Product and Manufacturing Systems Alignment: a Case Study in the Timber House Building Industry
10th Nordic Conference on Construction Economics and Organization
eISBN: 978-1-83867-051-1
ISSN: 2516-2853
Publication date: 1 May 2019
Abstract
Purpose
The purpose of the study was to investigate the alignment between current product and manufacturing systems and how it could be achieved.
Design/Methodology/Approach
Case study research method was chosen for the collection and analysis of empirical data. The data was of qualitative nature and was collected using research techniques such as observations through video recordings of processes, documents and open and semi-structured interviews.
Findings
The variation of outer side sub-element of the exterior wall element was found to not be aligned with its corresponding assembly. A hybrid assembly of outer side sub-elements characterised by flexibility and reconfigurability can be developed.
Research Limitations/Implications
The study is limited to the exterior wall element and corresponding manufacturing system.
Practical Implications
The presented approach was formulated with the aim to be used both for the analysis of existing products and manufacturing systems as well as for the design of new manufacturing systems.
Originality/Value
So far, this is the first study in the context of timber house building where the alignment between product and manufacturing systems was investigated by considering product variety and flexibility of manufacturing systems.
Keywords
Citation
Popovic, D. and Rösiö, C. (2019), "Product and Manufacturing Systems Alignment: a Case Study in the Timber House Building Industry", Lill, I. and Witt, E. (Ed.) 10th Nordic Conference on Construction Economics and Organization (Emerald Reach Proceedings Series, Vol. 2), Emerald Publishing Limited, Leeds, pp. 357-364. https://doi.org/10.1108/S2516-285320190000002037
Publisher
:Emerald Publishing Limited
Copyright © 2019, Djordje Popovic, Carin Rösiö.
License
Published in the Emerald Reach Proceedings Series. Published by Emerald Publishing Limited. This article is published under the Creative Commons Attribution (CC BY 4.0) licence. Anyone may reproduce, distribute, translate and create derivative works of this article (for both commercial and non-commercial purposes), subject to full attribution to the original publication and authors. The full terms of this licence may be seen at http://creativecommons.org/licences/by/4.0/legalcode
1. Introduction
To address the volatility of market demand, high competitiveness, and the need for product differentiation, mass customization (MC) has become an established manufacturing paradigm in many industries (Fogliatto et al., 2012). MC is related to the capability of designing products and services tailored to the needs of each customer and using flexible and efficient processes to produce and deliver these products and services. Companies that successfully employ MC achieve economies of scale through the standardization of components that can be combined in many ways, creating end-product variety, therefore achieving economies of scope (Jiao and Zhang, 2005).
Within industrialised house building, customer involvement in the specification process of a house is inevitable, causing high levels of product customization and need for design variety and flexibility (Nahmens and Bindroo, 2011). At the same time, remaining competitive by decreasing costs and achieving a high-quality production of houses poses a challenge. Balancing between product commonality and distinctiveness, where the latter directly corresponds to customer value and the former to predefined and standard parts, is of crucial importance (Marchesi and Matt, 2017).
Modern manufacturing paradigms achieve responsiveness towards market demand by developing manufacturing systems whose constituents embody an adequate type of flexibility for the given product part produced (ElMaraghy et al., 2013). Aligning the flexibility of manufacturing systems with the product variety, sales volumes and future development, where platform and unique parts of a product are considered, can contribute to higher internal efficiency (Kvist, 2010). So far, such analysis in the housebuilding context is missing in the literature. Therefore, the research purpose was to investigate the alignment between current product and manufacturing systems and how it could be achieved. Exterior wall element variation and manufacturing system flexibility are considered in this study.
2. Frame of reference
A distinction could be made between a dedicated, flexible and reconfigurable manufacturing system (ElMaraghy et al., 2013). A dedicated manufacturing system is designed for a single product variant with high volume standardized product parts. Product distinctiveness gives the highest value to the customer but often causes the need for extra engineering of details that lie outside the product solution space. Therefore, it can have variable requirements for the manufacturing system in terms of functionality and capacity. In this case, a flexible manufacturing system having a wide range of built-in general functionality and capacity is needed. For a variety of predefined product parts that can form different part families and that can also change over time, a manufacturing system that can reconfigure between current families and according to future demand in terms of functionality, capacity, as well as with a minimum penalty in terms of cost and time is needed. In this study the match between the product variety and existing manufacturing system flexibility is termed alignment.
