Tag Archives: MakerCam

ShapeOko 2 tutorial – Dominion turntable – part 8

If you missed part 7, please find it here.

Milling the cutout of the quarter circle

At this point we’ve finished milling the surface of this quarter of our Dominion turntable and there are two things left to do, before we can continue working on the next quarter of the Dominion turntable:

  1. We need to mill the outline of this quarter – but just the curved part and the straight part along the y-axis. The straight line along the x-axis is not milled.
  2. We need to prepare and move the lumber to a position where the next quarter of the Dominion turntable is going to be milled.

This way we can mill half the turntable without having to glue two parts together.

InkScape

We need to make a svg-file with the path for the cutout. For that purpose I use InkScape. If you’re not familiar with InkScape you’ll find several tutorials here. We need to draw an intersection of two quarter circles with the smallest having the same radius as our Dominion turntable, i.e. 274 mm. The larger circle has a radius of 279 mm leaving us with a 5 mm gap between them. Furthermore, we need a rectangle with dimensions 5×279 mm. Putting it all together in a combined path it looks like in the photo.

Cutout path made in InkScape

Cutout path made in InkScape

Last but not least we need to place the figure in the right position. That is: we need to place it so that the upper inner corner of the rectangle is placed at (0,0). Then save the figure as a svg-file.

MakerCam

I use MakerCam to create the g-code. Go to http://www.makercam.com to start MakerCam (there is a beginners tutorial here).

First we need to setup MakerCam so it fits the svg-file created by Inscape. In the upper right corner I select cm instead of inch. Then select Edit -> Edit preferences to open the preferences dialog shown in the photo.

MakerCam setup

MakerCam setup

Set the value of SVG Import Default Resolution (px/inch) to the value 90 and Machine Tolerance (in) to the value 0.001 and press Ok. Then select File -> Open SVG File, select your file and press Open.

Select the path (it will turn orange) and select CAM -> Pocket Operation and MakerCam will show the dialog below.

MakerCam - Pocket operation

MakerCam – Pocket operation dialog

Set the following values:

  • Name = pocket 1 (default value)
  • Tool diameter (mm) = 3.2 (in my case I use a 3,2 mm flat cutter)
  • Target depth = -26 (in my case the timber is 26 mm thick)
  • Safety height = 5 (default is 15 mm but I see no reason to have that much)
  • Stock surface = 0 (default value)
  • Step over (%) = 40 (default value)
  • Step down (mm) = 1 (default is 1,5 mm but I prefer to go a little less)
  • Roughing clearance (mm) = 0 (default value)
  • Feed rate (mm/minute) = 1000 (this value is depending on your CNC machine)
  • Plunge rate (mm/minute) = 500 (this value is depending on your CNC machine)
  • Direction = counter clockwise (default value)

Press Ok to close the dialog. Then select CAM -> Calculate all to get MakerCam to calculate the g-code for the pocket operation. When the calculation is done, select CAM – Export g-code to get the dialog shown here.

MakerCam - save g-code dialog

MakerCam – save g-code dialog

Press Export Selected Toolpaths and save the g-code in a file with the extension .nc

Again, I view my g-code in a g-code viewer just to check that the code looks fine.

GCodeViewer showing the generated cutout g-code

GCodeViewer showing the generated cutout g-code

Β Cutout

After a test run of the g-code, we’re ready to make some noise. πŸ™‚

Part 9.

ShapeOko 2 tutorial – Dominion turntable

Introduction

This is the first part of my tutorial on using the ShapeOko 2 for building a Dominion turntable looking a little like this one.

First of all you’ll need a CNC machine. I got mine from Inventables and upgraded it with a Kress 800 FME spindle (the ShapeOko forum has some nice posts on the bigger Kress 1050 spindle). I posted some posts about building my ShapeOko 2 (here’s another one). I’m very pleased with the performance of my new spindle. The stock spindle (the Dremel clone) wasn’t strong enough for continuous work in my opinion.

Then there is software: there is a lot of free and open source software out there for the purpose of drawing, generate g-code and sending the g-code to the ShapeOko 2. I find the following combination of software useful:

OpenSCAD: An open source CAD program. It doesn’t have a lot of fancy drag and drop features but it is solid and gets the job done. There is a lot of documentation and tutorials on the homepage for the beginner so don’t be scared by the programmatic approach (which suits a mathematician and programmer like me very well πŸ™‚ ).

Inkscape: Another open source program for drawing SVG files which sometimes are handy when creating simple tasks for the ShapeOko 2. Again the homepage contains a lot of useful information for the beginner: tutorials, videos, blogs and a strong community.

MakerCAM: An on-line g-code generator. It’s simple to use and I use it for simple tasks. A good tutorial on how to use Makercam can be seen here and some more useful information can be found here.

FreeMILL: A free program from MecSoft (thank you for making this excellent program free πŸ™‚ ). If you get fascinated by making things on a CNC machine (like me) then you should consider some of their non-free products (no, I don’t get paid for writing this!).

Grbl Controller: A open source g-code sender for communicating with the CNC machine. There is also a tutorial on how to run Grbl Controller on a Raspberry Pi. A list of g-code senders can be seen here.

Last but not least: I needed a small utility for breaking down the g-code generated by FreeMILL so I made one (I will make it available for download later on). The thing is that FreeMILL generates g-code describing the surface of a solid (imported as STL) which often isn’t possible for the ShapeOko 2 to run directly because the cuts are simply too deep for the machine to handle in one run. Therefore, I created a small tool to break down the file from FreeMILL so it can be milled a few millimeters at a time. I’ll write more about it, when we reach that part. πŸ™‚

At the end of this tutorial we’ll have created something like this:

Dominion turntable

I’ll take you through the process step by step and tell you about my experiences with the ShapeOko 2 along the road (Murphy has been a very frequent but uninvited guest in my workshop since I got my ShapeOko 2!). πŸ™‚

Part 2.