Blocking issues

[valerier]

I am ready to pull my hair out.. having issues with segs not being straight. We are an in office lab. I have one new employee blocking and also a 20 year seasoned employee. We are sporadically having problems with lined and no line lenses. I have checked calibration on all machines, tracer, edgers and blocker (optronics 3B). I recently lost the gentlman that did all the blocking, and at that time we had no issues. I dont know what else to look at. I have to assume it is user error, but not sure what to do at this point. Any help or advice would be greatly appreciated.

[Chad Sobodash]

I am ready to pull my hair out.. having issues with segs not being straight. We are an in office lab. I have one new employee blocking and also a 20 year seasoned employee. We are sporadically having problems with lined and no line lenses. I have checked calibration on all machines, tracer, edgers and blocker (optronics 3B). I recently lost the gentlman that did all the blocking, and at that time we had no issues. I dont know what else to look at. I have to assume it is user error, but not sure what to do at this point. Any help or advice would be greatly appreciated.

To what degree are they inclined, and in what direction? If you find that out, it will tell you if you're having problems with the edger turning lenses, which can happen depending on how the previous employee "finessed" his blocking (pushing the pads in after blocking or using an extra AR sticker at 90 degrees, etc). If you're positive everything is calibrated, then this is most likely your last option, and it would make sense with it being "sporadic."

Or, the easier solution is to fire your employees, set fire to your equipment, and walk away from the burning hulk of your office with a new-found freedom, risen from the ashes like a phoenix.

[valerier]

The turning is usually only 2-3 degrees. Not just AR or any certain material. Also thin and thick lenses,not just the right or left eye and out of 2 different edgers. Normally a person can figure it out by process of elimination, but let me tell you this has me at the end of my ropes... I am liking the last of your ideas... I live in the cold midwest, maybe it is time to find a warmer climate.

[WFruit]

Are single vision lenses coming out off axis? 2~3 degrees is passable for most cylinder powers so you may not have noticed if it's happening. If single vision is not coming out off as well, then it's almost certainly user error. Try doing the blocking yourself for a couple of days and see how things come out. That should also help.

Is there anything in the blockers that's loose that when "nudged" might cause slight misalignment? Higher power lenses can cause the segs to appear off when blocking, but if it's happening on all power lenses, that's probably not it.

Are they always turned in the same direction, or does it vary? If they're always turned the same way, i.e. right lens has the temporal side of the seg up, and left lens has the nasal side of the lens up, then it's almost certainly the tracer, either in the settings or in how the frames are being traced. Settings would usually cause all lenses to be turned, but if the frames aren't being put in the tracer right, that could be sporadic.

[valerier]

We really do not notice it on single vision. I do have a new lens holder coming because sometimes it looks like one of the pegs has some play in it. There does not seem to be any sort of a pattern with the direction it is turning.. I ruled out al the obvious such as the tracer and machine calibrations.. and also the blocker calibration seems right on. I am hoping the new lens holder will fix it.
I may do all of the blocking for a coupld of days and see if it happens to me.

[sharpstick777]

all good ideas, you need to figure out if its user error, edging twist, or blocking equipment.

If you want to eliminate the edger, run a FT slow 5 over and reblock, then run again. If its on, then you have twist in your edger. Which could be pads, pressure, etc.

[CME4SPECS]

I bet that it wasn't a problem when the other guy was blocking is that he knew he had to block lenses a little of axis to get them to turn out right. Heaven forbid is someone came into my lab and tried to block lenses, they'd have pd's that were off every time.

[peyes]

What kind of edger?

[valerier]

I have an Optronics 7E and also a Santinelli LE 1000. I know blocking pads can be a nightmare. I have been using the DAC hydroedge, but maybe it is time to look in to something different.

[Mick]

Are you using a good quality blocking pad? and also an intermediary pad on AR? Also we upon the suggestion of the blocking pad supplier, let the lenses sit for at least 5 minutes after blocking for the adhesive to set up more securely. Also make sure when handling the pads, don't touch the surface more than necessary. I had an employee who had 10! thumbs and would paw all over the pads before they touched the lenses, with lots of slippage problems.

[WFruit]

We use the Hydroedge pads for almost all of our lenses, so I'd be surprised if it was that.

Is it happening on one edger or both? For the 7E, make sure the blades are sharp (which is funny, because even a dull one of those blades is sharp enough to cut your finger right down to the bone, and then sometimes even score the bone).

I know you said the edgers and blocker have been calibrated, but I was referring to the axis offset settings in each. If those are off or somehow got changed, that would cause the problem, but it would be showing up on everything, not just every so often.

Also what Mick said about handling the pads is important, and make sure the lenses are clean. Pads don't stick as well to dirty lenses.

[valerier]

THANK YOU everyone for your input. I had never heard about letting them set for awhile after they are blocked. Before I mess with changing blocking pads I think I will see if any of the other things work.

[peyes]

Make sure the axis homing disc on the 7e is tight. Sometimes the set screw will back out just enough to cause axis issues