tool axis control

[Lord Wukits]

Are there any documents or visual aids in helping with Tool Axis Control?

I seem to stumble into what I want  more often than knowing what I am setting. From the Tool Axis Control window it would seem really obvious... but I guess not for me    
Specifically I am working with Morph [OMG what a tool path!].

3 axis - easy...
4 axis - Easy if I am facing directly  on an axis...
            The issue is that I am facing the outside of a U shaped wall. I want to keep my ball endmill locked at 45* on Z[b axis], but let the C axis rotate from 180* to 0*

I had assumed Fixed angle to axis [z 45]. This has the desired effect on one side, but plowing through the part on the other side.
Angle, and Rotate around axis seem to be based on Z being normal to surface... which has the tool spinning like a record, round round right round.

Back to fixed, I have tried limits[one at a time]. This seems to lock the endmill only in angles of 0* to 180*  Ok Flip angle fixes this [allows 180* to 360*].
Limit in XZ seems to keep the endmill in the right angle, but I do not have any axis control in the Y[seems obvious].
YZ seems to be limiting me on XY.
Is the Limit feature based on Z being normal to surface, or is it based on the WCS "Fixed" axis?




I'll clarify this in a bit if needed, but I have to take a walk   
[as stated I am interested in learning what is going on more so than just playing with it till it is right]

[crazy^millman]

Are there any documents or visual aids in helping with Tool Axis Control?

 

I seem to stumble into what I want  more often than knowing what I am setting. From the Tool Axis Control window it would seem really obvious... but I guess not for me    

Specifically I am working with Morph [OMG what a tool path!].

 

3 axis - easy...

4 axis - Easy if I am facing directly  on an axis...

            The issue is that I am facing the outside of a U shaped wall. I want to keep my ball endmill locked at 45* on Z[b axis], but let the C axis rotate from 180* to 0*

 

I had assumed Fixed angle to axis [z 45]. This has the desired effect on one side, but plowing through the part on the other side.

Angle, and Rotate around axis seem to be based on Z being normal to surface... which has the tool spinning like a record, round round right round.

 

Back to fixed, I have tried limits[one at a time]. This seems to lock the endmill only in angles of 0* to 180*  Ok Flip angle fixes this [allows 180* to 360*].

Limit in XZ seems to keep the endmill in the right angle, but I do not have any axis control in the Y[seems obvious].

YZ seems to be limiting me on XY.

Is the Limit feature based on Z being normal to surface, or is it based on the WCS "Fixed" axis?

 

 

 

 

I'll clarify this in a bit if needed, but I have to take a walk   

[as stated I am interested in learning what is going on more so than just playing with it till it is right]

 

What I have found works best with limits is to create a normal line on the shape I am cutting. Then use that line as my control axis for limits. Then limit the travel amounts using that line to drive them from. As powerful as this toolpath is it is not kinematic aware. You must do that for this toolpath. What do I mean by that? Well on full rotation machine where you don't bump into limits you will normally never run into this issue, but on machines with limited Axis travel for one or both of the rotation axis you run into this problem a lot. Why is this? Well Mastercam doesn't consider travel limits of the machines you are programming for. It is up the the programmer to take those into account. Most posts have the ability to give the programmer the ability by adding switches and triggers to work this out, but sometimes they fail because the programmer didn't approach the toolpath correctly from the start. By knowing these limits up front and keeping toolpaths within those limits then it is manageable, but when you don't know those limits and run into them what do you do? You learn what they are build you a working envelope zone and then keep all programming project with Planes and other things into account and you are good to go. Mastercam is a great 5 Axis programming package, just take a little while to wrap your brain around it. Once you do then you realize you can put that exactly where and how you want even on the most difficult part. 

[Lord Wukits]

"By knowing these limits up front and keeping toolpaths within those limits then it is manageable"

 

 

Hence me wanting to control the Axis. We have  a Motionmaster form 199#-something with a C axis limit of -1 to 361. COntrol using other toolpaths were pretty strait forward, allowing me to avoid "unwinds" or deliberately place them at the beginning/end and trim them manually after posted. 

[Jim at Gentex]

 

I had assumed Fixed angle to axis [z 45]. This has the desired effect on one side, but plowing through the part on the other side.

 

 

Sometimes it can be just as simple as splitting the surface, then approaching the side that works well with the fixed angle normally, then approaching the side it was plowing into from the opposite end of the surface. (Not sure if that's clear.)

 

Or doing half with the tool fixed at 45 degrees and the other half with it fixed at -45.

Without seeing your machine I am just guessing here.

 

As with any 5-axis program there are many ways to come at it.

I use multisurf with fixed angle quite a bit and it's a nice way of doing things once you learn the little tricks. 

[crazy^millman]

Sometimes it can be just as simple as splitting the surface, then approaching the side that works well with the fixed angle normally, then approaching the side it was plowing into from the opposite end of the surface. (Not sure if that's clear.)

 

Or doing half with the tool fixed at 45 degrees and the other half with it fixed at -45.

Without seeing your machine I am just guessing here.

 

As with any 5-axis program there are many ways to come at it.

I use multisurf with fixed angle quite a bit and it's a nice way of doing things once you learn the little tricks. 

 

You can do the same thing with the Morph Between 2 Curves. I will use 2 limits on Axis control to get it to stay within limits. Also don't be afraid to make dummy surfaces to use in Collision control to tilt away the axis this will also fake it out and keep it within limits. Want to dome a complete shape draw a surface above your cutting surface that will allow the tool to cut the surface, but not all the holder to. Now use that in collision control and it will tilt the tool into the cutting  area, but not allow the limited axis to go to the travel it would have without it. This one you have to see what works best on your machine. In Wulkuts issue I would create it at 12 on the clock and test it then rotate to 6 on the clock and test it. May need 3 or 9, but one you see how it works then you have that as part of your template file. Import it in and now you can program using this awesome toolpaths and manage limits using a odd way, but has worked in some situations when other things wouldn't.

 

One might ask how did I figure that out? Well I had to cut a shape that has this kind of feature designed into it. Once I clocked the part on the machine the right way I could machine the full swing I needed out of the limited travel machine. Then it dawned on me I could do the same thing on open shapes. Once I made my dummy collision Wedge it seems to help in a couple situations. One some 100" diameter parts where it is in a cut for 20 hours these things make all the difference in the world.

[Jayson Kramer]

Some time you need to start at say a minus 180 or you need to find the start for the C axis.

[Lord Wukits]

Some time you need to start at say a minus 180 or you need to find the start for the C axis.

Right now I have it starting at 180 with positive B axis to keep it there... 

As stated above, older toolpaths seemed to handle half of the mold fine. This new[er] toolpath seems to be only capable of handling quarters.