5 tips to improve your cnc post-processor

Are you running a bad CNC Post-Processor?

In this article, we will help you understand why you are running a bad CNC Post-Processor and show you tips on how to improve it to maximize your manufacturing performance. A bad CNC Post-Processor can have many disadvantages, to fix them, there will be some manual adjustment to perform to your post.

1. You need to manually adjust tool compensation values.

Tool length and diameter compensation play a huge role in making sure your part comes out to spec. Unfortunately, some generic posts simply output offsets with the same number as the tool. While that may be fine in some situations, more complex setups often require references to specific offsets.

Manually adjusting those offsets after you’ve posted your code is a wasteful and often risky move. To solve the problem, make sure your post is accurately mapping the tool offsets you set in your CAM system.

2. You need to manually add or change COOLANT/PRESSURE M codes to your G code.

Coolant does much more than just keep the temperature of your tool and stock under control. It clears chips that could otherwise get in the way of a cut and lead to sub-par surface finish. That’s why precise control of when and when your coolant turns on and off are important.

A quality post is built not only to match your machine’s specific coolant and pressure codes, but also incorporates some logic to automatically issue those codes under specific circumstances.

3. Tool and operation names are missing

Proper structuring, organization and labelling make lengthy part programs can greatly simplify a CNC operator’s job and makes pinpointing issues that arise at the machine easier. Unfortunately, most generic posts don’t transfer the naming of your operations at the CAM level to the G-Code.

Edit your post to grab that data from your CAM and output it along with other useful information like tool listing and more.

4. Your Head-Table 5-axis mill is leaving dwell marks on your workpiece

One of the principle causes for dwell marks on a Head-Table machine is when one of the rotary axes is at or near zero, a position referred to as a singularity. When the position of the axis oscillates between positive and negative, the head will often rotate erratically in an effort to find the “best” kinematic solution.

This is what leads to strange dwell marks and sub-standard surface quality. A good CNC post-processor will look ahead to see those issues and limit the rotation of the head to avoid them.

5. Your Table/Table 5-axis mill tilts the workpiece to the back of the machine; obstructing your view.

Keeping a keen eye on your machining operations is critical, especially when proofing the program and on its first run. Unfortunately, on most table-table machines, a generic CNC post processor will rotate the part towards the back of the machine, obstructing the CNC operator’s view.

Although this may be the simpler kinematic solution, it’s obviously not ideal for real-world situations. A good custom CNC post processor can make sure your workpiece is always in sight by using preferred table tilt angles.