Research of Method to Achieve a Personnel Quantity Optimization through
Reasonable Number of Production Shift in Manufacturing Enterprises
Ge Wen 1, Xiao Huang2
1
Management School, Chengdu University of Information Technology, Chengdu, China
2
Sichuan College of Education, Chengdu, Chian
(jl.kj@hotmail.com)
Abstract - how to achieve personnel quantity
optimization, especially for the management of production of
front-line staff of the manufacturing enterprise is one of the
nuclear content of human resources management. This
paper put forward that output from the scheme to proceed,
through the right equipment, and planned production
capacity of the relationship between the measured and
reasonable operation of the frequency of production in order
to achieve personnel quantity optimization. The AC’s case is
used to detailed description of the method of measuring
production shift.
Keywords - Manufacturing management, job analysis,
production shift, personnel quantity optimization
I. INTRODUCTION
Labor force quota is an important foundation work of
business management. Preparation of labor fixed number
of persons so that enterprise can be reasonable, efficient
use of labor and improve labor productivity operation [1].
On the labor force for the study, there is one important
factor often overlooked, namely: reasonable number of
production shift (NPS). Regarding the manufacturing
industry, in order to improve the utilization ratio of the
equipment, and shorten the production cycle of the
products, often using a shift system. Therefore, reasonable
NPS becomes the important link to personnel quantity
optimization.
II. METHODOLOGY
A. Determination of reasonable number of production
shift is an important link for personnel quantity
optimization
Fixed number of persons is the enterprise in certain
production technology condition, in order to ensure their
normal production activities, and set all kinds of
personnel with the quality requirements and the number
of boundaries [2]. Fixed number of persons is based on the
period of the plan specified workload and work
efficiency. Personnel planning forecasts from the number
of personnel equipped with production and non
production in manufacturing enterprises. To determine the
size of the enterprise, the main business and organization
are determined, nonproductive personnel quantity
according to a certain proportion of the total number of
staffs; and the level of staff in a certain period of time is
relatively stable[3]. On one hand, due to the influence of
the market, the product yield is changing; on the other
hand, as a result of improvements in technology,
equipment efficiency in continuous improvement,
equipment hourly production capacity will also change
accordingly. Therefore, for manufacturing enterprise,
personnel quantity optimization is the key to the
production line staff for optimization.
Although shift continuous production can improve the
utilization rate of equipment, reduce the production cycle,
reduce unit product cost [4] [5], however, enterprises still
need according to the yield and efficiency of the
equipment to determine the operation time, thereby
determining the NPS. In the manufacturing enterprises
found in the survey, 78% of the enterprises arrangement
didn’t do quantitative analysis when arrange the
production shift. They increase the number of shift
because of heavy task, often work overtime and reduced
due to yield significantly decreased than in the past. And,
in the enterprise that is investigated, only less than 10% of
the enterprises reduced the number of shift, the enterprise
of 90% above is in using determined the number of shift
many years ago, or increase the number of shift. Due to
the lack of quantitative calculation process, the manager
of production department makes it unclear if the current
NPS is to achieve optimal.
B. Steps and method of calculation of NPS
Influence of NPS factors are mainly the number of
product, overall equipment efficiency (OEE) [6], singleshift production capacity (SSPC). They are shown in
Figure I.
Calculation NPS steps are as follows.
1) Estimation of OEE: Due to the need for
equipment maintenance, all of the equipment can’t
produce to meet production number theory. At the same
time, in the production process inevitably produce bad
products, so it can only be used overall equipment
efficiency to describe equipment effective capacity.
OET
OEP
OEE
GPR
EC
AOT
SSPC
Fig. I. Influence of NPS factors
TP
NPS
Method of estimation of overall equipment
efficiency is as shown in (1). Equation (2), (3) and (4)
indicate the calculation of operation efficiency in time
(OET), operation efficiency in performance (OEP) and
good product rate (GPR).
(1)
OEE  OET  OEP  GRP
OT
(2)
OET 
 100%
LT
LT  TWT  PDT
(3)
SPC  TP
(4)
OEP 
 100%
OT
Where OEE represent overall equipment efficiency;
OET is operation efficiency in time; OEP denotes
operation efficiency in performance; GPR is good product
rate; OT is operation time of equipment; LT is load time
of equipment; TWT denotes total work time of equipment;
PDT is planned down time of equipment; SPC is Standard
production cycle; and TP presents total production.
2) Calculation of SSPC: SSPC refers to a shift in the
year average operation time in the actual production can
product quantity [7] [8]. In calculating the SSPC, in addition
to consider the OEE, but also needs to consider the
employee statutory working time [9]. Equation (5) is the
Calculation formula of SSPC.
(5)
SSPC  OEE  EC  AOT
Where SSPC denotes single-shift production capacity;
OEE is overall equipment efficiency; EC is equipment
capacity theory; and AOT is average operation time.
