Slot Material Conditions

[[Me...]]

Why can't I use MMC/LMC for slot features? I can make a simple formula to do it, but I don't understand why it isn't a set option. Using Calypso 2015.

[[Cl...]]

You can in at least one direction if the side walls are large enough to measure as planes. Use two symmetry planes (special geometries). The other direction would require a formula. The symmetry plane option allows the MMC option.

[[Me...]]

I get what you are saying. But what I'm really after is why the actual slot feature can't be used for MMC. I just don't understand why it isn't an option. Or maybe it makes sense not to include that feature, and I'm just not smart enough to realize why. 🙁

[[Er...]]

You can recall the slot position in and create a circle base on that. Recall width as diameter.

To check it "by the book" takes some effort, but usually what Clark describes or a circle if you cant measure as planes is good enough. But if it is good enough for your particular part. I cant say..

[[To...]]

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With a slot, it's not just about the size. There is orientation, too. So, I don't think the math is so simple. If you think about it, the important part of the slot is probably the side walls. The length of the slot probably does little to locate a mating part. So a position using a symmetry plane will at least deal with the size and orientation and you can select a single direction in the "Shape of Zone" drop-down list.

Does your position show a diametral tolerance zone? Or did they break it out into 2 separate positions, one for each direction?

[[Mi...]]

if your TP is in the width you can create a symmetry point, then a distance symmetry from that symmetry point. Create your TP for the symmetry point. Set the "shape of zone" to the direction you need and the mmc will be available with the distance symmetry as your diameter.

[[An...]]

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[[To...]]

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I often try to think, "What would the hard gauge look like to meet the requirements?"

[[An...]]

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[[Me...]]

Just to clear some things up. I have no problem making a program to print regarding slots. I was just curious why I couldn't use the actual slot feature for TP, instead of having to make symmetry planes and whatnot. Also, the slots I typically see have 2 true position call outs, one for the length and one for the width. The width is normally the planar datum. Example below.

Slot MMC.PNG

[[An...]]

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[[Te...]]

I measure it as a slot and then create theoretical circles using formulas for the length and the width (getactual.width and getactual.length for the diameter) and use that for TP with MMC. Works great. Width is not in the list but if you type it in, it works.

[[Jo...]]

No need for two gages. One will do it.

[[An...]]

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[[Jo...]]

Andreas. I don't know what this chart is showing but the radius calculation is incorrect. The radius is going to be half the width of the gage. This is a big reason that ASME doesn't actually call out out the end radius. It's only 2X R with no dimension or tolerance. The implication is that the radius is half the width of the feature, whatever it winds up being. That concept translates to the gage. ISO might be different but this is how ASME does it.