GUITAR NECK: trouble with Z-axis clearance

[jimbocurtis]

hello-

I have a guitar neck I am milling and an having trouble with the Z-clearance of the upper heel portion (see model attached).

I am trying to get the bit to not rapid to the top of that height and travel across, for some reason (and I think it's because I barely do not have enough z-clearance with my machine) it retracts up and goes across rather low, no matter what I set the retract to.  is there a way to get it to not go up and over like that?  back behind could work, I suppose, but I'd rather it not go back there either.    any help or suggestion anyone can make would be greatly appreciated!

thanks

james

[daniel_lyall · Accepted solution]

It's the heights, ramp clearances heights and safe distances that control where the cutter lifts to between cuts.

Now as you said your height is limited, it would be easier and more than likely faster if you break up the cuts into area's heel, middle bit the bit at the other end (I don't know what the parts of guitars are called). and use a toolpath like 3D adaptive.

I will pop an example up soon

[daniel_lyall]

@jimbocurtis What I have worked out to reduces the Z clearances issue is if you do a 3D adaptive to a set height you can remove 1/2 of the stock then go back and cut each section out useing a 3D adaptive and rest machining this keeps the tool down.

For this to work properly you need to model your stock.

After the first cut you get left with this

Then the next cut removes this part it only cuts the area in blue I restricted it's height to where the red line is.

The 3rd is like this

Then the last roughing cut is this

You will still need to go through the toolpaths and make sure they are ok for you to use on your machine ( as the saying goes use at your risk).

To do the stock model just put a plane on the bottom of the model 

then project the outline of the guitar on to the plane this is so you can easily find the center of the model, then sketch a center rectangle on the plane and set it to the width and length of the stock, then do a extrude new body to the height of the stock.

Then in your setup for the stock you pick the stock model then in the WCS you pick the guitar as your model.

example attached

[jimbocurtis]

Thanks for your suggestion-  i have been able to mill the smaller versions of this instrument with great success using the 3D contour tool path (photo below) and then a Trace around the head.  I have my setup stock built into the model, so it doesn't waste any time really.  I did as you suggested, just breaking up the tool path into 3 sections and it ran the heel very nicely without goin up and over the end part - which solved the problem.  the photo attached it the 3D contour tool path from another instrument.  the tool can go up and over that one with impunity.   thanks again for your help!