Development and Optimization of a Manual Fed Cassava Root Chipper for Household Cassava Processors

A motorized, manual fed cassava root chipping machine was developed, evaluated and optimized. The objective of the research is to investigate the effect of moisture content and speed on the chipping sizes, efficiency, throughput and machine capacities. Obtained results showed that the cassava initial moisture content significantly affected the chipping size, machine capacity, throughput capacity and chipping efficiency within the tested moisture content range of 52 to 68% w.b. The machine speed also affected the chipping size, chipping efficiency, machine and throughput capacity. The average chipping size for the cassava chips at the four ranges of moisture content, speeds and constant feed rate of 89±26.6 kg h-1 ranged from 0.56 to 0.96 cm with optimum thickness 0.618 at 450 rpm and moisture content of 65.27% based on desirability factor. The average chipping efficiency ranged from 60 to 90% with an optimum value of 79.57% at 533 rpm and moisture content of 68 % while the throughput capacities of the machine ranged from 49 to118 kg/h with optimum value of 118 kg/h at a speed of 600 rpm and 68% moisture content.

Study on hole machining for the constant feed rate of Al2O3 engineering ceramics through low-frequency axial vibration

Engineering ceramics are increasingly extensively applied in the aerospace, vehicle, armor protection and other fields due to their excellent performances such as high compression strength, high hardness, low density and high protection performance. However, engineering ceramics are typical difficult-to-machine materials, especially in the hole machining under constant feed rate, which limits the promotion and application. In this study, by combining a specially developed novel thin-wall diamond trepanning bit with a low-frequency axial vibration machining, the hole machining process for the constant feed rate of Al2O3 engineering ceramics was experimentally studied and the influence of the low-frequency axial vibration process on the axial drilling force, hole-wall surface roughness and edge chipping size of holes machined was analyzed. The results showed that the low-frequency axial vibration machining obtained a lower axial drilling force and a smaller edge chipping size compared to the traditional drilling process. Moreover, both the axial drilling force and the edge chipping size declined markedly with the rise in amplitude. However, the hole-wall surface roughness presented a rising trend due to the hammering effect of vibration. The process technology proposed in this article realizes the hole machining for a constant feed rate of Al2O3 engineering ceramics and provides a reference for the engineering lot-size hole machining of engineering ceramics.

A study on the effect of cooling on microstructure and mechanical properties of friction stir-welded AA5086 aluminum butt and lap joints

In this paper, the effect of water cooling on mechanical properties and microstructure of AA5086 aluminum joints during friction stir welding is investigated. For doing so, the mechanical and microstructural behavior of samples welded both in air and in water was analyzed. Tests were performed involving both butt and lap welds and the results were compared. The effect of rotational speed at constant feed rate of 50 mm/min and changing rotational speed ranging from 250 to 1250 r/min was investigated. The results showed a significant change in the tensile behavior of the butt-welded specimens due to water cooling. In addition, welding was performed at constant spindle speed of 800 r/min and various traverse speeds (25 mm/min to 80 mm/min) to determine the effect of feed rate. The strength increases at first, but then decreases dramatically along with the feed rate which is due to the occurrence of a groove defect. Results showed some generally positive impacts of water cooling which are discussed in terms of tensile results, hardness distributions and microstructure analysis.

Effect of Type of Cutting Tips on Cutting Forces in Turning

The aim of this article is to demonstrate the efect of cutting materials and geometry of cutting tips on cutting forces in turning as well as the quality and precision of machined surface. The experiment focuses on measuring cutting forces when turning a sample of steel 11 523 at a constant feed rate and cut depth and at varying speeds of a spindle. Measurements were made using exchangeable cutting tips of diferent types. The results will be evaluated in terms of the impact of diferent characteristics of cutting tips and variable spindle speeds.

AN APPROACH FOR COMPARATIVE PERFORMANCE TESTING OF SURGICAL BURS

In this paper, a numerical procedure for obtaining a cutting performance "signature" for a bur is proposed. This procedure is applied to a comparative analysis of the cutting performance of a surgical bur under various operating conditions. An experimental method, which uses a constant feed rate and measures feed force, is utilized to perform tests leading to the data needed for the aforementioned procedure. Several proof-of-concept tests are performed and their results are presented. The proposed approach shows capability for tracking the cutting performance of a bur as it gets duller.

Nonisochoric Reactor with Constant Feed Rate of One Component

For a chemical reactor with constant volume feed rate equations have been derived which describe the time dependences of concentration of the reaction components, and their approximation has been suggested. The applicability of the approximation has been verified on a model redox system Ce(IV)/V(IV) in sulfuric acid medium.

Discharge Measurements by a New-Formed Relative Salt-Dilution Method in Small Turbulent Streams

Water discharges in small turbulent streams are determined by injecting concentrated salt solutions at constant feed-rate and measuring the dilution level downstream by conductivity readings in situ. This new-formed method is comparable with the traditional relative salt-dilution method, as well as with other methods, with respect to accuracy. In small streams with complicated hydrodynamic structures the new-formed method seems to be most practical and reliable.