Tips on tracing / edging high wrap frames

**choppa** · 04-21-2012, 04:28 PM

I was wondering if anyone had some tips on edging high wrap frames. I am currently using a 4t / 6e and the frame is an 8 base. I think the main problem lies with the frame, it is an older, somewhat flimsy plastic sports wrap frame.. The bevel isn't too deep and its has been hard getting the correct B size as well. I tried tracing one eye and also tracing the frame but nothing has been working for me. Any tips in the tracing / edging process? I do not want to ruin another polarized free form wrap so any help is appreciated! Thank you

**braheem24** · 04-21-2012, 04:37 PM

Have you tried moving the bevel placement to match the 8 base curve of the frame? It's been a feature on optronics edgers since the Horizon I, secondly check the backside of the lens especially temporally to ensure it's not hitting the frame and not allowing the lens to seat into the bevel, you may need to "roll the edges" as needed.

**jonathan barber** · 04-21-2012, 04:49 PM

I agree with braheem about specifying a base curve bevel. I've used both the 6E and 7E and it is an absolute breeze...9 times out of 10 it works like a charm!

**choppa** · 04-21-2012, 05:02 PM

Thank you braheem,

I pushed the bevel towards the front, maybe I will need to push it more..
The customer's RX is
0.25 -1.00 097
0.75 -2.00 112
if that makes any difference.

**choppa** · 04-21-2012, 05:03 PM

I think one of my main problems lies in the tracing, the A size doesn't seem to match very well

**braheem24** · 04-21-2012, 05:20 PM

Choppa, bevel needs to be pushed further back not forward and needs to contour to 8 base not a 6 base lens with all the cyl at the 90 it should be easy. The bevel should be at it's most forward point above and below the lens OC, from there it needs to move further back nasally and temporally to simulate an 8 base lens.

**choppa** · 04-21-2012, 05:33 PM

Okay, thank you I will try that. So push the bevel all the way front, above and below the OC and push it back nasally and temporally. Now the problem lies with getting a good trace.

**braheem24** · 04-21-2012, 05:45 PM

trace the demo, size it using a plano first.

**choppa** · 04-21-2012, 06:24 PM

my 4t doesn't seem to reach the edges while I trace the demo, any calibration measures I need to take for this?

**braheem24** · 04-21-2012, 06:53 PM

try tracing inside out

**PRECISIONLAB** · 04-23-2012, 10:05 AM

As mentioned in earlier posts..Tracing is key. Can you modify the shape with your tracer? I believe a software upgrade is available for the 4t to make it a 4ti. This will allow shape modification. For example if the B is 30.5 you can adjust to 31.0..adding to the B only which will help with overall fit. There are also special profile blades available from Optronics...order the High Wrap blade which should work in the 6E. You will have to adjust cut speed and start almost 1.0 mm box larger. Since the resultant power is overall minus @ 180, leave the edger in auto bevel mode assuming the Rx lenses were processed on a matching base curve to the demos or current lenses in the frame. We process most of these types of jobs on a 7 BC lens using a Dimension Tracer and & 7E with shape modification with great results.

**MakeOptics** · 04-23-2012, 11:48 AM

I have the greatest success with the next flattest curve lens, while modifying the bevel curve to frame spec. So if the frame base calls for an 8 use a 7 or even a 6, then put an 8 base bevel on it. Also the lens behind the bevel should be shaved down with either the wrap blade or by hand to avoid splay.

When tracing i find that i get a more accurate trace when i trace one side of the frame with the other side pulled slightly out of the tracer so the trace plane is tangent to the A size demensions. It is worth checking the raw trace file to see if your tracer takes Z data or heights for the trace points. If it doesnt, then it becomes even more important to make sure the trace is taken as flat as possoble to avoid having shape distortion introduced to the A size.

**Barry Santini** · 04-23-2012, 08:48 PM

Originally Posted by PhiTrace

I have the greatest success with the next flattest curve lens, while modifying the bevel curve to frame spec. So if the frame base calls for an 8 use a 7 or even a 6, then put an 8 base bevel on it. Also the lens behind the bevel should be shaved down with either the wrap blade or by hand to avoid splay.

When tracing i find that i get a more accurate trace when i trace one side of the frame with the other side pulled slightly out of the tracer so the trace plane is tangent to the A size demensions. It is worth checking the raw trace file to see if your tracer takes Z data or heights for the trace points. If it doesnt, then it becomes even more important to make sure the trace is taken as flat as possoble to avoid having shape distortion introduced to the A size.

+1!

I would add that we rountinely additionally modify the B dimesion by +0.25-+0.40, depending on the degree of wrap and A dimension size.

That said, a new generation of "wrap" tracers are on the way. Santinelli's new one has gotten a "pre-prod" work out at a major wrap lab, and Santinelli/Nidek (they do work together on product development and refinement) are revising this new tracer before production begins this summer.

I'm hoping to add it to my Me1200 as an outboard tracer for higher precision on all frames.

FWIW

B