Parallel Steep Finish

[kwolf]

Hi,

I have a question about Parallel Steep Finish. Consider a semi-sphere with radius of 100 for simplicity and want to finish it in x direction using steep angle from 45 to 90 degrees. What I expect (when viewed from top) is a doughnut boundary around sphere from z=0 to z=70.7 but what I get are two separated regions of that doughnut. In general even by choosing from 0 degree to 90 degrees you have 2 separated boundaries limited between two lines "y=x" and "y=-x" (when viewed from top). It seems these 2 boundaries always lie between these two lines no matter what the starting and ending angles are.

Tell me why I don't get doughnut and why it's limited between two constant lines.

BTW I get what I want with shallow finish by setting angles from 45 to 90.

[Zero]

I'm a shallow fan myself.I find that for what I do,I can can get just about anything done with a rough pocket,finish contour and shallow, and sometimes a leftover.

[Camdude®]

kwolf,

in my experience parallel steep only "looks"

at surfaces that are perpendicular to the angle of cut, surfaces that are parallel to the cut motion are ignored. So i think that as the toolpath runs it is ignoring the surface as it transitions from the "X" plane to the "Y" plane

( curve of the donut), so you will get two separate cuts as it ignores the "Y" plane and reaquires the "X' plane on the other side of the donut. i may be way off on this one so take it with agrain of salt as i am basing this guess on personal experience only.

[gstephens]

Parallel Steep is designed as a clean-up routine for Parallel. If a surface is "steep" in a direction perpendicular to the cut direction, there are fewer passes along it due to the top projection of the passes. Running Parallel Steep in the perpendicular direction will only cut those places that will be left heavy by the Parallel path. Only those surfaces (or parts of surfaces) that are within the defined angles from the xy plane (45-90 in your case) in the direction of the cut are processed.

In the case of a doughnut shape, Scallop would almost always be my choice as long as you have the appmch.dll patch installed and activated so that you don't jump back and forth across the part.

[kwolf]

Okay I got the idea. Thanks alot.

But let me add some comment , if you have set any angle other than 45 ,for example 60 to 90 , you just limit your toolpath in Z direction and again those 2 virtual constant lines exist. I upload "steep-parallel.jpg" to pictures folder. Can someone tell me why toolpaths limited between these two constant lines?

Thanks

[kwolf]

Well I guess the toolpath must always between -45 to +45 to cut direction and the height/depth of cut controlled by setting start and end angles in toolpath parameters. Am I right?

[gstephens]

Sort of...

The "virtual line" you are talking about is where the surface is less than 45 (or 60 or whatever you set it to) degrees from the xy plane - in the direction of the toolpath (cut direction). If you have a constant curvature in that area it would end up a line, but if the surface is changing curvature you'll get a spline type edge. Basically you can look at it like a parting line with the part rotated in the cut direction by an angle equal to the minimum angle setting in the toolpath.

Are you completely confused now???

[kwolf]

Gstephens,

Thanks again. I completely got the idea about parting line. But what I want to know is , is there a way to expand toolpath to parting lines other than 45 degree? The software calculates parting lines to -45 and 45 only. If you look at picture you will see that by setting start angle to 45 or 60 , these two parting lines be the same (always 45 with respect to cut dir). And if you even set the start angle to 80 and end angle to 90 , again you limit your toolpath to those two parting lines.

Is there a parameter to control angle of parting line ?

Again thanks in advance,

Kevin