Rest Machining Problem

[Phil]

I'm making a plaque as an anniversary gift for my daughter. The problem is that the rest machining missed a major part of the machining.The banners are fine but the cutter missed the flourishes and the lion. I Z-zeroed from the same surface with the .25" cutter and the .062" cutter. As you can see in the photo there is essentially no detail in the flourishes and the lion.
I need to create a file that only includes the parts that were missed but I don't know where to set the Z-zero. I use the aluminum Z-zero plate that was furnished by Shopbot.
The file is too large to attach here. However, the only help I need is to recut part or the plaque.

Phil

[SteveNelson46]

In your pic of the toolpath, it doesn't show anything missing but, you may have the detail set to "minimum". You can use the slider in the toolpath setup to increase or decrease the amount of detail you want. There are a lot of factors involved, Type of bits, diameter of the bits, stepover,etc. In the maximum detail pic shown here I used a 1/16" TBN with a stepover of 8% and a 1/32" TBN with a stepover of 8% also. I think the carving time on the maximum setting will take about 8 hours or an increase of about 2 hours using just one bit.

[Jimcad]

Hi Phil,
This may help.




You should know the height of the face to be carved on so Zero off that and adjust to suit perhaps?
But try an "AIR" cut first.

Jim

[SteveNelson46]

You stated that you used a 1/4" and a 1/16" bit. I am assuming that they were both ballnose or tapered ballnose bits. I think the problem is that the 1/4" bit will not fit into the smaller areas and you don't have enough detail set for the 1/16" bit. When using the automatic rest machining process there is a balance between the bits used. If the first cutter is relatively large the smaller bit(s) will have to do more work. Try using a 1/8" TBN instead of the 1/4" as the primary bit.

[Phil]

I've cut quite a few projects like this not using the rest maching technique. Before the option was avaliable in the latest Aspire version I would do an initial cut with a 1/4" BN followed by a 3D finishing cut with a 1/16 "BN. I never had a problem, just excellent results.
With this project, when I ran the 3D finishing cut, 1/16" BN, the cutter was not touching the wood. I considered stopping the cut but I was hoping that it would move closer at some point.

Phil

[SteveNelson46]

If you're cutting air after a tool change then you are probably not getting a good z-zero setting after the change.