Today I worked on getting the 4th axis set up and dialed in on the Haas Minimill.
My boss showed me how to load the collets and dial in the position using a gauge pin and indicator. Using a 5/8" round gauge, I swept the dial indicator along the six inches of stick out and taping the base with a rubber mallet until it was within one-tenth (0.0001") from end to end. It took a stupid amount of time to get the 4th axis base locked in and still am a little frustrated.
From there, I used an edge finder on both sides of the rod, then divided the values by 2 to get the Y-axis origin, then did it again to ensure I didn't make a mistake the first time and got the same result as before. After that, I was able to load the mini fixture plate in the collet and tried facing it with an endmill to ensure I had a flat workpiece aligned with the machine but didn't get a perfect surface finish. My boss ended up tossing it on the lathe and cleaning the face it manually.
After loading it back onto the minimill, I retook the edge finder and touched off the outside face for the X-axis origin. After that, I loaded one of the parts onto the fixture plate and secured it down; I then took the dial indicator and swept one of the flat faces to set the A-axis rotation origin.
The final thing that I need to do is setting up the tools and setting the heights off the centerline of the X-axis line. I'm able to do this by using a 4" gauge block off the minimill table, the height of the 4th axis machine is precisely four inches above the face of the table so I can use that as a reference height.
I also made sure to mark the top of the fixture plate and set up the CAM to have the engraving side always facing me; this ensures I don't make mistakes when loading the parts on the machine.