Saving A Part-Way-Through Failed 3D Print

June 3, 2017 by Jenny List 17 Comments

This will be an experience shared by all 3D printer owners; a long print is mostly done, and something goes wrong. Result: most of the print and a heap of plastic vermicelli, or worse still, a print with an obviously offset layer in it.

[Simon Merrett] had a large part running on his printer, and 2.5 hours in to a 3 hour print the nozzle caught the edge of what he had already done, and as a result he was extruding into thin air (He told us in his tip email that his machine build was the likely culprit). Being fortunate enough to see it happening, he was able to hit the stop button in his Repetier software and bring the calamity to a swift halt.

How he rescued the situation is an interesting tale which he’s recorded in the screen capture video we’ve placed below the break, it involved using a spreadsheet to analyse the G-Code and remove the lines for the part he had already printed before inserting a new set of Z-axis dimensions to start the remaining section of print from the bed upwards. A few further fixes, and he was able to print the rest of his part, which he could then glue to the unfinished top of the section he had already printed. He points out in his YouTube description that he emailed the Repetier folks, and they told him a quicker way to deal with the Z-axis: using the G92 command to reset it.

You might ask why if he was prepared to spend this amount of time he didn’t simply reprint the entire part. But he points out, in that event the print could well have failed again at exactly the same point.

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3D Printering: Non-Planar Layer FDM

July 27, 2016 by Moritz Walter 40 Comments

Non-planar layer Fused Deposition Modeling (FDM) is any form of fused deposition modeling where the 3D printed layers aren’t flat or of uniform thickness. For example, if you’re using mesh bed leveling on your 3D printer, you are already using non-planar layer FDM. But why stop at compensating for curved build plates? Non-planar layer FDM has more applications and there are quite a few projects out there exploring the possibilities. In this article, we are going to have a look at what the trick yields for us.

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3D Printering: G-Code Post Processing With Perl

July 20, 2016 by Moritz Walter 31 Comments

Most of our beloved tools, such as Slic3r, Cura or KISSlicer, offer scripting interfaces that help a great deal if your existing 3D printing toolchain has yet to learn how to produce decent results with a five headed thermoplastic spitting hydra. Using scripts, it’s possible to tweak the little bits it takes to get great results, inserting wipe or prime towers and purge moves on the fly, and if your setup requires it, also control additional servos and solenoids for the flamethrowers.

This article gives you a short introduction in how to post-process G-code using Perl and Slic3r. Perl Ninja skills are not required. Slic3r plays well with pretty much any scripting language that produces executables, so if you’re reluctant to use Perl, you’ll probably be able to replicate most of the steps in your favorite language.

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Pen-Plotter Firmware Written Completely In Ada

June 9, 2016 by Elliot Williams 43 Comments

[Fabian Chouteau] built a plotter out of CD-ROM parts. Yawn, you say? Besides being a beautiful physical build, this one has a twist. He wrote the software and firmware for the entire project himself, in Ada.

Ada is currently number two on our list of oddball programming languages that should be useful for embedded programming. It’s vaguely Pascal-y, but with some modern object-oriented twists. It was developed for safety-critical, real-time embedded systems (by the US Department of Defense), and is used in things like airplanes, rockets, and the French TGV trains. If that sounds like overkill for your projects, [Fabian]’s project shows that it’s still very tractable.

In his GitHub, he re-implements the GRBL G-code generator and then writes a GUI front-end for it. In his writeup, he mentions that the firmware and its simulator for the front-end use exactly the same code which is quite a nice trick, and guarantees no (firmware) surprises when moving from the modelled device to the real thing.

We looked quickly around for Ada resources and came up with: GNAT, the GNU Ada compiler, and its derivatives: GNAT for ARM (STM32-flavor), ARM-Ada (LPC21xx flavor), AVR-Ada, and MSP430-Ada.

Any of you out there use Ada in embedded work? We’d love to hear your thoughts.

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Converting Kids’ Hand-Drawings To G-Code

May 11, 2016 by Steven Dufresne 12 Comments

[Martin Raynsford] wrote a program that converts a black-and-white 2D image to G-code so that his laser printer could then etch the image. Not satisfied with just that, he used his laser printer to make a scanner that consists of a stand for his webcam and a tray below it for positioning the paper just right. The result was something he took to a recent Maker Faire where many kids drew pictures on paper which his system then scanned and laser etched.

Screenshot of Martin's scanning and G-code maker program — Martin’s scanning and G-code maker program

[Martin’s] program, written in C#, does the work of taking the image from the webcam using OpenGL and scanning it line by line looking for pixels that surpass a contrast threshold. For each suitable pixel the program then produces G-code that moves the laser to the corresponding coordinate and burns a hole. Looking at the source code (downloadable from his webpage) it’s clear from commented-out code that he did plenty of experimenting, including varying the laser burn time based on the pixel’s brightness.

While it’s a lot of fun writing this code as [Martin] did, after the break we talk about some off-the-shelf ways of accomplishing the same thing.

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Generating Laser Cut Boxes In C

December 4, 2014 by Brian Benchoff 31 Comments

[Mike] is a laser cutting newbie and has never had the opportunity to create a file and send it off to a laser for cutting. He knew he didn’t want to squint at a CAD package, nudging lines by tenths of a millimeter, only to screw something up and have to do it all over again. His solution, like so many other automation tasks, was to create a program that would generate a box of any size in .SVG format.

[Mike]’s program runs in C, and only requires a few variables set in the program to create a box of any size. There’s no argc or argv for the program – the one thing that would turn this into a command line utility that simply creates SVG boxes. Perhaps another time.

The rest of [Mike]’s hackerspace, Fab Lab xChc, was impressed the program worked the first time. With this small bit of C code, [Mike] has an easy, simple tool to generate laser cut boxes. The only remotely complicated bit of C this program uses is printf(), so even an Arduino can spit out the SVG for a laser cut box.

Turning The Raspberry Into A CAD Workstation

November 2, 2014 by Brian Benchoff 14 Comments

Inventables has been working hard on a successor to the extremely popular Shapeoko CNC milling machine, and to bring digital fabrication to the masses, they’ve created Easel, possibly the easiest 3D design software you’ll ever use. [Sacha] was trying out the beta version of Easel and mentioned to the dev mailing list he was running his installation on a Raspberry Pi. One of the developers chimed in, and after a bit of back and forth we now have a workflow to use Easel with the Raspberry Pi.

Easel is a web app, but since the graphics, design, and g-code generation are handled locally, even the most rudimentary CAD suite would choke the decidedly low power Raspi. Instead, [Sacha] is using the Raspberry to grab 2D and 3D files, turn that into g-code for a machine, and send it off to a Shapeoko router.

Easel doesn’t yet have local sender support that works on Linux, so a separate piece of software is used to shoot the g-code over a serial port to the machine. That’s something that will probably be added in a later version of Easel, making a Raspberry Pi a great way to control router or milling machine.