Help with Vector Calculation

[Ceeph]

Can anyone help me calculate the correct approach vectors for a surface that is in an angled bore. The bore angle is 26 degrees to my leveling datum and I am using a tip angle of A60 B-180. The surface is not on the cad model so I can't get the vectors that way. I used to know how to do this but it has been since my mm4 days that I last used it.

[JamesMannes]

Take a look at this....

http://www.box.net/public/39xjrv1i3g

[cmmguy]

Another option

If you dont have excel or would like to try an alternative.

Go Here

[Ceeph]

That is great but I guess I was not clear enough in my post. I am not measuring a circle but a machined step(plane) in the bore that is sitting at a 26 degree angle to my datum surface. I need the normal vectors for the surface that is not on my cad model.

[JamesMannes]

The excel spreadsheet link I gave you has 8 worksheets on it. The 3rd one labeled Cheat sheet has the info that you need on it. A 26° angle has vectors of.898879,.45399,0.000. Change the axis' of the vectors a s you need.

[Ceeph]

Thanks a million that is what I needed. Must have had a brain fart there and didn't see the other worksheets.

[craiger_ny]

cos 26º = 0.898794046 or what the previous posters offered. Check it out they did solve it for you.

Craig

[Don Meredith]

Vectors can be calculated very easily with any calculator with trig functions.
You just need to understand that the 2D vector is the sine and cosine of the angle. For example, the vectors for 30deg are 0.5 & 0.8660524. The axis with greater movement is assigned the larger vector because that axis must move farther to approach/retract normal to the surface.

HTH

Edit: Craiger only gave you the cosine. You need sine also - 0.4383711

[craiger_ny]

Or cosine of the compliment. Sine of angle = cosine of compliment, 6 of 1 half dozen of another really. That is all I do, calculator style but it is cool to see people putting together tools for it.

Craig

[Ceeph]

I couldn't remember if it was sin, cos or -cos. I actually got the number you gave me I just didn't want to plug it in my CMM without someone verifying I was correct.


DUH PCDMIS will calculate for you. I just put 26 in for one of the vectors and it calculated the others.

[tking]

Take a look at this....

http://www.box.net/public/39xjrv1i3g

Nice one, thanks, Iron Man!



TK

[djayne]

DUH PCDMIS will calculate for you. I just put 26 in for one of the vectors and it calculated the others.

Cool - I didn't know that worked. I always rotate to any angle and use 0,0,1 0,1,0 or 1,0,0. Just laziness on my part I guess.

[#2#]

That is great but I guess I was not clear enough in my post. I am not measuring a circle but a machined step(plane) in the bore that is sitting at a 26 degree angle to my datum surface. I need the normal vectors for the surface that is not on my cad model.

I know I'm late to the party but I was off yesterday.

This is what I would do. I would re-align to your bore. For example, level the bore to z-plus and set the x and y orgins on the bore. Then, your plane's vector will be 0,0,1 and it's location will be 0,0,z. After the plane, recall your previous alignment. This way, if the cylinder is off of location or orientation just a bit you will still get good hits. Also, you can get your probe to take hits .005 or less off of the cylinder wall.

I do this all the time. It works wonderfully!