scholarly journals Laser Drilling Effusion Cooling Holes in Low NOx Turbine Engine Components

1996 ◽  
Author(s):  
Terry L. VanderWert ◽  
Scott A. Litzer ◽  
Loh Wai Meng
Keyword(s):  
Fuel Efficiency ◽  
Laser System ◽  
Major Change ◽  
Laser Drilling ◽  
Drilling Process ◽  
Combustion Chambers ◽  
Turbine Engine ◽  
Minimum Number ◽  
Key Aspects ◽  
Cooling Air

The move to turbine engine designs featuring low NOx emissions and greater fuel efficiency has resulted in a major change in design and manufacture of certain engine parts such as combustion chambers. For example, effusion cooling combustor designs use thousands of 0.5 mm diameter, shallow angle (less than 30 degrees from the surface) holes to provide a film of cooling air over the surface of the combustor. A variety of thermal barrier coatings are also used to protect the surface during operation. Laser drilling is playing a key role in the production of effusion cooling holes. Laser drilling, which uses the focused output of a high power industrial pulsed Nd:YAG laser to trepan the holes, has become the process of choice for producing these because of: - low heat input - rapid drilling rates - ability to drill ceramic coated metals - a minimum number of process variables contributes to reliable, repeatable processes This paper reviews the laser drilling process for producing effusion cooling holes, characteristics of the holes, and developments aimed at increasing the throughput and, therefore, reducing the cost for laser drilling. The paper also summarizes the key aspects of the laser system required to produce combustors that meet airflow and other quality (metallurgical) specifications.

scholarly journals Advances in Laser Drilling of Turbine Engine Components

1995 ◽  
Author(s):  
Terry L. VanderWert
Keyword(s):  
Process Control ◽  
Laser Processing ◽  
High Speed ◽  
Laser Drilling ◽  
Drilling Process ◽  
Automatic Production ◽  
Turbine Engine ◽  
Laser Systems ◽  
Engine Components ◽  
Improved Methods

The application of laser systems for drilling turbine engine components has continued to grow. New designs for components are being made as understanding of the process has increased and as capability of laser systems has grown. Advances in process control have led to higher throughput and quality in automatic production. Greater understanding of the laser drilling process has led to improved methods for controlling the spatter and remelt that are characteristic of laser processing. Availability of high speed. PC based controls has facilitated high speed sensing of the component location for precise and repeatable positioning of laser drilled features. This paper describes recent advances in laser drilling turbine engine components. Current capabilities of laser drilling are summarized.

CO2 Laser Drilling of Microvias Using Diffractive Optics Techniques: I — Mathematical Modeling

2005 ◽  
Author(s):  
Chong Zhang ◽  
Sachin Bet ◽  
Islam A. Salama ◽  
Nathaniel R. Quick ◽  
Aravinda Kar
Keyword(s):  
Mathematical Modeling ◽  
Laser Beam ◽  
Co2 Laser ◽  
Thermal Energy ◽  
Laser System ◽  
Damage Threshold ◽  
Laser Drilling ◽  
Diffractive Optics ◽  
Prototype System ◽  
Drilling Process

This paper is the first of three parts summarizing the research to use diffractive optics at the CO2 laser wavelength to drill microvias in the 40–50 μm range for organic packaging applications. This first part mainly focuses on mathematical modeling of the drilling process, which is used to define the characteristics of the laser beam necessary to achieve the required geometry of the microvias. These laser characteristics and the properties of the incoming laser beam of the CO2 laser system are then used to provide a deterministic approach for obtaining performance data for the diffractive optics design. The targeted optics are designed based on the modeling result and are then integrated into a prototype system to execute the drilling operation. The model is based on the conversion of optical energy into thermal energy due to laser-substrate interaction, propagation of thermal energy in the substrate, thermal as well as radiation damage threshold of the substrate and other important laser drilling parameters (e.g., fluence, temporal and spatial characteristics of the beam, residue at the via bottom).

scholarly journals Analysis and optimization of laser drilling process during machining of AISI 303 material using grey relational analysis approach

