Citation: Wang, X.; Zhao, J.; Yang, Y.;
Xu, Y. Cross-Regional Dynamic
Transfer Characteristics of Liquid Oil
Contamination Induced by Random
Contact in Machining Workshops in
Shanghai, China. Appl. Sci. 2022, 12,
4765. https://doi.org/10.3390/
app12094765
Academic Editors: João Carlos de
Oliveira Matias and Paolo Renna
Received: 7 April 2022
Accepted: 7 May 2022
Published: 9 May 2022
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Article
Cross-Regional Dynamic Transfer Characteristics of Liquid Oil
Contamination Induced by Random Contact in Machining
Workshops in Shanghai, China
Xin Wang
1
, Jinchi Zhao
1
, Yinchen Yang
1
and Yukun Xu
2,
*
1
School of Environment and Architecture, University of Shanghai for Science and Technology,
Shanghai 200093, China; wangxinshiyun@126.com (X.W.); zhaojinchi2022@163.com (J.Z.);
193791875@st.usst.edu.cn (Y.Y.)
2
School of Mechanical Engineering, Tongji University, Shanghai 200092, China
* Correspondence: yxu_tj@tongji.edu.cn
Abstract:
In industrial sites, the movement and contact behaviors of workers are random, but their
frequency and statistical characteristics can be determined. Particularly in machining workshops,
metalworking fluids (MWFs) cause liquid oil contamination on the processed workpieces, and the
contamination spreads to the entire workshop given the random contact of workers or the handling
of workpieces. This study proposes a contact transmission model based on the Markov chain to
quantify oil contamination transfer. First, the transfer efficiency between the glove and the workpiece,
which is regarded as a key model parameter in this research, was determined through experiments.
The model was used to characterize and predict the spread of oil contamination across different
regions, including production and assembly areas. Specifically, the oil contamination concentrations
on workbench surfaces in seven locations of a machining workshop in Shanghai GKN HUAYU
Driveline Systems Co., Ltd. (SDS) were measured on-site. Findings showed that the model could
feasibly depict the transfer process of oil contamination across different surfaces. Then, the variation
law of oil contamination concentration on the workbench surfaces over time was analyzed, the oil
contamination distribution map of the entire workshop plane was drawn, and the effectiveness of two
cleaning measures to reduce oil contamination concentrations was compared. The proposed contact
transmission model offers a basis for identifying highly polluted surfaces in machining workshops
and controlling the spread of liquid oil contamination.
Keywords:
liquid oil contamination; dynamic transfer characteristics; random contact; machining
workshop; on-site measurement
1. Introduction
The development of the machining industry has led to the massive use of metalwork-
ing fluids (MWFs). When machine parts collide strongly, MWFs atomize or evaporate,
generating numerous solid particles and oil mist droplets. Then, these pollutants spread to
the entire workshop environment along with the airflow in the machining workshop [
1
–
3
].
Particles with a diameter of fewer than 10
µ
m can stay in the air for a long time and thus are
regarded as suspended particles; these pollutants easily enter the respiratory system and
seriously endanger human health [
4
,
5
]. Studies have shown that suspended oil droplets can
pass through the respiratory tract to reach and be deposited in the lungs [
6
,
7
]. Long-term
exposure to suspended particles can cause respiratory diseases, such as sinusitis, asthma,
and hoarseness of the throat [
8
,
9
], and it may even lead to kidney cancer [
10
]. Meanwhile,
anatomized MWFs are thrown off the inner wall of machines along with the rotation of
turning tools to form surface-adhering oil contamination. Large-size droplets in the air also
settle on surfaces in the workshop to form sedimentary contamination [
7
]. This kind of
surface oil contamination presents challenges to the normal operation of machines [
11
,
12
].
Appl. Sci. 2022, 12, 4765. https://doi.org/10.3390/app12094765 https://www.mdpi.com/journal/applsci
