Rimless Grooved in Poly chipping

[rdcoach5]

I have seen way too many poly lenses chip around the edges in grooved rimless.Is this because my local lab grooves the lens after the backside hard cote is applied? If so, then would Opticotes Poly seal prevent this chipping?

[Chris Ryser]

I have seen way too many poly lenses chip around the edges in grooved rimless.Is this because my local lab grooves the lens after the backside hard cote is applied? If so, then would Opticotes Poly seal prevent this chipping?

I would guess that you have more of a stress factor problem.

Check the Opthalmic Forum under "lab manager" , there is a whole discussion going on the subject.

[fundy]

Sounds more like a dull grooving wheel

[LilKim]

It's either the grooving wheel, or they're not making the groove wide and deep enough to properly fit the line into. If they make a shallow, narrow groove, they have to "smush" the line into it so it's not sticking out around the edge, and over time this will cause the stress cracks. It could also be those horrid groove frames that have no plastic line lining at the top (the figure 8 lining), so the lens is mounted directly into metal. They need to make sure the groove is wide and deep enough to accommodate this, with no stress, before they send it out.

Backside hard coats are generally applied to an uncut lens in the surfacing dept., and plays no role in whether or not the lens develops stress cracks after edging.

[Barry Santini]

I would guess that you have more of a stress factor problem.

Check the Opthalmic Forum under "lab manager" , there is a whole discussion going on the subject.

Chris, Just where is this forum?

Barry

[bob_f_aboc]

Chris, Just where is this forum?

Barry

Here it is:

http://www.optiboard.com/forums/showthread.php?t=33901

[Chris Ryser]

Chris, Just where is this forum?

Barry

On OptiBoard


Ophthalmic Optics (4 Viewing)
Discussion of ophthalmic optics and related topics. Not for the faint of heart


Thread:

question for lab managers.... ( 1 2) jb@kso

[eryn]

Our office is having the same problem, from two different labs in two different states. Poly grooved Rimless with tons of chipping and large stress cracks after just a couple of weeks or months of wear. No one seems to know why. We are starting to go with trivex when possible to minimize this.

[fjpod]

I'm gonna go with a dull edging or grooving surface.

[chip anderson]

#1 Reason for grooved edges chiping: Edges made too thin not allowing each edge to have enough strenght .
#2 Reason for grooved edges chiping: Trying to alighn temple or chassis with lens in the frame or without enough support given to chassis when raising or lowering temple.
#3 Frame gets dropped and puts impact on edge of frame, especially of those with metal instead of plastic interliner.
#4 Too much tension on lens from nylon chord, and or chassis.
#5 Groove not deep enough, lens will have a tendancy to slip out, with each slip lens can become chipped when it twist in frame or hits the floor.
6) Nylon chord is too wide for groove.
7) Idiot dispenser is unwilling to cut (because he doesn't know how to replace) chord to remove lenses for replacement or adjustment.
8) Lens either warps from time an heat and will not fit chassis part of frame any more.
9) Chassis is wrong shape (and should be hand formed) to curve of groove at top of lens.
Many labs and many practioners concider "thinness" to be the most important part of dispensing "quality" work. When this is over-done, especially on plus lenses, the edges chip. Maybe not from lab to dispenser, sometimes not from dispenser to patient, but sooner or later.

Doesn't really matter too much what material is used.

Chip

Duh!