4. CNC Group Assignment¶
In this group assignment, we are going to examine the procedure followed to test the important parameters affecting the CNC machine performance. To begin with, a wooden sheet was constructed with the feed rates and rotational speeds that are going to be tested. The feed rates range from 60 to 150 in/min and the rotational speed ranges from 8000 to 17000 RPM. When testing one parameter, the other is held constant. Consequently, when testing the feed rate, the rotational speed is held at a constant value of 14000 RPM and when testing the rotational speed, the feed rate was held at a constant value of 60 in/min.
The following picture shows the design used for testing:
When switching to the tool path, you can see the settings for the drill bit, you can set the diameter of the drill bit, pass depth and other parameters like the feed rate and rotational speed as shown below. Also, you can see the cutting path which is indicated by the dotted pink line:
A warning will show indicating that the depth specified corresponding to the number of passes is higher than the thickness of the testing sheet. Ignore it as the presence of the sacrifice sheet will protect the machine of enduring any damage and ensures complete cutting, note that the extra depth is added to ensure the success of the cutting process. The warning is as follows:
This is where the constructed tool path is simulated, with an option at the bottom right corner for the order of the operations which are illustrated in the toolpath list:
The solid lines represent engraving as shown:
In order to add pocket to the wooden sheet, the pocket toolpath is used, the main difference between the casual toolpath used for cutting and the pocket toolpath used to add pockets is that in the latter the depth is specified as the depth of the pocket. The following picture illustrates the pocket toolpath:
This is how the simulation will look after executing the pocket toolpath:
The drilling toolpath is used in order to add holes to the wooden sheet. The drilling toolpath can be accessed from the toolpath operation. The same settings to the profile toolpath is used (i.e. same depth) with the only difference is the feed rate which is set to 100 in/min:
This picture illustrates how the drill bit path is going to be:
As stated previously, the test was conducted through first holding everything constant and changing the feed rate to see the effect of the feed rate, and the same thing is repeated with respect to the rotational speed (i.e. spindle speed). First, the spindle speed was held constant and the feed rate was changed as in the following pictures, where the tool path is used and the path is displayed in the sheet:
Same thing for the spindle speed, the feed rate was held constant at 60 in/min and the spindle speed is changed:
This is the view of the final simulation after making the final changes, the red lines represent the toolpath of the drill bit for each corresponding component:
This is the final design after using the CNC machine to make it:
