Hi guys,
I have a file with a spline cut in it, it looks like a half of an ellipse. I'm using a Prototrak. When I save a DXF and use it to generate the toolpath, I get a series of lines instead of a smooth curve when I cut the metal. Does anyone know how to get a smooth curve like what is in the part file?
Thanks for any assistance here!
-Mike
dxf doesn't recognize spline entities; your spline has to broken into approximate arcs, a smooth result being the product of manipulating your cad to match the shape of the spline. it sux, and it looks like hell but that's the reality of it.
how do you do this? I have the original solidworks file. Is there a program that automates doing this?
Thanks, Mike
I use to do this all the time with AutoCRAP files and DP Technologies Esprit X. In DP Technologies Esprit X it was called the LCA function. It converted lots of tiny lines to arcs so you got a smoother cut and the wire EDM didn't jerk.
What CAM software do you have or is all you have the ability to lay down toolpath on a .dxf with the Prototrak?
Jon Banquer San Diego, CA
I found out mastercam can do it, so I'll go that route. Thanks for the help!
Most CAM products can.
Be careful that you don't simplify the spline too much as what you are doing is an interpolation using arcs to replace the lines. If you go too far your part might no longer be in tolerance.
Jon Banquer San Diego, CA
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[begin quote]DXF Group Codes (version number u14.1.03.)
-------------------- ENTITIES Section
SPLINE
--------------------
The following group codes apply to spline entities.
Spline group codes Group codes Description
100 Subclass marker (AcDbSpline)210 Normal vector (omitted if the spline is nonplanar) DXF: X value; APP: 3D vector
220, 230 DXF: Y and Z values of normal vector70 Spline flag (bit coded):
1 = Closed spline 2 = Periodic spline 4 = Rational spline 8 = Planar 16 = Linear (planar bit is also set)71 Degree of the spline curve
72 Number of knots73 Number of control points
74 Number of fit points (if any)42 Knot tolerance (default = 0.0000001)
43 Control-point tolerance (default = 0.0000001)44 Fit tolerance (default = 0.0000000001)
12 Start tangent--may be omitted (in WCS). DXF: X value; APP: 3D point.22, 32 DXF: Y and Z values of start tangent--may be omitted (in WCS).
13 End tangent--may be omitted (in WCS). DXF: X value; APP: 3D point.23, 33 DXF: Y and Z values of end tangent--may be omitted (in WCS)
40 Knot value (one entry per knot)41 Weight (if not 1); with multiple group pairs, are present if all are not 1
10 Control points (in WCS) one entry per control point. DXF: X value; APP: 3D point20, 30 DXF: Y and Z values of control points (in WCS) (one entry per control point)
11 Fit points (in WCS) one entry per fit point. DXF: X value; APP: 3D point21, 31 DXF: Y and Z values of fit points (in WCS) (one entry per fit point)
[end quote]Bonus question: What's the difference between a Solidworks spline and a Solid Edge spline?
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