Big CNC 3D printer

[Electrodynamic]

Thought I would throw this out there if anyone is interested.

My latest project was a $500 CAN 36"x60" CNC. I built it from this video,
Most of the Z axis and motor mounts are 3D printed.

Using FreeCad and Blender for building STL files, 3 axis Arduino-grbl board and gSender stepper controller. I tried the grbl software but it was really buggy and difficult compared to gSender. Works well with no issues and I use 1/8" and 1/4" compact routers with 3D printed motor mounts.

Wondering if anyone has any recommendations for a good DIY 3D printed extruder head. Lots of stuff out there but much of it looks kind of sketchy.

[jpanhalt]

That is neat.  Good job.

For your bed, have you considered MIC 5 or 6 aluminum. It is quite flat?

Here's one discussion: https://industrialmetalservice.com/metal-university/comparing-alca-5-vs-mic-6-cast-aluminum/?srsltid=AfmBOoqI3ImhWZ8AkoCtnzBi41lAbgL-8KwWIFuSQKipPMeDumzHGKPf

[Electrodynamic]

Hey jpanhalt

For your bed, have you considered MIC 5 or 6 aluminum. It is quite flat?

Of course, we could always go bigger and better but I was looking at absolute cost efficiency. Can we build a reliable platform which could potentially generate enough income to pay for itself in one day and operate for an extended period of time?. Also the cool factor and I have a lot of projects I want to build which require a CNC machine.

As well, in this day and age bed movement isn't the problem it used to be 10 years ago. Do we spend thousands of dollars upgrading our bed or map any bed distortions and use software to detect and compensate for them?. 3D printers already use bed mapping and it's by far the cheaper solution imo.

[Kean]

For your bed, have you considered MIC 5 or 6 aluminum. It is quite flat?

It doesn't make sense to spend big money on that material for a low budget machine that will have limited precision due to 3D printed parts.  The machine can also surface its own bed or spoil boards, but will likely take a long time at that size.

I tried to use that website to see pricing for large plate as OP would need, but it would only say "Out of stock".  I have an idea of rough pricing as I have bought MIC 6 plates for my much smaller CNCs, and it would exceed the OPs budget several times over.

[Kean]

To answer OP's question...

It is hard to suggest anything without more detail on what you want to print, or a budget.  On a machine with a bed that size, you might want a high-flow extruder for a large nozzle.
I bought some extruders many years ago to try adding 3D printing to my CNCs, but I never really used them once I got a bigger enclosed 3D printer which does a much better job.

You might want to take a look at CNC Kitchen or All3DP reviews to get a better idea of what is available and you are after.
e.g. https://www.cnckitchen.com/blog/which-is-the-strongest-3d-printing-extruder

[jpanhalt]

I tried to use that website to see pricing for large plate as OP would need, but it would only say "Out of stock".  I have an idea of rough pricing as I have bought MIC 6 plates for my much smaller CNCs, and it would exceed the OPs budget several times over.

I didn't check any links to buy it. That was only to show what cast MIC aluminum plate is.  Coremark has 3/8" x 4' x 8'  for about $1,000.  I doubt it's the cheapest.  Ryerson quotes about the same price for 5052 rolled plate of the same dimensions.  In the past,I have found new materials (steel and aluminum)  in Cleveland for about half the online prices.  Most important, it was not a criticism but a consideration if the author goes into commercial production of large parts.

[Electrodynamic]

jpanhalt

Large aluminum plates has it's own set of problems relating to warping due to non-uniform thermal expansion. I have worked with aluminum and a large non-cast 3/8" by 4x8 sheet is not rigid. Wood has come a long way and the latest claim is some manufactured laminates can have the same load bearing properties as steel.

I found 3/4" high density MDF is more than adequate and I have excellent cutting resolution down to 0.25 mm. For my projects 0.25mm accuracy is more than enough. Why fix it if it ain't broken?.

[Electrodynamic]

Spent the day rebuilding my CNC.
Added 4 ch opto-isolation board for my limit switches, relay board for spindle control and rebuilt my side panels. I needed an extra 4" travel on the Z axis for carving bigger objects.

The problem was 3D carving bigger hydrofoil boards 5' x 5" thick. With a 4" long 6mm wide 4 flute end mill plus 3" of Z axis I was at my limit. A longer tool is needed to clear the work. The nice part was being able to cut the new cnc side panels on my cnc. Build a 2D cad model in freecad and profile cut two new panels in under an hour. Damn, it saves a lot of time.

Included a picture of my new 48" x 24" x 2" foil board made in blender. The EPS foam cuts really fast so it was a 2hr job. The 36" x 6" x 0.5" high aspect hydrofoil wing was about 4hr.

Looking forward to cutting some big stuff.

[lichurbagan]

Skip fully 3D-printed extruders as they tend to wear out and cause inconsistent extrusion. Start with a cheap, proven setup like the MK8 Extruder J-Head Kit to get reliable results quickly. If you want better performance, upgrade to a dual-gear (BMG-style) system for stronger filament grip. For a more advanced, compact solution, consider something like the BIQU H2 Direct Drive. Keep your setup lightweight to avoid stressing your CNC gantry. Design your mount to be modular so you can easily upgrade later.