The research was conducted by Sunardi, Arya Bagas Saputra, and Rinasa Agistya Anugrah from the Faculty of Engineering and Vocational Program at Universitas Muhammadiyah Yogyakarta. Their work focuses on improving vapor blasting parameters to help industries clean aluminum engine components more effectively without causing excessive damage to the material.
Aluminum crankcases are widely used in motorcycles and other combustion engines because aluminum is lightweight, corrosion-resistant, and durable. However, crankcases are constantly exposed to oil residue, dirt, combustion byproducts, and fine metallic particles during engine operation. Over time, these contaminants accumulate on the surface and inside cavities, making cleaning and restoration increasingly difficult.
Industries commonly use abrasive blasting techniques to clean metal surfaces, prepare components for coating, and restore damaged parts. Traditional dry blasting methods can generate high levels of dust and may aggressively erode the material surface. Vapor blasting, also known as wet abrasive blasting, has emerged as an alternative because it combines water, compressed air, and abrasive particles to create a more controlled cleaning process with lower dust emissions.
According to the researchers from Universitas Muhammadiyah Yogyakarta, spray angle remains one of the most important yet least standardized variables in vapor blasting operations. Different impact angles can alter how abrasive particles strike the surface, influencing erosion, surface texture, and dimensional changes.
To investigate the issue, the research team prepared 12 aluminum crankcase specimens measuring 30 × 30 × 3 millimeters. Three specimens were left untreated as a control group, while the remaining samples underwent vapor blasting at spray angles of 60 degrees, 70 degrees, and 80 degrees.
All blasting conditions were kept constant throughout the experiment. The researchers used:
- Air pressure of 40 psi
- A 5 mm nozzle
- Glass bead abrasive particles sized 90–150 micrometers
- Spray distance of 5 cm
- Blasting duration of five minutes
The team then measured thickness reduction, surface roughness, and hardness using industrial testing equipment and statistical analysis.
The results showed a clear relationship between spray angle and material removal. The untreated aluminum specimens had an average thickness of 3.00 mm. After vapor blasting, the thickness decreased progressively:
- 2.95 mm at 60°
- 2.93 mm at 70°
- 2.92 mm at 80°
This means the highest spray angle produced the greatest erosion effect on the aluminum surface.
Surface roughness also increased dramatically as the spray angle became steeper. The untreated specimens initially recorded a roughness value of only 0.122 micrometers. After blasting, roughness values increased to:
- 0.639 micrometers at 60°
- 1.075 micrometers at 70°
- 1.200 micrometers at 80°
The researchers explained that higher spray angles create stronger perpendicular impacts from abrasive particles, producing deeper indentations and more pronounced surface textures.
“Spray angle primarily governs material removal and surface texturing during vapor blasting,” the authors from Universitas Muhammadiyah Yogyakarta wrote in the journal article.
The study found a different trend in hardness measurements. Surface hardness changed only slightly after blasting. The untreated material showed an average hardness of 65.7 HV, while treated specimens ranged from 66.41 HV to 66.84 HV. Statistical analysis indicated that spray angle did not significantly affect surface hardness under the tested conditions.
Cross-sectional hardness measurements showed a small but statistically significant increase. However, the researchers noted that the overall effect remained practically limited compared with the much larger changes observed in thickness and surface roughness.
The findings suggest that vapor blasting mainly modifies the outer geometry and texture of aluminum surfaces rather than significantly changing the internal mechanical properties of the material.
The research has important implications for automotive workshops, restoration businesses, and manufacturing industries that regularly handle aluminum components. Selecting the correct spray angle can help technicians balance cleaning effectiveness with dimensional preservation.
Lower spray angles may be preferable when maintaining tight tolerances and preventing excessive material loss is critical. Meanwhile, higher spray angles may be more effective for aggressive cleaning, surface texturing, or preparation before coating and finishing processes.
The researchers believe the study can also support broader industrial efforts to improve sustainable and precision-based surface treatment technologies. Because vapor blasting generates less airborne dust than conventional blasting, it is increasingly considered a cleaner and safer option for industrial maintenance applications.
Sunardi and his colleagues from Universitas Muhammadiyah Yogyakarta also recommended further research into other vapor blasting variables, including pressure, abrasive size, spray distance, and blasting duration. Future studies could additionally examine how vapor blasting influences corrosion resistance, wear resistance, residual stress, and fatigue performance in automotive aluminum components.
Author Profiles
Sunardi is a lecturer and researcher in the Department of Mechanical Engineering, Faculty of Engineering, Universitas Muhammadiyah Yogyakarta. His research focuses on manufacturing processes, surface treatment, and material engineering.
Arya Bagas Saputra is a researcher from the Department of Mechanical Engineering at Universitas Muhammadiyah Yogyakarta with interests in manufacturing technology and automotive materials.
Rinasa Agistya Anugrah is affiliated with the Automotive Engineering Technology Program at Universitas Muhammadiyah Yogyakarta. His expertise includes automotive systems and engineering materials.
Source
Article title: Influence of Spray Angle in Vapor Blasting on Thickness Reduction, Surface Roughness, and Hardness of Aluminum Crankcase Material
Journal: Formosa Journal of Science and Technology, Vol. 5 No. 5, 2026
Authors: Sunardi, Arya Bagas Saputra, and Rinasa Agistya Anugrah
Official URL: https://journalfjst.my.id/index.php/fjst/article/view/61
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