Another swarf 5 axis question

[Jim at Gentex]

I am still trying to get the hang of using this toolpath, so please bear with me...

 

I notice some spots on the wall have a smooth, clean finish, and other spots are a bit choppy. I tried minimizing the control points on the splines thinking that would reduce the choppiness.

[*]Is this the right approach?

[*]Can I also increase or decrease the maximum step increment to get a smoother finish?

[*]Which would be better, chord height or step increment?

[*]I am using chord height set at .001 for the wall following method with a max step of .005 on the finish cut... Should I try step increment instead of chord height, or increase or decrease either value?

I realize my questions are many, but I know someone out there has gone down this (tool)path before!

 

Thanks.

 

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Thought for the day:

Alcohol and calculus do not mix...so don't drink and derive!

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[gcode]

Jim,

I've had the best results in 5X swarf toolpaths

using a surface to define the walls,

 

Try creating a ruled surface with your chains.

If you have trouble doing that, or the surface

has twists or kinks in it you can expect similar trouble using those chains to drive a tool.

 

When you get the two chains into a state where

you get a nice clean ruled surface, you can expect a nice clean toolpath as well.

[Jim at Gentex]

Thanks, gcode. I had previously tried using a surface to define the wall and posted questions about that in an earlier thread. My problem there was surface normality which seemed to be reversed on that particular surface on the original model. However, I didn't try creating a new ruled surface as you suggest. I will try that approach and see what happens.

Thanks for the quick reply!

 

Anyone else wanting to contribute further thoughts on this would be greatly appreciated.

[John Summers]

I hope you know you can reverse any surface normal with MODIFY-NORMAL [select].

[crazy^millman]

Jim have you treid the points along the chains and use the sync method with points. If doing a very complex surface does your machine have a compenation way to make uop for this on the control. The Thermwood will give you the ability to adjust the machine with a tangency factor and sometimes helps for making toolpaths smoother but you may lost accuracy in your cut so watch that also.

 

HTH

[Mike Whitten CAD/CAM Contractors]

Jim,

 

Be aware that certain toolpaths may require point generators. I have also had many issues until I figured this out.

 

Thanks

[Jim at Gentex]

Thanks all for responding.

 

John, I knew there was a way to change normality, I just wasn't sure how to do it. I do mostly the machining end of things here, so my modeling skills are limited. Thanks for the info. I took gcode's most excellent advice and created a ruled surface between the upper and lower splines then picked that surface as the wall. That seems to work nicely. I also switched from chord height to step increment and tried .025 steps to start. This looks fairly smooth...quite a bit better than before using chord height .001 and .005 max increment. I think the bigger step makes it less choppy and gives a smoother finish. The other way may have been too tight since my machine only has a 9600 max baud rate and gets choppy sometimes just from slow data transfer.

 

Millman, I am running an older Fadal w/ AB table attachment so there is no comp capability at the control. Yes,the pionts were synced on the splines, but I think the step increment had more to do with it than anything. Thanks for your suggestions.

 

Michael, I have never used the piont generator feature, so I am at a loss here. The lenses I'm cutting are coming off good now, so I'll run with it. I'll tinker with the point generator feature next week when I'll be writing a new toolpath to cut a different size lens.

 

Thanks again all...this web board is an awesome resource!

[Mike Whitten CAD/CAM Contractors]

Jim,

 

I believe that Point Generators are a must in Five axis Toolpath. CNC has some real nice Power Points for Five axis training that show how to use these.

 

Mike