Q: Is a skim cut NECESSARY?
A: Taking a skim cut is not necessary for the OMIO CNC Tube Fixture to function. It is however a recommended step to take to have the highest possible accuracy when machining features. The skim cut will guarantee that the OMIO CNC Tube Fixture and the machine axis is aligned across the full travel of the machine. On OMIO’s we have seen a deviation on +-0.005” between the travel of the axis and the Tube Fixture. There has been extra material added along the stop of the Tube Fixture to allow this cut to be taken and not affect the function of the clamps.
Q: Is an additional skim cut required if the fixture is removed from the machine?
A: An additional skim cut may or may not be required. If the fixture is removed and then placed in the same location, the additional skim cut will most likely not be needed. It is always good practice to use an indicator to measure this. If the values are within an acceptable value for your use, then this additional cut is not needed.
Issue: Part will not fit between clamp and side wall of the Tube Fixture.
Possible Solutions:
Tighten the fixture clamps being used fully. Then loosen them up to 1 full turn. As the fixture clamp is being loosened it will cam open and the tube will slip into place.
Verify that the tubing is the correct size for the fixture clamp locations chosen. Reposition if necessary
A common issue in extruded aluminum tubing is that the outside will not be perfectly square on all four corners. This can lead to lifting of the part when it is clamped into the Tube Fixture or to possible errors in feature location when the parts are machined. This can be seen in the diagrams below. Depending on the issue and the tolerances that are being held, this may or may not need to be corrected. Some tubing will also not have this issue so it does not need to be taken into consideration.
A general solution that will work for all instances, whether the issue is present or not, is to set the location for the program after clamping the tube into the Tube Fixture. Setting all zero’s after guarantees that the part is in the correct location when machining.