3) Calculation of NPS: NPS depends on SSPC and
TP [10], it can be calculated as equation (6).
TP
(6)
SSPC
Where TP represents total product of a kind of
production and SSPC is single-shift production capacity.
Sometimes TP can be replaced with the annual production
planning number [11].
When the NPS is determined, the need of staff can be
calculate. It will show how this method is use to solve
practical problems through a case analysis.
NPS 
II. APPLICATION CASE
AC Company is a Pieces of Chinese Medicine
enterprise, under the jurisdiction of the AC1 and AC2 two
production workshop that make different types of
production.
AC1 workshop executes four shifts three operation
organization modes. Every shift has 157 persons; four
shifts are total 628 persons. It plans to produce 550000
pieces 2012 year, OEE is 82%, EC is 3058.1 pieces/day.
AC2 workshop executes three shifts two operation
organization modes. Every shift has 129 persons; three
shifts are total 387 persons. It plans to produce 430000
pieces 2012 year, OEE is 82%, EC is 2070.6 pieces/day.
1) Diagnosis of AC Company’s current NPS:
Following through on calculation NPS, diagnosis of if AC
Company’s current NPS existing two workshop is
reasonable. According to the regulations by Ministry of
labor and social security, years working time is 250 days.
Based on the statistics of staff service time, calculate that
employee's average annual leave for 11 days in AC1
workshop and annual leave for 10 days in AC2.
Calculations are as Table I.
Table I. represents calculations for SSPC and work
load rate. The work load rate of AC1 workshop is only
74.77%. Employees of the legal working time utilization
rate is poor, which do not meet the personnel quota
principle. In this case, AC Company should consider from
two ways to solve the problem, one is to increase the
order, so as to make full use of equipment and labor, two
is to reduce the persons, saves the manpower cost.
The work load rate of AC2 workshop is 105%,
which exceed 100%.
2) Re arrangement production shift throng estimation
of NPS: According to the above calculation，the SSPC of
AC1 workshop is 199800 pieces/year. Its NPS can be
calculated as equation (7).
580000 pieces / year
(7)
NPSAC1 
 2.9
199800 pieces / year
Where NSPAC1 is the number of production shift for
AC1 workshop.
According to NSPAC1, AC1 workshop can arrange
three shifts to produce, and reduce one shift. At this time,
Work load rate becomes 96.67%. After reduced one shift,
it can reduce staff 157, personnel quantity is 471.
According to the above calculation ， the SSPC of
AC2 workshop is 139100 pieces/year. Its NPS can be
calculated as equation (8).
430000 pieces / year
(8)
NPSAC 2 
 3.09
139100 pieces / year
Where NSPAC2 is the number of production shift.
TABLE I
ESTIMATIONS OF SSPC FOR AC1 AND AC2 WORKSHOP
Estimation Data
Workshop
OEE
(%)
EC
(piece)
Years Working Time
(day)
SSPC
(piece/year)
Work Load Rate
(%)
AC1
82
3058.10
239
199800
74.77
AC2
82
2070.60
240
139100
105
for AC2 workshop. If AC2 workshop arrangement four
shifts, Work load rate becomes 77.25%. Thus, Work is
inadequate. If still according to three shifts for production,
Work load rate becomes 103%. Every staff each standard
work day increased work time is 14.40 minutes and so
throughout the year each staff work more 57.60 hours. In
this case, it can be given to employees for overtime, but
does not increase the number of shift. Because adding a
shift requires increased by 129 persons, labor costs
increase significantly.
IV. CONCLUSION
A. Dynamic management of enterprise
Quantity
Personnel
The reasonable personnel quantity is the important
work of enterprise human resources management [12], but
also builds harmonious enterprise, implementation
manpower cost optimal; effectively avoid the risk of
employment base. Because of the goal of enterprise
development changed, personnel work ability promoted,
technology improved, the continuous upgrading of
equipment efficiency, the developing enterprise should do
job analysis every 2 to 3 years. Thus enable enterprises to
maintain optimal allocation of human resources,
reasonable, effective use of labor force.
B. Through the estimation of NPS to maintains personnel
optimization
According to the equipment capacity and the
production task to calculate the NPS is the reasonable
arrangement of equipments premise, also is the
foundation of effective utilization equipment. When
annual production planning developed, Human resources
department should forecast NPS, which is the important
work archive personnel quantity optimization and labor
costs controlling.
C. Correctly handle
relationship
the “add” and “decrease”
When the work load rate is slightly greater than 1,
there are two ways without any increase in personnel of
the circumstances. One is that for the personnel quantity
from the influence of equipment can account for the post
between the work adjustments to balance work load rate.
Another is that personnel quantity by the influence of
equipment can consider additional overtime to
compensation, such as AC1 workshop’s way in this case.
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