Surface Quality Improvement of Aspheric Pressing Mould Using Parallel Grinding Method

2005 ◽  
Vol 291-292 ◽  
pp. 133-138
Author(s):  
Fei Hu Zhang ◽  
L.J. Li ◽  
Shen Dong
Keyword(s):  
Surface Quality ◽  
Optical Glass ◽  
Cost Effective ◽  
Optical Quality ◽  
Grinding Method ◽  
Mould Surface ◽  
Aspheric Optics ◽  
Grinding System ◽  
Parallel Grinding

It is a cost-effective technology to obtain aspheric optics made from optical glass and other brittle materials using pressing mould. The optical quality of molded optics is determined mostly by the surface quality of the mould, which means poor mould surface with lots of cutter marks will result in adhesion phenomena and error replication between the optics and mould. [1] In this article, a chatter model about parallel grinding system was presented, and the reasons of chatter induced by velocity feed back was analyzed and simulated. By using parallel grinding system integrated ELID technology, and wheel with greater cross-section radius in rough grinding and constant grinding velocity in fine grinding, the amplitude of cutter marks in the surface of mould was minimized and the quality of the mould surface was improved.

Development of Parallel Grinding System of Aspheric Optics

2007 ◽  
Vol 339 ◽  
pp. 365-370
Author(s):  
L.J. Li ◽  
Fei Hu Zhang ◽  
S. Dong
Keyword(s):  
Tool Path ◽  
Aspheric Surface ◽  
Key Factors ◽  
Factors Affecting ◽  
Optical Instruments ◽  
Grinding Method ◽  
Aspheric Optics ◽  
Profile Accuracy ◽  
Grinding System ◽  
Parallel Grinding

The roughness and profiles accuracy of aspheric surface are two key factors affecting the resolution and other characteristics of optical instruments. In this paper a new grinding system-parallel grinding system was built, and an CNC system controlled by PMAC (programmable multi-axis controller) was developed, the parallel grinding system can realize Arc Envelope Grinding Method (AEGM) only through controlling 2-axis and the wear of wheel was diminished, the tool path calculation was simplified. Using this system, the roughness and profile accuracy of aspheric surface are improved.

scholarly journals Investigation of Surface Quality of CoCrMo Alloy Used in the Tibial Component of the Knee Prosthesis According to the Methods of Turning and Turning-Grinding

2019 ◽  
Vol 26 (1) ◽  
pp. 41-48
Author(s):  
Erkan BAHÇE ◽  
M. Sami GÜLER ◽  
Ender EMİR
Keyword(s):  
Surface Quality ◽  
Tibial Component ◽  
Thermal Stresses ◽  
Knee Prosthesis ◽  
Cutting Speed ◽  
Tool Geometry ◽  
Depth Of Cut ◽  
Cocrmo Alloy ◽  
Grinding Method

CoCrMo alloys, which are well-known Co-based biomedical alloys, have many different types of surface integrity problems reported in literature. Residual stresses, white layer formation and work hardening layers are some those, matters which occur as a microstructural alteration during machining. Therefore, such problems should be solved and surface quality of end products should be improved. In this paper, the surface quality of CoCrMo alloy used in tibial component of the knee prosthesis produced by means of turning was investigated. An improvement was suggested and discussed for the improvement in their machinability with the developed turning-grinding method. Finite element analyses were also carried out to calculate temperature and thermal stresses distribution between the tool and the tibial component. The results showed that many parameters such as cutting speed, feed rate, depth of cut, tool geometry, and tool wear affect the surface quality of workpieces of CoCrMo alloy. In the turning-grinding method, the machining time is reduced by about six times compared to machining only method. The EDX analysis performed on the surface after machining showed that metal diffusion occurred from tool to the tibial component.

