how to prevent deep tool dive in 3d operations

[conjured2018]

Hi, I am using parallel for 3d contour operation on parts. My parts are cut out of 3/4 inch plywood. I have added linear rails, getting rid of plastic wheels, and Z does not have noticeable deflection now.

Issue I have is tool will take a helix down to .69, which is bottom of part and then move to make what looks like a chicken foot. From this first deep dive the tool then makes step overs to finish part.

This first deep dive is stressful to me and to the spindle. Today  I am using axial passes to make step downs less aggressive.

How do you guys move your mill into material? Do you use a more gradual ramp? Or is fix to use the axial passes?

I have found scallop is most aggressive dive deep. Morph does same. Please suggest a operation that I can use that is easier on mill.

Thanks JR

[seth.madore]

3D Adaptive and 3D Pocket Clearing are roughing toolpaths. Everything else in the 3D toolpaths are for finishing. As such, they assume that material has been removed. I suggest using one of the aforementioned toolpaths to remove the material 🙂

[conjured2018]

wow, Thanks Seth. I did not know this. JR

[conjured2018]

Seth, @seth.madore do  you have recommendations on 3d adaptive and pocket clearing specs for 3/4 inch plywood. I make two types of cuts, a more flat cut approximately 20 degrees from a bottom of -.71 to stock top of 0, (attached file.) Other cut is more vertical 70 degrees to 90 degrees along part edge.

Now I am using 3d adaptive for 3d, then a 2d contour with tabs to get part out of board. I also us a drill operation which helps me align parts during glu up.

My spindle is 220 3.5  horsepower. I am using a half inch ball for 3 d adaptive.

can you please suggest optimal load and maximum roughing stepdown settings? Just looking for starting points.

thanks, JR

[seth.madore]

@daniel_lyall you have loads more experience on woodworking parameters than I do, punting this one to your knowledge 😉

[daniel_lyall · Accepted solution]

@seth.madore Thanks Man

@conjured2018 A lot of what to do depends on how rigid the machine is for a start with the size spindle you have you can take big cuts but can the machine handle it.

You also need to take the time to learn what the machine can do once you know what the machine can handle then doing the cam is really fast as you know what it can and can not do.

With your part to rough it out you have 2 options Adaptive or Pocket pocket is faster than adaptive but harder on the machine as it can just go in and cut and it can be full width even if you don't want it, adaptive goes in at an arc what loads the cutter from nothing to something in an arc so you can take bigger cuts as there is no sudden big load.

The depth to take just start with 4mm depth and 1/4 of the cutter's width max for this part with an adaptive or pocket toolpath for roughing it out on other parts after this if it works well you can go deeper with a bigger step over.

This gives you I know it can do this so I can cut more.

For finishing the top have a look at the attached model for how I did it, if you have flat surfaces even on an angle you can use an endmill to cut it you just have it cutting in the long direction of the surfaces and you can get away with not using a ball mill or bullnose cutter the 2 other angled surfaces they have an extra finishing toolpath.

Now to the cutout toolpath using the contour toolpath you have two options with the cut depth using multiple depths (passes tab) or using the ramp settings(linking tab), I always use the ramp setting to do it as it gives a toolpath that just keeps going down with basically the same load all the way unless it hits the max ramp step down, for the tabs use triangular as the cutter ramps up and down when it gets to the tab otherwise it plunges and can leave a bad finish. 

The settings in the attached model are my defaults for my little machine and that has an 800-watt router on it, but use it at your own risk and test first any questions yell out.

Chur

[conjured2018]

Thank you Seth and Daniel, super helpful. JR