===Meeting the customer’s needs in house construction with a maintained factory efficiency through mass customization===

==Abstract== 

\\ Finding the balance between standardization and customization in house construction is a difficult dilemma. As the carpenter’s work is as old as our oldest ancestors, the construction process is quite reluctant to change, but in the next decade, constructors are forced to change to meet the new regulations of energy efficient housing. This moment is therefore an excellent opportunity to break the old paths. Walls can be constructed in many ways with many different materials. To evolve, the mind must be open to new solutions.\\ 


\\ The common basic construction design must be found by the share of information between different projects. To obtain this, a strong centralized organization must be created. Also different choices of materials must be taken into consideration for a basic common platform as well as the study of material flow and a cost analysis of half-finished modules. The parameters of suppliers' products and the common construction platform will affect the efficiency of the production. The right suppliers and design goes hand in hand. Parametric design could be a way of making the supply chain more efficient and build a bridge between production and supplier. This can provide a better structure of the product lines to obtain higher efficiency.  \\ 

\\ New and more efficient basic construction techniques can provide a new product range and the connection between design and production could be managed by creating rules in a parametric model. The possibility to standardize certain house attributes and make some other attributes optional is of high interest. Parameterization can be used in order to open up for different alternatives in an otherwise set product. A study of a Swedish house builder shows that the purchase department in many ways rules the outcome of the building process. \\

==Introduction==

\\ A construction project is characterized by great complexity. This is because the elements are complex and because it is a process of many flows and activities. The driving force for changes in logistic structures is usually to cut costs (Brege & Abrahamsson, 1995). To be able to coordinate the activities and thereby make the building process more efficient the problems in the process must be identified so that the right resources can be put at the right place. 
Coordination can only be obtained with information of how the process looks like; this information is today not clearly identified and documented. Through the mapping of material- and information flows a standardized process can be formed which could cut the costs. The lack of information between different parts of the process is a source of problems. The building process is often fragmented and based on individualistic goals. Christopher (1986) describes the market channel as a number of intermediaries acting independently of each other often with conflicting objectives and requirements.Through team-work with centralized goals and standardized techniques the people will be less chattered and collaborate better. Clear rules of meetings and frequent short information meetings can avoid double-work and improve efficiency. Also there most be education sessions for all employees of the factory plant to understand the company’s goals and routines. In general, with standardized work routines, the non-value creating time can be reduced. The lead time can be shortened by parallelization and synchronization of activities. To shorten the production time, it is very practical to have a standardized work schedule by every work station. This should be based on the method of best practise and should be continuously be revised by measurements for constant improvement. It is of special importance that the activities in the beginning of the process are well organized as it constitutes the base of the entire process. If there are issues left to be solved in the sales process, these issues will tag along as waste of time and money throughout the whole process. Customers’ possible choices must therefore be carefully thought over in terms of easiest possible building solution. Another critical point in the building process is to make the material arrive in time. The material supply depends on the purchase department. The delivery and order process must therefore be investigated. According to lean principles problems in delivery must be documented and followed up by statistic charting. In this way problems can hopefully be identified and solved with the supplier. Moreover the purchase process should, just like the sales process mentioned earlier, also be thought over in terms of easiest building solution. It can be practical to build with standardized parts that could be put together in different ways. \\

==The first step, the sales process==

\\ The company that has been studied receives blueprints from the customer’s architect. This can cause problem in the production process if the blueprint is not adapted to the company’s production resources. The blueprint is therefore modified to fit the production plant. The software that is used is AutoCAD and DDS. None of these can make lists of how much material that is needed for the blueprints of this company. There are often errors in the blueprints of the size of the inner walls. Also holes for ventilations and cables are missing sometimes.  \\

 {{:louise:sales_m.jpg?|}}

\\ According to Mintzberg (1983) and Van de Ven et al. (1976), a large organization needs direct supervision in a hierarchy instead of acting ad hoc on own initiatives. Simple tasks and processes should be standardized. \\

== The second step, the purchase process==

\\ The list of materials of choice must be carefully planned before the sales process documents are established. The purchase process should be an administrative routine process.  In the studied company there is no accurate control of how much materials that needs to be ordered. The purchase department must for example count all the radiators on the blueprint before ordering and information about customers’ choices comes spontaneously into the office from time to time. Making the blueprint takes time and the purchase department has to call the technician that makes the drawing for information about amounts of material from time to time. This non-standardized way causes delays and problems later in the process. There is no plan of how much and when to order material. Some materials are kept in stock and others are specific for a certain project. The purchase department has no direct control of stock levels, only through the incoming logistics department. Often there are materials missing which is of course a hindrance in the production. Below is a figure that shows the purchase process of a Swedish house builder. \\

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\\ With a proper coordination the purchase process can be a lot simpler. At present the purchase department is responsible of the description, calculation of material an ordering of materials. Therefore there are clearly problems in the production because certain materials are not adapted or in the right amount. The purchase department clearly needs some assistance and standardization techniques in these matters. \\

==Third step, production at the plant (prefabrication)==

\\ The process of prefabrication of outer walls is working satisfactory if they have all the materials at hand. With all the materials at hand, it is possible to make 5 walls per day. Variations of walls are generally no problem except for larger windows that is not adapted for the machine.

The production line of floor and roof is similar to walls except for the plumbing and electricity installations that are present in the roofs and floors. Often there is not enough material for the electrician to do his work and the missing holes for plumbing are not discovered before the arrival of the plumber.

Outer walls, floors and roofs are piled up because they are much faster to make than the prefabricated volume elements.

The blueprints for the inner walls are often incorrect. These inaccurate sizes are often not discovered until the actual assembly of the volume elements. 

There are three production lines of the volume elements. The wet room elements like bathroom and kitchen takes longer time and has therefore its own line. The work at the volume element line is not very well organized and can be seen as the bottleneck of the factory. With proper documentation of all the problems in these lines the gained experience would make the production line more efficient. \\

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==Fourth step, assembly and finishing at the site==

\\ Assembly means putting all the prefabricated modules together and finishing are all the things that could not have been done before assembly like painting, balcony attachment etc.

Outer roof and other outer material are delivered directly to the site. These parts are put together in 2-3 days.

The foundation is made earlier by the customer. The assembly at site takes less than one day to complete. An important dependant factor of assembly is the crane that is expensive and must be booked far in advance.

The finishing part is characterized by chaos. It is a search for components and move round of components to put everything in place. This part is often conducted under extreme time-pressure with extra hired personnel and overtime. \\

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==Conclusions and findings==

\\ The conclusion of this study is that it all depends on the first decisions in the building process of how the rest of the process will work out. This means the main responsibility lays on the technician that construct the building and the choices that the customer does in the sales process. If these things are clear, it is much easier for the purchase department to make the correct orders of materials.

An easy standardized building technique that can be used in all the projects would be beneficial. Making all the joints and walls standardized with standardized work descriptions would minimize the defect walls.

The information of stock levels to know when to order stock material and expected use of material should be easily accessible for the purchase department. \\

===References===

\\ Abrahamsson, M. & Brege, S., (1995) Distribution Channel Reengineering – organisering av logistik och marknadsföring i internationella företag. Linköping University.

Christopher, M. (1986) The Strategy of Distribution Management. Heineman professional publishing. Oxford

Mintzberg, H. (1983) Structure in fives. Prentice Hall. New Jersey.

Van de Ven, A. et al. (1976) Determinants of Coordination Modes within Organizations. American Sociological Review. Vol. 41: 2, s. 322-338. \\

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~~DISCUSSION~~