Hello guys hope you're are all doing well. I'm new member here and I'm also a newly recruited in optical lab / surfacing department and I'm eager to know more about this job. I'm currently learning to work on generator and there is some things still blurry for me like Crib diameter for example. Can someone of you explain that to me. Thank you
Hey Jay,
I suggest getting this book: https://www.abebooks.com/servlet/Sea...e-_-all-_-link
I would begin reading it from the beginning and then use it as a reference going forward. This will give you the basics of surfacing lenses, in the older ways (i.e. before digital surfacing was a thing) which will give you foundational knowledge that you can use to understand the newer technology.
As for your initial question, I believe that when you refer to cribbing a lens it could refer to two different actions. First, reduction of the total lens blank diameter. This might be done to remove excess material from the lens so that fining and polishing is only being done on parts of a lens that will be used in the finished pair of eyewear (as opposed to parts that will be removed in edging anyway). Second, would be a cribbing of a high back curve by cutting a flatter curve just on the part of the lens that creates a sharp edge so you dont hurt your fingies. In both actions the usable lens diameter is reduced and should be done carefully so that the lens does not end up cut smaller than the minimum blank size.
Optical Cross: n. crucifixion apparatus used by the New Jersey State Board.
"It is not knowing, but the love of learning, that characterizes the scientific [person]." -Charles Sanders Peirce
"A concept is a brick. It can be used to build a courthouse of reason. Or it can be thrown through the window. -Gilles Deleuze
Originally Posted by Kujiradesu
Optical Cross: n. crucifixion apparatus used by the New Jersey State Board.
"It is not knowing, but the love of learning, that characterizes the scientific [person]." -Charles Sanders Peirce
"A concept is a brick. It can be used to build a courthouse of reason. Or it can be thrown through the window. -Gilles Deleuze
Hi thank you for the explanation and the picture. I will definitely check the book since I’m in fact using an old school generator I think it’s gerber sl 2.
Can you help me by explaining these numbers / terms that is written on paper
Hi Jay! And welcome to OptiBoard! Crib diameter is going to be the overall size that the generator trims the lens down to. It's something to focus on for higher prescriptions, as when you begin to shape the lens on the edger, it gives the edger less lens to have to cut for sizing. That becomes more important on the higher prescriptions, like minuses, as the edges can be thick and can cause the lens to twist on the edger. Helps prevent lenses from being cut off axis. Another way it helps, it can help keep wear and tear down on your edger wheel/blade because it's trimming less material. On the flip side, for larger frames, having a larger crib diameter will make sure you don't run into cut out issues on the edger. A small but important detail on the generator. If you have any further questions feel free to PM!
There are currently 1 users browsing this thread. (0 members and 1 guests)
Posting Permissions
Reply With Quote
Bookmarks