Hello All! I recently stumbled into the world of MPCNC and am digging it. My goal is to build a relatively simple pen/ paint brush plotter. I’ve seen a few instances here, but have a few questions:
My goal is to make something rather large, that can plot on A0 paper (33.1 inches by 46.8 inches), I know this pushes me more into the Lowrider range, but given that I’m only planning to use pens/ brushes, would the MPCNC Primo be stiff enough, my gut says yes.
I have a bunch of 1.5" square aluminum extrusion so I’d be sizing up from the 2040 series used here (.75" x 1.5") and could use some linear bearings to make the gantry slide pretty easily
I’ve been in aerospace mechanism design for 10+ years, and CAD is a strong suit, but this would be my first deep dive in to mechatronics/ single board computer land.
Looking for suggestions/ guidance.
I am not planning on speed runs, but read the max speed of a MPCNC is in the 120mm/min range, which feels a an order of magnitude slower compared to some pen plotter specific builds.
Goal is to stay under $500, and with the aluminum extrusion I have, thats a big chunk of cost I can save. Does a coreXY system have limits on size?
A comparable gantry style pen plotter is over to $2k, and has less parts than a basic 3D printer, can’t figure out why they are so expensive! I do realize this is a cartesian setup more similar to the MPCNC with fixed belts, and not a coreXY plotter, so its a bit different than the other linked above. Honestly, I really like the iDraw and would just try to replicate it as much as possible.
It might still sag in the middle, and my experience is that while cutting something with a drag knife or plotting something with a marker it matters (marker lines get thicker). Ballpoint pen is okay.
Mine jogs with 8000mm/min. So something you read was definitely off by quite a margin.
Interesting. I’m still looking to plot on flat thing like paper/ canvas, so that wouldn’t really be relevant for what I need. That CNC in the picture is interesting though. Is that a PrintNC?
I think Dreyfus is saying that the rotary y-axis could move the paper while the plotter just has to go left to right and up and down (x, z). This might economize space. Essentially how a printer or a “bedslinger” 3d printer works. Although that seems like it would be trickier than simply building a lowrider/mpcnc and taping or using magnets to hold the paper.
a couple things that come to mind:
if you use aluminum profiles as rails, over time steel bearings may wear into them and cause issues
the dimensions you mentioned are a bit beyond the recommended build size for the mpcnc. if you bought larger OD stainless steel tubing (with thick walls) you might be able to negate some of the sag concern, but at a cost
this really does seem like the perfect use-case for a lowrider
I built and used an MPCNC (router) and enjoyed it a lot, but it can be a bit annoying to reach around the rails and harder to get a good look at the work being done; as someone else mentioned, a lowrider would let you reclaim your work space as well as get your paper in and out with less fuss or concern
maybe you could consider a less robust core (or at least save some filament in printing) since you’ll really just be pulling a pen/brush along a smooth surface
you can use a lowrider/mpcnc as a router/plasma/laser/a million other things. but if you build a lightweight aluminum motion system specifically for the purpose of pen plotting, it’s likely your machine will lack the rigidity and capability to be something else, should you want that in the future
I have an axidraw (a3 size) which I would really like to use more often, but have had rather frustrating experiences with the software; at present I can’t get the extensions to work at all, don’t enjoy having to lay things out in inkscape, and don’t really have the time or desire to look into open-source solutions or otherwise. So on the off chance that you have some knowledge or a workflow/tooling advice, I’m interested to hear.
