Hi all, my first time posting on here.

I am fairly new to 3D printers but I have been learning fairly fast. I do have existing mechanical knowledge and some decent equipment though.



What I want:

In terms of size I am looking to make is something that is capable of printing a box around the 600X x 350Y x 400Z mm mark (24 x 14 x 16") with the greatest reliability to the lowest maintenance possible.

Due to the long time it's going to take for the larger prints I want to be able to leave it unattended for as long as needed. If this means 24 hours a day for a whole week then that's what it has to be be able to do, if possible and without ever having an issue. I also don't want to ever have to recalibrate it or do any sort of tweaks. I wish to use it for my auto business so this means I just want it to work and in the shortest amount of time possible. If this means going to much more trouble and cost initially making it then so be it.

I do have the means to line things up nice and level and square in general. For example I will use my mill to cut each section down to length and square off the ends. Done at the same time and with the same cutter this will make everything be damn near identical in length. The joys of a digital read out.

With all these demands luckily I only need to use PLA so no heated bed and I can use a fairly course resolution print, these don't need to look pretty.



Current planned concept:

- No round linear rails or support rails, rather all square type linear guides for all 3 axis. Very likely all 15mm in width.

- No belts either, they stretch, wear out and have elastic issues so it's not an option unless it's 16mm wide and no more than 200 to 300mm long in total. Instead I wish to use ball-screws assemblies for the X and Y-axis and twin acme screws for the Z-axis. In my limited research it seemed to indicate that stepper motors can have RPM/missed step issues with normal ball screws, so instead I plan on using only ones with a 10mm pitch. This means for 80mm per second they will be doing 480 RPM which should be completely reliable.

- Main rectangular frame made out of 40 x 40 extrusion channel with flat aluminium gussets for all the outside corners

- A lifting table for the Z-axis made from maybe 30x30 channel, still thinking about this one. I may bolt down an aluminium plate, face it off flat and then put a piece of glass on it. I will also probably have the guides on the four outer corners with one cariage each.

I already have purchased an NSK 360mm travel lead screw assembly for my Y-axis, despite being used I can feel no slop at all with any amount of force, it's amazing.

- Single Nema 23 frame steppers for the X and Y-axis, probably a 17-frame for either of the lengthways ends of the table and the same with a reduction box for the extruder.

- Print nozzle on the large size- possibly 0.5mm? Also with a temperature stabilised tip, lucky for me I don't need to do any of this part.


Now the top cross-bridge is harder to describe but that's what's in the 3D images. So here's the basics:

- A vertical and horizontal 30 x 60 extrusions joined together

- Guide rail on top and bottom of the vertical section, with a joiner between them that holds the print head assembly

- 30 x 30 sections bolted to twin linear carriages for each end

- Light weight brackets and supports to keep the inertial weight down.


Pictured:

In my 3D model I have the cross boom with the 2 of 30 x 60 sections across, 30 x 30 ends, my existing lead screw shaft, ball screw nut, nut to Y-axis carriage bracket, top and bottom linear guides and a single carriage for each.

I don't however have the bracket between the top and bottom linear carriages yet and hence why my ball screw nut bracket is just floating there.


3d-printer-A-3.jpg3d-printer-A-1.jpg3d-printer-A-2.jpg


Estimated cost:

That's the basics, as a rough guess I am estimating it will cost me $1500 to $2000 all up ready to go. But if I have a budget blow out then it will go ahead regardless, even if I don't have much cash this is something I really need.



So with that wall of text if anyone read all or part of it then I would appreciate any suggestions as I have a lot to learn still. Tell me that I am fooling myself if need be, just be specific as to how and why.