i am just starting to use a romer arm. i have used PC-dmis for 5 years but am looking for tips on how to use the leapfrog alignment. any tips would be great and no matter how trivial you might think they will be helpful. thanks in advance
I've only used it once besides in class, and that was just to set up an 'example' program.
I have "probe cups" on magnets. Stick them to the part. Follow the directions for leapfrog, use those 3 cups, they are pretty straight forward. Single point for each, not a sphere. I would suggest that you let the arm settle as much as possible before triggering the point when taking and re-taking the measurements. I was using MOST of the arm's reach, got numbers that matched within 0.0015" total.
You can also use something as cheap as some hex nuts from a hardware store and hot glue them in place. The one thing to know is that you will get some stackup error when using leapfrog and that error grows the more leapfrogging that you do. The other bad thing is if i remember correctly if you make a mistake leapfrogging there is a really good chance that you will have to start your program over if it is in the middle. I avoided leapfrogging at all costs just because I didn't want to deal with the extra error. It is not a bad feature as it does give you "room to grow" but try to avoid using it if you cant afford the additional error or you are trying to minimize it. There is a good chance if you take a couple extra minutes in the setup you can find a good spot to place the arm so that you can avoid that step.
Also not to beat a dead horse but this was also a big reason why I would tell customers looking to buy arms to think about all applications that they would be using the arm, because you may be buying it for this one part that is 12" square but have 40+ parts that are 50" square. So it is worth the extra couple tenths of volumetric error to get a little bit bigger of a arm to cover these larger parts so you dont have to leapfrog.
