I've operated a Romer Arm, but I've never programmed one and I'm still relatively new to iterative alignments. Therefore, this is a complete guess on my part, so please treat it as such. But I'm guessing that an auto trigger is used with an arm for iterative alignments. If you don't know what that is, it's like a game of hot and cold. The arm will make a beeping sound that gets faster and faster the closer you get to the theoretical point and when you are within the target radius, the arm automatically takes the hit. So, if I was going to incorporate an iterative alignment into my program for an arm, I would actually do two of them. The first one would use a large target radius and would not iterate. It would just accept the points taken by the operator and create a rough alignment from that. Then I would do another iterative alignment that actually iterates, and I would program in an auto trigger to guide the operator to the target points for each iteration. So essentially, it's the same process as a DCC CMM, only the arm is "telling" the operator where to manually move the probe so it can take the hit on its own once it's close enough.
Again, that is my best guess, and I could be completely wrong. So don't go shouting from a mountain top that this is how ESchertz says it's supposed to be done.
there is no difference between the alignments, an alignment is an alignment, the only difference is in how you measure the features and the machine used to measure them.
All of our Romer programs have at least two alignments, the ones someone realllly cared about have three. Manual alignment, then auto point trigger alignment, then if your feeling special another point trigger alignment.
If all you have are operator directed manual alignments then you will have very poor repeatability even measuring the same part multiple times, with the same operator, let alone measuring the same part with different operators.
we have fixtures, so it is generally either 3 bushings (circles w/ sample hits) or tooling balls. Only need 1 alignment when that is what you are working with.
I don't program Romer Arm routines, nor do I operate one anymore. That was an old job and all I did was execute routines someone else wrote. Mostly fabricated sheet metal parts from a press brake. I knew next to nothing about alignments or programming in general at the time, so I couldn't say how many alignments were involved. All I did was probe where it told me to.
