Source: Hacker News
Source: Hacker News
Source: Hack a Day
One of the most crucial aspects of FDM 3D printing is ensuring sufficient material is extruded. Determining the right flow rate can be done manually, but some printers these days automatically perform this adjustment, which is very convenient. [Stefan] of CNC Kitchen investigates how to add similar functionality using existing bed-leveling sensors.
A major complication with extrusion in FDM printers is that the flow rate has to fit the printing speed. However, you can’t just immediately speed up or reduce the flow rate, as the melting filament is flexible and thus acts like a spring, especially as the extruder is exerting significant force on the filament, which adds compression.
The moment you reduce or increase the speed of the nozzle, you can get over- or under-extrusion, but the delayed response by the extruded filament means that you have to adjust for this change in advance. Ergo, the name ‘pressure advance’, also known as the K-value. Obviously, this is a parameter that differs with each material, printer, and other factors, so a direct measurement is always the best.
In the Bambu Lab X1 FDM printer, a Lidar scanner was used to scan various test patterns to automatically determine the optimal setting. This was later moved to the purge section of the extruder in newer Bambu Lab printers. On other FDM printers, the only available sensor in that area is typically the pressure sensor for bed leveling. Could this sensor make a similar measurement?
This wasn’t just an idle thought, but was inspired by the Snapmaker U1, which runs open-source Klipper, with tantalizing glimpses of how it does pressure-advance sensing in its extruder. This extruder also only contains a load cell, as do some Prusa printers. These much more open printers thus provided a test bed for some experimentation.
With load cell data available, [Stefan] measured how various extrusion rates affect the load cell, which can then theoretically be correlated with the appropriate K-values for specific transitions. He created a calibration tool for a range of Prusa printers that works with stock firmware, though this is definitely still a work in progress. There are also a couple of similar open-source projects, such as this Auto PA Calibration project by [Mark].
Overall, K-value presets tend to work pretty well, but adding a pressure-advance calibration feature to existing FDM printers is definitely an interesting idea. There’s also the prospect of lateral sensing using this same bed-leveling sensor, which could allow the printer to sense much more than just the bed.
Source: Hacker News
Source: Published articles
Bug 522075 has been causing JUST enough load and thus heat on my i7-1365U to be annoying (warm back, spinning fans). That machine runs Neon so it got 6.7.3 this morning, it looks like the two relevant patches sufficently solved/mitigated it. Many thanks to Xaver and Vlad.
Source: The Verge - All Posts
Epic Games and Google have just jointly withdrawn their attempt to retroactively settle the lawsuit that's changing how Android app stores work in the United States - and that means Google will be forced to carry rival app stores inside of its own. In fact, Google tells the court, it's ready to begin carrying third-party app stores on Wednesday, July 22nd. Does that mean it's time for Microsoft to launch an Xbox game store on Android?
In October 2024, Judge James Donato originally agreed that forcing Google to carry rival Android app stores within its own Google Play store for several years, and forcing it to share its own entire catalog of …
Source: Ars Technica
An industry-wide standard Microsoft invented to protect Windows, and later Linux, devices from firmware infections has been trivial to bypass for 13 of its 14 years of existence. The discovery was made by researchers at security firm ESET after identifying 11 firmware images, at least one from 2013, that were known to be defective but remained signed by the software company anyway.
The images are known as shims, which were invented to extend Secure Boot to Linux devices and utility software. Using a technique simple enough to be performed by novice hackers, these old, forgotten shims can be used to completely circumvent the protection, which is embedded into the UEFI (Unified Extensible Firmware Interface) of the device's motherboard. The gaffe is the result of the failure by Microsoft, which oversees the signing of shims, to revoke the publicly available images once vulnerabilities were found in them.
The threat extends to Windows and Linux users alike, since the shim can be installed on devices running both operating systems. From there, an attacker can subvert the mandated chain of digitally signed firmware to install malicious firmware that loads early in the boot process and persists after either the OS is reinstalled or a hard drive is replaced.
Source: Hacker News
Source: Hacker News
Source: Hacker News
