1 Points to note when designing a ArtCAM model for 3D manufacture: Model depth should not generally exceed 20-30mm as this is the maximum that the standard tooling on the CNC router / miller can accommodate Very fine detail will increase machining time, and may not be achievable with standard tooling available. When you have completed your ArtCAM Pro model, it should be saved as an.art file in case you need to work on it again in ArtCAM. You will now need to convert your model to a file format that the CNC machines will understand - in this case a.stl (or stereolithography) file Open Create Triangle Mesh in the Relief Operations menu Click Create Triangles (NB. The Triangulation Parameters can be varied to produce a more detailed model, but this also affects file size and machining times) Scroll further down the window and click Save Triangles to convert the 3D file to an STL format. This should be saved to an appropriate destination (eg. your Homespace / USB flash stick etc) You can now close down ArtCAM Pro and open up either Boxford Design Tools if you are intending to manufacture your design on either the Boxford 260 Miller or Boxford HSR 500 Router. In this case you should select Import 3D Geocam in the File menu 3D Geocam if you are using another brand of CNC machinery; eg. Unimatic, Denford, Trend, Suregrave etc
2 When you are in 3D Geocam, the Select Model screen appears, which allows you to browse to select the *.stl file you wish to manufacture The model can be tumbled using the LH mouse button the view can be altered using the icons on the top toolbar Click Next when ready Define Cut Plane allows you to decide the direction and depth of the machining operation. This is a particularly useful function if you are machining a full 3D object in two halves it is then possible to machine to mid-plane from both sides Entering a zero value will machine to the full depth of your model In the Select Material screen you are asked to define the material to be machined from the pull-down list. Default materials are listed for all popular CNC manufacturers. Select the material of your choice. The software will automatically decide the appropriate speeds and feeds for the selected material. You should also select the billet size (size of machining blank) at this point. This should be at least equal to your model size plus 2 x the tool diameter in both X and Y directions.
3 In the Model Resize screen, the default setting is fit to material. This will stretch your model to fit the billet size. To change back to your original model size, uncheck the Fit to Material box and set the Percent (%) box to 100% The Model WorkShift screen allows you to reposition the workpiece within the billet if the Fit to Centre box is checked, the workpiece will automatically be centred in the billet In the Select Tooling screen, you need to select your chosen tool for both roughing and finishing operations. (NB. For most small scale 3D work this will be the 3mm ball end tool) (The percentage Step over settings are set by default at 90% for the roughing operation and 15% for the finishing cut.)
4 The next screen defines the finishing allowances that is, the maximum amount of material that is to be left on after the roughing operation has been carried out by default this is set a 1.00mm for the roughing operation The Footprint Control screen is set by default to rough over the entire surface of the model The Roughing screen allows you to choose your machining strategy for the roughing cycle.
The Finishing screen allows you to choose your machining strategy for the finishing cycle. (the options will be covered in more detail in the teaching sessions) 5 1 For best results, choose Combination Milling with a Stroke Angle of 90 degrees. In the Tool Paths, select Compute. The toolpaths will then be generated automatically When this process is complete, click Simulate to see an on screen simulation of the machining cycles (as shown below).
6 1 In the Post Process screen you will save the machining file. The software allows you to save in a variety of formats, which match the most commonly available manufacturing systems in schools. Select the appropriate format from the pull-down menu. For example if a Unimatic machine is to be used as the means of manufacturing, then Unimatic should be chosen. Click Save. The resulting file should be saved to a floppy disc, zip disc or USB flash stick for transfer to the computer attached to the CNC machine.