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
V. Chengal Reddy ◽  
Thota Keerthi ◽  
T. Nishkala ◽  
G. Maruthi Prasad Yadav
Keyword(s):  
Surface Roughness ◽  
Process Parameters ◽  
Grey Relational Analysis ◽  
Pulse Frequency ◽  
Laser Drilling ◽  
Simultaneous Optimization ◽  
Fibre Laser ◽  
Drilling Process ◽  
Relational Analysis ◽  
Grey Relational

AbstractSurface roughness and heat-affected zone (HAZ) are the important features which influence the performance of the laser-drilled products. Understanding the influence of laser process parameters on these responses and identifying the cutting conditions for simultaneous optimization of these responses are a primary requirement in order to improve the laser drilling performance. Nevertheless, no such contribution has been made in the literature during laser drilling of AISI 303 material. The aim of the present work is to optimize the surface roughness (Ra) and HAZ in fibre laser drilling of AISI 303 material using Taguchi-based grey relational analysis (GRA). From the GRA methodology, the recommended optimum combination of process parameters is flushing pressure at 30 Pa, laser power at 2000 W and pulse frequency at 1500 Hz for simultaneous optimization of Ra and HAZ, respectively. From analysis of variance, the pulse frequency is identified as the most influenced process parameters on laser drilling process performance.

scholarly journals Ceramic Thermal Barrier Coatings for Turbine Engine Components

1982 ◽  
Author(s):  
D. S. Duvall ◽  
D. L. Ruckle
Keyword(s):  
Thermal Barrier Coatings ◽  
Ceramic Coatings ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Turbine Engine ◽  
Thermal Environments ◽  
Strain Tolerance ◽  
Endurance Testing ◽  
Plasma Sprayed ◽  
Cooling Air

The durability of plasma sprayed ceramic thermal barrier coatings subjected to cyclic thermal environments has been improved substantially by improving the strain tolerance of the ceramic structure and also by controlling the substrate temperature during the application of the coating. Improved strain tolerance was achieved by using ceramic structures with increased porosity, microcracking or segmentation. Plasma spraying on a controlled-temperature substrate also has been shown to improve durability by reducing harmful residual stresses. The most promising of the strain tolerant ceramic coatings have survived up to 6000 cycles of engine endurance testing with no coating or vane platform damage. In side-by-side engine tests, thermal barrier coatings have shown that they greatly reduce platform distress compared to conventionally coated vanes in addition to permitting reductions in cooling air and attendant increases in engine efficiency.

scholarly journals Significant Reduction in Energy Consumption and Carbon Emission While Improving Productivity in Laser Drilling of CFRP Sheets with a Novel Stepped Process Parameter Parallel Ring Method

2022 ◽  
Vol 6 (1) ◽  
pp. 7
Author(s):  
Menghui Zhu ◽  
Chao Wei ◽  
Wei Guo ◽  
Zhizhou Zhang ◽  
Jinglei Ouyang ◽  
...  
Keyword(s):  
Ring Laser ◽  
Energy Input ◽  
Processing Parameters ◽  
Laser Drilling ◽  
Parent Material ◽  
Hole Drilling ◽  
Drilling Process ◽  
Cfrp Sheets ◽  
Hole Drilling Method ◽  
Drilling Quality

Although laser drilling of carbon fibre-reinforced polymer (CFRP) composites offers the advantages of zero tool-wear and avoidance of fibre delamination compared with mechanical drilling, it consumes considerably more energy during the drilling process. This research shows that by using a new, stepped parameter parallel ring laser hole drilling method, an energy saving of 78.10% and an 18.37 gCO2 reduction for each hole, while improving productivity by more than 300%, can be achieved in laser drilling of 6 mm diameter holes in CFRP sheets of 2 mm in thickness, compared with previous laser drilling methods under the same drilling quality. The key reason for this is an increase in energy input to the inner rings enabling more rapid removal of the material, while the lower energy input for the outer ring provides a shielding trench to reduce the heat loss into the parent material. The results are compared with single-ring laser drilling and multiple-ring laser drilling with constant processing parameters, and a discussion is given on comparing with mechanical drilling and future prospects, including a combined mechanical drilling and laser pre-scribing process.

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