During this week we finally finished our 6th Continuous Polisher.
All the polishers at Lunt are custom designed and fabricated on site. They are currently all 48″ diameter with a capacity for about a 12″ part. In our application we use plastic fixtures on the lap to hold multiple sizes. We also utilize a large conditioning wheel that runs continiuously on the lap to maintain the required flatness to the parts being polished.
The 48″ granite lap is supported on a thick steel plate which mounts via a very heavy duty machine bearing to our custom tables. Our tables are designed and manufactured to be very solid. The lap is driven by a 5HP motor with a large gear reducer, all controlled by a variable speed controller. Due to the fact that our laps generally run 24 hours a day, 7 days a week, we have ensured that all components are over sized for the job.
The granite forms the solid and thermally stable foundation for the polishing pitch. We use a Gugolz fine pitch. We heat the pitch up in a very large pot and once fully liquid, we add secondary components to ensure that the lap will remain firm and stable for long periods of time.
These additions make the lap very “hard.” The trade off is that it takes many hours just to push a lap 1/4 wave in each direction. The benefit is that the lap remains flat for extended periods of time, allowing us to finish an entire batch of glass in that timeframe. This also ensures that the laps cannot drift too far while being run overnight. The hardness of the lap and the fine polishing compound assure that our flats are very precise and have no roll off at the edge.
Our next project is the fabrication of a 36″ Continuous Grinder. David, our glass grinder, spends 8 hours a day grinding glass from rough cut to fine grind. A second machine will allow us to provide just a little more ground parts than the optics shop currently needs freeing David to hekp in other areas.
In addition to the 6 48″ CPs, we are in the middle of construction on our 72″ Continuous Polisher. The granite has arrived, and the steel base is finished. This machine will be used to manufacture precision flats up to 24″ in diameter. Recent large flats were finished on a large draper style machine. Although we eventually met the specifications of 1/10th wave over 20″, we have certainly concluded that a large CP is the way to go.