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I'm an optician student at Douglas College in Vancouver, BC. My lab instructor has suggested we do some research so we can explain the difference between a surfacing lab and a finishing lab. What is processed in each of these labs? When might you choose a surfacing lab?
Any feedback will be useful. I know it seems a simple question to you veterans but to us students it can be muddy waters. :nerd:
Thanks for the help!
Simply put, a surfacing lab manufactures the Rx lens blanks and the finishing lab cuts and edges the blanks and inserts them into the frame. Most surface labs also have finishing capabilities.
Thanks, that's a good start. :-D
Your professor may also want you to explain why it would be beneficial to have a surfacing lab vs just a finishing lab or vice versa.
You may want to look into equipment cost and maintenance, wages/payroll for qualified operators/techs, time, overall cost and potential profit, etc. With a surfacing lab, you have more "options" in regards to base curves, powers, materials, etc. whereas a with finishing lab, all you'll be dealing with is a finished lens, ready for edging. In my opinion, a finishing lab would be ideal for a small to medium sized optical business and leave all the surfacing to the wholesale lab people.
Surfaceing and Finishing lab, a surfaceing lab surface grinds lenses and a finishing labs edge grinds lenses. The most common in office lab is going to be a finishing lab since the investment is minimal comparatively and the work is easier in comparison to a surface lab.
Surface grinding is when a semi finished lens blank (which looks like a hockey puck) is ground on one surface to provide the correct power and thickness to meet the patients frame and prescription requirements. The process starts by picking the lenses, taping the front surface, then blocking them up with either alloy or wax. Blocking is applying a metal circle to the front of the lens which will give the various equipment a surface to grab onto without damaging the lens. Once the lens is blocked the lens is generated in a CNC lathe along the z-axis to the correct curvature to match the patients prescription. Once the lens comes out of the generator the lens has lathe marks and must be fined then polished. Fining is done by applying a fine grit pad to a corresponding tool witht he opposite curvature that matches the lenses grinded surface, the lens and tool are then clamped together in a cylinder machine which oscillates the tool and lens against each other to smooth out the lathe marks fromt he back of the lens. The cylinder machine sprays water on the pad to help both reduce the amount of heat and debris on the pad and lens surface. Once the lens coms out of the cylinder machine the lens is then sent to a polisher which is the same machine except set up with a mixture or slurry of aluminum oxide in a suspension. This slurry is sprayed on yet another pad this time instead of having a coarse grit the pad is soft and velvety and the lens is run longer. Whent eh lens is removed from the polisher the lens will be optically clear and ready to be deblocked. Deblocking is just taking the previously applied metal block off of the lens since th esurfaceing operation is complete. This is done via shocking the lenses loose by placing the block inside a cylinder and holding the lens against the edge of the cylinder while slamming it against a table, or with the use of equipment that uses air pressure and a scissor like motion to squeeze the wax and break the seal from the lens and block. Once deblocked the lenses are cleaned and inspected for any lathe marks or imperfections. From here the lenses are verified for accurate power then sent to be coated or fonished if the lenses were ordered with no coatings.
