Urgently I need help with Edging High prescription lenses.

[ANINOS]

Any one can help when I do edging high prescription lenses like -8.00 and up when I check lenses after edging in the lens meter I am getting the lenses either off axis or slip so the PD will be off or even more than that the segment height changed although I am using anti-slippage stickers applied to the front and back of lenses .Any solution to this urgent problem. Urgently I need help with Edging High prescription lenses. I appreciate any suggestions.

[AngeHamm]

When I edge 1.74, very thick 1.67, and/or extremely slippery ARs, I will use non-stick pads on the front and back AND put an edging pad on the backside as well. It's a bit of a pain to unstick the pad from the chuck when it's done, and it may be a bit of overkill, but it solves the problem for me.

[ANINOS]

When I edge 1.74, very thick 1.67, and/or extremely slippery ARs, I will use non-stick pads on the front and back AND put an edging pad on the backside as well. It's a bit of a pain to unstick the pad from the chuck when it's done, and it may be a bit of overkill, but it solves the problem for me.

Okey, thanks for your answer but I wonder regarding the edging pad when I will put it to the back surface of the lens should I remove the piece of paper covering the other side of the edging pad so in that case the edging pad will stick on the lens clamp of the edging machine, it is very hard to take out the back of the lens from the lens clamp of the edging machine!

[Michael22]

Okey, thanks for your answer but I wonder regarding the edging pad when I will put it to the back surface of the lens should I remove the piece of paper covering the other side of the edging pad so in that case the edging pad will stick on the lens clamp of the edging machine, it is very hard to take out the back of the lens from the lens clamp of the edging machine!

I do the same thing with an exposed sticky pad on the back of the lens, but I'll take off half of the paper, so that when I go to peel it off, it comes off a little easier. I've found that little bit of extra stickiness can help especially with really high cyl.

Also, when you stick the pad onto the blocker. I use the lens edger to press it on very hard by chucking it, and I'll leave it for a bit like that depending on how high the Rx is. After blocking it up, I'll then use the same process where I will leave the lens chucked for a bit (up to an hour or so) before starting the edging process. Some opticians will even leave them blocked overnight just to be sure. Also make sure you clean up the spot where the blocker is being put on, so that there is no oil, water, debris that is getting in between the pad, and the lens. Make sure the plastic blocker isn't damaged at all. Had a few where the corners started coming off, and that definitely caused slippage. I think they make some with magnets in them also, which I believe helps with blocking the lens iirc

[CME4SPECS]

I do the same thing with an exposed sticky pad on the back of the lens, but I'll take off half of the paper, so that when I go to peel it off, it comes off a little easier. I've found that little bit of extra stickiness can help especially with really high cyl.

Also, when you stick the pad onto the blocker. I use the lens edger to press it on very hard by chucking it, and I'll leave it for a bit like that depending on how high the Rx is. After blocking it up, I'll then use the same process where I will leave the lens chucked for a bit (up to an hour or so) before starting the edging process. Some opticians will even leave them blocked overnight just to be sure. Also make sure you clean up the spot where the blocker is being put on, so that there is no oil, water, debris that is getting in between the pad, and the lens. Make sure the plastic blocker isn't damaged at all. Had a few where the corners started coming off, and that definitely caused slippage. I think they make some with magnets in them also, which I believe helps with blocking the lens iirc

You are asking for trouble if you are cleaning the lenses prior to edging. The better coatings have a topcoat that you do not want to remove prior to edging, it is designed to prevent slippage. You shouldn't need to go through all of that to edge a lens.

[AngeHamm]

Okey, thanks for your answer but I wonder regarding the edging pad when I will put it to the back surface of the lens should I remove the piece of paper covering the other side of the edging pad so in that case the edging pad will stick on the lens clamp of the edging machine, it is very hard to take out the back of the lens from the lens clamp of the edging machine!

Yes, I remove the paper.

[ANINOS]

You are asking for trouble if you are cleaning the lenses prior to edging. The better coatings have a topcoat that you do not want to remove prior to edging, it is designed to prevent slippage. You shouldn't need to go through all of that to edge a lens.

I agree with your comment.

[ANINOS]

I do the same thing with an exposed sticky pad on the back of the lens, but I'll take off half of the paper, so that when I go to peel it off, it comes off a little easier. I've found that little bit of extra stickiness can help especially with really high cyl.

Also, when you stick the pad onto the blocker. I use the lens edger to press it on very hard by chucking it, and I'll leave it for a bit like that depending on how high the Rx is. After blocking it up, I'll then use the same process where I will leave the lens chucked for a bit (up to an hour or so) before starting the edging process. Some opticians will even leave them blocked overnight just to be sure. Also make sure you clean up the spot where the blocker is being put on, so that there is no oil, water, debris that is getting in between the pad, and the lens. Make sure the plastic blocker isn't damaged at all. Had a few where the corners started coming off, and that definitely caused slippage. I think they make some with magnets in them also, which I believe helps with blocking the lens iirc

Thanks a lot you answer is a solution to this problem.

[ChrisBowers]

History first…
Blocking pads technologies date back to the 70s. The hole in the center was to allow light from a blocking device to align with an ink drawn (trojan marker) line. The newer hydrophobic/hydrophilic just are not compatible with this older technology.
I used to ask pad manufacturers how much foot inches of pressure it took before their pad failed. None could ever give me an answer. I built a device using a torque wrench and sourced the best product.
Things you can do…
Make a slow rotation macro.
Buy an edger the had front and back powered rotation.
Make sure you have the pad attached correctly (there is a front and back)
Blocks must be base curve compatible.
Change the floating chuck every 6 months. The bearing and the rase will fail under pressure.
Whatever the manufacturers say the blade /wheel life is, back off by ten percent. When you calculate the cost per cut you will see that hedging that cost over your lens cost is a fool’s errand.
Outsource that -8.00 or buy a 2000-pound edger.

Good luck,

Chris

[ANINOS]

Thanks a lot ChrisBowers for your valuable information.