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1

Machining of TiAl6V4 using lubricants containing renewable microalgae-born performance additives

Koch Thomas, Wenzel Dominik, Gläbe Ralf

Acta Mechanica et Automatica

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2024

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Vol. 18, no. 1

55--59

EN

Titanium and its alloys represent a special class of materials. A density of 4.81 g/cm³, a tensile strength of over 1,200 MPa, a fatigue strength greater than that of steel, a low modulus of elasticity and its self-passivating, inert surface make titanium an ideal material for lightweight structures in aerospace, marine applications, the chemical industry and medical implants. Although titanium is inert in its oxidised state, its nascent surface created in machining reacts with almost everything in its environment, including the tool. Moreover, its poor thermal conductivity results in high thermal stress on the tools. Overall, these properties lead to high wear rates and result in the requirement for finding a particularised solution for processes such as milling that involve the need to overcome such challenges. Such processes therefore require lubricants with well-selected performance additives. However, most of these performance additives are based on mineral oil and thus come from a non-renewable resource. In the presented work, environmental-friendly alternatives to conventional mineral oil-based performance additives were investigated. Due to the working mechanisms of performance additives in machining, this work focusses on sulphur- and phosphorus-containing polysaccharides and proteins from microalgae. It has been successfully shown that lubricants using extracts from microalgae as performance additives can be used for high-speed milling (HSC) of TiAl6V4. The investigated extracts were able to reach the performance level of conventional additives in terms of tool lifetime and wear. The results obtained show that appropriate alternatives to mineral oil-based additives exist from renewable raw-material sources.

2

Non-Tubercle Mycobacteria and Other Contaminants in Metalworking Fluids from Small Turneries

Abu Shaqra Qasem, Al Groom Rania, Al-Gabbiesh Ahmad

Journal of Ecological Engineering

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2022

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Vol. 23, nr 4

315--324

EN

Non-Tuberculous Mycobacteria (NTM) have frequently been isolated from metalworking fluids (MWFs) used in large machining industries. This paper concerns the microbial detection, particularly NTM in MWFs employed in small metalworking shops. A total of 21 samples were collected from different turneries and were tested for several microbiological parameters. A total microbial count above 106 CFU ml-1 was observed in 66.6% (14/21) of samples and none of the samples had the count <102 CFU ml-1. The dominant contaminants were Gram-negative bacteria with 90.5% (19/21) of samples revealing the presence of Pseudomonas aeruginosa. Sulfate Reducing Bacteria (SRB) were detected in 52.4% (11/21) of samples, whereas NTM were recovered from 14.3% (3/21) of samples only. Two species of NTM were identified by biochemical reactions as Mycobacterium chelonae and Mycobacterium abscessus. It was concluded that MWFs used in small turneries are usually contaminated with Gram-negative bacteria and SRB but NTM are not common contaminants of these fluids.

3

Mikrobiologiczne ciecze obróbkowe do frezowania

Jemielniak K.

Mechanik

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2018

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R. 91, nr 5-6

344

PL

Większość komercyjnych cieczy stosowanych w obróbce skrawaniem zawiera oleje mineralne. Poważnym problemem jest rozwój mikroorganizmów w cieczach na bazie wody. Alternatywą może być zastąpienie emulsji (zawiesin kropelek oleju w wodzie) cieczami na bazie mikroorganizmów.

4

Evaluating Workers’ Exposure to Metalworking Fluids and Effective Factors in Their Dispersion in a Car Manufacturing Factory

Andani A. M., Golbabaei F., Shahtaheri S. J., Foroushani A. R.

International Journal of Occupational Safety and Ergonomics

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2014

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Vol. 20, No. 2

273--280

EN

Introduction. Metalworking fluids (MWFs), which are widely used in metalworking operations, can cause different adverse effects, e.g., dermal and respiratory disorders, and cancer. Evaluating workers’ exposure to MWF mists and the effective factors in their dispersion were the purpose of this study. Materials and Method. Seventy-five out of 300 workers working in metalworking workshops were randomly selected. MWF concentrations were measured with the National Institute for Occupational Safety and Health (NIOSH) 5524 method. Air temperature and velocity were also determined as the predicted effective parameters on the level of exposure. Results. The results indicated that exposure to MWF mists in one workshop was higher than in the other ones (p < .05). The findings also showed that temperature was an effective factor in the dispersion of MWF mists (p < .05). Discussion. The exposure of almost all workers was under the threshold limit value of 5 mg/m 3, but it was over the value recommended by NIOSH of 0.5 mg/m 3. Air temperature was an effective factor in workers’ exposure (r = .576).

5

Skażenie mikrobiologiczne cieczy chłodząco-smarujących i sposoby jego ograniczania

Trafny E. A.

Obróbka Metalu

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2012

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nr 4

40-41

PL

Stosowanie cieczy chłodząco-smarujących (chłodziw) podczas obróbki skrawaniem stanowi element procesu wytwarzania części metalowych. Zastosowanie chłodziw pozwala na zmniejszenie tarcia pomiędzy narzędziem skrawającym a elementem obrabianym i na wydajne obniżenie temperatury procesu, a dzięki temu na precyzyjną obróbkę spełniającą wysokie wymagania. Wysoka biostabilność używanego chłodziwa jest bardzo istotna i wpływa na jakość wytwarzanego wyrobu. Producenci unowocześniają stale skład cieczy chłodząco-smarujących, tak aby zapewnić zachowanie ich optymalnych parametrów przez długi okres użytkowania.

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Influence of metalworking fluid on machining of bearing materials

Mičúch M, Čilliková M, Mrázik J, Štekláč D

Mechanik

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2012

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R. 85, nr 8-9CD (SOS)

446--452