About Turning Stock Transfer

Access:

Ribbon: CAM tab Turning panel Stock Transfer

The Stock Transfer strategy is intended for automatic stock transfer between the two spindles. No toolpath is associated with this strategy. The post processor is responsible for outputting the desired NC code.

Geometry tab settings



Confinement

Toolpaths can be contained within a specific region using the Confinement button to select confinement boundaries. Confinement regions can be defined with a combination of edges, surfaces, or sketch points.

Frontside stock offset:

Specifies the distance to machine beyond the frontside of the model.



Negative Frontside Offset



Positive Frontside Offset

Note: This offset applies to the backside of the model or containment region, and can be used at the same time as a frontside offset.

Radii tab settings



Clearance

Set this height to control the radius where the tool enters and exits the toolpath. The tool approaches and retracts from inside the stock along the Z axis (spindle axis) at this radial clearance offset. The value displayed on the orange tab represents its current radius relative to the setup axis.



Outer Clearance Radius

Note: The Clearance radius must be larger than, or equal to, the Outer radius to generate a valid toolpath.

Clearance offset:

Specifies the clearance offset value.



Outer Clearance Offset

Outer Radius

Defines the radial confinement by limiting the outer radial range of the toolpath. You can choose from the following:



Outer Radius

Outer radius offset:

Specifies the outer radius offset value.

Inner Radius

Defines the radial confinement by limiting the inner radial range of the toolpath. You can choose from the following:



Inner Radius

Inner radius offset:

Specifies the inner radius offset value.

Passes tab settings



Tolerance:

The machining tolerance is the sum of the tolerances used for toolpath generation and geometry triangulation. Any additional filtering tolerances must be added to this tolerance to get the total tolerance.



Loose Tolerance .100



Tight Tolerance .001

CNC machine contouring motion is controlled using line G1 and arc G2 G3 commands. To accommodate this, CAM approximates spline and surface toolpaths by linearizing them; creating many short line segments to approximate the desired shape. How accurately the toolpath matches the desired shape depends largely on the number of lines used. More lines result in a toolpath that more closely approximates the nominal shape of the spline or surface.

Data Starving

It is tempting to always use very tight tolerances, but there are trade-offs including longer toolpath calculation times, large G-code files, and very short line moves. The first two are not much of a problem because Inventor HSM calculates very quickly and most modern controls have at least 1MB of RAM. However, short line moves, coupled with high feedrates, may result in a phenomenon known as data starving.

Data starving occurs when the control becomes so overwhelmed with data that it cannot keep up. CNC controls can only process a finite number of lines of code (blocks) per second. That can be as few as 40 blocks/second on older machines and 1,000 blocks/second or more on a newer machine like the Haas Automation control. Short line moves and high feedrates can force the processing rate beyond what the control can handle. When that happens, the machine must pause after each move and wait for the next servo command from the control.

Stock in chuck:

Specifies the amount of stock in the chuck.

Eject stock:

Specifies the amount of stock to eject from the current chuck.

Parent topic: About Turning