Cutting to leave a specific amount of materia

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theideacreek
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Joined: Mon Mar 26, 2012 4:22 am
Model of CNC Machine: Shop Sabre 3636

Cutting to leave a specific amount of materia

Post by theideacreek »

I am trying to take a board that is glued up and about 13/16" thick and make it exactly 3/4". I'd like to just use the CNC to plane it down. If I set the z zero to the table, how do I use the pocket to make sure exactly 3/4" is remains when done milling?

tmerrill
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Re: Cutting to leave a specific amount of materia

Post by tmerrill »

The Cut Depth will reference the top of the material based on the Material Thickness you have entered. So if you specified a material thickness of 0.8125 (13/16), you would set the Cut Depth to 0.0625.

If you set the Material Thickness to 0.9 to allow some tolerence, then the Cut Depth would be 0.15.

Tim

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P.Passuello
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Re: Cutting to leave a specific amount of materia

Post by P.Passuello »

To machine a piece to a required thickness I create a pocket with a depth of 0.
I set the cutter to the table and in this case would call it -3/4"
Not jog the cutter to any height above the stock to ensure when you do start cutting it won't crash when it moves to the origin.
That's it. Doing calculations gives me a headache and it U have to do make a custom file for each piece my head would explode.
This is the simplest way of doing this that I know and it it doesn't matter what thickness the stock is or what thickness you want the stock to end up. It will be determined by the value you give to the cutter when it is sitting on the table.
Here is a video I did on it. The bit that you are interested in is around the 4:30 mark but you need to watch the start as it covers making the pocket.



Hope it helps.

Cheers
Peter
The ingenuity of idiots is unlimited.
http://www.youtube.com/user/cncnutz

tmerrill
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Re: Cutting to leave a specific amount of materia

Post by tmerrill »

Doing calculations gives me a headache
Well, we can't have that and Vectric is looking out for your well being :D

Simply let the program do the calculation for you. It recognizes 't' and 'z' as the Material Thickness so in the Cut Depth box enter the expression 't-0.75=' or 'z-0.75=' (no quotes) where 0.75 is the thickness you want remaining. Bingo, there is the value you need.

Tim

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P.Passuello
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Re: Cutting to leave a specific amount of materia

Post by P.Passuello »

tmerrill wrote:
Doing calculations gives me a headache
Well, we can't have that and Vectric is looking out for your well being :D

Simply let the program do the calculation for you. It recognizes 't' and 'z' as the Material Thickness so in the Cut Depth box enter the expression 't-0.75=' or 'z-0.75=' (no quotes) where 0.75 is the thickness you want remaining. Bingo, there is the value you need.

Tim
Danger, Danger, Information Overload. :lol:

Never really used the calculations function and didn't know about using the T and Z variables. I suppose reading the manual would help.

I started using the method I outlined because I found that making files to suit individual pieces of wood to be a pain when using the surface as a reference. The great thing about this hobby is there are so many ways to do the same thing.

Must have a play with the calculations sometime.

Cheers
Peter
The ingenuity of idiots is unlimited.
http://www.youtube.com/user/cncnutz

theideacreek
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Joined: Mon Mar 26, 2012 4:22 am
Model of CNC Machine: Shop Sabre 3636

Re: Cutting to leave a specific amount of materia

Post by theideacreek »

The video was great and really helped me understand how to do this. Thank you all for the help!!!

mrorange
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Re: Cutting to leave a specific amount of materia

Post by mrorange »

Why not just set a pocket for zero, then zero your Z axis to a reference piece of 3/4" material? Then the machine will cut exactly to 3/4" thickness. No calculations.

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