"Crop Circles" are not a result of the Max Arc movement. These are generated for two reasons. I will tell you why and give you a solution for each below:
Case 1: Accuracy error
In this case what happens is there is an entity or entities in the profile that are smaller than the alloted decimal output for the control. For example an arc with a small sweep where the beginning is X0.12453, Y0.2526 and the end of the arc is X0.12449, Y0.25263. When the system generates the code it rounds these values to get it down to 4 decimals. Now you have an arc that begins and ends at the same location (full circle).
To correct these errors:
Click on File => Environment.
Click on the Defaults tab.
Change the General Accuracy to 0.0001" or 0.001mm.
Then click OK.
Case 2: Non-tangent Arc segments
In this case the system is generating an arc move around a corner produced at the intersection of an arc and line or an arc and an arc. This is done because the arcs are not tangent to the adjacent entities. Believe it ornot, this type of problem is the most common and is, more often than not, due to the part design and not the program.
To correct these errors:
Select the geometry used to create the toolpath (before the toolpath is created).
Then click on Change => Reorganize => Make Arcs tangential.
In the dialog the Max Acceptable Angle is the largest angle of deviation you will allow. I normally set this to .001.
The Max Angle for correction is largest angle of deviation you want to fix or make tangent. As you make changes the Number of Corrections to do field will be updated.
After clicking OK the corrections will be done and you should apply the toolpath.
This is more of an art than a science a lot of time, so you may need to play with it a bit to get it down to a science for your parts. But either of these cases, or even both, will resolve the issue with "Crop Circles".
Regards  |