CR30 3DPrintMill

[Steve_GScale]

Have been sidetracked doing “getting ready for a long, cold Winter” stuff. Cut/split/stacked six cords of wood, equipment serviced and back in barn, etc. etc. etc.

Started back on the cars now. I can spend the Winter feeding logs to the fire while I print Pullmans

Trying to dial in the eSun PLA+ filament. First half-dozen tries were dismal:

But late last nite I got a very nice test print:

This is a 4" section of the middle window panel. Going to try the top & bottom panels next and see how they paint/assemble.

[Steve_GScale]

So while I’m waiting for the 3rd (top) panel to finish printing I thought I should review the slicer programs for the CrealityBelt.

Kiri:Moto is considered the best, but is cloud-based so out for me…
IdeaMaker was suggested by my vendor, used it some.
BlackBelt Cura wouldn’t work for me.
CrealityBelt Cura for windoz.

I had multiple failures with IdeaMaker, shown in the last post. Unfortunately Creality hasn’t ported CrealityBelt to linux yet, so I’m stuck with running the windoz version under Wine - it crashes every now and then. But when it stays up it creates an .stl that prints pretty well. I’ve tried running it on my windoz laptop, but it doesn’t size properly on the attached DisplayPort monitor, being almost unusable. When run on the laptop screen its scaled too small for my old eyes to see. I might try another monitor to see if it works any better…

[Steve_GScale]

Here are the 3 pieces, top (lettering), middle (window) and bottom (will eventually be ribbed) panels after touching up the edges:

And after applying several coats of Rustoleum gray primer:

I’ll lightly surface sand with 1000 grit in a few hours and then topcoat with red and orange.

[Steve_GScale]

So I didn’t do enough surface prep:

My plan B is to print the side as 1 piece, here (on the right) with heavy primer:

I’ll sand with an orbital sander till the lines are completely gone, then I expect, another light coat of primer.

[Steve_GScale]

Some insight, please…

I realized I could use a sheet of flat plastic stock for the Pullman bottoms, only printing the truck mount posts and then attaching them to the flat stock. These could be printed on the flatbed printer (CR10), eliminating more than 25% of the belt printer work - a BIG savings!

Browsing on Amazon I found possible selections of ABS, PVC and Acrylic sheets. Keeping in mind that I will be gluing printed PLA+ sides and ends to it, which would be most appropriate?

I could also use something entirely different such as aluminum/metal or even wood. When converting the deadrail boxcar I discovered a sheet of metal sandwiched between the boxcar floor and the bottom body. The plastic portions would have been more than rigid enough, especially with the boxcar body screwed on. I concluded it was for weight - to keep the boxcar from bouncing off the tracks.
The Pullmans have no such metal plate, but being 2-1/2 times longer they are already heavier. Anyone have any insight on this? If its for weight perhaps I should use metal sheet for the bottom?

[Steve_GScale]

===========================================
The Daylight build portion of this thread is now here

[Steve_GScale]

I added a linear rail to the extruder rail:

In this photo the rail is installed and the old wheeled carriage is shown lying on the bed.
No discernible difference in performance, I suspect the rail will remain in spec much
longer than the wheels would have, can already see some wear on their bearing surfaces.

[Steve_GScale]

I added a pair of upgraded motors, new on the left, stock on the right:

They are larger, so they supposedly run cooler. But more importantly they have support bearings on the top end of the shaft. You could literally see a tiny amount of bend on the stock shaft - NOT GOOD -

At first I had the belts replaced incorrectly and it couldn’t home. An email to RepKord with a pic of the setup and Alan responded within 15-20 minutes with what he suspected was the problem - it was.
You can’t beat service like that!

CR30 PrintMill

[Steve_GScale]

Been back at trying to dial in my eSun PLA+ In post #25 I reviewed the slicers I was using. I’ve been revisiting that issue as I’ve never gotten a great print with eSun PLA+

The wine/windoz version of Cura (top) and linux Blackbelt Cura (bottom) both have issues with the Z axis edges:

So I fired up the linux version of IdeaMaker (middle print) and did a sample of where I left off before abandoning it:

Note the irregular/rough top surface. I could never steer it out…

Then I imported the NAK3D printer profile for the CR30 from the IdeaMaker site, along with their generic PLA filament profile. I also imported an eSun PLA+ specific profile from the IdeaMaker site. These prints are both with the NAK3D printer profile. The top print is with the generic NAK3D PLA profile, the bottom with the eSun specific profile:

Note that the Z-axis edge are now almost perfect

The top surface is a little rougher, will tackle that next. There is also a very slight hump where the window frame ends (middle right):

I’m hoping a raft will remove this.

