DAC International, Inc.
RxD Lathe

Description

The DAC International RxD Lathe is a high precision diamond turning lathe for spectacle lens back surface generation. All turned plastic lenses are ready for Soft Lap Polishing.

 A dual diamond tool assembly is mounted on an air bearing slide and voice coil driven by a proprietary digital control system. The tool is precisely positioned in synchronization with the spindle to generate the spherical and cylinder curves. Use of air-bearing slides for the high speed tool assembly oscillation and cross slide eliminates one of the highest maintenance components of traditional generators, while assuring consistent surface finishes. All machinery is mounted on an air suspension granite base for long term accuracy and stability.

A patented electronic/mechanical force and vibration cancellation assembly eliminates over 99% of machine frame vibration, resulting in a lens surface that is ready for Soft Lap Polishing.

The spindle speed is automatically set by the computer to optimize production throughput while maintaining surface finishes that are ready for soft lap polishing. All axes are precisely controlled through the use of high resolution digital encoders.

DAC International's proprietary Specialty Lens Menu Software takes you a step beyond conventional free form.  All free form shapes and asymmetrical designs are generated on the back surface of spherical  lens blanks.  The PAL menu works with customer-supplied points files to generate backside Progressive Add Lens designs.  The DAC Specialty Lens menu is used to create designs, such as Slabs, Round Segs, Lenticulars and Wraps, including the family of SportWrap^TM designs.

Operation

The operator scans the job number using a bar code reader. The blocked lens blank is placed in the foot pedal operated pneumatic chuck that has integral index pins. The safety door automatically closes and the operator presses the dual start button. 

Surface finishes of better than 1 micron peak to valley roughness are produced for the full range of curves. At the end of the machining operation, the door opens, providing access to the machined lens.


The DAC Voice Coil Driven - Vibration Compensated Tool System

Traditional lathing generators use lead screws and followers to oscillate the tool to generate the prescribed back curve. This sliding action causes wear in the mechanical parts which in turn produces surface roughness and form error on the lens. This wear, and the resultant quality problems, are progressive and require constant attention and maintenance. Further, the oscillating motion results in reaction forces that are coupled to the machine frame, and ultimately to the lens surface.

The unique voice coil driven / air slide mounted diamond tool assembly, and the air bearing cross slide assembly, provide DAC customers with previously unattainable form accuracy and surface finish consistently over time. The absence of hard mechanical sliding interfaces eliminates the most common source of maintenance costs and poor surface finishes. The quality that is seen at start up will last for years without major maintenance. Reactions to tool oscillation in other three axis oscillating designs resulted in surface artifacts that had to be removed by fining and polishing.

The DAC Reaction Eliminator module actively provides counter forces to internally and externally generated forces. This results in virtually no surface artifacts, yielding a lens surface that is ready to coat in most modern coating systems.

DAC Unique User Benefits

Eliminating the need for hard lap fining and polishing results in a finished lens with heretofore unequaled quality with respect to prescription accuracy and surface quality. Delivery to your customer is better because of the elimination of the traditional secondary surfacing operations. 


Specifications