Introduction: The Coaster-Lid. Machined With a 3-axis Mill. Designed in 3ds MAX.

The Coaster-Lid.

It began it's life as a slab of acrylic. Using a 3-axis CNC mill, it was machined into the perfect piece for office desktops. Use it as a coaster to keep rings off of desks and utilize the spoon sill to catch drips. It is also used as a lid to keep dust and pathogens as you transport the beverage from the tea room to the workspace.

Step 1: Step1. the Design.

A basic drawing was done of the project and measurements were taken from a variety of coffee mugs to confirm dimensions. The completed item would be cut from a piece of acrylic 9.5mm thick. Tea spoons were also compared to settle on an appropriate diameter for the spoon recess.

The measurements used for this item.

-D1 (circle for the main recess) = 84mm
-D2 (circle for the spoon recess) = 26mm

I draft of the 2D mechanical drawing was then done in a sketch book for reference.

Step 2: Step2. Design in 3dmax.

The easiest step. A 2D mechanical drawing was done in 3ds MAX by creating shapes based off of concept sketches combined with measurements.

All shapes in this drawing will serve as a boundary or a path for the machine to follow.

- Both inner circles will have material removed within to a specified depth using a slot drill.

- The Machine will follow the lines forming the text using a V-Bit.

- The Machine will then follow the circles and the outside shape using a V-Bit to slightly bevel the edges and remove the harsh 90 degree angle.

- The slot drill is used again to perform the final cut.

A simple 3d model is made and rendered to provide a preview of the finished item.

The final drawing is exported as a CAD .dwg format to be imported into Artcam where tool paths used to direct the machine are created.

Step 3: Step3. Importing Into Artcam to Create Machine Tool Paths.

A new model is opened in Artcam with dimensions large enough to have the design fit with approximately 1cm of clearance on each side to prevent the machine tools from colliding with the clamps used in the machine to secure the piece of acrylic.

The model .dwg file is then imported and placed in the center of the model.

There are three types of tool path that were used with this project. 

- 2D Engraving.
- Machine Along Vector.
- 2D Profiling.

The created toolpaths are then exported and then opened with Mach2 Mill, the program that controls the CNC Milling machine.

An acrylic piece, the same dimensions of the Artcam model is secured in place in the machine.

The tools used in the mill.

-3mm End Mill

Step 4: Tool Path One. 2D Engraving

The first tool path is created using the two circle vectors. Material needed to be removed to a depth of 5mm. To do this the tool path, 2D engraving was used.

The start depth had to be entered as 0mm at the surface of the material. The process would finish at a depth of 5mm.

The tool used for this process is an end mill with a diameter of 3mm.

Step 5: Tool Path Two. Machine Along Vector

Now that material had been removed to a depth of 5mm, the text could be milled into the new surface. So with the words 'coaster' and 'lid' selected, we used on 'Machine along vector' tool path.

The start depth had to be entered as 5mm because the surface of the material was now 5mm lower as a result of the previous machining. The process would finish at a depth of 5.2mm.

The tool would be changed from the 3mm end mill to a V-bit to create a sharp, precise groove along the vectors. During the tool change the  X and Y positioning of the machine would not be altered so nothing was misaligned.

Step 6: Tool Path Three. Machine Along Vector

The V-Bit is left in the machine for the next process.

The machine follows all vectors except for the text and cuts to a depth of 3mm which creates an angular finish on the edges.

Step 7: Tool Path Four. 2D Profiling Outside Vector.

Finally the 3mm End mill is used again to perform the final cut-out procedure by using the 2D profiling tool.

The outside vector is selected and the tool path is created so that the machine moves along the outside of the vector to a depth of 10mm to free the coaster from the acrylic block. 

Step 8: Saving Tool Paths and Using the Machine.

After all tool paths are created in Artcam they must be exported or saved in Anderson .ncc format to be opened with Mach 2 Mill, the program that uses these files to move the machine in appropriate directions and speeds to perform the jobs.

 Using a jigsaw, a piece of acrylic, with the same dimensions as the Artcam model is cut out and secured into the machine.

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