Sub-cell turning to accomplish micron-level alignment of precision assemblies
High-Precision Mounted Lens Production
Directional adhesive bonding versus alignment turning
High Precision Lens Assembly with Alignment Turning Machines
On Machine Metrology for the Alignment Turning Process
Alignment Turning Stations for the High-Precision Machining of Mounted Lenses
ATS – Alignment Turning Station
High-precision centering, alignment and machining of mounted lenses and lens groups
During alignment turning, the mount edge and the flange surfaces of mounted spherical, aspherical and cylindrical lenses are produced so that the axis of symmetry of the mount coincides with the optical axis of the lens. UV or IR lenses can also be processed with high precision. The ATS alignment turning machine combines the proven OptiCentric® centration measurement system with an ultra-precise turning machine. This makes it possible to adjust and control all relevant parameters while processing the mount, such as diameter of the mount or the distance of the lens from the contact surfaces of the mount. The high-precision measurement of decentering and the extremely accurate processing of the mount prevent cumbersome, iterative adjustment steps in the overall optical system. The intuitive operation results in operator-independent results during measurement and processing.
The compact alignment turning station
ATS 100 is optimized for the processing of lens systems with a diameter of up to 100 mm and a weight of up to 3 kg.
Automated alignment chuck
- Reproducible manufacturing with a repeatability of better than 2.5 µm
- Easy to clean via integrated chip extraction
Suitable for cycle time optimized processing of large batch sizes
The high-precision alignment turning station
ATS 200 is designed for processing small and medium-sized lenses in medium batch production.
Optional with hydrostatic spindle
Automated adjusting chuck
Great stiffness and thermal stability due to optimized granite base
- Reproducible manufacturing with a repeat accuracy of better than 1.0 µm
The ATS 200 UP is a variant of the ATS 200 with an identical basic structure. What sets it apart is the
use of an extremely stable spindle with hydrostatic bearing supports. This increases its rigidity even
more and offers excellent damping, ensuring that very high accuracy requirements of better than 0.5 microns can be achieved.
Adapted to your requirements
Achieving the best possible manufacturing process often requires individual circumstances to be taken into consideration with regard to the work piece, the test room, the periphery and the requirements. Automation of the process is also often a challenge. This is just another example of TRIOPTICS’ expertise.
Further increases in efficiency can be achieved by adding a robot to the ATS for automatic loading and unloading. The robot is integrated directly into the process, so that the ATS-specific manufacturing process starts seamlessly after the optics have been inserted.
The ATS 400 is currently the largest alignment turning station in the ATS family. It was specially developed for the requirements of the semiconductor industry and is therefore designed for machining large and heavy lenses with the highest accuracy.
The ATS 280 was also an adaptation for the semiconductor industry. Larger cells can also be processed here. However, in order to make this possible on the still small footprint of the ATS 200, some options that were not required were omitted.
Your turning point to higher efficiency
The perfect solution for an adjustment-free assembly of mounted lenses
With their universal design and versatile metrology options, the alignment turning stations ATS can process all mounted lenses and lens assemblies, including those with infrared and aspherical lenses or with mounted cells that cannot be glued. The choice always falls on the ATS when it comes to increasing efficiency. Here the system has not only excelled in mass production but also in the manufacture of customized lenses.
One software for all measurement and production processes
The ATS Control combines operation of the machine functions with the routines for measurement of centering error and alignment. The user is guided step by step, both in setting up sample geometry and carrying out the processing procedure. The software continually monitors the results of the production process.
|Parameter||ATS 100||ATS 200||ATS 200 UP|
|Machine type||Mineral casting base||Granite frame||Granite frame|
|Workpiece diameter||Up to 100 mm||Up to 200 mm||Up to 200 mm|
|Max. workpiece weight||3 kg||5 kg||5 kg|
|Workpiece material||brass, aluminium, NiP-Steel||brass, aluminium, NiP-Steel||brass, aluminium, NiP-Steel, invar, titan, steel|
|Production accuracy||Up to < 2.5 µm||Up tp < 1.0 µm||Up to < 0.5 µm|
(h x w x d)
|ca. 2.0 m x 1.0 m x 1.0 m||ca. 2.20 m 1.55 m x 1.10 m||ca. 2.20 m 1.55 m x 1.10 m|
|Weight||approx. 1,400 kg||approx. 2,500 kg|
|Type||Stand alone||Stand alone||Stand alone|
Upgrades & Accessories
- Aerostatic spindle
- Hydrostatic spindle
- Tactile sensor
- Optical sensor
- Temperature sensor
- Workpiece temperature sensor
- Sensor for aspheres
- Second autocollimator
- Quadruple tool changer
- Head lens changer
- Minimum lubrication
- Chip extraction
- 2D code reader
Measurement and alignment turning of optical assemblies
Alignment turning is the only method by which all relevant parameters of a mounted lens can be aligned, in particular the gap between two apex points and the contact surface.
In addition, a large number of different cell sizes can be processed. And finally, high precision turning machines achieve excellent production accuracies of up to 0.5 μm. The alignment turning method is described in the figures below (Fig. 3). In alignment turning, first the lens cell is fixed in an adjustable alignment chuck with the lens in place. Then the position of the optical axis of the lens to the spindle axis is measured with the OptiCentric® system. Using this alignment chuck, the lens is then aligned so that its two centers of curvature are located as closely as possible to the axis of rotation of the spindle.
Then the spindle is rotated and the contact surfaces of the cell are machined with a sharp (diamond) turning tool, resulting in a precisely machined surface of the cell, aligned parallel to the spindle axis. In addition to the outer surface of the cell, it is also possible to machine the front and rear contact surface during the turning process. To do this the turning tool is moved perpendicular to the spindle axis instead of along the optical axis.
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The lens is already fixed in the cell during the alignment turning process. This means that low-stress adhesives with very long curing times can be used for highly precise optics. Similarly, the lenses can be crimped or held by screw rings when the available adhesives are not suitable for the intended application. Since the lens has been aligned at the beginning of the process, the optical axis of the lens and the mechanical axis of the cell are precisely aligned when the cell is machined on a turning machine corresponding to the optical axis of the lens. In order to achieve high accuracy TRIOPTICS has integrated additional measurement technology into its alignment turning stations, alongside the high-resolution autocollimators. These include tactile and optical test systems that ensure a highly accurate measurement of the relevant mechanical parameters. This means the highest precision is achieved by a gradual machining process, in which the cell accuracy is checked after each machining step. The cells used in alignment turning do not need to meet exceptionally tight tolerances before machining. The cell offset only needs to be large enough to meet the required tolerance after machining.
The distance from the lens vertex to the upper contact surface can be manufactured with an accuracy of up to ±0.5 μm. Similarly, the diameter can be manufactured with an absolute accuracy of ±2 μm. The remaining centration error can be reduced to less than 0.5 μm by using a suitable alignment chuck. Moreover, a low coherent interferometer can be used to measure the center thickness on the machine, so that the contact surfaces can be manufactured with high precision with respect to each lens vertex. Multiple mounted lenses manufactured by alignment turning are then assembled to an objective lens. The method of machining in the micron range ensures that all lenses are aligned to each other. This allows mounted lenses to be assembled in a tube without further adjustment steps