3D Printing - "It's all about design and quality output. Not how fast the printer can run."
A little project at the request of my spouse. She was admiring my 3D printed holders for my wax carving tools and files. However, the holes were too small for the things she wanted to hold. I was tasked with creating holders with larger holes.
The first one was using three holes with a hole design diameter of 12mm. I “project named” it the TriHolder. A square sided cube wouldn’t be aesthetic so I created some curves on two sides. They widen the base and make it look a bit better.
This print is for my daughter. I made the green Yoda for her twin brother, so I needed to balance my generosity! Ha! Vause is the fancy word for a cheap plastic vase...
It’s another design I gathered from Thingiverse. This one is in the form of an SCAD file. That is a CAD drawing program that has parameters which can be changed or altered to create variations of a design.
This is not an original creation of my own. My adult (45ish) son is a Star Wars fanattic. So I thought I should make him a Yoda to add to his collection.
I picked this one out on Thingiverse for no particular reason. It is call pot à crayons / pen holder starwars Yoda by TiZYX. (https://www.thingiverse.com/thing:2225855) Go get the files if you are interested.
I printed one in orange at about 50% to see what it was like and to save time and materials. It was the color already in my printer. I decided it didn't need all the automatic supports, so I eliminated about half of them on the green Yoda. The chin and ear tips are the most critical support areas.
I have a new 3D print original project. My wife has a makeup box setting on the very long built in sink counter in our bathroom. It is located between the two sinks built into the counter top. All one piece.
Splash water will sometimes accumulate around this box. It is made from pressed wood and has absorbed some of this water and bulged out a bit on the bottom edge. She asked me if I could make something to raise the box off the surface so the water on the counter top could not get to it.
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 fun part of inventing is creating exactly what is desired for a particular application. Inventing is discovering a need and finding a way to fulfill that need. I recently did that sitting here at my computer.
I often pull out the drawer in front of the screen to prop the keyboard at an angle and at a lower position than setting flat on top of the desk surface. It works well in that position and I decided I needed a more reliable system.
I hardly believe this myself. I started a new hobby model construction project. I am now working on building large scale model train equipment. I have been posting a little about whimsical model railroading in a few blog posts and the desire started to grow.
The first step is a powered wheel set (truck) for a diesel-electric locomotive. It is made using 3D printed parts. That is the prime reason I am doing it. I want to see if I can, with 3D printing. A proof of concept. Then see if I can make it operate. It will have an electric motor and gearbox.
I don’t think I am going to complete the entire model. The working powered truck is my immediate goal. I may try to sell it once it is done and operating.
I want to use this project as a trial experience. To see if I will really get more involved building with plastic. The size of this powered truck is substantial but the engineering was done by someone other than myself. It’s mostly a print and assemble project. As I said above, it’s going to be my proof that 3D printing is or is not worth the effort in model construction.
This may be enough to get me back to the machine shop and working on my live steam engine. I shall see. That project is mostly mostly a brass and steel construction.
I did some research on the internet about 3D printing in real world (non-hobby) applications. It’s growing rapidly. Some of it for the same reasons Laser Cutting and engraving has grown.
Old school machine shop work is mostly subtractive. Milling removes material with cutting tools that is not part of the desired product. A large variety of cutting tools are required. They get worn out and sometimes break. A large investment in tooling is required.
3D printing is an additive process. No tooling is required. It builds using layers and very complex shapes can be made, especially in areas where cutting tools can never reach.
The real world is combining both processes. Each have a strength and both have weaknesses. But the smart people are using the strengths where they make the most sense.
In this first 3D printed railroad component, I have to admit I am not excited about using 3D printed plastic wheels. The axels are steel and that’s good. But the plastic wheels will probably be far from true and durable.
For a display-only model, plastic wheels may be suitable. For an operating model, they definitely are not. I don’t plan to run this truck except for display. If It is going to be used in an operating engine, the wheels need to be changed to metal.
Here are a couple of early pics. More as the build progresses. Axels, bearings and motor are on order.
|The first parts in ABS||
Wheels and gears in manufacturing.
The parts ordered have arrived so here is the next 3D printing step. I need a way to secure the electric motor on the mounting box. I decided a split bushing would do the trick. But I would have to design it myself. No problem of course.
The photos below show what I have done. I don't take a lot of pains with my pencil sketchs when noodling out a design. It's just for reference for the real drawing in CAD so I will have a reference for all the dimentions.
The split bushing takes up the space between the electric motor housing and the previously made housing box. In the picture I have not forced it all the way "home" as I may need to adjust the position before I do that. I lightly filed the edges to take away any ridges and create a small chamfer so the gap in the picture looks bigger than it really is. The fitup is very secure and tight.
The slot is not square but rather wedge shape with the apex at the center of the circles. Little details are important.
I have run out of ABS black and I had Bronze ABS in the printer, so that is why the new part is bronze. The color is not important and I actually like the contrast. The split ring is 100% fill amd 0.2mm layer height. Three shells wall thickness. The first ring was slightly undersize due to ABS shrinkage. I made measurements, caluculated the undersize amount as a percentage and enlarged the drawing by the same amount. That drawing printed exactly correct.
|My ususal quick dimentional hand sketch||Rendered in RhinoCAD and exported as a .OBJ file|
|First split ring fresh off the 3D printer. The ink mark on the side is to identify it as the first print.||2nd and final split ring in place on the motor housing.|
A great application for 3D printing is proof-of-concept prototype printing. This is an example.
I create Sterling silver lost wax cast jewelry pieces. I use two creative processes. The first is hand carving the wax master. Totally a manual process. Sometimes I start carving with just a sketch or photographs of what I want to create.
The second process is CAD/CAM, computer assisted drawing / computer assisted manufacturing. I use a computer 3D drawing program to design a piece to the ultimate detail and the send the file to a CNC, computer numerically controlled three or four axes milling machine. The milling machine carves the wax to match exactly what I have drawn in my design.
Hand carving usually takes days to complete. Machine carving may take days for the drawing and carves in one to as much as four to six hours.
From both these process, the carved wax is used to create the mold for the cast silver. The wax is destroyed in the process, thus the term, “Lost Wax”.
One benefit of the CAD/CAM is I can create a .STL file and produce the design on one of my 3D printers. If I were a rich man (Tweedel-deedle-deedle-dum) Fiddler on the Roof… I could print directly to a high-end jewelry wax 3D printer. Purchase prices start at the $10,000 range and supplies are also expensive.
I use a plastic filament (FFF) printer and can make plastic replica “proofs” in about 30 minutes before I commit to wax carving for many hours. I can also show the plastic proofs to a client with no fear of damaging the master. They are easily mail-able with no fear of damage.
The proofs shown here are printed at 0.1 resolution and show detail well, but are not good enough for actual casting even if they were wax. My Taig CNC mills use 0.003-inch ball end mills which produce better results directly in wax.
This is my first time “proofing” a design in plastic but I see it will not be the last when I have a client needing a durable and low cost proof on a custom design.
|Two sizes output on the 3D printer.||Cutting the "real" wax masters on the CNC mill.|
|Finished LWC silver. That's another story...|