I hate that I missed your live stream. I currently work in a metrology lab and will be taking CMM programming classes in a few months. Learning GD&T has been a challenge at times but your videos help me whenever I am struggling. Thank you!!
Hi Dean, I have a question for you, if you have a triangle part with a hole in the center, so while measuring on CMM how to create the 3 mutually perpendicular planes & how to locate the axis of the hole with the respective to A, B & C Datums?....in this triangle part I took, back face, bottom face and one of the angle side face as datums A,B,C....now how to generate the DRF frame
Good content. I like the way you related the profile tolerance and position tolerance in the beginning of the video. When you relate and explain things, it makes very clear for the viewers. We request you to make videos on how we can control symmentricity and concentricity using other control as the latest ASME version removed these 2 controls.
Good content. I like the way you related the profile tolerance and position tolerance in the beginning of the video. When you relate and explain things, it makes very clear for the viewers. We request you to make videos on how we can control symmentricity and concentricity using other control as the latest ASME version removed these 2 controls.
Thanks for the explanation. Perhaps I missed this in the standards but is there a way to only check form on a profile applied to a feature of size such as a slot?
So does a specific cross section does not matter with total runout? Copilot Sent by Copilot: Correct, for total runout, the focus is on the entire length of the part rather than specific cross sections. The dial indicator is moved along the length of the part while it rotates, capturing continuous readings. This method ensures that any surface irregularities along the entire length are accounted for, providing a comprehensive measure of the part’s geometric accuracy.
For total runout, so you have to take readings at 1 cross section at a time before moving infinity to the next cross section? For total runout, you actually take continuous readings along the entire length of the part rather than at discrete cross sections. Here’s how it works: Setup: Mount the part on a rotating fixture and position the dial indicator so that its probe touches the surface of the part. Zero the Indicator: Rotate the part to a starting position and set the dial indicator to zero. Take Continuous Readings: As the part rotates, move the dial indicator along the length of the part, continuously recording the readings. This way, you capture the surface variation along the entire length of the part. The goal is to measure the total variation in the surface as the part rotates and the indicator moves along its length. The Full Indicator Movement (FIM) for total runout is the difference between the maximum and minimum readings observed during this process. This method ensures that you account for any surface irregularities along the entire length of the part, providing a comprehensive assessment of its geometric accuracy.
Does this concept of FIM also apply to total runout? Yes, the concept of Full Indicator Movement (FIM) also applies to total runout, but with some differences. While circular runout measures the variation in a single cross-sectional plane, total runout measures the variation along the entire length of the part’s surface as it rotates. Here’s how it works: Setup: Mount the part on a rotating fixture and position the dial indicator so that its probe touches the surface of the part. Zero the Indicator: Rotate the part to a starting position and set the dial indicator to zero. Take Readings: Rotate the part and move the dial indicator along the length of the part, taking readings at multiple points along the surface. For example, if you take readings at several points along the length of the part and get the following dial indicator readings (in thousandths of an inch): 0.000" +0.003" +0.005" +0.004" +0.002" -0.001" -0.004" -0.003" Calculate FIM: Determine the maximum and minimum readings. In this example, the maximum reading is +0.005" and the minimum reading is -0.004". The FIM is the difference between these two values: FIM=Max Reading−Min Reading=+0.005"−(−0.004")=0.009" So, the FIM for total runout in this example is 0.009 inches. If this FIM is within the specified total runout tolerance, then the part is considered satisfactory. Total runout provides a more comprehensive assessment of the part’s surface variation along its entire length, making it a stricter and more inclusive measure compared to circular runout.
For the last example, if FIM .007 inches is less than the circular runout tolerance everyone's happy? Exactly! If the Full Indicator Movement (FIM) of 0.007 inches is less than the specified circular runout tolerance, then the part meets the required standards, and everyone should be satisfied with the result.
how do you calculate the FIM? please give an example using dial readings? Copilot Sent by Copilot: To calculate the Full Indicator Movement (FIM), you measure the total variation in the dial indicator readings as the part rotates 360 degrees around its datum axis. Here’s a step-by-step example: Setup: Mount the part on a rotating fixture and position the dial indicator so that its probe touches the surface of the part. Zero the Indicator: Rotate the part to a starting position and set the dial indicator to zero. Take Readings: Rotate the part slowly and take readings at several points (e.g., every 45 degrees) until you complete a full rotation. Let’s say you take readings at eight positions (every 45 degrees) and get the following dial indicator readings (in thousandths of an inch): 0.000" +0.002" +0.004" +0.003" +0.001" -0.001" -0.003" -0.002" Calculate FIM: Determine the maximum and minimum readings. In this example, the maximum reading is +0.004" and the minimum reading is -0.003". The FIM is the difference between these two values: FIM = Max Reading − Min Reading = + 0.004 " − ( − 0.003 " ) = 0.007 " FIM=Max Reading−Min Reading=+0.004"−(−0.003")=0.007" So, the FIM in this example is 0.007 inches.
Does the full indicator movement have to be less than the circular runout torlerance in order it to be call satisfactory? Copilot Sent by Copilot: Yes, for a part to be considered satisfactory, the full indicator movement (FIM) must be within the specified circular runout tolerance. Circular runout measures the variation in the surface of a rotating part, and FIM is the total variation observed when the part is rotated 360 degrees around its datum axis12. If the FIM exceeds the specified tolerance, the part does not meet the required standards and is considered unsatisfactory3.
