While multicolor printing eliminates painting steps and produces vibrant objects, there are two significant downsides; filament consumption and print time. A single-nozzle filament printer needs to switch from one color to another, and doing so involves switching to the other filament and then purging the transition filament that contains a mixture of both colors, before resuming the print with the clean new color.
[teachingtech] tests out a variety of methods for reducing print time and waste. One surprising result was that purging into the infill didn’t result in significant savings, even when the infill was as high as 50%. Things that did have a positive effect included reducing the amount of purge per transition based on light to dark color changes, and printing multiple copies at once so that even though the total amount of waste was the same as a single part, the waste per part was reduced.
All of the tests were with the same model, which had 229 color changes within a small part, so your mileage may vary, but it’s an interesting investigation into some of the deeper settings within the slicer. Reducing filament waste and print time is an admirable goal, and if you make your own extruder, you can turn all of that purge waste into various shades of greenish brownish filament. Continue reading “Reducing Poop On Multicolor Prints”
Evaluating the performance of 3D printers and component upgrades is a more difficult than it may seem at first glance, and subjective observations can lead to incorrect conclusions. To objectively determine the maximum flow rates of different FDM 3D printer hotends, [MirageC] is developing a robust testing standard backed by more than just visual observations.
Defining the max flow rate threshold is not straightforward. A common method is to run a test print while slightly increasing the flow rate with each layer, and visually making a judgment on the last acceptable layer. It would be easy to miss errors, or unconsciously be inconsistent with observations over time. [MirageC] wanted to back up observations with measurements. To do this, he is measuring the true feed rate of the filament with an encoder wheel, and the backpressure of the filament on the extruder using a load cell. A Bowden tube helps to isolate the extruder from the vibration of the moving printhead.
After much testing, [MirageC] determined that the numerical threshold would be a specific deviation percentage between the desired and actual flow rate. At temperatures above 230°C, [MirageC] found that the last visually acceptable layer was consistently around 5.75% flow rate deviation for one specific PLA filament. It does not mean that 5.75% will be the magic number for all filaments and nozzle size, but it does provide a measurable parameter to back up visual observations.
In a world of questionable product reviews this dedication to objectivity is a breath of fresh air. If you are looking to upgrade your 3D printer’s hotend [MirageC]’s tests would be a good source of information.
Continue reading “Objective Hotend Performance Measurement Is Hard”
In the name of saving weight and pushing plastic, it’s nice to see continuous tweaks on 3D printer extruders from folks in their spare time. And to go where no extruder has gone before, [wayne dalton] has managed to combine the rolling screw thread extruder concept directly onto a brushless pancake motor. The result is a filament pushing mechanism weighing in at just under 90 grams. What’s more, this modification arrives a few weeks weeks after we first saw an open source version of the rolling screw thread extruder land on Thingiverse back in September.
Getting a direct-drive BLDC extruder off the ground comes with a number of geometry challenges. First, filament needs to be fed through a motor with a hollow shaft. Since this motor will be operated under closed loop control via an ODrive, the motor also requires an encoder with a hole down the middle too. [wayne dalton] patiently walks us through all the changes made over seven iterations to produce a setup that will eventually mount onto a machine and start printing. But for that last step we’ll need to check back a bit later. Finally, this progress comes with the promise of a possible open source release of the design files, so we’re pretty eager to stay tuned for future videos.
In the last few years, we’ve seen state-of-the-art extruders move away from NEMA 17 motors in favor of more compact solutions like planetary gears and even lasers to push printers faster. We’re excited to see that folks keep trying to set the bar higher.
Continue reading “Rolling-Screw Extruder Goes Brushless”
Even a decade later, homebrew 3D printing still doesn’t stop when it comes to mechanical improvements. These last few months have been especially kind to lightweight direct-drive extruders, and [lorinczroby’s] Orbiter Extruder might just set a paradigm for a new kind of direct drive extruder that’s especially lightweight.
Weighing in at a mere 140 grams, this setup features a 7.5:1 gear reduction that’s capable of pushing filament at speeds up to 200 mm/sec. What’s more, the gear reduction style and Nema 14 motor end up giving it an overall package size that’s smaller than any Nema 17 based extruder. And the resulting prints on the project’s Thingiverse page are clean enough to speak for themselves. Finally, the project is released as open source under a Creative Commons Non-Commercial Share-Alike license for all that (license-respecting!) mischief you’d like to add to it.
This little extruder has only been around since March, but it seems to be getting a good amount of love from a few 3D printer communities. The Voron community has recently reimagined it as the Galileo. Meanwhile, folks with E3D Toolchangers have been also experimenting with an independent Orbiter-based tool head. And the Annex-Engineering crew has just finished a few new extruder designs like the Sherpa and Sherpa-Mini, successors to the Ascender, all of which derive from a Nema 14 motor like the one in the Orbiter. Admittedly, with some similarity between the Annex and Orbiter designs, it’s hard to say who inspired who. Nevertheless, the result may be that we’re getting an early peek into what modern extruders are starting to shape into: smaller steppers and more compact gear reduction for an overall lighter package.
Possibly just as interesting as the design itself is [lorinczroby’s] means of sharing it. The license terms are such you can faithfully replicate the design for yourself, provided that you don’t profit off of it, as well as remix it, provided that you share your remix with the same license. But [lorinczroby] also negotiated an agreement with the AliExpress vendor Blurolls Store where Blurolls sells manufactured versions of the design with some proceeds going back to [lorinczroby].
This is a clever way of sharing a nifty piece of open source hardware. With this sharing model, users don’t need to fuss with fabricating mechanically complex parts themselves; they can just buy them. And buying them acts as a tip to the designer for their hard design work. On top of that, the design is still open, subject to remixing as long as remixers respect the license terms. In a world where mechanical designers in industry might worry about having their IP cloned, this sharing model is a nice alternative way for others to both consume and build off of the original designer’s work while sending a tip back their way.
Continue reading “A Featherweight Direct Drive Extruder In A Class Of Its Own”