Hurco 5 axis simultaneous - rippled surface.

[sgt_rock]

We have a Hurco VMX42HSRTi which is a head+table (B+C) machine. We are trying to cut our first true 5 axis part (Its an aerospace wing). The C axis is 24" diameter. The part is also about 24". If we machine the surface using just 3 axis or 4 axis (B tilted) the part looks great. When we try to machine the part using all the axis combined then it shows "ripples" in the part towards both ends of the outer areas of the surface (the furthest away from center of the rotary). The center areas look fine. We need to use the full 5 axis paths to completely machine the edges of the wing so we can't just use the tilted B axis by itself.

We also noticed that after cutting the part with all 5 axis and then re-cutting it using just 4 axis that there was about a .002 difference in the outer ends of the surface where it didn't clean up like it's not following the same contours.

The distributer came out to look at the machine but didn't find anything wrong with it. They did try updating the software. The machine is just over one year old.
We've tried changing the SFQ (Surface Finish Quality) parameter at the machine and it did not improve.
The part is programmed using tool axis vectors (IJK) and .0002" intol/outtol (same for all types of tool paths).

Has anyone done any true 5 axis simultaneous parts on their Hurco's? I'm wondering if it's the machine or the Hurco software in it can't handle all the axis accurately. Really has us wondering if we should have purchased a different machine.

Here is the surface using just 4 axis.


Here is the same surface using all 5 axis.


Here is a stock photo of the machine layout.

 

[landm1]

Looks like you put a lot of money into a Hurco, are you happy you did that?

 

[gkoenig]

The other variable here is the code. Getting good surfaces in 5 axis simultaneous has a bunch of factors going into it, especially as the machine size climbs and you have a lot of moment on the edges of the travel.

I would look at the program and move my stepover transitions as far away from the part as they can be had, and/or use lift and mess with the profile so the big direction changes happen as far away from the part as possible. When you have multiple axies doing a 180 at speed, it is no shocker you're going to get some ripple unless you are buying the most expensive machines with just bonkers servo control and dynamics.

People write PhD thesis material on the topic of accurate 5 axis surfacing, so there are many rabbit holes to go down. Take a look at this demo using NX and a Grob with the highest end Siemens controls. Even with that tool chain, you still have the possibility of getting weird surface artifacts:

 

[Billy_C]

I agree. Programming has a lot to do with it. It’s easy to blame the machine for poor surface quality and sometimes the machine is to blame but when it comes to doing full 5, there is a lot more riding on the software to tell the machine what to do. I’m not familiar with Hurco and what should be expected from them in general when it comes to something like this. What does it look like when it’s running. Is it smooth or jerky? Usually it’s pretty easy to tell if there is something really wrong with how it’s running.

 

[5 axis Fidia guy]

Is your rotary table gear driven? If so, it will be tough to improve that finish.

 

[CNC Hacker]

Another thing to check is the surface quality in CADCAM itself. I've gotten lots of models over the years with messed up UV vectors and stuff that can leave weird visual artifacts on the machined part. Often times I end up creating a new surface to correct for that.