Abstract
We present the development of an active fabrication technology for controlling material removal on large precision surfaces of moderate departure from a sphere. The underlying philosophy was established as an efficient solution to the challenging problem of fabricating secondary mirrors of up to nominally 2.5 m in diameter for modern 8 m class telescopes and beyond. The facility described comprises a CNC profiler, two contact profilometers, and a full size active polisher. The trial work-piece was a convex surface of 830 mm in diameter on a zero-expansion ceramic ('Cervit') blank - a 1/3 scale hyperbolic mirror for a proposed 2.5 m diameter f/7 secondary mirror for the 8 m Gemini telescope. Using software error-correction from profilometric metrology data, a factor of 2 improvement in generating the convex aspheric profile was achieved. An active loose-abrasive polishing process is also described, in which a full-size tool is configured to deliver variable, edgeless, sub-diameter removal-footprints. Real-time monitoring of process variables is described, and approximately 10% convergence in each polishing pass is reported.
| Original language | English |
|---|---|
| Pages (from-to) | 295-312 |
| Number of pages | 18 |
| Journal | Mechatronics |
| Volume | 13 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 2003 May 1 |
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All Science Journal Classification (ASJC) codes
- Mechanical Engineering
- Computer Science Applications
- Electrical and Electronic Engineering
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Active profiling and polishing for efficient control of material removal from large precision surfaces with moderate asphericity. / Kim, Sug-Whan; Walker, David; Brooks, David.
In: Mechatronics, Vol. 13, No. 4, 01.05.2003, p. 295-312.Research output: Contribution to journal › Article
TY - JOUR
T1 - Active profiling and polishing for efficient control of material removal from large precision surfaces with moderate asphericity
AU - Kim, Sug-Whan
AU - Walker, David
AU - Brooks, David
PY - 2003/5/1
Y1 - 2003/5/1
N2 - We present the development of an active fabrication technology for controlling material removal on large precision surfaces of moderate departure from a sphere. The underlying philosophy was established as an efficient solution to the challenging problem of fabricating secondary mirrors of up to nominally 2.5 m in diameter for modern 8 m class telescopes and beyond. The facility described comprises a CNC profiler, two contact profilometers, and a full size active polisher. The trial work-piece was a convex surface of 830 mm in diameter on a zero-expansion ceramic ('Cervit') blank - a 1/3 scale hyperbolic mirror for a proposed 2.5 m diameter f/7 secondary mirror for the 8 m Gemini telescope. Using software error-correction from profilometric metrology data, a factor of 2 improvement in generating the convex aspheric profile was achieved. An active loose-abrasive polishing process is also described, in which a full-size tool is configured to deliver variable, edgeless, sub-diameter removal-footprints. Real-time monitoring of process variables is described, and approximately 10% convergence in each polishing pass is reported.
AB - We present the development of an active fabrication technology for controlling material removal on large precision surfaces of moderate departure from a sphere. The underlying philosophy was established as an efficient solution to the challenging problem of fabricating secondary mirrors of up to nominally 2.5 m in diameter for modern 8 m class telescopes and beyond. The facility described comprises a CNC profiler, two contact profilometers, and a full size active polisher. The trial work-piece was a convex surface of 830 mm in diameter on a zero-expansion ceramic ('Cervit') blank - a 1/3 scale hyperbolic mirror for a proposed 2.5 m diameter f/7 secondary mirror for the 8 m Gemini telescope. Using software error-correction from profilometric metrology data, a factor of 2 improvement in generating the convex aspheric profile was achieved. An active loose-abrasive polishing process is also described, in which a full-size tool is configured to deliver variable, edgeless, sub-diameter removal-footprints. Real-time monitoring of process variables is described, and approximately 10% convergence in each polishing pass is reported.
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U2 - 10.1016/S0957-4158(01)00088-5
DO - 10.1016/S0957-4158(01)00088-5
M3 - Article
VL - 13
SP - 295
EP - 312
JO - Mechatronics
JF - Mechatronics
SN - 0957-4158
IS - 4
ER -