Hello Pepstick!
I’ve just finished my build of a printer almost in the cubic meter range, and can say that there is one word that should be thought of in every part of the build: stability. If you want decent prints you need a frame that can’t flex, preferably at all, since the momentum of a moving printhead at the end of 500 mm long aluminum extrusions will be quite significant. When you are planning and designing your machine, don’t be cheap. Aim for beefier extrusions, bigger motors, etc.
In by printer the frame is a cube built from misumi extrusions 25*50 millimeters, and if I would build another one chances are that I would change some of these for 50*50 millimeters. Also, the wheels for the V-slot type extrusion are good, as long as you don’t have strong forces acting across their axis. Then you can see patterns in the parts that indicates that something that shouldn’t be moving is.
For linear motion I would instead recommend real linear guides (such as something similar to this:http://www.skf.com/binary/21-48477/LLMHS%2012_tcm_12-48477.png). They are expensive but can be bought second hand off eBay, and will outperform everything.
For Z-motion I hope that you are not planning on using the threaded rod that seems to be a bit to standard in the diy 3d-printing world.
Instead try to find real ballsrews, which is what I use in my printer, and the run beautifully. Also try to make some real supports for the end of these, especially the bottom one which carries the weight. Are you planning to have a moving bed? If the bed will move in Z I would strongly recommend that you use both thrust bearings as well as traditional axial ball bearings to support the bed.
For the bed, the silicone heaters are the way to go. Also, forget about the glass that most people use. Instead get a good precision milled and cast plate of aluminium. I have a 10mm plate with 2,2kW underneath. This heats to about 80°C in about 7 minutes. Try to aim for about the same wattage per cm^2 for reasonable heating times. Also: use mains power and a ssr relay (the cheap ones from eBay or aliexpress work well enough).
As a final recommendation I would say that you should think of encapsulating the build chamber and have this heated to about 60°C. Otherwise you will be limited to pla and maybe PETG, the rest of the materials would crack and delaminate.
If you have any more questions or want images of what I’ve built, just send me an email to bo.oscar.svensson@gmail.com
Good luck with your build!
