CNC Milling Setups Guide – Pocket NC’s Kinetic Control

With the release of the new Pocket NC’s Kinetic Control software and its major Tool Center Point Control (TCPC) feature, it’s an excellent opportunity to address the importance of CNC milling setups. Knowing how to set up your system correctly before each cycle is vital for CNC milling, unlike more streamlined technologies like 3D printing.

In the following sections, we’ll have a brief overview of the overall setup workflow, from design considerations to production, ultimately giving a more comprehensive view. Subsequently, we’ll compare why the release of this new software interface is such a big deal for Pocket NC machines considering the previous version limitations.

Subtractive Workflows from an Additive Perspective

With the rise of additive manufacturing, the reach of NC programming crossed beyond its traditional subtractive applications. Since both additive and subtractive processes share the same backbone, NC codes, we can understand CNC milling parting from a 3D printing perspective.

Both processes work under G-Code commands, which can be generated from a CAD model through CAM or slicer software.

However, one significant difference is that additive processes are more straightforward since 3D printers do not require

• Workholding Fixtures
• Frequent tool changes
• Stock measuring and positioning
• 5 axes to produce complex geometries
• Feed and Rates parameters
• Tool path strategies
• Further G-Code editing

Setting up a CNC milling process requires additional technical expertise, a better understanding of G-code programming and further metrology knowledge.

Now, let’s briefly review the CNC milling machine setup process to produce a part.

From CAD to CAM to Machine Setup

With CAD design and all its manufacturing requirements in check (Machine capabilities, axis number, geometric boundaries, positioning, available tool bits, stock materials, fixtures), the next step is to set a CAM environment.

Depending on your available software, you can export your model. Still, it’s well-advised to have it integrated into CAD, either directly or via add-ins, since updating your design to improve your operations is most likely to happen. Popular CAM software available on the market are Fusion 360, SolidWorks CAM, Solid Edge CAM, GibbsCAM and MasterCAM.

This interface fundamentally bridges your design with manufacturing operations and settings to ultimately generate an NC code. This interface enables users to define stock boundaries in reference to the final part, tool inputs, path operations, feeds and speeds configuration, among others. The intricacies of CAM are a whole subject in itself, but defining an appropriate coordinate system is one significant aspect of the process to note.

Stock Material Positioning

After the stock material dimensions are measured, confirming it matches the virtual stock, the next thing to do is to match positions fittingly. Again, key to CNC milling is to properly position your stock material in concordance with its virtual counterpart and strategically placing the 3 axis origin according to your workflow intent is a big part of a successful process.

Two common strategies to do so is by:

1. Matching the coordinate within CAM with the machine absolute coordinate
2. Selecting a point on the stock material, namely a vertex, to set the work coordinates there afterwards

The first approach requires setting the machine origin and offset distance from the worktable surface within the CAM environment. For Pocket NC machines, the origin where the A and B rotatory axes intersect (0.855 inches from the B table). The physical position of the stock material greatly depends on its fixturing setup. So how do we correctly match its virtual counterpart?

Edge finding is the process where you locate the offset distances by touching the stock’s faces with a tool attached to the spindle. After repeating the process in all XYZ axes, the resulting offset distances shown on the machine’s digital readout (DRO) must be set in CAM.

This approach is efficient if the aim is to use the same gcode for continuous cycles on a given machine. However, the slightest change in position, fixturing, and stock dimensions would require going back to CAM to set the stock all over again.

Users can download CAD representations of the table, its fixtures, and their offset in relation to the machine origin to ease the process. For instance, this CAD file embodies the Pocket NC custom vice fixture and is available online.

Previously, the only way of setting up Pocket NC machines was through this method. Thankfully, the Kinetic Control software update enables a change of approach.

Kinetic Control TCPC Solution

Contrary to the first approach, the second option enables users to set a coordinate system relative to a point within the stock piece independently from the machine’s absolute coordinates. This enables further flexibility involving CAM workflows since no workholding or offsets representations are required to set positioning, just the selected point.

With the gcode prepared, the only thing left to do is zero out the machine’s coordinate system to match the selected point, and this is what the new TCPC (Tool Center Point Control) feature allows us to do. The TCPC function is available within the “Setup” tab, where users can control spindle position throughout the “Jog” control interface.

Furthermore, the big deal with TCPC is that users can set the current spindle position or DRO as cero via the G92 command (Set Position) and then store a new coordinate system with G5X (Store Workspace Coordinate System). This means that users, throughout an edge finding process, can match the new coordinate system with a point within the piece of stock, set DRO to zero and then store the respective configuration within the machine. Afterwards, the machine will accurately calculate axis movements to match the updated coordinates.

With the coordinate system set and the tool length offset in place, you’re ready to go. This simple setup enables a much more intuitive approach, further ease of use and faster turnaround times without relying too much on CAM adjustments.

Kinetic Control Additional Features

Along with TCPC, Kinetic Control also improves rotary axis unwinding, potentially saving plenty of time for its users during machining cycles. Additionally, and most noteworthy, the new software interface was completely redesigned to offer friendlier workflows for its users. The developers took a particular emphasis on laying the groundwork for a robust update system. Just as John Allwine, principal software engineer at Pocket NC, stated:

“…One of the biggest reasons we wanted to develop it (Kinetic Control) was to plan for the future, for future developments. In the older software, we had a way to update very localized pieces of the software, but we couldn’t update lower level features such as TCPC….”

Any file on the system can now be updated, and hotfixes can be quickly released to improve it over time.

For more information on the software interface, check the official overview guide.

Furthermore, you might also be interested in the following CNC milling essentials guide.

Need further assistance from experts? Solid Print is here to help you take an optimal decision involving this update or anything related to Pocket NC products. For more information, please call SolidPrint at 01926 333 777 or email info@solidprint3d.co.uk.