Scratching Experimental Research on Critical Cut Depth of Glass BK7

2013 ◽  
Vol 589-590 ◽  
pp. 194-197 ◽  
Author(s):  
Peng Jia
Keyword(s):  
Surface Quality ◽  
Optical Glass ◽  
Dimensional Accuracy ◽  
Cutting Fluid ◽  
Dry Cutting ◽  
Diamond Cutting ◽  
Fluid Properties ◽  
Indentation Experiment ◽  
Cut Depth

For the technology of diamond cutting of optical glass, the machinability of glass is poor, which hindering the practical application of this technology. In order to investigate and ameliorate the machinability of glass, and achieve optical parts with the satisfied surface quality and dimensional accuracy, this paper first conducted SF6 indentation experiment by Vickers microhardness instrument, and then the scratching tests with increasing depths of cut were conducted on glass SF6 to evaluate the influence of the cutting fluid properties on the machinability of glass. Based on this, turning tests were carried out, and the surface quality of SF6 was assessed based on the detections of the machined surfaces roughness. Experimental results indicated that compared with the process of dry cutting, the machinability of glass SF6 can be improved by using the cutting fluid

Super Polishing Behaviour Investigation of Stainless Steel Optical Lens Moulding Inserts

2009 ◽  
Vol 404 ◽  
pp. 97-102
Author(s):  
Kui Liu ◽  
S.T. Ng ◽  
K.C. Shaw ◽  
G.C. Lim
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Surface Quality ◽  
Optical Quality ◽  
Polishing Process ◽  
Optical Lens ◽  
Fine Diamond ◽  
Diamond Paste ◽  
Quality Surface

Super polishing experiments were carried out to investigate the effects of polishing parameters on surface quality of stainless steel lens moulding inserts, and to optimize polishing conditions. Experimental results indicated that optical quality surface of stainless steel lens moulding inserts can be achieved through a two-step polishing process: fast polishing with a soft wood head and coarse diamond paste, and fine polishing with a nylon-covered steel ball head and fine diamond paste. A diameter of 20 mm stainless steel lens moulding insert with a surface roughness Ra of 7.6 nm has been successfully achieved using the two-step super polishing process.

Detection of Laser Melting Bionic Stripe Quality on Mould Surface Based on Acoustic Signal

2011 ◽  
Vol 101-102 ◽  
pp. 926-929
Author(s):  
Li Jun Liu ◽  
Tie Nan Di ◽  
Zhi Xin Jia ◽  
Ji Qiang Li ◽  
Yi Qiang Wang ◽  
...  
Keyword(s):  
Surface Quality ◽  
Acoustic Signal ◽  
Target Surface ◽  
Quantitative Detection ◽  
Signal Characteristic ◽  
Mould Surface ◽  
And Control ◽  
The Relationship

In order to rescue the problems of controlling laser bionic strengthening local stripe of mould surface quality, it is put forward thoughts about the laser bionic local melting stripe of mould surface quality detection based on acoustic signal. Analyzed with the relationship between defocusing distance and acoustic signal characteristic, laser bionic strengthening local stripe quality, the results show that acoustic signal is weakened with the increased absolute value of defocusing distance. As the defocusing distance is 0mm, the role of the laser is primarily ablation and the stripe quality is the worst; the function of laser on the surface materials is too weak to strengthen when the defocusing distance is -4mm; laser on target surface plays its role of strengthening, mainly owing to melting, with defocusing distance of +4mm. Overall tests show that, based on the quantitative detection of acoustic signal characteristic, it could inspect and control the quality of strengthening stripe, and it will realize the overall control of laser bionic strengthening mould surface quality with guiding significance.