To be responsive to change the manufacturing system must be characterized by flexibility and/or reconfigurability. General flexibility can be achieved through both manual and automated assembly which also influences productivity (Lotter and Wiendahl, 2009). The two concepts – (1) flexible manual and (2) flexible automated assembly systems – are therefore proposed with the conclusion that the optimum solutions would be hybrid assembly systems, i.e. combination of the two concepts (ibid.).
The manufacturing system includes several sub-systems that all must interact to fulfil the purpose of the system (Bi et al., 2008). A division can be made into four sub-systems: (1) the technical system, (2) the material handling system, (3) the information system and (4) the human system. Technical system (1) corresponds to hardware directly linked to the production process. The material handling system (2) includes hardware related to loading, positioning, and unloading on to/from the machine as well as transport between stations. The information system (3) is used to coordinate and/or control the above components. The human system (4) relates to workers including direct and indirect labour.
3. Method
Achieving the purpose of the study required a deeper understanding of exterior wall element variation and manufacturing systems flexibility that are and could be used to produce these wall elements. For that reason, case study research method was chosen for the collection and analysis of empirical data. The data were of qualitative nature and were collected using several research techniques. Observations through video recordings of assembly processes gave insight into all assembly moments that take place in the current exterior wall assembly line. It enabled the analysis of its flexibility aspects. The data about the assembly process were further complemented with the data obtained through open interviews with the operators, team leader and the production manager. Semi-structured interviews were used to collect the data about the product part. The interviewed persons were the technical manager and the head of the design department. Finally, two types of documents were collected. The documents related to the assembly line layout and production drawings for exterior walls achieving comprehensive data from three sources.
4. Empirical data
A case was studied within a Swedish company producing standardized and customised single-family timber frame houses and standardized multi-family timber frame housing. These three brands, together with several more Nordic house building companies, are owned by a leading Nordic real estate concern. As of July 2017, with all the brands combined, the concern held second market position in sales. Customised single-family timber frame houses are prefabricated in panelised elements while the other two brands are prefabricated in volume elements. Production capacity of the company is around 500 living units per brand per year.
4.1. Exterior wall element description and its variation
The structure of the exterior wall elements (EWEs) can be further divided into two levels: sub-elements and components (Figure 1). There are four identified sub-elements of which an EWE can be made of: a wall frame, window/door/electrical box (WDE) units and outer and inner sides.
Wall frame sub-elements belong to the platform and variants with different length can be created through scalable modularity. The height and thickness of the walls are standard while length varies in 600 mm modules. Platform variants can be created through adding and positioning of WDE units which also have predefined sizes and positioning possibilities. Outer side sub-element can vary between platform standard to unique units. A platform standard is related to a façade with vertical siding panels (in 8 per cent of all EWEs). Vertical siding panel variants (10 per cent), horizontal wooden panels (75 per cent), masonry (1 per cent) and plaster façade (6 per cent) are platform variants. Unique outer side sub-elements include cut-out sections from lower level roof. The inner side sub-element varies within the platform. Platform variants are made through different length modules and two different materials that are used for inner sheeting, namely, gypsum and plywood boards. Similarly, as with the wall frame sub-element, here a platform standard is assembled to a plane wall without any WDE units. Together with different sizes of gypsum boards that are assembled in this sub-element, reinforcement in form of plywood is characterising a platform variant. The EWE structure, including sub-elements and components is given in Table 1.
