Smoothing for Steep and Shallow reference

Improve part quality and make CNC machines run more smoothly with Smoothing.

Toolpath tolerance

When generating a toolpath, you must specify a Tolerance value. A tolerance value determines the distance a toolpath can deviate by when compared to a nominal toolpath. A tighter tolerance value results in longer calculation times but provides a better surface finish on a part. Generally, tight tolerances are appropriate for finishing toolpaths and loose tolerances for roughing toolpaths.

1 - Nominal toolpath

2 - Toolpath tolerance

3 - Actual toolpath (polygonized lines connected at points that are within the specified tolerance)

Smoothing tolerance

By default, the tolerance that Smoothing uses is half (smoothing tolerance factor = 0.5) the toolpath tolerance.

Selecting a smoothing option

The animation below shows how the different smoothing options affect where the points, which connect the polygonized lines, are placed on a toolpath.

1 - Smoothing not applied - places the points along the toolpath for the required tolerance.

2 - Fit arcs applied - reduces the number of points by replacing multiple lines with arcs where possible.

3 - Evenly spaced points applied - removes existing points and replaces them with points that are a fixed distance apart where possible.

Smoothing for older machine tools

Use Fit Arcs to replace multiple linear moves on a toolpath with arcs (G2/G3s) that are within a given tolerance. Fit arcs reduces the toolpath file size and improves the quality of a part by making the CNC machine run smoothly.

For example, when using Fit arcs, multiple lines around the outside edge of a part are converted into arcs, reducing the overall number of points, which are represented by orange points along the cutting moves.

Smoothing not applied	Fit arcs applied

Smoothing for newer machine tools

Use Evenly spaced points to place a multitude of points on a toolpath that are a fixed distance apart. Adding a large number of points increases the calculation time for the toolpath. However, having evenly spaced points results in a smoother motion on the machine tool, which improves the surface finish of a part and can result in significant machine cycle time reductions. Points may be clustered closer around corners, or where appropriate so, to stay within the tolerance.

Smoothing not applied	Evenly spaced points applied
	1 - Evenly spaced points
	2 - Closely clustered points

Specify a Maximum Spacing value to place the points along the cutting moves a set distance apart that cannot be exceeded.

Apply smoothing

1. In the Steep and Shallow strategy dialog, in the Passes tab, select Smoothing.
2. In the Passes tab, specify a Tolerance value.
3. From the Smoothing Mode drop-down list, select an option that is appropriate for your machine tool.
4. If you select Evenly Spaced Points, enter a Maximum Spacing value.
5. If necessary, edit the Smoothing Tolerance Factor.

Edit the tolerance factor

Smoothing uses a tolerance, which is a factor of the tolerance specified for the toolpath. By default, this value is set to 0.5 * tolerance. Advanced users may want to edit this factor for better control. To edit the tolerance factor:

1. Generate a steep and shallow toolpath that has the Smoothing checkbox enabled.

2. Right-click the steep and shallow toolpath in the Browser and click Compare and Edit.

3. In the search box, located at the bottom-center of the dialog, type Smoothing Tolerance Factor.

4. Right-click the default value and click Edit Expression.

5. In the Edit Expression dialog, enter a tolerance factor.

   Tip: If you want your Smoothing tolerance to be the same as your toolpath tolerance, specify a smoothing tolerance factor of 1.

6. Click OK. The toolpath is now out of date and requires regenerating for the new tolerance factor to take effect.