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This was a good project to master inkscape and gcode tools. There is a nice tutorial on how to render gears and then use the gcode tools plugin to create the gcode here: http://www.cnc-club.ru/forum/viewtopic.php?f=15&t=35&start=20

I started by using the gear rendering extension included with inkscape.

I launched the gcode tools when I was ready to create the gcode for my design. It took a bit of tweaking and experimentation but eventually I got some good gcode. I needed to set up a tool in the tool library as well as the preferences before creating the gcode. Note that you have to be in the 'Path to Gcode' tab for it actually do its thing.

Here's what the tool path for the gcode looks like in the Mach3 tool path window.

I followed the same procedure to create the smaller gear that is attached to the stepper motor.

Karl Williams

The CNC router machine has been busy cutting more CNC art experiments. The larger face above is 3-1/2 inches wide and the smaller faces are 1-1/2 inches wide. I wanted to see how small I could make the faces and still be recognizable.

The faces were all done with a staight .045 inch cutting bit.

Click through to see more cnc art fun...

Help, I'm stuck inside a tree!

A seahorse cut into foam (the kind used to stick flowers in).

Seahorse swimming in a box.

A basswood fridge magnet seahorse.

Susan Arnold, photographer, graphics artist, and friend of Kwartzlab, painted the cnc tree!

Karl Williams The robots are here.

Now that the CNC Router is complete, I have been experimenting with CNC art. The really cool thing about using a computer and a CNC router to create art is that the end results can be unpredictable and surprising. My first experiment was to take a picture of a tree, convert it to black and white, invert the image and then render it for cutting. I liked the idea of taking a living tree, converting it to ones and zeros, and then cutting the image into a processed wood product (MDF). The cutting path is one continuous spiral starting from the top outer edge.

The computer generated cutting path for a circular tree.

Another experiment was to render a picture of Audrey Hepburn using an x-axis raster technique. The Audrey on the left of the MDF panel was done at a lower line resolution. The panel was spray painted black and then white was added.

Click through for more art...

The next piece of artwork is a larger panel of plywood cut with the 3D surface of a bee hive. An actual picture of a bee hive was used to generate the tool cutting path.

I'm happy to announce that the CNC router table is now complete. We're one step closer to having rapid prototyping capability. The router table can be used to cut a variety of materials under computer numerical control (CNC). Objects are designed using CAD (computer aided design) software and then exported to a CAM (computer aided manufacturing) file format. CAD may be used to design curves and figures in two-dimensional (2D) space as well as curves, surfaces, and solids in three-dimensional (3D) objects. I'm in the process of sorting out the software and have had success using MACH3 to run the machine. Mach3 has a lot of flexibility for tuning the stepper motors of each axis and also includes a 3 dimensional rendering of the G-code to verify that the tool path is correct. Click through for more info...

Here is a condensed history of the router build since my last DIY CNC blog post.

Designed and built the electronics: 3 stepper controller boards, a parallel port break-out board, front and back panels. Used 3 power supplies - 1 per axis.

Used the Taig CNC milling machine to cut out mounting holes for the DB-9 connectors on the back panel and for the light emitting diodes on the front panels.

Everything is mounted in a computer case and each axis has its' own power supply and on/off switch. The LEDs on the front panel display the stepping sequence which is useful for debugging (and looks cool when the machine is cutting).

Desinged the Y-axis using a CAD program and then printed out the full sized parts, glued them to MDF and then cut them out.

A hole saw was used to cut half way through the MDF to hold the side conduit structure pieces in place.

Electrical conduit was used as the rigid side pieces. Threaded rods running through the conduit and frame pieces were used to hold the frame together.

The router cutting tool is attached to the Z-axis. This axis determines the depth of cut as the tool moves along the X and Y axis.

The Robots are coming. Karl Williams

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The positive photo fabrication method was used to create the boards. The supplies are from MG Chemicals and are readily available at Sayal electronics. After the boards were designed, the top and bottom traces were printed onto transparencies in an inkjet printer. Because these boards are double sided, vias are used to connect the top layer traces to the bottom layer traces. The transparencies are cut to size and carefully aligned so that the vias on each side line up perfectly. I staple the transparencies together and then slide a double sided, pre sensitized, board in between.

The transparencies and the board are then sandwiched between two sheets of glass and held together with some paper clamps so that nothing can move out of place when the board is being exposed to ultraviolet light. The side opposite to the one that is being exposed to the UV is covered with light blocking plastic. when the top of the board is finished being exposed, it is covered with the blocking material and the other side is then exposed.

I happen to have a UV eraser unit left over from the 'good old days' of microcontroller programming and eprom erasing so I use that as my UV light source but a regular fluorescent bulb will also work. Note that I cover the entire unit up when it is operating so that I'm not exposed to UV.

After the board has been exposed it is developed much like a photograph. The areas that were exposed to the UV light are washed away and the circuit board pattern that is left will protect the copper from the etchant during the next step. This is where the whole process can get messy with chemicals. When Darin White completes his board mill we won't have to deal with this any more.

What's that cooking on the hot plate? That delicious black tar is ferric chloride, a metal etchant. The ferric chloride dissolves the unprotected copper from the board and leaves the circuit design intact. The solution gets darker as more copper gets dissolved and it takes longer to etch a board. I heat it up so that it is warm and then turn the hot plate off. This stuff has to be put back into the bottle and disposed of at a chemical waste drop off site when it gets saturated.

Etched boards washed and dried.

The boards are then drilled.

Here are two completed stepper motor controller boards attached to the parallel port breakout board. Note that the cables connecting the breakout board to each controller were fabbed out of an old hard drive ide cable by cutting the header on a band saw and splitting the ribbon cable. That saved me a lot of time soldering.

The Robots are coming. Karl Williams