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This or That: 3+2 Automatic Roughing Vs. OptiRough

This or That: 3+2 Automatic Roughing Vs. OptiRough

We’ll help you decide when to use Mastercam's 3+2 Automatic Roughing or Dynamic OptiRough from multiple angles in a 3+2 programming situation.

By Callie Morgan and John Stauffer
Tuesday, July 26th, 2022, 3:30 PM PDT


Dynamic OptiRough

As of Mastercam 2022, Mill and Router, and Mill 3D and Router 3D, licenses give you access to the powerful Dynamic OptiRough toolpath. OptiRough is a 3D roughing toolpath designed for maximum material removal rates. Since it contains Mastercam’s Dynamic Motion Technology, using this toolpath correctly can dramatically reduce roughing cycle time on your machine from 25% even up to 80%. Like the Dynamic Mill toolpath, it takes Z step-downs and XY stepovers until the geometry is reached. However, OptiRough also can take Z step-up passes, which are ideal for roughing non-vertical walls.


3+2 Automatic Roughing

To access the 3+2 Automatic Roughing toolpath, you must have a Multiaxis license. Automatic Roughing cuts very similarly to Optirough, but, unlike OptiRough, Automatic Roughing can do its own planar shifts. Automatic Roughing generates a single multi-plane, 3+2 axis toolpath for roughing by using a computer algorithm. The model and the stock are analyzed by Mastercam and the remaining stock is calculated on each plane. Then, a new roughing direction is generated for each plane, and the operation keeps calculating a new toolpath on each plane until the specified amount of stock remains (which you set on the Model Geometry Page). This is why having an accurate stock model is key to Automatic Roughing’s accuracy.

Automatic Roughing can do step-ups (called “Intermediate Slices”) in the Depth Step setting in the Parameters. This toolpath has the option to do either After Last Depth Step or every Depth Step for step-ups, and the best option depends on what material you’re cutting to assure your tool doesn’t wear out.


Comparing OptiRough from Multiple Angles and 3+2 Automatic Roughing

The "spaghetti monster" toolpath lines for all planes created by 3+2 Automatic Roughing toolpath in Mastercam 2023


A downside of Automatic Roughing is the display of the toolpath. Because this is a single toolpath that approaches from multiple angles it typically creates a bit of a “Spaghetti Monster” of toolpath backplot lines. This can make it more difficult to see what is happening from the Mastercam Graphics window. Make sure you are using Verify or, even better, full simulation, to check your toolpath motion before running this toolpath on a machine.

Another thing to keep in mind with 3+2 Automatic Roughing is that while the motion looks like OptiRough, it is not utilizing Dynamic Motion. This means that this toolpath will not output the most optimized version of the roughing possible, but gives you a good balance between cycle time, tool life, and programming time. This is okay for short runs, prototypes, or one-off parts, but isn’t ideal for longer runs where cycle time and tool life can start to add up.

Using OptiRough for multiple planes on one plane in Mastercam 2023. When viewing all planes at once, both 3+2 Automatic Roughing and OptiRough are very similar in toolpath appearance.

OptiRough can provide a much cleaner result overall because you are in full control of the toolpath. A single OptiRough toolpath can do the work of up to six different roughing toolpaths, making it a good way to cut down on your operations. This toolpath is excellent for removing material in Mill and Router, and can reduce cycle time significantly for through cuts. Using OptiRough on parts with multiple angles will take longer to set up, but is more efficient on the machine and will get you better tool life. 

Both toolpaths can have their operations exported and then imported into different part files, which will save you a ton of time on your future programming tasks. However, when importing to a new file, Automatic Roughing will automatically adjust the parameters for the new part because it is stock aware and has automatic linking. When importing OptiRough to a new file in a 3+2 programming situation, you will need to make manual adjustments for the toolpath in each plane that the toolpath sits on. The OptiRough toolpath has very specific linking planes and needs specific parameters to machine each of those planes, such as clearance, min and max values for steep/shallow, and containment boundaries, etc.

OptiRough is one of the most powerful toolpaths in Mastercam, but it is also the most misused. OptiRough is meant to be used with settings that take full advantage of the flute length of the tool in the initial depth cuts, followed by step-up passes that can rough any non-vertical walls in. Automatic Roughing also works in this manner, but because it doesn’t utilize Dynamic Motion, it is not quite as effective at reducing cycle time nor improving tool life.


When Should I Use 3+2 Automatic Roughing?

If you’re looking for the fastest way to get a program running on a machine, then use 3+2 Automatic Roughing. Since it can tackle a part from multiple angles automatically, this is a great way to get a machine running quickly because you don’t need to take the time to optimize the roughing angles in the program. This is especially good when you pair Automatic Roughing with a situation where you have to remove a lot of material. While the machine is running, you can use that time to work on other aspects of the program. This is also a great approach when programming for a prototype, a single part, or a short run of parts because it can greatly reduce your programming time. 

You can also use Automatic Roughing to mill the stock down to a Wrap bounding box of your part, which can be helpful in situations where material might be very tough, or in situations where roughing time will take a while and you just want to get the spindle turning.


When Should I Use OptiRough?

If you’re looking for the most optimized version of roughing possible and you want to extend tool life, then use OptiRough from multiple angles. OptiRough is a more optimized toolpath because it takes advantage of Mastercam’s Dynamic Motion Technology, which reduces cycle time and improves tool life. Using OptiRough from multiple angles will take longer to program in most cases (assuming that you are comfortable with both toolpaths), and will typically require creating multiple stock models to make it very efficient. This tends to increase the file size on your computer or network due to the stock models.

OptiRough may also be beneficial to you if you think you might need to regenerate many times to test settings. Because you can regenerate in sections with this method it can save you some time compared to regenerating 3+2 Automatic Roughing, which has to regenerate all the roughing at once. 


Learn OptiRough and 3+2 Automatic Roughing on Streamingteacher

You can find lessons on OptiRough for Mastercam 2023 on Streamingteacher here. For a more in-depth exploration of uses for OptiRough on various parts for Mill and Router, check out our presentation “Roughing Revolution” with a Pro account. 

We will be adding new 3+2 Automatic Roughing toolpath lessons for Mastercam 2023 in the coming weeks! These lessons will be linked here once they become available.



For access to more in-depth Mastercam training content, sign up for a Streamingteacher account here!


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