Traditional CAM vs. FeatureCAM

January 2, 2023 Ed Gillman

CAM (computer aided manufacturing), by definition, is the use of computer software to create the code and commands to drive CNC mills and lathes. It provides manufacturers the ability to automate machining operations that used to require tedious, manual inputs. This digital method has revolutionized the industry and changed how quickly, accurately, and safely parts can be made.

Similar to CAD, CAM allows the operator to visualize the way a part will look in a 3-dimensional workspace. The motion of tools and the material being removed can be simulated and perfected before setting foot on the shop floor.  Adjusting the feeds, speeds, and other parameters in CAM reduces the inputs required on the machine controller. This all leads to a more efficient and more repeatable workflow.

Traditional CAM Workflow

In a traditional CAM workflow, there are several stages that require manual inputs and decisions. For each feature in a model (e.g. pocket, slot, hole) the operator must choose what strategy, boundary, tool, feed, and speed to use. Many decisions are made along the way as 3D geometry is dissected and converted into CNC toolpaths. More steps creates more opportunities to make mistakes. This process is also then repeated for every feature in the model. For large, complex parts this can be very time consuming.

 

Naturally, the traditional CAM process leads to large amounts of tribal knowledge. There are so many decisions in the process that each operator will begin to form their own methodologies. Depending on how they were schooled, or what their background is, the resulting toolpaths and programs can become vastly different. There's no system in place for sharing knowledge to create consistent repeatable programs. For example, take the pocket feature on the part shown below:

 

Machinist "A" might choose to use a high-speed machining strategy to remove material in the pocket. They select a 1/4" flat end mill and use large step downs (depth of cut) and small step overs (width of cut). A pocket strategy is selected to finish the bottom and sides of the region. Because of the minimal tool load - the feed rate can be much faster. The total time to run the program is only 4 minutes and 30 seconds.

Machinist "B" programs it a different way. They decide to machine the pocket with a larger end mill (3/8") using small step downs. However, this strategy uses large step overs (width of cut) that will require a slower feed rate to avoid damaging the tool. They also choose a different ramp strategy (helix) that will likely be more optimal for this feature. The total time to run the program is around 12 minutes and 15 seconds.