Don’t understand z-axis

[Anonymous]

I’m a frustrated beginner. I have designed a carved top guitar. In f360 cam I set the Stock top = model top.

so my thought is that during a parallel toolpath should always be in contact with the stock. However when it is being cnc’d The top middle part of the body which technically should be touching the stock is carving 1/4” above the stock top. I have the z axis on my machine calibrated to .001” and check all calibration before I start the job. I use ugs with Grbl on an Arduino based 3 axis cnc

[seth.madore]

Where the stock is being machined is dependent on where your Work Coordinate System (WCS) is set. This is established at the point of creating your Setup.

Can you share your file so we can see what you have designated?

File > Export > Save to local folder. Return to thread and attach the .f3d file in your reply?

[Anonymous]

thank you for your reply!

[seth.madore]

Alright, so lets check a few things out on the machine, shall we?

1) At your machine/control, where have you established your WCS z setting? 

2) Is your tool length offset established correctly?

3) Is your stock actually 2" thick?

As an aside, you are likely going to have better machining results if you run your Pocket toolpath before the Parallel. The plunge moves that are occurring in your Parallel are going to lead to tool and material issues. Granted, there are lots of improvements that can happen in your toolpath, but that's outside the scope of the original question. I'd suggest making a separate thread to cover those needs...

[Anonymous]

1) the z axis is set to the top of the stock using a touch plate (the exact measurement was entered)

2) yes using a micrometer I measured all of the bit properties.

3) the stock indeed is 2”.

i am definitely interested in any cam training specific to the work I’m doing. I have wasted a ton of plywood trying to get this right.

this is attempt 5.

i had the toolpaths in this order:

2d face

3d adaptive clearing

3d pocket

boring

parallel

2d contour

im just trying to test the body shape and contour now.

i threw the pockets in to finalize measurements 

i have no idea even where to start on the back.

thanks,

Ron

[johnswetz1982 · Accepted solution]

Some tips to start out with,

1. Attach your new file with the additional operations you had mentioned.

2. I would always set up the stock to be at least .015 above the model top so that you are machining into fresh material and taking care of any irregularities in the stock (you are working with dead tree carcasses).

3. Machine the inside pockets, Drill your holes, then adaptive or pocket the exterior around the body with stock to leave.

4. Then do your parallel / finish contour passes with the last one being a 2d contour with tabs. then you can just saw of the remaining stock.

5. You have the 4 holes that you can locate off of for the back side but you'll have a hard time holding that without machining a negative to place the front on. You should really plan that out before you go cutting with your good stock.

6. About that, I would get the operations so they seem to work like you think they should. Save a copy of the file then scale it down to something 2x4ish so that you are using some cheap stock and not wasting plywood experimenting.

7. You said you set your tool right, but did you check it after the cutting started? did it maybe get pushed in? If looks like you have some burn marks in the lower part of you picture so maybe the bit was not cutting well and got pushed in? I would check the feeds you have. At least with file you provided the feeds were way low.

8. For a parallel path you probably want a ball mill.

I attached a general idea of what I would be trying for, the mill can get to all locations because it is not long enough, needs drill bits, slow feeds etc.