We are encountering smearing problems with ST28 + Lenticular during the HC process (Dip Coat).
Any idea how to solve this issue. Would changing to Spin Coat solve everything or it may arise other problematic events.
We are encountering smearing problems with ST28 + Lenticular during the HC process (Dip Coat).
Any idea how to solve this issue. Would changing to Spin Coat solve everything or it may arise other problematic events.
Would have to know if you get smears on both sides or + or - side.
On a dip coat you can get run off from excess coating material running off the ledge of the bifocal, this could appear as a coating buildup in a straight line off the edge of the bifocal.
I received lenses with smear on the segment region. Are there any ways to solve this if we are using the dip coat process for hard coating.
Dip coat is the better product but more complex. If you have the run-off already then this would be from the manufacturer. You can strip their hardcoat and apply your own.
Things to take into account are dip speed, viscosity of resin, angle of lens in holder and base/add curve of lens.
It is possible to produce lenses that have no visible run-off (or that which can not be seen with the naked eye) but you need to control your process effectively.
It’s so simple to be wise. Just think of something stupid to say and then don’t say it.
When I say "no run-off" i am referring to the lower powered lenses. With lenticulars we find quite a few issues with the run-off but have discussed with our customers what they can expect. Most understand the problem we face and are happy to accept the lenses with the slight run-off. If the large manufacturers can allow it, then i dont see why we cant.
There is also minimal "visible" run-off once lens has been cut into the frame, unless the frame is absolutely massive.
It’s so simple to be wise. Just think of something stupid to say and then don’t say it.
on deep hard coat bifocal lens is very important the angle af the lens (normaly it must be near vertacal (arround 8-15°) and the thickness. in general the chemicals with a hight solid residues need max 2 micron , the chemicals at low solid reisidues (les of 25 %) need 3.5 microns.
I suggest you to try to adjust the extraction speed on your plant to try different
thickness.PLs note: if your plant use a primer, some time the trouble is connect with the wrong dry of the primer layer.
Yes, we have also tried the angle of the FT to be around 20°. This will ensure the run is not vertical but sometimes will follow the curve of the FT, which looks a whole lot better.
Thickness also has a great deal to play, but you can compromise endurance and hardness by having a thinner coating. You will have to do the regular tests to see if it passes your quality inspection.
I would stay away from using a primer, although it i possible to do, it will create a second run line which you have to account for. It is already very difficult on regular FT so on higher power lenses it would be a bit harder to control.
It’s so simple to be wise. Just think of something stupid to say and then don’t say it.
There are currently 1 users browsing this thread. (0 members and 1 guests)
Posting Permissions
Reply With Quote
Bookmarks