Electropolishing of Orthodontic Bracket Produced by Investment Casting Process

2016 ◽  
Vol 842 ◽  
pp. 397-401 ◽  
Author(s):  
Sugeng Supriadi ◽  
Tito W. Sitanggang ◽  
Bambang Irawan ◽  
Bambang Suharno ◽  
Tjokro Prasetyadi ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Investment Casting ◽  
Casting Process ◽  
Orthodontic Brackets ◽  
Metal Injection Molding ◽  
Tooth Decay ◽  
Orthodontic Bracket ◽  
Difficulty Breathing ◽  
Common Technique ◽  
Investment Casting Process

Malocclusion or improper teeth arrangement is the most common problem in the field of orthodontics. If the malocclusion is not corrected, it will promote more serious problems, such as bleeding gums, tooth decay, cavities, difficulty breathing and other problems. Currently, the most common technique used to cure the malocclusion is using treatment of orthodontic brackets. Normally, orthodontic brackets can be produced by machining, metal injection molding and investment casting processes. In the previous research, orthodontic brackets have been successfully produced using investment casting process. The investment casting is selected, since the technology was developed well in Indonesia which is shown by existing number of investment casting industries. However, surface roughness of the bracket produced by investment casting is still high, valued at 0.91 μm. On the other hand, surface roughness of the commercial orthodontic bracket is 0.53 μm. In this current work is focused on surface modification of investment casting brackets by using electropolishing. The best result shows that the surface roughness of cast brackets achieve up to 0.44 μm. It shows that opportunity to fabricate orthodontic brackets domestically is applicable.

Debinding Rate Enhancement of 17-4 Precipitation Hardening Stainless Steel Solvent Debinding on Metal Injection Molding Process as the Material for Orthodontic Bracket

2018 ◽  
Vol 929 ◽  
pp. 200-208 ◽  
Author(s):  
Sugeng Supriadi ◽  
Deni Ferdian ◽  
Gerra Maulana ◽  
Rizki Hidayatullah ◽  
Bambang Suharno
Keyword(s):  
Surface Roughness ◽  
Injection Molding ◽  
Investment Casting ◽  
Removal Rate ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Vacuum Furnace ◽  
Molding Process ◽  
Orthodontic Bracket ◽  
Binder Removal

Brackets fabrication should be done by a suitable process to produce great result. Processes commonly used are investment casting, machining, and metal injection molding. Investment Casting has a drawback in which the surface roughness is quite high for the standard of brackets and require further processing. Machining is done by removing unwanted part to get desire shape, whereas bracket shape requires a high accuracy and is quite complicated. In Metal Injection Molding, feedstock is injected into a mold where complicated shapes can be achieved with a better surface roughness. The weakness is the stages within the process are quite long. One of the problem is the efficiency of debinding stage. We conducted an experiment to enhance binder removal rate through solvent debinding with stirring and under vacuum condition. Sample use for this experiment is a cubic shape of 0.5 x 0.5 x 0.5 cm3. Experiment is done on magnetic stirrer and in vacuum furnace. The temperature is hold at 50°C. Drying process afterward is done in the vacuum furnace for 1 hour with temperature around 50°C. Amount of binder left is confirmed by STA and the particle morphology is seen by SEM. Results showed that stirring treatment enhances binder removal rate due to stirring mechanism that causes possibility of collisions between particles increases. Binder removal rate on the vacuum treatment has a mechanism similar to stirring, but with the addition of the solvent to be done on a regular basis due to decrease of solvent boiling point under vacuum. There were no cracks found on the surface with an increased rate of debinding. Stirring is use for experiment with sample of actual bracketorthodontic form. Debinding rate of the bracket sample is faster than the cubic sample. This result is affected by the dissimilarity on the volume to surface area.

Investigating the Effect of Shape Factor, Slurry Layers and Pouring Temperature in Precision Investment Casting

2013 ◽  
Vol 751 ◽  
pp. 35-44 ◽  
Author(s):  
Rupinder Singh ◽  
Jagdeep Singh
Keyword(s):  
Surface Roughness ◽  
Investment Casting ◽  
Shape Factor ◽  
Surface Hardness ◽  
Dimensional Accuracy ◽  
Casting Process ◽  
Pouring Temperature ◽  
Controllable Factors ◽  
Investment Casting Process ◽  
Single Response

This paper aimed to investigate the effect of shape factor, slurry layers and pouring temperature in precision investment casting. Three controllable factors of the precision investment casting process (namely: shape factor, slurry layers (mold thickness) and pouring temperature) were studied at three levels each by Taguchis parametric approach and single-response optimization was conducted to identify the main factors controlling surface hardness, dimensional accuracy (Δd) and surface roughness (Ra). Castings were produced using aluminum (Al), mild steel (M.S.) and stainless steel (S.S) at recommended parameters through ceramic shell precision investment casting process. The micro structure analysis has been used to study the surface morphology. Analysis shows that for surface hardness, contribution of shape factor, slurry layers and pouring temperature is 0.07%, 0.70% and 99% respectively. As regards to surface roughness, contribution of shape factor, slurry layers and pouring temperature is 1.14%, 16.80% and 81.90% respectively. Further for Δd contribution of shape factor, slurry layers and pouring temperature is 1.53%, 22.47% and 72.88% respectively. Confirmation experiments were conducted at an optimal condition showed that the surface hardness, Δd and Ra of the precision investment casting were improved significantly.

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