Iterative Alignment remeasure

[ronnan]

Hi People!
Newbie here and very first post. I don't understand the purpose to remeasure an iterative alignment? What I have been doing is using the manual iterative alignment just to snap to the cad coordinates then creating a DCC ailgnment to the datum features I require. This method has been working fine without any problems. I am a former machinist/G-Code programer and have a year experience with this cmm. Could someone help me understand the remeasure option better?

[JamesMannes]

Hi People!
Newbie here and very first post. I don't understand the purpose to remeasure an iterative alignment? What I have been doing is using the manual iterative alignment just to snap to the cad coordinates then creating a DCC ailgnment to the datum features I require. This method has been working fine without any problems. I am a former machinist/G-Code programer and have a year experience with this cmm. Could someone help me understand the remeasure option better?

That is the priciple behind an "Iterative" alignment. The definition of "Iterate" is along the lines of this...
repeat something: to say or do the same thing again.

So, it is a refinement of the first alignment, getting closer and closer to the nominal value until it either gets there or runs out of radial tolerance allowed. That work for you?

[ronnan]

Using this procedure I always had at least three bores and sample hits on the same plane, and it always snapped to the cad nominals. Maybe it is just beginners luck. Is the remeasure option for other feature types?

[JamesMannes]

I ma not sure what your procedure is, but, here is the methodology I use...

Go HERE

[Roberto]

Hi People!
Newbie here and very first post. I don't understand the purpose to remeasure an iterative alignment? What I have been doing is using the manual iterative alignment just to snap to the cad coordinates then creating a DCC ailgnment to the datum features I require. This method has been working fine without any problems. I am a former machinist/G-Code programer and have a year experience with this cmm. Could someone help me understand the remeasure option better?

So, your second alignment (DCC) is not iterative correct?
In my opinion you'll be fine then.

[ronnan]

That is the procedure I almost always use, Iterative followed by DCC. Is there a situation where this procedure will not be possible?

[John Kingston]

An iterative alignment can be DCC. DCC stands for Direct Computer Control. A fancy way of saying automatic, not all DCC alignments are iterative.

I don't use iterative often due to the types of parts we make, it is very useful for parts that are more profiled, not having flats or full circles. It "searches" for your datum points within a tolerance zone that you create. it will iterate (repeat) until it adjusts them into place.

[JamesMannes]

Using this procedure I always had at least three bores and sample hits on the same plane, and it always snapped to the cad nominals. Maybe it is just beginners luck. Is the remeasure option for other feature types?

That is the procedure I almost always use, Iterative followed by DCC. Is there a situation where this procedure will not be possible?

Both of these posts offer only half explanations of what your "procedure" is.

Do you use an Iterative Alignment in the manual alignment and then use the Iterative Alignment in DCC mode, followed by an alignment to your datum structure called out on your blueprint? If yes, then you have done a good job of aligning your part(as long as your blueprint alignment constrains all 6 degrees of freedom).

There are other ways of snapping your model to the measured features also, but I will wait for a complete response from you before going further.

Don't mean to sound like a horses pa toot but you keep leaving vague answers.