Mastercam Post Editing

Are you tired of having to call support for post edits in Mastercam? Good news, there are ways to change your NC output without having to edit the Mastercam post itself.

Here are a few tips to help you achieve the desired results:

G54 work offset:

When programming a 4-axis job with multiple sides of a part, the G54 work offset is set to automatically change to the next available offset. However, if the job is rotating around the X-axis, it is important to set the work offset to the center of rotation and keep the G54 offset constant to avoid unwanted moves. In Mastercam’s toolpath, under the plane tab, you can change the work offset from automatic to manual and set it to use any desired offset.

How to do we achieve this:

In Mastercam’s toolpath, under the plane tab we have the work offset section.

You will most likely see it set to -1

This means that the offset is set to automatic.

If we set it to use the manual mode we can set it to
use any desired offset.

0 = G54

1 = G55

2 = G56

Most controllers can use up to 6 different offsets.

IJK vs Radius:

Choosing between IJK and Radius for your CNC machine is often overlooked but can affect the performance of your machine. Each machine can act differently based on the type of controller fitted, and caution needs to be taken when using IJK in older controllers. In Mastercam, you can open your control definition and go to the ARC tab to change the arc settings available.

Where do we set this in Mastercam?

In Mastercam you need to open your control definition.

Go to the ARC tab which will open the various arc settings available.

Delta start to center

For the IJK method, you can set your XY Plane to use the delta start to center. If you are using planes other than Top, you can set these too.


Like the IJK above should you need the Radius method you can simply set it to use Radius.

Adding comments and code without editing Mastercam post:

Mastercam has a feature called Manual Entry that enables users to include additional code or comments in their output without manually modifying the post. In the toolpaths group, simply right-click and select Mill Toolpaths then Manual Entry. Users can import txt files or add comments or code temporarily for that output.


By utilizing these tips, you can avoid the hassle of calling support for post edits and achieve the desired results in your NC output.

For more cool new features and technology advancements,  check out Mecad’s newly developed Custom Taper Thread c-hook, that allows you to program, verify and cut customized thread profiles, on a tapered angle, within Mastercam!

Contact the Mastercam Team on 012 645 4300 or Email us