Each axis is driven by linear motors with position feedback from linear encoders with sub-nanometer position resolution. The technology of the air-bearing slides eliminates air restrictor ports and provides ultra-smooth motion that translates to ultra-smooth surface finishes.
The lathe base is a 200 mm thick granite surface plate for accuracy and stability. The complete machine and electronics are housed in a single cabinet.
The Y axis is mounted directly to the granite and carries the spindle. The X slide is also mounted on the granite
and precisely positioned at 90° to the Y slide. This machine geometry assures that machining loads are
well centered within the travel of the slides and that the spindle mounting is stiff and stable.
Multiple sets of tooling and a front surface gauging system are mounted on the X slide. The optional Oscillating Tool Technology (OTT) system can be added at the time of purchase or later to meet customer needs. The lathe spindle is a carefully balanced, air-bearing high-frequency unit with programmable speeds of 0 to 10,000 rpm. A DC motor with encoder feedback provides torque at all speeds and the ability to synchronize with the OTT tooling.
It is recommended that all parts turned on the ALM Lathe be blocked. Special collet configurations are available upon request. The roughing natural diamond tool is used to remove the bulk of the material. As the finishing tool removes only a minimal amount of material, its edge (and life) is preserved.
All cuts are made by X or Y motion, or by XY interpolation. Any number of spheres and aspheric surfaces (front or back) can be machined. In addition, with the OTT option, the complete range of toric and atoric front and base curve surfaces can be turned. DAC has developed more than 50 algorithms that laboratories use to create their own special lens offerings. These include lenses that are spheres, aspheres, torics, atorics, bitorics, and keratoconus solutions for their clients. Because of the fine resolution, the surfaces require little or no polishing, depending on the material used and the manufacturer’s process.
Edge radiusing is accomplished by utilizing a special tool with XY interpolation to produce the desired contour. Typical contact lens base and front curves can be produced in 30 to 60 seconds, depending on geometry and material used. Very complex designs, such as crescent toric segmented bifocals, will take longer.
“Menu” type queries, on the color monitor screen, guide the user quickly through machine set-up, calibration, alignment, and tool replacement. The Windows-based software, along with our DAC Script Language (DSL), employs a subset of RS-274D machine language. This high-level programming language is easily understood by the user and is included in each lathe. Our Windows based software gives the flexibility to interface with host computers and other Windows-based products, such as measuring equipment.
If all lens design parameters are known, the user simply enters the appropriate numbers using the keyboard. The machine calculates variables, such as junction thickness, after the entry of basic design factors. A display of a lens cross-section aids the user in the design process by graphically presenting the actual design. The machine’s
computer automatically converts lens design specifications into the machine language program necessary to machine
the desired part.
DAC software presents the laboratory with a wide range of options for the creation of lenses to meet the most challenging requirements.
The DAC Digital Motion Control (DMC) system is at the “heart” of all DAC Lathes. It is housed in the on-board computer, mounted with the servo amplifiers, in the base of the machine behind doors for easy access. Each axis is driven by a linear servo motor with linear encoder feedback.
Auxiliary functions such as actuating lights, vacuums, air blow-offs, autoloaders, misting, etc., are controlled by outputs from the programmable logic control.
These robust tool holders are adjustable to accommodate a wide range of tool shank sizes.
DAC International offers the industry’s most comprehensive lens manufacturing software — easy to use and easy to customize. Full details on DAC International Software
|Slides:||Air-bearing slides are DC linear servo motor and have linear encoder feedback. (Custom X-slide lengths are available as shown below.)|
|Travel:||203 mm ( 8″)|
305 mm (12″)
356 mm (14″)
|203 mm (8″)|
|Traverse rates:||Maximum of 18 meters/minute (720 IPM)|
|Spindles:||Precision air-bearing spindles, encoded or non-encoded, dependent on application.|
0 to 10,000 RPM
|Collets:||Standard collet supplied with lathe—12.7 mm x 12.7 mm (0.5″ x 0.5″) with dead length stop|
Specials supplied upon request.
|Power:||208, 220, 230, 240 VAC, single phase,|
50/60 Hz, 20 Amps
|Air:||7 SCFM @ 80 PSIG|
(9 m3/hr. @ 5.6 kg./cm2)
Air quality per ISO 8573.1 (2001), Class 2 or better
Clean, filtered, dry; supplied by user
|Temperature:||68 to 74 degrees Fahrenheit (20 to 23 degrees Celsius)|
|Vacuum:||User-furnished 58 mm (2.25″) diameter|
|Minimum floor space:||1,219 mm x 1,270 mm x 1,778 mm|
(48″ x 50″ x 70″)
|Minimum floor weight:||1,089 kg. (2,400 lbs.)|
|Minimum shipping weight:||1,271 kg. (2,800 lbs.)|