTEC 400 Shape Laser Ablation System appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.