Next generation rear axle assembly - A case study of Scania CV AB

Abstract

Title: Next generation rear axle assembly - A case study at Scania
Authors: Richard Andrae & William Bergmark
Background: Following the development of industry 4.0, new production technologies
enabling more efficient assembly processes constantly evolve. Scania is a
leading manufacturer of trucks in Sweden, offering a wide product portfolio
and the possibility for their customers to customize their orders. A large
portion of the production of rear axles for Scania is today made at four
different assembly lines (also called “Zones”) at Södertälje. The assembly line
at Zone 1 is approaching the end of its economic lifespan. Simultaneously, its
current design complicates the introduction of new products, which may
complicate the transition to producing trucks with electrical power trains.
Purpose: The study aims to evaluate how Scania can design a new assembly line for rear
axles at Zone 1 which improves its production flexibility, the production
efficiency and ergonomics. The study consists of three research questions:
Research Question 1
(RQ1):
How can Scania meet the present and future challenges at Zone 1 of the rear
axle assembly line?
Research Question 2
(RQ2):
How can a new assembly line be designed to increase the production
flexibility, production efficiency and ergonomics of the rear axle production at
Scania - and at what cost?
Research Question 3
(RQ3):
How can the method for evaluating this challenge be applied to other assembly
line projects?
Methodology: The study is based upon a case-study built upon mainly qualitative data from
interviews and observations and quantitative production data. In the beginning
of the study an exploratory research design was applied, which was later
succeeded by a problem-solving research design. The overall method can be
divided into three steps; The theoretical background/literature study, Empirical
Research at Scania and Concept generation and evaluation.
Conclusions: The results of this study concludes that the current assembly line has multiple
imperfect solutions. Through automating tasks that are currently performed
manually Scania can improve the ergonomic grading of the assembly line,
reduce the labour costs and free up both space and time to introduce new
products. Furthermore, a method that is applicable for designing new or
renovating old assembly lines is developed and presented.
Keywords: Assembly line, Rear Axle, Automation, Industry 4.0, Ergonomics, Takt time