EWE variation
| Sub-elements | Components | ||
|---|---|---|---|
| Type | Variation | Type | |
| Framing | Platform standard/Platform variant | Horizontal plates | |
| Vertical studs | |||
| Insulation | |||
| Wind protection sheet | |||
| WDE unit | Platform standard/Platform variant | Window/Door/el.box | |
| Vertical studs | |||
| Horizontal studs | |||
| Insulation | |||
| Vertical siding panels | |||
| Window sill | |||
| Outer side | Platform standard/Platform variant/Unique | Air studs | |
| Nail studs | |||
| Mouse protection net | |||
| Siding panels | |||
| Window sill | |||
| Inner side | Platform standard/Platform variant | Humidity protection plastic | |
| Plywood | |||
| Gypsum boards | |||
4.2. EWE assembly line
The assembly of EWEs is performed on 14 work stations. The process for the assembly, shown in Figure 2, begins with framing (1). Work stations 2-7 constitute the assembly of the outer side of the wall. Thereafter, the assembly process continues on the inner side through work stations 8-13. However, the sub-process that precedes the assembly line is WDE sub-element preassembly (0). The whole process is optimised for the assembly of EWEs with vertical siding panels. The WDE sub elements can be pre-assembled where the framing and the outer side are completely done and as such are fed into the main assembly line (1c). Consequently, the cycle times at every work station can be kept well below the required takt time. However, in case of EWEs with the horizontal siding panels, the WDE units can be preassembled only to the level of framing without any work added on the outer side sub-element. This in turn adds more tasks at the assembly line (2, 3, 4 and 7) leading to cycle times being often higher than takt time. Finally, unique outer side sub-elements with cut-outs for the lower level roof bring the assembly complexity to work stations 2, 3, 4 and 7 regardless of the type of siding panel being assembled.
Framing (1) is in its major part performed on one station, which is a dedicated numerically controlled system but with the assistance of the operator who sets the pace of the assembly by controlling the sequence of machine codes and assists with the component feed and positioning. Since the machine code is automatically created in the CAD/CAM environment and is imported into the assembly line control unit the information sub-system is regarded to be reconfigurable. Following components are fed, positioned and assembled by the system: assembly of horizontal plates (1a), vertical studs feed (1b), WDE unit storage/feed (1c) and cutting/feed rock–wool insulation (1d).
At the following three work stations (2, 3 and 4) the flexibility of assembly, material handling and planning is achieved manually. The components assembled in these stations are wind protection sheet (2a), air and nailing studs (2 and 3), horizontal siding wood panels and mice protection net (4). Air and nailing studs and horizontal siding panels are fetched manually from the pallets (2b and 4a, respectively). Fixed (dedicated) laser projection is used on Stations 2, 3 and 4 to aid manual positioning of the studs. The system used for assembly of the vertical siding panels (5) is a dedicated system controlled by machine code. It performs a nailing operation and handling and positioning of siding panels. The technical system used for assembly of the horizontal siding panels (6) is dedicated as it performs only nailing operation but has partly reconfigurable information sub-system as the operator defines the nailing positions only in one dimension (lengthwise), while the positions in other two dimensions are automatically recognised by the nailing machine (6a). Following work station (7) is a part of butterfly table system and is used also for manual standardized tasks of finalizing the outer side.
Description of flexibility across four manufacturing sub-systems.
| Station | Manufacturing sub-systems | ||||
|---|---|---|---|---|---|
| Technical | Material handling | Information | Human | ||
| 0 | Dedicated | Manual flexible | Manual flexible/Reconfigurable | Flexible | |
| 1 | Dedicated | Dedicated | Reconfigurable | Flexible | |
| 2-4 | / | Manual flexible | Manual flexible/Dedicated | Flexible | |
| 7-8, 11-13 | / | Manual flexible | Manual flexible | Flexible | |
| 5 | Dedicated | Manual flexible/Dedicated | Manual flexible/Reconfigurable | Flexible | |
| 6 | Dedicated | Manual flexible | Manual flexible/Reconfigurable | Flexible | |
| 9 | / | Manual flexible/Dedicated | Reconfigurable | Flexible | |
| 10 | Dedicated | / | Reconfigurable | Flexible | |
After the completion of the exterior side, wall units are rotated 180 degrees using a butterfly table. On the other side of the butterfly table (8), the inner side of wall elements is assembled. Here, the lifting belts are assembled as a standard on every wall element and depending on the wall type, plywood boards are manually assembled. While moving on towards the next system (9), positioning and assembly of humidity protection plastic (9a) is done. The following dedicated material handling sub-system for the standardized gypsum/plywood boards (9b) is controlled by machine code, and it fetches the boards from the pallets (9c) and puts them into defined positions on the wall element. Assembly of gypsum/plywood boards and routing of window openings (10) are performed with two more technical and dedicated sub-systems, namely, a nailing machine (10a) and a CNC router (10b). The following three work stations (11, 12 and 13) are used for the completion of the inner side of wall elements and quality control. The detailed description of manufacturing sub-systems flexibility is given in Table 2.
