Abstract.One of the main present industry challenges is finding the most efficient manufacturing process for a certain part. When parts are made of strong steels like Hardox, their fabrication method is usually difficult. Abrasive waterjet cutting (AWJ) is one of the cutting processes which can be used in this case. This paper presents an experimental research on the machinability of Hardox steel by AWJ. The experiments were conducted using a factorial design model considering two of the main influence parameters like the traverse speed and the distance between the nozzle and the surface of the material. Based on the measurement of the dimensions and the roughness of the parts, the influence of the parameters was revealed and analyzed. The manufacturing time was also compared, as it directly influences the production cost. Further research is considered to develop a mathematical model which can be used for a proper choice of the process parameters depending on the initial requirements.

Abstract. The manufacturing process of special steels like Hardox is usually difficult. Abrasive waterjet cutting (AWJ) is one of the machining processes which can be used in this case, with good results, as proved in previous research of the authors. This paper presents an experimental study on the influence of the AWJ main process parameters to the dimensional accuracy of holes manufactured in Hardox steels. The experiments were conducted using a L8(2 4 ) fractional factorial design matrix considering four parameters: the traverse speed, the part thickness, the hole dimension and the material type. Based on the measurement of the dimensions of the holes, the influence of those parameters was revealed and analyzed. The manufacturing time was also registered, as this parameter directly influences the production cost. Further research aims developing a mathematical model which will be a useful tool in workshop process planning.

The efficiency of laser cutting processes is generally treated in technical literature in qualitative terms, referring to ways to increase it. The present paper is focussed on metal cutting by laser and proposes some quantitative means to estimate the process efficiency. For certain working conditions – machine-tool, material to be processed, specific costs and other – the effectiveness and the specific power consumption are computed based on the main cutting parameters: laser power and cutting speed. The proposed mathematical relationship can be successfully used when the criterion of process optimization is the environment friendliness. A relevant case study is presented, as well. When significant different samples are to be compared, the criterion used to evaluate laser cutting efficiency becomes very important.

This paper presents an experimental investigation on the abrasive waterjet machining (AWJM) of Hardox steels. A full factorial plan was designed and carried out to determine how the traverse speed, the material thickness, and the material type influence the surface roughness. Two materials were machined during the experiments: Hardox 450 and Hardox 500. The experimental data were analysed using statistical methods, and a mathematical model was obtained. Additional experiments were made to validate the model. The results proved that the analysis is accurate and the mathematical model will be a useful tool in industrial environments for process planning when abrasive waterjet machining is used for the considered material.

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The paper presents a frame for applying the core tools for managing the production of automotive parts, supplied to the Original Equipment Manufacturers (OEM). Those core tools and another quality management tools and procedures are required to be applied by the automotive customers, according with the OEM’s requirements. The requirements in discussion are condensed within the PPAP (Production Part Approval Process) documentation. The study presents a way for starting the design and implementation of such a procedure for a tier 1 automotive supplier, according with the appropriate various Customer Specific Requirements (CSR). The study is useful especially for those ones that supply simultaneous for several global automotive OEM (BMW, Chrysler, Fiat Group Automobili, Ford Motor, General Motors, PSA Peugeot Citroen, Renault).

Laurentiu -Aurel

The paper presents an optimization by using the robust engineering approach, for the optimization of the deep drilling process by assessing the surface roughness by the Ra parameter. The trials were developed according with the Robust Engineering principles, by applying the Taguchi Method. The parameter for decision is the average profile height (Ra) of the roughness. Finally, there are presented solutions for the setting-up the deep drilling parameters levels in such a way to assure the best quality at the level of the generated surface. The method results to be reliable for being applied for achieving the optimal setup machining parameters used for the deep drilling process.