Shallow angle profile cut in acrylic mirror

[joe]

I, for one, can't imagine the machine being that whacked up. It looks like substrate movement.

I just can't imagine the machine could be that loose. If this was my machine, I'd "SCREW" some masonite down on the bed, set some good type and carve away. Lets say you try some 2" script and Helvetica as a first test. Use Screws, not vacuum.

Joe

[scottp55]

Brady, You still helping people to set up machines and solve specific production issues, or has that fallen by the wayside in the last year? You're not cheap, but I've seen posts saying you are worth every dollar and it was the best money they ever spent.

[Brady Watson]

Scott,
Yes - Still doing that sort of thing, although I did take a hiatus for a few months this Summer. In the past year we had a number of family members that were sick or passed away - including my boy Grover (who you see sitting on the SB in my VR article) - and that had to take priority over all else. Things have simmered down, although there will be a few more moving on in the next few months. Such is life - and I felt no need to share sad news, because we ALL have our own 'stuff' to deal with on a daily basis. Just being thankful and showing gratitude puts all into perspective.

We now return to your regularly scheduled thread...

-B

[scottp55]

Brady, Good to know, Sorry to hear.
Still can't believe I couldn't "Sell" you on the idea of visiting the "Tourist Mecca" of Kennebunkport and helping me set up "Gratis" I must be slipping, But probably learned more by doing it myself

[magazines]

Hi All,
I wanted to pick up this thread that had so much helpful information. Sorry for my slow response. In short, school started, everything got super busy, time on the shopbot was slashed, and we got it to work much better quickly.
Joe, you were right! Sure enough we had some real piece movement on some of our cuts with the original text cuts. The thing was that we screwed it down just to be sure after cutting about half of what we had done. The vacuum was just not strong enough with the small pieces. We had a newly leveled bed, but it couldn't do it. Now we are doing both vacuum and screw down. I have to say I don't like the screw down - and I don't like cutting through to a sacrificial board, but with tabs it makes it work and 1 sheet of mdf for every 10-20 cutting sessions is workable.
Also, we are now using the pre-mask on the surface of the mirror, thanks for this suggestion as well.
And thanks as well to those who suggested the two pass system. We are running the oflute 1/8" first over each of the toolpaths and then chasing it with the tapered end mill (no more ball nose). It is producing a cleaner cut now. Both o-flute and end mill are going at 14k and .5ips now. IT's accurate, it seems to still wobble a bit if we speed up much beyond this, but we don't really need to. Still makes me think we may have something a bit loose in the Shopbot, but it certainly was not the cause of the big wobbles that originated this thread.
Thanks to all for the help and suggestions. Sorry for the delay in response.
Peter