Fixing CoreXY and CoreXZ (Patreon)

Marlin supports a variety of 3D printer designs, including Cartesian, which moves X, Y, and Z directly, Delta, which moves the carriage indirectly, usually with three arms mounted on vertical carriages, and SCARA, which uses a dual-rotary-arm to move in XY. All of these designs are well-supported in Marlin 1.0.2, and work even better in 1.1.0-RC3.

Most recently we've been adding support for CoreXY and CoreXZ printers. These designs use two stepper motors in conjunction with a special belt arrangement to move an XY carriage or an XZ carriage. Support for Core designs has been coming along since 1.0.2, but there are still incompatibilities. For example, bed probing and endstop hit position simply report the wrong values.

So last night as I was going through the Marlin Issue Queue, I decided to bloody-well fix CoreXY / CoreXZ once and for all! I've already submitted a couple of patches to fix up CoreXY issues, but other bug-reports have been sitting in the queue for months without any progress. I'm happy to report that the changes were not very hard to implement, but required taking lots and lots of notes. Today I submitted pull requests for both Marlin and MarlinDev. If the new code passes the test, you should see this working in 1.1.0-RC4.

I don't personally have access to any CoreXY or CoreXZ printers, so if you have a Core or H-Bot printer, and don't mind testing pre-release software, either check out the RCBugFix branch with my patches applied, or get RC4 as soon as it's ready and give it a try. Marlin need all the feedback and testers we can get!

You Can Help

In other news I desperately need patrons for 2016! The RepRap community has been enthusiastic and optimistic in encouraging me to explore crowd-sourcing, but so far only a few kind souls have shown up to show their gratitude and back my work. Meanwhile, several 3D-printing-related Kickstarter campaigns that received full backing went on to explode on the launchpad. The difference here is that there's nothing to lose! The time is in and the work is done. I've spent countless hours making Marlin better, faster, and strong, and I want to continue. But I'm so far in the red that I will likely need to abandon Marlin and chase other work.

If you're a RepRap 3D printer enthusiast who loves all that Marlin makes possible, please consider becoming a patron at the $5 or $10 level, or consider making a one-time donation to my GoFundMe campaign.

Thank you!

Scott