Assignment For Diameter

[cmmcaliguy]

I have a bolt circle pattern with (3) pins, 120 degrees apart. I'm in need of
an "assignment" that would give me the diameter across the (3) pins. Like
using a three-way mic, but I want to be able to record diameter using
pcdmis.

[Wes Cisco]

To get the bolt circle, measure the three pins and then create a circle, selecting all three pins. That will create a circle thru the centers of the pins. If you need a circle that circumscribes the pins you will need to do the following:

1) Create the bolt circle as described above
2) Create a 2d line from the center of each pin to the center of the bolt circle. That will be a total of 3 lines and make sure you select the pin 1st because for this project vectors really matter.
3) Now for each pin you will create a pierce point where the line intersects the pin. You must select the line first and then the pin. This should give you the outside tangent point of each pin. * If for some reason you get the inside tangent point, create 3 new 2d lines from the existing ones using "reverse" and try to create the pierce points again.
4) Create a circle using the three pierce points.
5) Drink a beer and give me some good rep for the help.

I hope this helps, I am going home now, but will be in Sat morning at about 5am central time. Good Luck. (By the way I have used this method to do this very thing more than once and it will work if done correctly.)

[cmmcaliguy]

Wes, Thanks for your attempt at helping me. I understand all that basic
information. What I'm looking for is an "Assignment Variable" that would
give me the diameter reading across the pins. But yes, your way works nicely.
Thanks for the input. I work nights and do a 4hr turn around to be back at work saturday morning. So I feel your happiness about coming into work.

[Tested]

If you really need a assignment for this this should work... But I would go with Wes's unless you really need the assignment.

ASSIGN/V1 = (((CIR1.R+CIR2.R+CIR3.R)/3)+CIR4.R)*2
CIR5 =FEAT/CIRCLE,RECT,OUT
THEO/7.7,-7.7,0,0,0,V1
ACTL/7.7,-7.7,0,0,0,1,134.168
CONSTR/CIRCLE,CAST,CIR4

[JamesMannes]

I thought the question was answered correctly. Can you post a snippet of your print? or I'm making an assumption here, do you want the distance from one pin to the other? If that is the case you can use the distance feature you know? It is work plane dependant, but works real well. Post further info or questions. I'm at the bread and butter making place until about 10:00 a.m. cst.

[cmmcaliguy]

Hey, don't beat me up. Wes gave me a great answer and I thanked him for it. I am just trying to get into using "assignments". I would include a snap shot of the B/P but I have no acesss to a scanner. Thanks again Wes,Tested, and IRON MAN for your input.

[kbotta]

couldn't you just assign variables from your measured '3 pin' circle already? Don't understand what you are trying to do.

[Wes Cisco]

Hey, don't beat me up. Wes gave me a great answer and I thanked him for it. I am just trying to get into using "assignments". I would include a snap shot of the B/P but I have no acesss to a scanner. Thanks again Wes,Tested, and IRON MAN for your input.

Cmmcaliguy, I do not think anyone was trying to beat you up. They were only trying to point you in the direction they felt would best acheive the result they understood you to be trying to acheive. Working with complex 3D geometry, GD&T, and Pc-Dmis using text only on a forum like this makes clear communication sometimes difficult. If we are failing to grasp what you need, then please provide us with clarification. Simply saying you want to use an assignment to do something that is not best done with an assignment, does not make a lot of sense, even if you just want to practice doing assignments! For practice you should choose an application well suited to the skills you want to practice. There are people who know this software and all of it's special features very well, but they do not know basic inspection technique or best cmm measurement practices and they therefore get questionable at best results. We are trying to help you, but we can only advise based on the information you give us. Ok, therapy session is over, let's go to the off - topic forum and find someone to beat up! LOL

[craiger_ny]

Hey, don't beat me up. Wes gave me a great answer and I thanked him for it. I am just trying to get into using "assignments". I would include a snap shot of the B/P but I have no acesss to a scanner. Thanks again Wes,Tested, and IRON MAN for your input.

Wes gave you the answer. Tested's solution may work sufficiently but because he is using an average of the three pins it will not be as near perfect as Wes' solution. There is not "magic assignment" that you can declare that knows what you want. You need to invent the answer that will fill your variable. That is all a variable assignment is, a container to hold a solution. An assignment is empty unless you fill it. If you are looking for a canned assignment that understands that you want to measure over the pins no such variable exists until you create it.

Craig

[John Kingston]

As I understood the question, he wants to measure the 3 pins, then construct a circle that would tell him what size tube would fit over the 3 pins. Wes's and Tested's methods would work. I'd probably have gone Tested's route as I understand variables and assignments better than pierce points. Seems like cmmcaliguy wants to learn more about assignments.

[craiger_ny]

As I understood the question, he wants to measure the 3 pins, then construct a circle that would tell him what size tube would fit over the 3 pins. Wes's and Tested's methods would work. I'd probably have gone Tested's route as I understand variables and assignments better than pierce points. Seems like cmmcaliguy wants to learn more about assignments.

As each pin varies in size from the other Tested's method will loose accuracy. The closer each of the three pins are in size to each other then the more precise it will be. I would go with Wes' method for precision. Tested's method is shorter code. If you can be sure that the pins will be the same size and that whatever variation in size there is will be within your acceptable bounds of precision then use it. Wes has a longer solution code wise but as the pins vary it adjusts the size and location appropriately.

[John Kingston]

As each pin varies in size from the other Tested's method will loose accuracy. The closer each of the three pins are in size to each other then the more precise it will be. I would go with Wes' method for precision. Tested's method is shorter code. If you can be sure that the pins will be the same size and that whatever variation in size there is will be within your acceptable bounds of precision then use it. Wes has a longer solution code wise but as the pins vary it adjusts the size and location appropriately.

I agree with you. I've never had the need for this. I learned something new today. I just was pointing out that cmmcaliguy asked about assignments. Assignments are awesome and a lot of fun. At least this way he got an idea how they work, and a better way to check his part.