5. Results and discussion
By combining the findings about product variety and manufacturing system flexibility, it is possible to see where the alignment has and has not been achieved. The alignment is achieved for the assembly of WDE units, framing and inner side sub-elements (Table 3) as the combination of dedicated and manually flexible solutions handle the EWEs variation well under the required takt time. The variety of outer side sub-elements that spans from platform standard to unique causes the bottleneck in the assembly and, therefore, points to the need for higher flexibility levels than dedication, combined with the productivity higher than that of manual work.
The alignment overview
| Station | Manufacturing sub-systems | Product sub-systems | ||||
|---|---|---|---|---|---|---|
| Technical | Material handling | Information | Human | |||
| 0 | Aligned | WDE unit | ||||
| 1 | Aligned | Framing | ||||
| 2-7 | Reconfigurable/Flexible/Manual flexible | Reconfigurable/Flexible/Manual flexible | Reconfigurable/Flexible | Flexible | Outer side | |
| 8-13 | Aligned | Inner side | ||||
Separation of the main assembly of standardized and predefined parts of low variety from the side assembly of high variety and unique parts, is beneficial in terms of achieving internal efficiency when modular products are produced (Mortensen et al., 2010). The same principle can be applied in this case, where outer side sub-element assembly is separated from the main assembly into a side assembly. Upon completion, outer side sub-elements could be assembled to the rest of EWEs. For this solution, reconfigurability, flexibility and hybrid assembly can be considered in the manufacturing system to be able to handle the variation of outer side sub-elements. Moreover, the side assembly process should be almost equally productive as the main assembly as the outer side sub-elements with siding panels are a part of the structure in 93 per cent of all exterior wall elements. However, with the inclusion of reconfigurability and flexibility in technical and material handling sub-systems, information sub-systems become essential as it is necessary to provide the data in terms of assembly instructions for the operators and machine codes for the equipment. Parametric modelling and design automation within CAD system, as well as digital integration with manufacturing become a necessity to enable the efficient and effective generation of information.
An interface between the unique roof cut-outs of the outer side sub-system and the framing sub-system is unique. Furthermore, the interface would have to be assembled on the framing sub-system during the main assembly. Reconfigurable laser projection together with digital information carriers is suggested as a solution for the information sub-system to assist the operators at the main assembly. The technical sub-system at the outer side sub-element assembly should, besides nailing, have the flexibility for the routing of the panels to fit the cut-outs.
The building system which is a design solution for all the parts of the house has evolved over time and the design for manufacturing and assembly (DFMA) principles were only considered occasionally, for example, when the described assembly line was developed. The evolution of the building system was a result of changes initiated from market need and governmental regulations. For these new building system solutions, the capabilities and limitations of the manufacturing system were not considered, rather the designs were pushed to the manufacturing department to solve the assembly.
6. Conclusions
The research purpose was to investigate the alignment between the product and manufacturing systems and how it could be achieved by analysing exterior wall element variation, and manufacturing system flexibility using case study. The results showed that product and manufacturing system alignment has not been achieved for outer side sub-elements. This alignment can be achieved by developing hybrid assembly solutions that combine manual work with reconfigurability and flexibility of manufacturing systems in a separate process owing to the variation of outer side sub-elements.
The presented analysis can be used both for the existing products and manufacturing systems as well as for the design of new manufacturing systems. So far, this is the first study in the context of timber house building where the alignment between products and manufacturing systems was investigated by considering product variety and flexibility of manufacturing systems. The future work might include further analysis of the product by considering future development and variation of all house elements and corresponding manufacturing systems as well as process cycle time variation. Workshops can be arranged for the representatives from the case company and manufacturing system suppliers to conceptualize designs of new solutions that address the needs identified in the study.
