As far as physics demonstrations go, the Newton’s Cradle is probably one of the most recognizable. Named after Sir Isaac Newton, the Newton’s Cradle demonstrates the law of conservation of momentum using swinging ball bearings.
[Scorchworks] decided he wanted to build his own Newton’s Cradle. The frame appears to be cut from MDF or particle board and then screwed together. That material is really easy to obtain and also to work with using inexpensive tools. The tricky part was the ball bearings. Most of the time when you see a Newton’s Cradle, the ball bearings have a small hole drilled in the top with an eye hook attached. The string is then attached to the eye hook.
[Scorchworks] decided to do something different. His plan was to make custom injection molded plastic rings that would fit perfectly around the ball bearings. The most interesting thing is that he designed the injection molding plates entirely on his smart phone while at his child’s baseball practice. To do this, [Scorchworks] used his own Android app, ScorchCAD. ScorchCAD is a free clone of OpenSCAD that is designed to run on Android devices. Most of the functionality of OpenSCAD has been implemented in ScorchCAD, though not all functions work yet. You can find a list of all the supported functions on the project’s website or in the Google Play store.
Once the plates were designed within ScorchCAD, [Scorchworks] exported the STL file and then used Meshcam to generate the gcode for his CNC milling machine. Once he had the plates machined, he just placed the ball bearing into the mold and injected the molten plastic around it. The plastic formed a perfectly shaped ring around the bearing with small loops for the string. [Scorchworks] repeated the process several times to get all of the ball bearings finished.
Finally, the bearings were strung up using some fishing line. A Newton’s Cradle is very sensitive to the positioning of the ball bearings. To account for this, [Scorchworks] tied each end of the fishing line to two different screws on top of the cradle. This way, each screw can be tightened or loosened to adjust the position of each ball bearing.
So you have a 3D printer, and you’re getting tired of printing out octopodes and weighted companion cubes. Good! With a 3D printer, you can make just about anything, but only if you have the modeling experience to turn your design into an .STL file. This 3D Printering column is going on a tangent for a few weeks with some tutorials on how to make a ‘thing’.
This week, we’re starting off with OpenSCAD, a 3D modelling program that’s more like programming than drawing. A lot of useful 3D printable objects – including the parts for a lot of RepRaps – are designed in OpenSCAD, so hopefully by the end of this you’ll be able to design your own parts.
This isn’t meant to be a complete tutorial for OpenSCAD; I’m just demoing SCAD enough to build a simple part. Next week I’ll most likely be designing a part with AutoCAD, but if you have an idea of what software tools I should use as a tutorial to make a part, leave a note in the comments. Check out the 3D Printering guide to making a part with OpenSCAD below.
Continue reading “3D Printering: Making A Thing With OpenSCAD”
Recent experiments with the Arduino CapSense library led [Bryan] around the Internet looking for interesting applications. He hit upon a very cool touch scroll wheel made entirely with PCB traces, but the geometry – three interleaved zig zags is impossible to build in the decidedly ungeometric Eagle PCB package. One thing leads to another and now [Bryan] has a cap touch wheel Eagle part designed entirely in OpenSCAD.
The touch scroll wheel implementation [Bryan] found came from an ST touch controller datasheet and used oddly-shaped patterns to create a capacities sensor. Eagle is terrible for designing anything that isn’t laid out at a 45 degree angle, so he fired up OpenSCAD to draw these triangles. Importing into Eagle was another challenge, but a quick Ruby script to convert a DXF file into a set of coordinates for Eagle’s POLYGON command made everything very easy.
If OpenSCADing touch sensors isn’t your thing, there’s also an Eagle library full of them – something we found last week.
Here’s an enclosure which was designed with OpenSCAD and cut out on a CNC router. [Matthew Venn] wrote about the project because he sees tons of 3D printing hacks that use the software, but almost never hears about it as a tool for laser cutting or CNC router/mill work. When we read that we thought we must have seen a lot of 2D hacks but a search of Hackaday’s previous offerings proved us wrong. Just this week we heard about the software in use with the Makerbot. Or you could go back about a year and read about creating 3D molds. But nothing on 2D work.
His post is a quick read and shows off the bare bones of the case designs he’s been working with for a few years. By referencing the code itself, and playing with how it changes the render in OpenSCAD he makes a strong case for quick and easy enclosure design. If you use this technique make sure to document your experience because we want to hear about it!
Although having a 3D printer means you can create custom object of your own design, that doesn’t change the fact that most object printed on Makerbots and RepRaps are copies, or slight derivations, of already existing object. If you need a gear, just go grab an OpenSCAD file for a gear, and a custom smart phone case can be easily made by modifying an already existing one. The problem with this approach, though, is you’ll need to learn OpenSCAD or another 3D design tool. Enter the Makerbot Customizer, a web app that allows you to create custom versions of other people’s work right in your browser.
The idea behind Customizer is simple: someone creates an OpenSCAD file with a few variables like the number of teeth on a gear or the number of turns on a screw. Customizer takes this OpenSCAD file, puts sliders and radio buttons on a web page, and allows you to create custom objects based on user-created templates.
Already we’ve seen a lot of Hackaday readers send in some pretty cool customizable things, like [Bryan]’s coil form for DIY inductors and [Greg]’s customizable PVC pipe couplers. If you already know OpenSCAD, it’s easy to create your own objects that are customizable by anyone on the Internet.
For all the 3D models out on the Internet, including the STL files on Thingiverse that are copied by other makers every day, there hasn’t been a good way to put your John Hancock on a three-dimensional piece of plastic you’ve designed. [Chris] has been thinking about the fact that an STL file released on the Internet is completely out of the creator’s hands for a while now, and he finally came up with a good solution to signing 3D prints.
[Chris] had been looking into ‘stamping’ a maker’s mark on the first few layers of a print, but this wasn’t always practical. Sometimes the bottom of a print needs to be a smooth surface, so [Chris] moved his initials up a few layers into the main body of the print.
By subtracting a 1.0 mm-thick version of his initials from the interior of a print, [Chris] is able to put his maker’s mark on the inside of a 3D object, visible only for a short time during the production process.
The signature isn’t impossible to remove, but it does give a little bit of credit to the original designer, all without some strange DRM scheme or metadata attached to an STL file.
You can check out [Chris]’ printer laying down a few layers of his logo after the break.
Continue reading “Signing your 3D prints”
A decade or so ago, a line of jigsaw puzzles called Puzz3D brought the joys of fitting pieces of cardboard together into three dimensions. If you’ve ever put one together, you’ll remember being slightly disappointed at these 3D puzzles – they were made of two-dimensional foam board and only lived up to their expectations on the vertices of their 3D objects. Now that just about every hackerspace in the land has a 3D printer, it might just be time to create better 3D puzzles, and [Rich Olson]’s OpenSCAD library is up to the task.
There are a few other tools that cut 3D models up into smaller objects, but none of these had the features [Rich] wanted. He created a library that is able to position the puzzle cuts anywhere on the X and Y axes, adjusts the kerf for a tighter or looser fit, and exports one piece at a time for 3D printers with a smaller build area.
Right now the library is limited to generating up to four interlocking pieces, but [Rich] says the code should be easy to modify for a truly absurd 500-piece puzzle of the Taj Mahal,