DeskProto user forum

Do you have a proven method for determining and setting Y axis at "exact center" for machining a two-sided project which uses a material midpoint centering jig?
Thanks,
JR

Hi JR,

When you know exact dimensions of your 4th axis unit you can make the cutter touch some vertical surface of that unit: as you know the Radius of the cutter and the distance of that surface to the rotation axis you can calculate where to set Y=0.

A different trick is:
- approximately set Y=0
- machine a cylinder with a flat cutter at Y=0 and Z at (say) 10 mm
- touch that cylinder with the cutter from both sides: both Y-values should be plus and minus the same distance. If not then you can calculate which correction is needed for Y=0.

Important is that the rotation axis also should be exactly aligned with the X-axis.

Lex.

Sorry I failed say this is a FLAT three axis job. Part is flipped along the X axis to machine the opposite side.
JR

Ah, I had imagined the two-sided job to be flipped using a rotation axis.

For a manual flip you can use a ruler, like prescribed by DeskProto's two-sided wizard (the wizard will explain, just as video videos-pictureframe.php#twosided ).

Alternative is to use two positioning pins in the machine table, with corresponding holes in the block (through its complete height), and the zero point exactly between the two pins. For both sides the block will be placed on the pins, so X=0 and Y=0 will be the same.

Lex.

Or did you men a setting in DeskProto ?
In the Part parameters, tab Zero-point, you can use the setting "Make center of material block zero".

Lex,
I think it is the 'home' zero setting in my CNC machine that I cannot exactly coordinate with the 'exact zero' required by DP that is not matching for me, thus the offset machining of the second side. Maybe these two settings are not supposed to match? I would upload a pic, but cannot get that function in Forum to work for me.
JR

Hi JR,

As far I know any controller or control software should have the option to set the zero point. For instance by moving the cutter to a certain position and then pressing some button to set the zero point on that position. Which may be different from a "home position".

Strange that the image upload does not work: what happens ?

Lex

I think file is too big
max. 1MB

Thanks, Lex and menix,
Lex--I always set the Home position using Mach 4, to the Y center as best as I can, set X position to a safe starting point on the material, set Z just touching material top ('set top as z zero' was selected) then set the DRO in Mach 4 to all zeros. Start the execution.

The file I tried was set to 640x480 and 53K. I tried both .jpg and .bmp. I selected an image file, file name appeared in the post dialog box, clicked 'post', message appeared that no file was selected or file too big. I renamed the file so the file name contained only LC letters--no go.
JR

Hi JR,

So in Mach4 you can indeed accurately set the Y=0 position. Then I come back to the two suggested options that I mentioned earlier:
- use a ruler, as done in the wizard "Two sides, manual flip". You can first set Y=0 and then machine the ruler.
- use two positioning pins, both on the Y=0 position (so first set Y=0 and then drill the holes for the pins), and in DeskProto set Y=0 in the center of the material block.

About the image: no clue why this does not work. For the image in this post (jpg file) I did exactly the same. You can email the image to info@deskproto.com, then I can try.