Radius turning questions

[washintonian]

I start a new job on monday that will include more programing than I have done before. I am good enough in programing to do chamfers tapers etc...
but I have never fully understood g02/g03 programing. I have spent the last week reading in these forums a couple hours each night but all i have gained is more confusion...

Could someone walk through programing these two examples step by step using g02/g03 without using R please?

Cut a full .5" radius on the end of a 1" part

and

Put blend radius on a chamfered end of a 1" rod
Ex: to do a .032" by 45 deg chamfer on a 1.5" diameter part with the parts face at 1" using a .016 TNR I would use:
G00 Z1.0 X1.436
G01 Z.9586 X1.5
I get those numbers using this spreadsheet I setup working out tnr comp.

How would I put a .005 blend radius at each end of the chamfer? I cannot find a working formula that I can make sence out of. So any help would be greatly appriciated.
Desmond

[dcoupar]

Just out of curiosity, what kind of control are you going to be programming? Fanuc?

Rather than spend time calculating intersections and compensation amounts, you might want to learn to use the control's tip nose radius comp function (G41/G42) if it's so equipped. Also, some controls have the option of Chamfering and Rounding built in. And some have a feature called Direct Drawing Dimensions Programming, which makes life real easy for manual programmers.

[angelw]

Originally Posted by washintonian I start a new job on monday that will include more programing than I have done before. I am good enough in programing to do chamfers tapers etc... but I have never fully understood g02/g03 programing. I have spent the last week reading in these forums a couple hours each night but all i have gained is more confusion... Could someone walk through programing these two examples step by step using g02/g03 without using R please? Cut a full .5" radius on the end of a 1" part and Put blend radius on a chamfered end of a 1" rod Ex: to do a .032" by 45 deg chamfer on a 1.5" diameter part with the parts face at 1" using a .016 TNR I would use: G00 Z1.0 X1.436 G01 Z.9586 X1.5 I get those numbers using this spreadsheet I setup working out tnr comp. How would I put a .005 blend radius at each end of the chamfer? I cannot find a working formula that I can make sence out of. So any help would be greatly appriciated. Desmond

The following formulae will get you the tool rad comp values for X and Z. Note that the X value is multiplied by 2 to get a diameter value. Accordingly, the formula shown in the attached picture can be modified as shown in the following formula to get a diameter value.

X = 2 * (tnr - (tnr * Tan(45 - (angle / 2))))
Z = tnr - (tnr * Tan(angle / 2))

Regards,

Bill

[washintonian]

ya will be done using a fanuc controller

Also I setup the cheat sheet for calculating the tnr comp before I wrote the program into my ti-89 I carry with me. It's how to put the blend radius onto a chamfer I am having trouble with since it's a partial arc it includes more trig than I can do on my own. Not all of the controls at the new plant will use g41/42 I want to understand it well enought tor write the program for my calc to solve blend radius on the floor. The problem I have is that I have not been able to find a acutual equasion to solve the problem.
Thanks

[g-codeguy]

Full radius from OD

X1.Z-(.5 + TNR)
G2X-(2 * TNR) Z0 R(.5 + TNR)

Full radius from centerline

X-(2 * TNR) Z0
G3X1.Z-(.5 + TNR) R(.5 + TNR)

In your example of a .032 x 45 deg. it should be

X1.4172 Z1.
X1.5 Z.9586

in order to be a 45 deg. chamfer.

The math is:

1-.9586=.0414
1.5-2*.0414=1.4172

Also I would never rapid to the face of a part.

Putting a .005R on the part using a .016R tool requires more math than I am willing to explain here. What I did was make myself a little chart. I almost always use a .003 or .005 radius on the part using either a .008R, .016R or .031R insert. These 6 values were soon memorized.

TAN[22.5] * .005 = .0021

Starting position for the criteria you specified is:

1.5 - (2 * .032) - (2 * .0021) - (2 * .016) = 1.3998

so X1.3998 Z1.

Moves from the face are X.0148 (radial) Z-.0062

so 1.3998 + 2 * .0148 = 1.4294
1. - .0062 = .9938

so far we have

X1.3998 Z1.
G3 X 1.4294 Z.9938 R.021

The neat thing about 45 deg. angles is the previous values for X & Z moves are reversed for the upper section (at 1.5). From here work backwards. Figure the ending position first.

1- (.032 + .0021 + .016) = .9499

So ending position is

G3 X1.5 Z.9499 R.021

Now work backwards.

1.5 - 2 * .0062 = 1.4876

.9499 + .0148 = .9647

so putting it all together we get:

X1.3998 Z1.
G3 X 1.4294 Z.9938 R.021
G1 X1.4876 Z.9647
G3 X1.5 Z.9499 R.021


I still have the chart for the different values for part radii and insert radii if you'd like me to email you a copy. I think I have even have an example of how to use the chart.

I had to be careful figuring your example because the face of my part is always Z0.