The effects of different spray angles (90°, 85°, 80°) on the microstructure and mechanical properties of a Y2O3 coating layer prepared using the atmospheric plasma spray (APS) process were studied. The powders employed in this study had a spherical shape and included a cubic Y2O3 phase. The APS coating layer exhibited the same phase as the powders. Thickness values of the coating layers were 90°: 203.7 ± 8.5 μm, 85°: 196.4 ± 9.6 μm, and 80°: 208.8 ± 10.2 μm, and it was confirmed that the effect of the spray angle on the thickness was insignificant. The porosities were measured as 90°: 3.9 ± 0.85%, 85°: 11.4 ± 2.3%, and 80°: 12.7 ± 0.5%, and the surface roughness values were 90°: 5.9 ± 0.3 μm, 85°: 8.5 ± 1.1 μm, and 80°: 8.5 ± 0.4 μm. As the spray angle decreased, the porosity increased, but the surface roughness did not show a significant difference. Vickers hardness measurements revealed values of 90°: 369.2 ± 22.3, 85°: 315.8 ± 31.4, and 80°: 267.1 ± 45.1 HV. It was found that under the condition of a 90° angle with the lowest porosity exhibited the best hardness value. Based on the aforementioned results, an improved method for the APS Y2O3 coating layer was also discussed.

A T-800 (Co-Mo-Cr) coating material is fabricated using Co-Mo-Cr powder feedstock and laser cladding. The microstructure and melted Al erosion properties of the laser-cladded T-800 coating material are investigated. The Al erosion properties of the HVOF-sprayed MoB-CoCr and bulk T-800 material are also examined and compared with the laser-cladded T-800 coating material. Co and lave phases (Co2MoCr and Co3Mo2Si) are detected in both the lasercladded T-800 coating and the bulk T-800 materials. However, the sizes of the lave phases are measured as 7.9 μm and 60.6 μm for the laser-cladded and bulk T-800 materials, respectively. After the Al erosion tests, the erosion layer thicknesses of the three materials are measured as 91.50 μm (HVOF MoB-CoCr coating), 204.83 μm (laser cladded T- 800), and 226.33 μm (bulk T-800). In the HVOF MoB-CoCr coating material, coarse cracks and delamination of the coating layer are observed. On the other hand, no cracks or local delamination of the coating layer are detected in the laser T-800 material even after the Al erosion test. Based on the above results, the authors discuss the appropriate material and process that could replace conventional bulk T-800 materials used as molten Al pots.

One of the challenges facing precision manufacturers is the increasing feature complexity of tight tolerance parts. All engineering drawings must account for the size, form, orientation, and location of all features to ensure manufacturability, measurability, and design intent. Geometric controls per ASME Y14.5 are typically applied to specify dimensional tolerances on engineering drawings and define size, form, orientation, and location of features. Many engineering drawings lack the necessary geometric dimensioning and tolerancing to allow for timely and accurate inspection and verification. Plus-minus tolerancing is typically ambiguous and requires extra time by engineering, programming, machining, and inspection functions to debate and agree on a single conclusion. Complex geometry can result in long inspection and verification times and put even the most sophisticated measurement equipment and processes to the test. In addition, design, manufacturing and quality engineers are often frustrated by communication errors over these features. However, an approach called profile tolerancing offers optimal definition of design intent by explicitly defining uniform boundaries around the physical geometry. It is an efficient and effective method for measurement and quality control. There are several advantages for product designers who use position and profile tolerancing instead of linear dimensioning. When design intent is conveyed unambiguously, manufacturers don’t have to field multiple question from suppliers as they design and build a process for manufacturing and inspection. Profile tolerancing, when it is applied correctly, provides manufacturing and inspection functions with unambiguously defined tolerancing. Those data are manufacturable and measurable. Customers can see cost and lead time reductions with parts that consistently meet the design intent. Components can function properly-eliminating costly rework, redesign, and missed market opportunities. However a supplier that is poised to embrace profile tolerancing will no doubt run into resistance from those who would prefer the way things have always been done. It is not just internal naysayers, but also suppliers that might fight the change. In addition, the investment for suppliers can be steep in terms of training, equipment, and software.

본 연구는 ‘상주둥시’ 감을 3개월동안 -1, 0.5, 3oC에 저장하면서 감 과실의 과실품질 변화와 저장장해 증상에 미치는 영향을 구명하고자 실시하였다. 저장온도에 따른 감 과실의 에틸렌 발생량은 저장온도가 낮을수록 그 발생량이 낮았으나 호흡율은 영향을 받지 않았다. 과실의 경도는 모든 처리구들에서 저장기간이 길어지면서 감소하였고 저장온도가 높을수록 과실 경도의 저하는 더 빠르게 진행되었다. 또한 저장기간이 길어지고 저장온도가 높을 수록 과실의 연화가 급속히 진행되었다. 과실의 감모율도 저장온도가 높을수록 증가하였고, 가용성 고형물 함량도 저장온도가 낮을수록 더 높게 유지되었다. 감 과실의 과정부와 과실측면의 과피색 L*, a*, b* 값의 변화는 저장온도 -1oC와 0.5oC에서는 저장기간에 따른 차이를 거의 보이지 않았으나, 3oC처리구에서는 과피색의 변화가 현저히 적었다. 저장중 발생하는 생리장해증상인 과피흑변, 과실연화 및 부패정도는 온도가 높을수록 그 증상이 심하게 발생하여 과실품질이 현저히 감소하였다.

‘Jonathan’ apples are relatively small size which contributes to enhancing fruit consumption and gaining popularity. Thus, this study was carried out to evaluate the effects of AVG (aminoethoxyvinylglycine, ReTain®), sprayable 1-MCP (1-methylcyclopropene, HarvistaTM), and fumigation 1-MCP (SmartFreshTM) applications on fruit quality attributes and storability in ‘Jonathan’ apple fruits during cold-stored. The Jonathan fruits were dipped with either ReTain (75 mg/L) or Harvista (125 mg/L) solutions for 5 min, or fumigated with SmartFresh (1 mg/L) for 18 hr before storage at 0±1℃ for 75 days. Flesh firmness and titratable acidity remained higher in all pre-treated apples than control ones during cold storage period. Flesh firmness was higher for apples treated with ReTain and SmartFresh than samples treated with Harvista, while soluble solid content and respiration rate were not affected by sample pretreatment. Internal ethylene concentration (IEC) of all pretreated apples remained below about 4.5 μL/L during the entire storage period while that of control sample greatly increased to 10.29 μL/L. Ethylene production was much higher in control fruits than in treated ones during cold storage. These results indicated that ReTain and 1-MCP treatments would be considerably effective in retention of fruit quality attributes of ‘Jonathan’ apple during cold-stored.