Export a Cam as a Smooth Curve to CAD

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Export a Cam as a Smooth Curve to CAD

Export a Cam as 'smooth'

Note: This topic was written before Save as Biarcs was developed for Cams. Biarcs are tangent and thus very smooth.

Also, you can use the Save as icon to save the cam as a STEP file.

In MechDesigner, you can also save a cam as a DXF File.

The DXF is intended for CNC machines that do not have a spline option, or cannot open the STEP file format.

tog_minusExport directly to SOLIDWORKS from MechDesigner

In the Cam-Coordinate Data dialog, you should calculate the Cam-Coordinates as:

•Equal increments of the Master Machine Angle - say 360 for a typical 'side-plate' size of cam.

Send Cam Data to SolidWorks button.

Make sure the SolidWorks is open, and a Part, existing or new, is the active document.

The data is sent to SolidWorks as a Curve Feature.
MD-SW-CamCurveFeatures

The Curve feature shows on the XY-Plane, which is the Front View in SOLIDWORKS.

Note: To move Curve feature to the XZ or the YZ Plane, then in the Cam-Coordinated dialog-box:

1.Click the Save as button, and save the Data as a TXT file.

2.Edit the data in Excel, and swap the X-data, or Y-data, with the Z-data.

3.Save the Data to NotePad

Then, in SOLIDWORKS:

4.Click Insert menu > Curve > Curve Through XYZ Points...
MD-SW-CurveExtrusded

In SOLIDWORKS:

1.Select a Plane that is coplanar or parallel to the Curve feature.

2.Start a sketch on the Plane

3.Use Convert Entities in SolidWorks® sketch editor

4.Extrude the Curve.

You can see the Cam does not have any facets.

To import into other CAD

tog_minusOpen Excel®

1.Open the file, with file-type as... *.TXT

2.Select a delimiter, as a ',' or 'tab'.

You want the 'X' and 'Y' Cam Points in separate columns, with each Cam Point in a new Row.

Experiment with the import options if necessary.

3.Tidy up the data, remove headers etc.

4.Move all the data so the first X Point starts at Cell A1, and the first Y Point at B1.

5.Add a Column for the Z-Axis, and fill it with Zeros (0).

6.If necessary, make the first and last point to be identical.

Experiment as necessary. Some CAD will close the cam for you, other CAD will not.

7.If necessary, scale the Cam-Data to the units you are working in your CAD

8.Save your data as an Excel® spreadsheet, for back-up purposes.

9.Save your Data to a NotePad® file.

You will use the file that you save in Excel® or NotePad® to import into your CAD.
tog_minusImport Cam Data into CAD

The next steps depend on the CAD you are using.

Solid Edge

MD-SolidEdge - Insert Object - Curve byTable

Select:

1.Surfacing tab → Curves group → Curves → Curve By Table

2.On the Insert Object dialog-box, set the 'Create from File' option and click OK.

Browse to your Excel® spreadsheet and click ‘Open’.  

Curve by Table uses an Excel spreadsheet to define a construction curve. The spreadsheet, which is embedded in the Solid Edge document, allows you to better import and manage engineered curves.
MD-SolidEdge-CurvebyTableParameters

Curve by Table Parameters

Curve Fit

•Linear Segment

Creates line segments between the data points in the table.

•Smoothing Off

Applies the direct curve fit method to the data points in the table.  Using this method, the curve passes directly through the points.

•Smoothing On

Applies the 'least squares' curve fit method to the data points in the table.  Selecting this option enables the tolerance drop list.  Using this method, the curve path is controlled by the tolerance value and does need to touch the points.

•Tolerance

Allows you to specify a tolerance for the Smoothing On option.  Gives the maximum distance the curve can deviate from the points.
MD-SolidEdge-Excel

Curve End Conditions

•Open

Allows you to specify an open curve. For example, the first and last data points do not touch each other or any part of the curve.

•Closed

Specifies a closed curve. For example, the first and last data points can touch one another or any part of the curve. When this option is set, the Periodic and Natural options become available.

•Periodic

Connects the first data point with the last data point to make a smooth tangent closed curve.

•Natural

Creates a closed curve without a tangency condition.

Note: The 'Curve by Table' Feature will fail if the first and last data points in the spreadsheet are coincident. If you select 'Closed', delete the last point in the table that is coincident with the first.

Coordinate System

Allows you to select coordinate systems to offset the curve data to. Make the coordinate system prior to creating the curve through table of points.

number-of-points

Records the total number-of-points in spreadsheet.

Now, you can extrude the Curve as a Surface, I believe!