HydroSpeed Polishing Technology

The challenge of polishing the second side of a lens is the possible damage of the already polished first side. That often happens when using a traditional membrane chuck.

There is a way to by-pass this problem by placing protective paint on the polished side. That necessiates to take the lens out of the process chain, painting and drying it in an additional step before processing the second side. It is easy to see, that this is opposed to the aspired linkage of generators and polishing machines.

The solution for this problem is our HydroSpeed^® Polishing Technology. Using this technology, the lens is pushed against the polishing tool by the polishing fluid that is pumped through the chuck. To do so, the polishing fluid unit is equipped with an additional high-pressure pump that pumps polishing fluid through the lower spindle. As a result the lens "sits" on the fluid and is guided all around.

HydroSpeed^® has the following advantages:

1. Consistent pressure distribution and support of the lens over the whole surface. The deformation of the lens, as happening when using a traditional membrane chuck, is significantly lower and the fitting accuracy is much better.
2. The emerging heat of the polishing process can not be dissipated when using a traditional membrane chuck, which results in an additional deformation of the lens. Using the HydroSpeed^® Technology, the lens is surrounded by polishing fluid that absorbes the processing heat and leads to a much lower temperature gradient of the lens.
3. The most important advantage is the fact that HydroSpeed^® Polishing makes protective paint redundant. Due to the missing mechanical contact between the backside of the lens and the clamping system, the backside doesn't need any protective paint.

That means:

• No interruption of the production process
• No work station for protective paint necessary
• No storage space for lenses that wait for their painting and drying lenses needed
• No protective paint at all required
• No solvent for lens cleaning needed
• No disposal of the solvent needed
• Significant higher throughput speed of the lenses in the production process

An production cell with this technology was first introduced by OptoTech at the OPTATEC 2002. The production cell only consists of one generator and one polishing machine with the following production steps:

• Generator: Pre-, fine grinding and 3C processing of the lens
• Polishing machine: HydroSpeed^® Polishing of the lens

HydroSpeed^® Polishing has especially been developed for large scale production, but can also show its advantages at lower scales. Due to the fact that no special membrane chuck is needed, the complexity of the tool production is considerably lower.