New large format printer design (work in progress)

Here's a video and photo of a new large format 3D printer I'm designing. The overall build volume is about 285x285x285mm. (I'm calling it the Lobo3D printer for lack of a better name, although my wife suggested I call it the Cobble-not.) This is another printer I designed as a project with the local high school. The construction is mostly laser-cut acrylic panels and 3D printed parts, but it does require a little bit of lathe work and a little bit of milling. A good project for a high school with a metal shop.


youtube video

The X-Y motion uses a cross-rod design. Rather than driving both sides of each rod, the rods have gears on the ends that roll on racks on either side - this keeps the rods running parallel. The Z-axis platform is lifted by 3 lead screws all driven from a central motor. Horizontally, the platform is constrained by double-row U-groove bearings running on the corners of the 4 steel posts. The different corner mounts for these bearings have some flexibility built in so that you don't have to fuss about getting the steel corner posts exactly parallel. The video gives a little more detail, as well as showing the thing moving.

There's still lots of work to be done (extruder, heated build plate, eliminate some noise, make it print), but it's coming along pretty well. Once the dust settles, I'll be open-sourcing the plans at lobocnc.com.

How are those geared rods for X/Y motion driven?

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DonaldJ
How are those geared rods for X/Y motion driven?

The gears on the ends of the rod are not driven directly - they just roll on the rack as the rod is pulled back & forth by the belt. The entire cross-rod assembly is just gravity loaded against the racks to take out any backlash. (There is lip just above the rack that keeps the gear from lifting up too high and disengaging the rack.) I've tested it at accelerations of 5000mm/s^2, though, and the gears stay engaged with the racks without any problem.

Okay, that makes more sense to me.

For a minute I thought you would end up with 3 motors on the extruder carriage...Yikes!

Please keep us posted.

Still some work to be done (mostly figuring out a heated bed solution) but I have my Lobo3D printer printing! Here is a youtube video and also some photos of my first successful print. This was done in PLA at 120mm/sec, 0.25mm layer thickness. It's about 200mm tall and took about 90 minutes (2 perimeter shell). The build cost was about $350. I hope to get the plans posted soon at [lobocnc.com].

Wow...that's pretty impressive...

And a nice print too!...

I'll be watching this one. Might be a good follow-up to my I3...

Thanks for sharing!

Very cool low cost printer. I am very interested to see where this is going to go. Do you have any updates on the plans? I would very much like to build one!

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Tbrandall
Very cool low cost printer. I am very interested to see where this is going to go. Do you have any updates on the plans? I would very much like to build one!

Thanks! No update on the plans yet. I keep coming up with little changes and thinking OK, I'll put together a package after the next mod. It's starting to stabilize though, so pester me in a few weeks if I haven't posted anything.

Quick questions, what have you encased the hot end in? Looks like plaster, but have no idea.

What power laser did you use? I'm looking at Chinese 50w can boxes at the moment.

Could you post some pics of the X and y assemblies?

Much appreciated, looks Reay good.

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UkIan
Quick questions, what have you encased the hot end in? Looks like plaster, but have no idea.

What power laser did you use? I'm looking at Chinese 50w can boxes at the moment.

The hot end is wrapped in teflon pipe thread tape. I've got about 10-15 wraps which both binds the wires in place (I'm using several wraps of nichrome wire for the heater) and insulates the hot end to the point where I can touch it without getting burned.

As for the laser cutting used for the acrylic panels, I had a local shop do that and I believe they have a 60w laser.

And here are some close-up pics of the X-Y assembly. Note that only one end of each rod is driven, and the other end keeps the rod running parallel by the rack & pinion.

That is excellent, looking forward to seeing some plans