LEBAR A., BLATNIK O., JUNKAR M., ORBANIC H. (2012): Vibration assisted cutting of Gouda cheese. Czech J. Food Sci., 30: 1-8.The influence of vibrations on the process of cheese cutting applied in order to reduce friction and the cutting force was studied. The forces needed to cut through the cheese samples were measured against the variations of the temperature, cutting speed, and vibration frequency. The hypothesis which induced the research work was that assisting vibrations reduce the cutting forces and make the cutting easier for the user. In the experiments, Gouda cheese was used at 10 degrees C and 22 degrees C. The further, a conventional kitchen knife was used with four different cutting speeds from 12.5 mm/s to 75 mm/s and six vibration frequencies from 0 Hz to 150 Hz. The results confirmed the hypothesis presuming that up to 3.4 times lower forces are needed to cut through a cheese sample at 22 degrees C, and 1.55 times lower when cutting cheese samples at 10 degrees C. The results also confirmed the already known facts that the cutting forces increase with increasing cutting velocity, 2-4 times on average with cutting at 75 mm/s instead of 12.5 mm/s. Also, 2.5, times lower cutting forces were measured in cutting the cheese sample at 22 degrees C instead at 10 degrees C.

Microproduction is one of the fastest-growing fields in industry, with new demands from the market increasing every day. This work presents an alternative microtooling strategy, which was applied to a microfluidic device case study. This original strategy for a replication process, like hot embossing or injection molding, is based on the combination of the micro-electro-discharge machining (MEDM) process and an electrode machined with water-jet technology (WJ). The final tool was tested with a hot-embossing process by making some test parts in polymers. The process is considered in its global perspective, starting with the fabrication of the tool electrode that will be used to produce the mold involved in the final cast of the microproduct. The addressed issue consists of identifying the capability of each process and then choosing the machining process parameters that will allow the best process combination to obtain the final microproduct. During this investigation several ideas emerge. They should help to identify the most advantageous characteristics of the involved processes in order to develop a reliable and cost-effective tooling strategy, which are discussed in this contribution. Additionally, an insight is given into similar research activities at the University of Ljubljana.

To achieve high removal rate and low electrode wear when roughing by the sinking electrical discharge machining process (EDM), appropriate average surface power density is required in the gap between the workpiece and the electrode. Since machining surface varies with the depth of machining, the rough machining parameters have to be selected on-line to obtain appropriate average surface power density in the gap. In this paper, a system for on-line selection of the machining parameters according to the given machining surface is presented. The selection of the machining parameters is based on the acquisition of only one process attribute, i.e. the percentage of short-circuit discharges, which is significant improvement comparing to known systems.

Microproduction is one of the fastest-growing fields in industry, with new demands from the market increasing every day. This work presents an alternative microtooling strategy, which was applied to a microfluidic device case study. This original strategy for a replication process, like hot embossing or injection molding, is based on the combination of the micro-electro-discharge machining (MEDM) process and an electrode machined with water-jet technology (WJ). The final tool was tested with a hot-embossing process by making some test parts in polymers. The process is considered in its global perspective, starting with the fabrication of the tool electrode that will be used to produce the mold involved in the final cast of the microproduct. The addressed issue consists of identifying the capability of each process and then choosing the machining process parameters that will allow the best process combination to obtain the final microproduct. During this investigation several ideas emerge. They should help to identify the most advantageous characteristics of the involved processes in order to develop a reliable and cost-effective tooling strategy, which are discussed in this contribution. Additionally, an insight is given into similar research activities at the University of Ljubljana. (c) 2007 Journal of Mechanical Engineering. All rights reserved.