The finishing lab starts wit a finished lens blank which has either just been surfaced or came from a stock blank. Once the lens is picked and ready teh process begins, if the frame is a patients previosu they are ultrasonically cleaned, if they are new they are preped for tracing. This is accomplsihed by removeing the demos from a full metal frame, marking the 180 on a grooved frame and removing the lens, or picking the pattern for the frame model. This frame, lens, or pattern is mounted inside of a tracer which uses a stylus to trace the pattern and digitize the shape of the frame, this data can be stored in a computer attached to the tracer and edger or be traced directly to the edger depending on the configuration. Once the frame is traced the lenses are then marked nt he lensometer on the major reference point and along the 180. Then the lenses are taken to the blocker which is loaded with a block similar concept to the surfaceing side except that the blocks don't need to be as substantial since the lenses will have less forces applied for less time, the blocks are often made of plastic or metal and are approximately 10mm in diameter. The blocks have double sided stickey foam wafers attached to them and the lens is decentered along the x-axis to match the patients PD and the y-axis to match the patients segment height or optical centers, then the block is applied to the geometric center of the lens, pattern, or frame shape. From here the lens goes over to edging which is just as it sounds edge grinding the lenses to the proper shape. The setttings on the machine are adjusted for the corresponding bevel, material, and coatings. The edger uses a diamond impregnated wheel spinning at a high RPM to grind away at the edges of the lens, often water is sprayed to keep the lens and wheel cool. Another type of edger is a dry cut edger which uses a rotating blade to cut away at the edge of the lens. Once this is complete the lens is safety or pin beveled (many machines now include this feature, however high production operations will opt to skip it since it drastically reduces the number of jobs that can be processed if the option is utilized this also goes for grooving unless the operator is running multiple machines in which case one may be dedicated to groove jobs while the other are used to run the bread and butter jobs. Once these bevels and grooves are completed the lens is sent fro tint treatments or edge polish if necessary then off to the benchman they go. This person can differentiate a good quality lab form a poor quality lab, a good benchman will nto onyl insert and bench align a frame they will make sure that any damaged screws are replaced and that lock tite is used on all screws. I have seen some labs where the benchmen have even replaced nosepads and touched up missing paint on patients own frames it's a nice touch but time consuming so doesn't happen often enough. Once the frames are put together and bench aligned they are then verified. The most common measure used of course is the ANSI Z80.1-2005 standard if the job passes it is sent to the shipping department to be shipped off to the account, if the job fails it is sent to customer service to be notified and then new lenses picked and the job started over again.
I had a much longer version of these prcesses typed out earlier today and then hit the submit reply button and I had been typing so long I had to log back in and lost the post, anyway still long enough with all the information but I cut out more of the details this time around hope that helps.
Great post Bro!!!
http://www.optiboard.com/forums/images/icons/icon14.gif:cheers::cheers::cheers:http://www.optiboard.com/forums/images/icons/icon14.gif
Great post Harry. Knowledge for everyone.
Thanks Harry. That's more than this old lab rat wanted to know at 6:00 AM.
Need more COFFEE !!!
Anyway, back to the question. The best way to find out is to visit an independent wholesale lab and see for yourself.Quote:
Originally Posted by cindiaugustine
Thanks so much SenorWes and Harry and everyone else. This is exactly the info I need. We will be visiting a surfacing lab next month and I'll be heading there with some good base info. I'm off now to share this with my fellow students, so you've been a great help to more than just one optician-in-training! :cheers:
C.
I wanted to share that Cindi did some edging today in our clinic (she's doing her first practicum with us), and she did an awesome job! She did some great dispenses today too. So she's gotten her feet wet in the finishing lab and in the dispensary....and hasn't run away screaming, so I think we have a wonderful optician-in-training on our hands :bbg:
Awww, shucks!! Thanks, mlm. I think choosing a good practicum site and taking advantage of the opportunity to learn on the front lines is one of the most important things a person can do when starting a new profession. Being a student for me means picking EVERYONE's brain. That means my instructors, the experienced lab techs and optic professionals on the board here, and the amazing front liners on my practicum. Doing that first edging was a bit intimidating but the support and patience I had made it a successful experience.Quote:
Originally Posted by mlm
Ps: I run away screaming in my head. The smile is just a good cover. :eek:
What school?Quote:
Originally Posted by cindiaugustine
I'm attending the Douglas College Dispensing Optician program in Vancouver BC. It's a one year course, with an option to take a second year to become a contact lens fitter.Quote:
Originally Posted by HarryChiling
I'm due to graduate mid-June after a final 6 week fulltime practicum. Board Exams will follow within a few months and then I'm unleashed upon an unsuspecting world! :drop:
Cool, good luck and e-mail me if I can help in any way.Quote:
Originally Posted by cindiaugustine
Th:nerd:anks, I know there'll be more questions. LOLQuote:
Originally Posted by HarryChiling