Popular Abstract

Next generation rear axle assembly
Richard Andrae & William Bergmark - Faculty of Engineering, Lund University, July 2021
The shift in demand towards electric vehicles combined with the rapid development of industrial and
manufacturing technology has created both the need and the necessary means to take the automotive
sector through a fourth industrial revolution.
1. Introduction
The rapid development of technology and its
industrial appliances, often referred to as
Industry 4.0, is changing the way
manufacturing companies operate. With
Industry 4.0, it is possible to automate
complex tasks and manufacture products at
higher speed with a lower cost.
At the same time, the electrification of vehicles
is driving a shift in the automotive industry.
Truck manufacturer Scania CV AB is in a
position where its rear axis assembly line in
Södertälje will require substantial investments
to keep the production speed at the needed
levels to meet demand. To add to this,
electrification is likely to cause changes on the
product design of Scania’s rear axles in the
near future.
This has led to the need to perform a pilot
study on how Industry 4.0 and automation can
be leveraged to create a new assembly line
which is both more efficient and allows for
more flexibility in the design of future rear
axles.
2. Method & Empirical knowledge
In order to solve the issue of optimizing the
productivity, flexibility and ergonomics at the
Scania assembly line, both internal and
external sources of knowledge were used.
Initially, a literature study was conducted where
multiple topics relevant to Industry 4.0 and
automation were investigated.
Afterwards, resources at Scania served a
critical function in obtaining information.
Firstly, multiple site visit was conducted at the
Assembly Line in order to gain an
understanding of the working processes.
Secondly, internal training programs and
documents were utilized in order to deepen
the knowledge within relevant topic areas.
Thirdly, interviews were conducted with
experts at Scania to get a good understanding
of the practical uses as well as pitfalls of
certain technologies.
In order to find weak links and improvement
areas at the current assembly line every
station was graded from the perspective of
ergonomics, production efficiency, flexibility
and possibility for automation. Furthermore, all
tasks currently being performed at the
assembly line were put in a sequencing chart
to get an overview of which tasks could be
completed in a specific relative chronological
order.
Multiple ideas were generated through the
identification of improvement areas, and the
feasibility of all the generated solutions were
evaluated by Scania experts. The ideas that
were considered to be feasible were sent to
suppliers for an estimation of the price. Finally,
the ideas that were considered to be feasible
by both experts and suppliers were combined
and a new assembly line was created.
3. New assembly line – key results
Through combining current methods and
practices with new automated workstations a
new assembly line is proposed.
By rearranging the sequence of assembly
tasks, automating 4 out of 10 (previously
manual) workstations, the following
improvements have been identified:
Efficiency improvements
# of needed employees during full takt
(100%) time reduced by 50%, from 8 to 4
employees.
# of needed employees during double
takt (200%) time reduced by 50%, from 8
to 4 employees.
Required takt time reduced by roughly
2%.
Ergonomic improvements
Reduction by 57% of “Medium/high risk
for strain injuries” markings,
from 58 to 25, in Scania’s internal
ergonomic rating system.
Reduction by 46% of “Potential risk for
strain injuries” markings,
from 52 to 28, in Scania’s internal
ergonomic rating system.
Flexibility improvements
Several changes to layout and material
flow to facilitate assembly line logistics,
resulting in reduced cost and increased
storage space.
Number of needed workstations reduced
from 10 to 8.
The proposed assembly line is estimated to
have a payback time between 2 – 8 years
depending on final prices and future
production takt.
4. Designing an assembly line
The Master's Thesis proved there are many
imperfect solutions currently at the Scania
Zone 1 assembly line, and that Scania can
improve its flexibility, productivity and
ergonomics by implementing more
automation.
Furthermore, through utilizing the same
method and framework companies similar to
Scania may improve their processes for
designing new assembly lines.
5. Contribution
A framework was developed as a tool and
basis for companies planning to renovate or
design a new assembly line.
The framework is divided into three
chronological parts; The Prephase, the Main
study and the Proposal & Evaluation. An
overview of the framework is presented in the
following column:
I. Prephase
• System definition
• Background & problem definition
• Objective & identification of key
variables
• Context & delimitations
II. Main study
• Knowledge acquisition
• Identification & sequencing of activities
• Identification of challenges
• Generation of conceptual solutions
• Estimation of feasibility
• Requirement's engineering
• Request for quotas
• Creation of balance sheet & layout
III. Proposal & Evaluation
• Workshop with focus group
• Presentation of final proposal
• Project evaluation
6. A final note on automation
Initial results of the assembly line design
indicate that significant improvements can be
made in terms of efficiency, ergonomics and
flexibility compared to the current line.
These improvements can be materialized by
mainly automating work stations at the
assembly line. While the case for automation is
strong, there are many pitfalls and risks
related to automating tasks.
Stop time, which is made up by the number of
stops and the time required to resolve a stop
during production takt is one key risk to
consider. Scania employees are today highly
efficient and reliable, setting the bar high.
Often, an operational reliability of well over
99,5% is needed to secure profitable
automation.
The carrier/conveyor system, which in this
case transports the rear axle throughout the
line, is a hugely important factor for overall line
performance. The flexibility of an AGV system
needs to be weighed against the rigidness and
precision of a fixed rail based system.
Finally, partly automating an assembly line
while keeping manual workstations will
change the operators work environment, for
better or worse. Understanding and mitigating
the effects that automation will have on the
operators is crucial at every assembly line.

• author: Andrae, Richard and Bergmark, William
• supervisor: Bertil Nilsson
• organization: Production Management
• course: MIOM05 20211
• year: 2021
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Assembly line, Rear Axle, Automation, Industry 4.0, Ergonomics, Takt time
• report number: 21/5676
• language: English
• id: 9065671
• date added to LUP: 2021-09-21 13:38:58
• date last changed: 2021-09-21 13:38:58