3D printing

In September 2019 we bought a Prusa i3 MK3S 3D printer. Over several weekends, my 10-year-old son assembled most of it himself, with with my supervision. In November 2019 we got the MMU2S multi-material upgrade but didn't get around to assembling that until February 2020, again over a few weekends.

Due to space constraints on the desk where the printer sits, we did not build the filament buffer but instead built auto-rewinders dryboxes as can be seen in the picture above. The designs are on Thingiverse, also listed below.

I started out designing things in Sketchup back when the desktop application was free, then moved to Tinkercad (which my son still uses), and worked with FreeCAD for a while. I still use Tinkercad on occasion, but now I design almost everything using OpenSCAD.

OpenSCAD seems daunting at first because you design things via a programming language and a GUI viewer instead of a full GUI experience, but now I find it easier to create things in OpenSCAD than any other 3D design software. All of my Thingiverse designs come with the OpenSCAD source code for anyone to modify (except for my first design, a drill bit, which comes with a Tinkercad model).

Articles

Thingiverse

My username on Thingiverse is Amatulic. Here are my designs that I have published:

Customizable gyro toy wrapped with engraved text

Hummingbird feeder flower replacement

Geodesic hemisphere with regular polygon equator

Perfect-fit plate stand / bowl stand

Retractable double-edge razor blade scraper

Platonic solid coin traps in OpenSCAD

Nuts&Bolt baby dexterity toy

King Kamehameha I spear head

Rubber-band powered paddle boat with Lego seat

Multi-color monogrammed Secret Butterfly Box, OpenSCAD customizable

Parametric strandbeest in OpenSCAD

Auto-rewinder stand for Rubbermaid 16 cup container

Auto-rewinder stand for Rubbermaid 21 cup container

Customizable sliding word-switcher

Buffed n Braced Einsy Door remixed for M5 T-nuts and screws

OpenSCAD Rubbermaid 21-cup container rim profile

Prusa i3 MK3S vibration absorbing Sorbothane feet

3D nozzle deburring / polishing bit

Comments

Post a Comment

Popular posts from this blog

Syncing Office 365 Outlook to Google calendar using Power Automate

Image
When my employer switched over from the Google office suite to Microsoft's Office 365, it caused unexpected disruption in my family. I had been sharing my work calendar with my wife (sharing no details, just busy times). It became an integral part of her calendar, to help her coordinate (between her job and my job) who picks up and drops off my son from school, and to let her know when I was free to take a phone call during my work day. Since the switchover to O365, my ability to share a calendar externally was eliminated. Based on documentation I could find, it should be possible, but the option doesn't appear in my employer's implementation of Outlook. I can view my personal Google calendar in my work Outlook calendar, but I can't share it the other way. Microsoft's Power Automate provides a way to solve this problem. It lets you create flows of data, triggered manually or automatically by events, to move data around, not only among the Microsoft products but
Read more

The water rocket: Thrust from water

Image
Launch tube thrust Thrust from air Once the rocket has left the launch tube, the water thrust phase of the flight begins. But before we begin those calculations, we need to have equations for ballistic flight, which is the last step described in the introduction . Why? Because during ballistic flight (coasting through the air), the only forces acting on the rocket are gravity and wind drag — but these are acting on the rocket during the thrust phase too. Ballistic flight is exactly the same, just without the thrust. Ballistic flight We need to know how gravity and drag affect acceleration, velocity, and ultimately altitude during all thrust phases as well as the ballistic trajectory afterward, so we'll start with the ballistic flight equations. Air resistance First we need to get the ambient air density. Denser air results in higher drag, and dry air is more dense than moist air. To get the density, we first need to know the partial pressure of water vapor in the air. T
Read more

The water rocket: Numerical calculations

Image
Thrust from air So now we're ready to put all the calculations together: launch tube, water thrust, air thrust, and ballistic flight. The launch tube calculation is more like an initialization for the water thrust phase; we just have one time step of the duration of launch tube traversal. Get the initial pressure \(P_0\) for water thrust from (L1), and the velocity \(v_0\) from (L4), and use these values in the first water thrust time step. You may also want to initialize the altitude achieved as the height of the tube. Water thrust calculation For the water thrust phase, we do the following calculations at each time interval, which should be 1 millisecond or less in duration: At the beginning of time interval \(i\): Get the pressure \(P_1\) from (W4), using the change in water volume from the previous time interval. From the water volume, calculate the height of the water in the bottle — needed for \(H\) in equation (W1). This can be approximated by calculating the
Read more