23-04-2012, 04:41 PM
selective laser sintering
Pravara Rural Education Society.doc (Size: 647.5 KB / Downloads: 115)
INTRODUCTION
Bonding common surface of adjacent particles touching each other in a mass of powder or compact by using heating is called sintering. Sintering is always necessary operation to impart the required strength and density to product. Sintering is related with powder metallurgy in which finely metal particle used to get finished or semi finished objects.
Selective laser Sintering can be consider an advance manufacturing. The selective laser sintering is rapid prototype which can create three dimensional parts by using laser as selective sinter (heat& fuse). Rapid prototype means use of group of techniques used to fabricate scale model of part or assembly by using three dimensional designs. Selective laser sintering is the first rapid prototype which is patented in 1989 by CARL DEKARD UNIVERCITY OF TEXAS STUDENT. After which company give wide range of RP
Selective laser sintering Process
Diagram for SELECTIVE LASER SINTERING process is shown in figure.SLS process start with 3D computer aided design which is converted to 2D manufacturing drawing. It consists of center processing computer with newly developed CAD software in which model of part can be constructed with detailing .this computer also used to control the laser beam intensity, and path. Laser unit provided with optics & galvanometer to get focused intense laser beam. A process chamber is provided in which roller mechanism is used to distribute powder evenly on chamber process platform. Powder filled cylinder is provided with motor by using which powder can be filled in process chamber. Another cylinder is provided which is used to support part which build already.
Input parameter
Before starting of any process its input parameter should be studied. For SLS it can be distinguish in following ways
2.2.1.Direct Input Parameter: - direct input parameter are used directly according to Standard. Some of the input parameter discussed below.
a) for laser: i) laser focus diameter ii) laser wave length iii) beam profile
iv) laser power v) Scanning velocity
b) For machine: i) platform temperature ii) hatch distance iii) type of material
c) Powder characteristics: - i) powder size ii) particle size iii) particle roughness
iv) Particle size distribution
Chemical Induced Bonding :-
In chemically induced binding to binder element is used. As interaction time for material is less the diffusion can not occur. In chemical induced binding the part of same material is used as binder by partial disintegration. For example for laser sintering of SiC material the SiC is disintegrated in Si & C so obtained Si will react with oxygen and forms SiO2.this SiO2 can utilized to binder material for SiC product.
APPLICATIONS of SELECTIVE LASER SINTERING
1. It can be used for making parts in aerospace industry where reduced weight &good strength are necessary.
2. It can be used in automobile industry to produce different concept cars. In automobile also weight and strength have equal importance both can be obtained using SLS
ADVANTAGES AND DISADVANTAGES OF SELECTIVE LASER SINTERING
Advantages
1. Use of newly developed software.
2. The Z’th dimension which is difficult to give on ‘PM’ can be given easily in SLS.
3. By using laser beam we can focus on certain area.
4. Decreased development time for model of part or assembly.
5. More flexibility in design process by the use of computer programming.
6. Material saving can be done up to 7% to 10%.
7. Different material can be mixed to get required strength.
8. Functional part is durable, heat &chemical heat resistant.
9. Surface finishes from 500to 32 micro inches.
Disadvantages
1. High power is required because of use of laser
2. Shrinkage may affect dimensional accuracy.
3. Skilled computer operator required.
4. Set up cost is high
CONCLUSION
From this we can conclude that Selective laser sintering supported by advance software is powerful tool for manufacturing complex part. The energy density given for product will decide the mechanical properties obtain for given part. The energy density should not cross its optimum level beyond optimal level the mechanical properties are strongly reduced. The accuracy of part obtain from selective laser sintering are affected by wrong building strategies result in the form of shrinkage.
Pravara Rural Education Society.doc (Size: 647.5 KB / Downloads: 115)
INTRODUCTION
Bonding common surface of adjacent particles touching each other in a mass of powder or compact by using heating is called sintering. Sintering is always necessary operation to impart the required strength and density to product. Sintering is related with powder metallurgy in which finely metal particle used to get finished or semi finished objects.
Selective laser Sintering can be consider an advance manufacturing. The selective laser sintering is rapid prototype which can create three dimensional parts by using laser as selective sinter (heat& fuse). Rapid prototype means use of group of techniques used to fabricate scale model of part or assembly by using three dimensional designs. Selective laser sintering is the first rapid prototype which is patented in 1989 by CARL DEKARD UNIVERCITY OF TEXAS STUDENT. After which company give wide range of RP
Selective laser sintering Process
Diagram for SELECTIVE LASER SINTERING process is shown in figure.SLS process start with 3D computer aided design which is converted to 2D manufacturing drawing. It consists of center processing computer with newly developed CAD software in which model of part can be constructed with detailing .this computer also used to control the laser beam intensity, and path. Laser unit provided with optics & galvanometer to get focused intense laser beam. A process chamber is provided in which roller mechanism is used to distribute powder evenly on chamber process platform. Powder filled cylinder is provided with motor by using which powder can be filled in process chamber. Another cylinder is provided which is used to support part which build already.
Input parameter
Before starting of any process its input parameter should be studied. For SLS it can be distinguish in following ways
2.2.1.Direct Input Parameter: - direct input parameter are used directly according to Standard. Some of the input parameter discussed below.
a) for laser: i) laser focus diameter ii) laser wave length iii) beam profile
iv) laser power v) Scanning velocity
b) For machine: i) platform temperature ii) hatch distance iii) type of material
c) Powder characteristics: - i) powder size ii) particle size iii) particle roughness
iv) Particle size distribution
Chemical Induced Bonding :-
In chemically induced binding to binder element is used. As interaction time for material is less the diffusion can not occur. In chemical induced binding the part of same material is used as binder by partial disintegration. For example for laser sintering of SiC material the SiC is disintegrated in Si & C so obtained Si will react with oxygen and forms SiO2.this SiO2 can utilized to binder material for SiC product.
APPLICATIONS of SELECTIVE LASER SINTERING
1. It can be used for making parts in aerospace industry where reduced weight &good strength are necessary.
2. It can be used in automobile industry to produce different concept cars. In automobile also weight and strength have equal importance both can be obtained using SLS
ADVANTAGES AND DISADVANTAGES OF SELECTIVE LASER SINTERING
Advantages
1. Use of newly developed software.
2. The Z’th dimension which is difficult to give on ‘PM’ can be given easily in SLS.
3. By using laser beam we can focus on certain area.
4. Decreased development time for model of part or assembly.
5. More flexibility in design process by the use of computer programming.
6. Material saving can be done up to 7% to 10%.
7. Different material can be mixed to get required strength.
8. Functional part is durable, heat &chemical heat resistant.
9. Surface finishes from 500to 32 micro inches.
Disadvantages
1. High power is required because of use of laser
2. Shrinkage may affect dimensional accuracy.
3. Skilled computer operator required.
4. Set up cost is high
CONCLUSION
From this we can conclude that Selective laser sintering supported by advance software is powerful tool for manufacturing complex part. The energy density given for product will decide the mechanical properties obtain for given part. The energy density should not cross its optimum level beyond optimal level the mechanical properties are strongly reduced. The accuracy of part obtain from selective laser sintering are affected by wrong building strategies result in the form of shrinkage.