Nanoprecision Micromechanical Fabrication

2008 ◽  
Vol 2 (1) ◽  
pp. 24-33 ◽  
Author(s):  
Hitoshi Ohmori ◽  
◽  
Weimin Lin ◽  
Yoshihiro Uehara ◽  
Yutaka Watanabe ◽  
...  
Keyword(s):  
Surface Quality ◽  
High Surface ◽  
Surface Grinding ◽  
Mirror Surface ◽  
Optical Components ◽  
High Surface Quality ◽  
Elid Grinding ◽  
Grinding Method ◽  
Electrolytic Dressing

ELID grinding is a method that realizes high quality mirror surface grinding in the nanometer order by use of electrolytic dressing metal bonded wheels consisting of fine abrasives. Currently, ELID grinding is increasingly being applied as an ultraprecision grinding method to achieve desired surface roughness, high surface accuracy, high surface quality, and high grinding performance. This paper introduces the ELID grinding and discusses some applications of ELID grinding to mirror surface grinding. For ultraprecision optical components, ultra fine smooth surface quality of sub-nanometer or sub-angstrom in Ra may be required. To satisfy these requirements, ultraprecision on machine measurement system had been developed. Synergistic the nano precision mechanical method, nano precision measurement method with nano resolution machine, the ultraprecision components can successful to fabricate.

Study on the Surface Quality of Optical Glass in Ultrasonic-Magnetorheological Compound Finishing

2008 ◽  
Vol 389-390 ◽  
pp. 181-186 ◽  
Author(s):  
Fei Hu Zhang ◽  
Hui Jun Wang ◽  
Jian Feng Liu ◽  
Dian Rong Luan ◽  
Yong Zhang
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Optical Glass ◽  
Processing Parameters ◽  
Optical Polishing

The paper presents a newly developed optical polishing method, Ultrasonic-magnetorheological compound finishing (UMC finishing). The mechanism of UMC finishing is introduced in the paper. Experiments are carried out to study the surface quality of the optical glass K9 in UMC finishing. The result shows that the surface roughness Ra of the optical glass is 4.0nm, which is measured by the profile meter. The rules of surface roughness for optical glass by the main processing parameters are also acquired by the experiments. The study will be the basis for the further study of UMC finishing technology.

Research on Machinability of SF6 in Diamond Cutting with Cutting Fluid

2013 ◽  
Vol 770 ◽  
pp. 234-238 ◽  
Author(s):  
Peng Jia
Keyword(s):  
Surface Quality ◽  
Optical Glass ◽  
Dimensional Accuracy ◽  
Cutting Fluid ◽  
Practical Application ◽  
Dry Cutting ◽  
Diamond Cutting ◽  
Fluid Properties ◽  
Indentation Experiment

For the technology of diamond cutting of optical glass, the machinability of glass is poor, which hindering the practical application of this technology. In order to investigate and ameliorate the machinability of glass, and achieve optical parts with the satisfied surface quality and dimensional accuracy, this paper first conducted SF6 indentation experiment by Vickers microhardness instrument, and then the scratching tests with increasing depths of cut were conducted on glass SF6 to evaluate the influence of the cutting fluid properties on the machinability of glass. Based on this, turning tests were carried out, and the surface quality of SF6 was assessed based on the detections of the machined surfaces roughness. Experimental results indicated that compared with the process of dry cutting, the machinability of glass SF6 can be improved by using the cutting fluid.

Imbalances in High Precision Cutting Machinery

2009 ◽  
Author(s):  
Jenny Niebsch ◽  
Ronny Ramlau
Keyword(s):  
Prediction Model ◽  
Surface Quality ◽  
High Precision ◽  
Optical Quality ◽  
The Other ◽  
Cutting Process ◽  
Experimental Platform ◽  
Ill Posed ◽  
Cutting Processes

In high precision cutting processes it is very important to have a highly balanced system in order to produce components in optical quality. Achieving the best possible balancing state is a time consuming process. Therefor the prediction of the influence of the balancing state on the surface quality of the component is desirable. On the other hand such a prediction model should enable us to compute an objective necessary balancing state for a desired surface quality and thus save balancing time. In this article we present a model of an high precision cutting experimental platform that describes vibrations of the platform caused by imbalances and forces from the cutting process. To compute imbalances from vibrational measurements, regularizations techniques for the solution of inverse and ill-posed problems are employed and presented.

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