Hey all. I was surfacing this 6061 plate with the langmuir flycutter and noticed these lines showing up. Is this normal or is this indicative of a tram issue?
Do you feel a ridge with your finger nail when you run it across the line? If so your spindle might be slightly out of tram. Of course a very small ridge could be only .001 out of tram.
It will never be perfect. Just get it as close as you are able, and run with it. I had my baseplate near perfect. Threw a huge chunk of Aluminum in the vise and faced that, and I have ridges. Apparently, the surface that my Z rails are mounted to was not machined very flat. It is what it is.
Yeah it is impossible to get it perfect. To set tram I actually used the fly cutter and extended the cutter out as far as I could to get the largest diameter cut. Then did passes in both X and Y spaced out and measured the ridge it made with a depth mic. Then fine tuned my tram with that information. Still not perfect at the end of the day. But you can also reduce your stepover to make the ridges smaller, but will add cycle time.
A large flat plate like that is hard to get that perfect mirror all the way across the surface. But if you have something like an engine case or something, where the surface you are decking is less thick than the width of the fly cutter. You can program the machine to trace the surface you are decking, instead of the traditional zig-zag facing pattern. That can prevent the ridges as well, unfortunately doesn’t work in your situation.