Ramblin' Dan's

3D Print Design Studio

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Marble Machine

Totally rebuilt the hot end of my Delta 3D printer. Replaced the threaded steel filament tube, the 5x10x120 mm aluminum heat block and the 0.04mm brass nozzle. This is not the first time except for the aluminum block. The threads in it were getting a bit worn and leaky.

The heater element and thermistor have been replaced previously.

That called for a big printing project to initiate the new parts. A marble machine was selected from Thingiverse. The machine selected is #2 designed by Tulio Laanen.

The design was intriguing and of reasonable size. I choose to print in 0.01 mm layer height. There are over 1000 layers in the main ramp part and took 24 hours to print.

Tullo is a good designer but the .stl files he offers are a nightmare. They must work OK on a Cura slicer but are totally inadequate on my Simplify3D. I had to repair all the separate parts files as I was not going to use the combined “repaired” set Tullo provided and print all the parts at the same time.

A word to the wise. Only use .stl’s that have been repaired for use by other than Cura slicers. I repaired my own but they are widely available on Thingiverse as well.

The bottom “axel pin” in the base of the screw tower is another weak point. It snapped off immediately. I drilled a hole, modified a piece of steel nail and press fit a steel pin for the end of the screw.

The shaft on the end of the jack screw is a second weak point in the original files. There is a hole created under the pin in the original file (and Simplify3D will create the hole), making it extremely weak. I fixed the file and had to run a new screw part (over 3 hours run time.) Lesson learned.

The marble machine was a nice project but I don’t think I’ll be making any more. At least of this style. The marble lift screw and especially the spin cap don’t work all that well. There is not a good connection with the finger spinner cap and the screw. I printed a second set of the finger hole spinner and the cap that are working a bit better.

I am printing a one-piece finger spinner and lift screw, and a new cap to fit. They will be in Yellow in my pictures. Always room to experiment with a design.

But like I said, drawing problems aside, the marble machine is interesting and a very good workout for my printer. The print surface quality is excellent with 0.01 mm layers. I am thinking I will have to do more printing of other projects using that layer height.

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 The marble machine is nearing the end of the 24 hour print session. There are over 1,000 layers in this print.  There was a printed (plastic) pin here that immediatelt broke off. I press fit a steel pin I made from a large nail.
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 I cut off about 3/8" of the nail, drilled this hole and press fit the pin.  .stl file flaws required I reprint this lifting screw. Note the use of a small (removeable) raft at the bottom.
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 The defective .stl file permitted a hole directly under this pin. Virtually noting holding it on. Here it is printed with a repaired drawing.  The pin (left) is still a weak point so here I am experimenting with a much more robust design for the screw. No little shaft pin to fail.
 
 Struggle with operation with original screw parts.  Re-made the elevator screw and cap and it's working fairly well. Lots of action!

The Author

Ramblin' Dan Kautz

dankautzThere is no doubt one of my hobbies is writing about my hobbies. I read somewhere a long time ago, the best things to write about are the things you know very well. I have been writing and publishing long before the personal computer became the tool of choice.  My first printed and published club newsletter was created in the late 60's.

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Our Mission

The intention of this web site and “Ramblin’ Dan’s 3D Print Design Studio” is to promote creative design thinking and demonstrate how ideas can be changed to tangible creations through the proper application and use of Three-Dimensional Printing systems.

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