Another Ormex question!

[Blake]

The darnedest thing happened at work today. I was running a pair of Ormex Transitions. After polishing them, I took them over to the lensometer to check the power, and noticed that one lens was about 30 to 45 degrees off axis (the other lens had no cyl.). Since it was a single vision, it was no big deal, but I'm wondering how this could have happened. The lenses have markings on them, which I used to line them up on the blocker, so I would expect the cylinder axis to be along that line on each lens.
I told one of my coworkers about it, and he said that it had happened to him and another lab tech before.
Has anyone had this happen to them, or know what causes it?

Blake

[shanbaum]

Please post a little more info - such as, which marker, blocker, generator, finer, and polisher you're using.

[Rick-Strong]

I have seen axis change when plastic, and poly lenses were edged incorrectly for metal frames. ie: Too large or shape not exact.
Rick
My 2 cents worth

[Blake]

Rick,
The incident (it's not really a problem) that I described happened before edging. When laying out the lens for edging, I compensated for that and it turned out fine.

Shanbaum,
I'm using a wax blocking system, not sure who the manufacturer is - I just know it as the "95W". The generator is a Coburn 113-MX. The cylinder machines are Coburn 5056's. Those are the only machines that had been used up until the point I noticed the cyl. axis was not where I ecpected it to be.
The obvious answer would be that I had blocked it at an angle, but I know that was not the case...

Blake

[Jo]

Jeff:

That sounds like one of the problems we were having with .25 cyls.

[morinput]

Alot of times lenses that appear off axis is the result of a wave in the lens,especially in .25 cyls, transitions seem to be particularly susceptible to this, check a few of these: blocker temp, polish temp and condition, C-Ring alignment in gen. and stroke pattern on cyl mach. hope this helps.

[spazz]

Blake,
Have you checked the stoke and alignment on the cyl. machines? Our 5056's are famous (infamous) for going out of alignment at the worst possible times.

[Blake]

Okay, I get the golden Dummy award for this one! I was creating a problem where there was none. The cylinder axis on the job I mentioned was just like it should have been - along the marked lines. But... those lines aren't going to be at 180 degrees if the cyl axis isn't 180! I feel like such a goofball...

Blake

[Jo]

That's OK Blake. When aspherics first came out people would look at the lens and notice the layout marks without looking at the work order. I remember getting SV jobs back because the dispenser couldn't read the add power. I didn't know whether to laugh or bang my head on the wall.