Cheap and cheerful $150 taobao knock-off 3D printer doing 200mm/sec
Channel: lkcl
Date: 2017-05-25

Documented here: http://hands.com/~lkcl/3dprinters/taobao_clone/taobao_clone.html

This is a video of a horribly-low-cost 3D printer sourced for $150 plus $40 shipping off of taobao, with its Marlin firmware set to 5,000 mm/s^2 acceleration on X and Y, and 9000 mm/s^2 on the extruder, running at 200 mm / sec *PRINTING* speed.  A Melzi 2.0 controller with only 1.3A A4982 drivers is being used.

Layer height of demo: 0.2mm.  Nozzle: 0.4mm.  Estimated extrusion rate @ 200mm/sec: 16 mm^3/sec 

The increased acceleration seems to get rid of "bulging" effects on corners and very thin (0.7mm) areas of the part.  Even at 120mm / sec if the acceleration is set to 2000 mm / sec^2 the bulging is quite marked and significant, whereas with much higher values the quality is as good as running at dramatically lower speeds (40 to 50 mm / sec).

Frame vibration is still clearly visible, resulting in a sine-wave "bouncing" (waves) on the return path of the 0.7mm thin part which, surprisingly, is only present for about 4mm before completely flattening out.

Overall this is a staggering achievement for something this low cost.  Improvements to the original design are:

* replacement of the x-carriage arrangement with a horizontal carriage that is as close to the x-rods as possible

* replacement of the MK2 printbed plus glass with a MK3 3mm aluminium printbed plus Printbite

* Addition of a 50mm cheap metal corner bracket nominally designed for bracing wooden structures.

Planned improvements to increase rigidity using acrylic, hardboard or MDF are described in the video.