With Kwartzlab’s recent 3D printer aquisition, we needed to put together a set of tools for members to create objects that could be printed by the machine. The RepRap printer we purchased has an associated open source project for loading standard 3D object files, called stereolithography (STL) files, and converting them to the printer’s machine language, called G-code.
Unfortunately, there was a potential show-stopper issue with the RepRap software – many of the STL files we tried to load, like this 3D version of the Kwartzlab logo I made, were getting corrupted.
The second part of my Sketchup experiments was to take a 3 dimensional sketchup model of a human face, convert it to G-code and then cut the object on my CNC router table. I browsed the Sketchup library and found a 3D face, imported it, and then sized it. Next, I used the skp-to-stl plugin and converted the object to an .stl file.
Sketchup is yet another reason to love Google! I have been experimenting with Sketchup, to see how it could be used for designing 3 dimensional parts and models, with the goal of generating G-code that could be run on my CNC router table.
The first thing I was hoping to do was to take a 3D model and turn it into 2D slices that can be cut on the router table and then assembled to form 3D objects. This technique is great for creating flatpack furniture, models, art and other similar objects.
For my first experiment I started off with a sphere and then sliced it down the Z-axis and the X-axis. The plugin prompts for the number of slices, slice thickness and the size you would like the joining slots for each slice intersection to be. The cross sections interlock in an open cell framework much like an egg crate. It also gives you the option to make copies of each slice, lay them out flat and number them so you can see where they fit together in the overall model. This makes it really easy to select an individual slice to convert to dxf format.
Next, I selected slice Z1 and then used the skp to dxf converter. The dxf file was imported into ArtSofts LazyCam and converted to clean G-code. Here’s what the tool path looks like in Mach3, ready to cut on the router.
Here is a vase converted to slices.
I’ll keep you posted on how the entire model translates to a real object cut on the CNC router table.
I needed to make some gears for a small power generator that I’m building. The device is going to use a stepper motor as a generator. I decided to cut the gears out of 1/4-inch thick cast acrylic with the CNC router machine.
The stepper motor controller boards for my CNC router project are based on the L297 controller and L298 H-bridge driver combination. The circuit board design is the same as the schematic shown in the L297 datasheet. To keep the size of the boards small, I decided to make them double sided. I also needed to build a parallel port breakout board so I did that at the same time. The schematic and boards were laid out using EagleCad.
Tonight I decided to try cutting a small intricate gear with the Taig CNC milling machine as a proof of concept experiment for another project that I’m working on. The gear is 1-7/8 inches in diameter. I plan on making much smaller gears but the smallest end mill that I have right now is 1/8 of an inch.
I pulled the CNC circuit board mill that I designed and built out of my basement lab and brought it to kwartzlab. I’m working with Karl on the CNC-DIY-FUN theme. This is a 3-axis vertical mill that I built with just a drill press and a hacksaw. The design goals were low-cost and accuracy down to 0.001″ to allow milling of circuit boards. While the mechanics of this mill were worked out a while back, it does need better driver electronics and some tramming. Karl, Ben, and I are putting together a kwartzlab toolchain for doing CNC milling (which would also support the eventual laser cutter). The idea is that we will all use the same tools in order to share knowledge/scripts/code/designs and get something together that just works. The components will be:
CAD or vector-graphics based program for design
CAM to convert design files to a tool path for cutting
Mill driver software to interpret the CAM-generated gcode and drive the mill’s cutting head
We’re building our own tools to support our vision of rapid prototyping, where we can go into the lab with an idea and have a working prototype in our hands within hours instead of weeks or months. That’s the goal. If you’d like to donate tools or materials, please contact me.
Gus decided to sell his Taig CNC Milling machine so it now has a good home in my basement.
I put it use right away, cutting out four aluminum support mounts for the 1/2-inch slide rails for the Y-axis of the CNC router that I’m in the process of building. The X-axis and Z-axis of the machine were built using hand tools. Watching the parts materialize as the endmill cut the aluminum was very exciting! The finished parts were perfect.
On February 23, Tom and Brian dropped by the lab to show us some of the amazing things they have built using their Taig desktop milling machines.
Tom showed us his fascinating Stirling engine . This machine runs on a heat source, in this case a mug of hot water. The cool thing about Toms engine is that it was all done with his Taig mill and lathe. The machine ran for hours sitting on top of the mug of hot water. Very nice precision work!