[Steve_GScale]

So the raft didn’t help:

The panel separated from the raft - disaster!

Tried it again without raft, additional top layer, and 40% infill. After sanding:

A look at the inside. 4 top layers and 40% infill:

It is quite strong:

I’m bending the thin part above the window opening.

I was able to bend it about 90 degrees before it broke:

[Steve_GScale]

Now that I can reproduce clean prints its time to deal with finish work.
I got a bottle of:
https://smile.amazon.com/gp/product/B07X34Z9SC

First I printed a fresh panel:

Then a quick coat of this resin:

Then a quick pass with 220 grit sandpaper on an orbital sander:

Two coats of the Rustoleum orange under the USB microscope:

The new part is on the left, the old sample (primer/sand/paint) on the left.

Here is a view with a normal camera:

With the naked eye you really can’t see any lines

If I were to take my time and sand with 400 then 800, then primer & sand, and then airbrush with genuine SP Daylight Orange I suspect it will look quite nice

Next I should create a panel with ribs. I won’t be able to sand those, so I’m hoping I can refine the resin process to make those look OK…

[Steve_GScale]

My first attempt at a ribbed panel:

I’ve since modified it to have the alternating large/small rib:

That one is in the printer now…

[Steve_GScale]

The test on the left had large/small ribs and was treated with 3D ABS resin for smoothing.
The test in the middle had large/small ribs and was treated with XTC30.
The test on the right had large ribs only and was treated with 3D ABS resin.

The gloss of the Rustoleum makes comparison tough, especially in webcam pictures.
The small ribs are almost beyond the ability of this printer, but refinement of the smoothing process should make that panel look better than the “large rib only” version.

Tomorrow I will work on smoothing with filling primer to compare results.

To that end I added the “Continuous Print” plugin to OctoPrint to automate things:

It can now print them faster than I can ruin them

[Bruce_Chandler]

Looks VERY nice Steve - as you have learned, 3D is not nearly as easy as it looks - nor as it should be…

[Steve_GScale]

I tried printing the ribbed panel test at a right angle. It looks MUCH better

The test on the left is the original method, the right is the right angle method:

They are placed on top of an MTH Daylight Pullman for reference. Note how the
FDM lines are almost completely absent with the right angle method.

So here’s the fly in the ointment: printed in this orientation I’m limited to about 8.25" length.
Which means I would have to print and join 4 sections for a 28" long Pullman. I could still
print the top and window panels full length as they have no ribs and can be sanded to eliminate
the lines.

How should I design the joints to keep them from showing?

• butt joint?
• slight gap on face to allow use of bondo or other filler?
• ???

[Bruce_Chandler]

Why not make the joint overlapping?

[Steve_GScale]

Bruce,

Why not make the joint overlapping?

See posts 26-28 of this thread where I did an overlapping joint test of the top/middle/bottom panel.
I had an issue with the thin lap curling, but that was before I had the PLA+ filament tuned in, guess I should try it again. When I removed the lap I found that the butt joint worked well and decided the lap wasn’t worth the effort.

If I do use a lap joint, I still have the issue of hiding that joint at the surface:

I found that if I held the joint flush there is ever so slight a pucker on the edged that will require blending of some sort…

[Bruce_Chandler]

A butt joint would have the same problem, although it would not be as strong.
I haven’t tried it with PLA, but I have had very good results at hiding joints with Bondo glazing and spot putty.

[Steve_GScale]

I’m not worried about strength. If I go back to the lap joint between the top edges of these 4 panels and the window panel it should be more than strong enough. I could also cut a thin piece of (whatever type of ) plastic 28" x 1" and glue it along the entire backside of these 4 pieces for additional strength.

The whole question is how to print them so as to hide the joints.

I did a VERY QUICK test where I sanded the ends with a hand-held orbital sandpaper (400 grit),
glued with superglue, touched up with brush in Dremel:

and applied 2 coats primer + 1 of Rustoleum red:

First, I’ve learned I need a jig for the sander to keep the ends square!

So, Bruce, would the Bondo glaze fill the cracks/imperfections shown in the 1st photo?
Or would purposely creating a crack of about 1/32" - 1/64" give a better surface to the bondo
to grip and level out?

I think this question applies whether I do a butt joint or a lap joint…

[Bruce_Chandler]

Sure…well, maybe. The Bondo glaze is almost a liquid so it will get into the crack, but it’s up to you to make it smooth. If you haven’t used it before, I sure practice a lot first. I think it will work.