by cgapeart, published
CNC or 3D printing - the final tool head is not set in stone yet.
Updated to make the SCAD/MCAD Library usage more standard.
Now with Customizer Support!
Added cutouts for the motor mounts, and cleaned up a few spots. Also, started work on a 2d projection for export to dxf for making diagrams for actually building it.
The base design idea for the drive elements and linear rails/bearings came from:
This is an early design, and has not been built yet. I want to post it early to make it easy to share with friends and I am opening seeking comments from people who have built something like this and might be able to see some pitfalls a newbie would miss.
The OpenSCAD file is fully parameterized, to easily adjust the dimensions of the final machine. The default values I am working with create a working volume of appoximatley 10.5 inches wide, 17 inches long, and 6.5 inches high. I also have it set up the design to 'control' the device so that it is easy to visually observe the range of movement and check for areas where parts might collide.
The design is missing any kind of end-stop at the moment, and I haven't drafted in the connections between the drive rods and the axes.
The main construction material is 3/4" MDF. The current plans are based on the lumber being actually 3/4" - I haven't adjusted that for the actual dimensions yet, but thanks to OpenSCAD, that is just one variable (BaseBoardThickness) to change.
The bearings are 608 rollerblade bearings, and the motors are set as NEMA14's. I am planning on using 8mm ACME threaded leadscrews if I can get them, otherwise I will go with standard 8mm metric threaded rods.
My biggest worry so far is that I built in routed out shapes on each of the axes to make is easy to keep the drive rod in close to the axis of movement and keep the off-axis torque down. Will the wood still be strong enough? I am hoping that the slots for the T-Slot rails can be cut into the machine mostly by itself.
An Arduino with any one of the available drive software packages and motor drivers will be used to control it.
The MCAD Motors library is required for the stepper motor. The library set is available from http://github.com/elmom/MCAD . You can adjust the path in the include statement at the top of the file based on where you install it.