Update
I've been chipping away at this project as time and motivation allows. Building these cars is like building a resin kit for the first time.
This has definitely been a great learning experience for growing my 3D design experience, and getting more familiar with the intricacies of the filament printing process.
One big take-away since I started printing parts for seven cars is how sensitive the PLA filament is to humidity. I had not properly stored my filament between prints, and I had not printed much from March thru June of this year. I was getting a LOT of stringing, and poor surface finish. I had already purchased a food dryer and converted it to allow me to dry filament. Instant cure of stringing after four hours of drying at 45 degrees C. An easy way to determine if you have hydrated filament is to run a purge cycle. If the filament doesn't extrude straight, and has a rough O.D. on the extruded filament, it needs drying. After drying, flows well and has a nice OD finish.
Extrusion issues, especially on my Prusa Mini printer could be due to extruder issues, or hot end problems. I did a cold pull prior to drying the filament to no avail, as well as cleaning the extruder. That is what drove me to the next step of drying the filament. Now, between prints, I unload the filament, and store it back in the box in it's sealed bag, with a bad of dessicant with it. BTW, I save the dessicant bags, and when I dry out filament, I dry the dessicant bags too so I can store them in a sealed, and humid free environment.
Here are the seven cars in production. All of the parts are printed, and five of the under-frames are fully assembled. Five of the tank prints are assembled, filled with putty where required, and sanded to smooth the surface after the putty has dried. I also go over the entire tank surface, first with a 400 grit sanding stick, followed by 600 grit, and finishing with 1000 grit. That is why you do not see any lines.
There are places where the lines are visible, particularly on the side sills. But they feel smooth to the touch, and I am HOPING that a coat of Tamiya primer will make them invisible. Based on results my friend had with parts I printed for him, I think it will.
I try to utilize the Z-axis to maximum benefit, and do most of my printing at the lowest setting 0.05mm. The amount of lines is very hard to see, especially once painted.
Here are some photos of the current build about two weeks ago.
Here is a shot of the tank parts prior to assembly. The end caps also need sanding with a sanding stick to get the lines out, even at 0.05mm Z axis resolution.
I've done next to no sanding on the under-frame components with the exception of some light filing to get parts to fit tightly together.
I had not given any real thought as to what I want to do with the files. I'll make a decision after I get a complete build and I can see if the end result is worth it. I definitely don't want to be in the 3D printing business, or selling completed cars.
Regards,
Jerry