References
Bi, Lang, Shen, & Wang, 2008Bi, Z. M., Lang, S. Y. T., Shen, W. & Wang, L. (2008), “Reconfigurable manufacturing systems: the state of the art”, International Journal of Production Research, Vol. 46, pp. 967–992.
Elmaraghy, Schuh, Elmaraghy, Piller, Schönsleben, Tseng, & Bernard, 2013Elmaraghy, H., Schuh, G., Elmaraghy, W., Piller, F., Schönsleben, P., Tseng, M. & Bernard, A. (2013), “Product variety management”, CIRP Annals - Manufacturing Technology, Vol. 62, pp. 629–652.
Fogliatto, Da Silveira, & Borenstein, 2012Fogliatto, F., Da Silveira, G. & Borenstein, D. (2012), “The mass customization decade: An updated review of the literature”, International Journal of Production Economics, Vol. 138, pp. 14–25.
Jiao, & Zhang, 2005Jiao, J. & Zhang, Y. (2005), “Product portfolio planning with customer-engineering interaction”, IIE Transactions, Vol. 37, pp. 801–814.
Kvist, 2010Kvist, M. (2010), Product family assessment, DTU Management, Lyngby, Denmark.
Lotter, & Wiendahl, 2009Lotter, B. & Wiendahl, H.-P. (2009), “Changeable and reconfigurable assembly systems”, In: Elmaraghy, H. (ed.), Changeable and Reconfigurable Manufacturing Systems, Springer, London, United Kingdom, pp. 127–142.
Marchesi, & Matt, 2017Marchesi, M. & Matt, D. T. (2017), “Design for mass customization: Rethinking prefabricated housing using axiomatic design”, Journal of Architectural Engineering, Vol. 23, pp. 1–20.
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Nahmens, & Bindroo, 2011Nahmens, I. & Bindroo, V. (2011), “Is customization fruitful in industrialized homebuilding industry?”, Journal of Construction Engineering and Management, Vol. 137, pp. 1,027–1,035.
This research project is part of the graduate school ProWOOD, which is collaboration between School of Engineering at Jönköping University, Linnaeus University, Nässjö Träcentrum, several companies and two research institutes. The graduate school is financially supported by The Knowledge Foundation (KK-stiftelsen).
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- Advancing Networking-Based Business Management in Construction Markets
- Contracts and Culture in a Partnering Project
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- The Hybridity of Strategic Partnerships and Construction Supply Chain Management
- Dynamic Capabilities and Risk Management: Evaluating the CDRM Model for Clients
- An Opposite Design-Build Procurement Method: Competing on Quality with a Fixed Price
- CONSTRUCTION AND PROJECT MANAGEMENT
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- Room to Manoeuvre: Governing the Project Provisions
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- A Simulation-Based Optimization for Contractors in Precast Concrete Projects
- Governed by Municipal Land Allocations: Implications for Housing Developers
- Situation Picture Through Construction Information Management
- Who Benefit from Crime in Construction? A Structural Analysis
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- Construction Programmes and Programming: A Critical Review
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- Exploitative Learning in Inter-Organizational Projects: Evidence from Dutch Infrastructure Practices
- The Transition from Design-Bid-Build Contracts to Design-Build
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- INNOVATIONS IN THE CONSTRUCTION PROCESS
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- 3D-Printing Technology in Construction: Results from a Survey
- Product and Manufacturing Systems Alignment: a Case Study in the Timber House Building Industry
- Opening the Black Box of Accessibility Regulation
- Orchestrating Multi-Actor Collaborative Innovation Across Organizational Boundaries
- SUSTAINABILITY AND RESOURCE EFFICIENCY
- Social Sustainability in Modelling of Value Creation in Housing Refurbishment
- Reviewing the Role of Sustainability Professionals in Construction
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- Underlying Causes for Risk Taking Behaviour Among Construction Workers
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- BUILT ENVIRONMENTS
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- From Theoretical to Practical Competence on Health and Safety
- A Test Platform of Viable Methods to Improve Production and Learning on Construction Sites