UIA 2017 Seoul World Architects Congress O-0426 Local Construction Techniques Using Digital-Fabrication with Local Wood Koki Akiyoshi *1, Yoshiyuki Kawazoe 2 1 Doctoral Student, The University of Tokyo, Japan 2 Associate Professor, The University of Tokyo, Japan Abstract This study proposes a new local networking system which focuses on local production for local consumption by introducing low cost but high efficiency Computer Numerical Control (CNC) milling machines to small-scale lumber industries which are now decreasing in Japan. Introduction of the CNC milling machines enables the local community to produce and fabricate wood by themselves and for themselves. Since the transportation cost is the biggest obstacle for forestry, local consumption is a key for sustainable management. This system will minimize the transportation distance which leads to curtail of cost and lower emission of CO2. As a social implementation, we have experimented this system through an architectural project conducted by a small public facility in SAKAWA, Kochi, the prefecture in the southern part of Japan. In this experiment, we have succeeded in completing all the construction process, from material procurement to installation, within a five-kilometer radius. Keywords: Local Production for Local Consumption, Sustainability, Digital Fabrication, CNC-Joints, Timber Structure 1. Introduction In Japan, mountains and forests cover two-thirds of the land area. Unlike fossil fuels, wood is a self-sufficient regional resource that is produced by human beings. Nowadays, the locally-grown and locally-consumed principle is increasing its importance to make an effective use of this rich resource. However, existing manufacturing process still transports local timber to the central prefabrication factory which increases the cost of timber and emits a large amount of CO2. Thus, there are so many small-scale forestry companies whose management conditions are failing. In such situation, CNC milling machines would bring in an innovative change to the lumber industry. Recently, CNC milling machines are becoming more and more easier to obtain. By utilizing this technique, this research proposes a method, which can fabricate timber structures locally with local wood. By introducing the technology to the lumber industry, we can produce the fabricated wooden components in the local town. Therefore, we can keep at a minimal transport distance and CO2 emission. In terms of logistics, the wooden components should be small and short. Joints are very important to make large structures with small components. Hence, we invented timber joints which can be made by using a CNC milling machine applying Japanese traditional wood joints techniques. * Contact Author: Koki Akiyoshi e-mail: kokiakiyoshi@gmail.com (The publisher will insert here: received, accepted) UIA 2017 Seoul World Architects Congress 1
2. Social Implementation at SAKAWA Village) We have conducted the research as an social implementation in 2016 at Sakawa, Kochi, where the population is a little over 130,000 and the total land area is 10,000 hectares (Fig.1). In Sakawa, mountains and forests cover seventy percent of the land. Before we introduced our networking system, most of the lumber companies in Sakawa were only selling trees and could not make much profit out of it; their management condition was not sustainable due to financial difficulties. For such small lot productions, we focused on adopting the American CNC milling machine called Shopbot. (Fig.2) In order to effectively utilize disturbed forests, diminution of transportation fee and making profit out of forestry was the key to sustain lumber industry. Shopbot was originally made for small-scale enterprise and even for sole manufacturer, and it only costs about 30,000 dollars. We have introduced Shopbot to Sakawa town hall in March 2016. The aim of this experiment was to create a model case of small-scale architecture by only involving small forestry and small processing machine to clarify the vision. The actual implementation was conducted for five days from August 29th to September 2nd. The theme of this implementation was to create a temporary building for a regional event which was held on September 3rd. The target site was in a district called Kuroiwa (meaning Black Stone in Japanese) in Sakawa which is located at seven kilometers away from urban area. Since the place featured cultural backgrounds and the building was for an event, we were required to design an installation which local kids would gather around and which could also bring out Kuroiwa. Fig.1. KUROIWA, SAKAWA / Fig.2. CNC milling machine Shopbot 3. Design We designed the wooden arch-shaped structure with eighty sheets of lumber from ten thinned-wood. The size of one sheet is 150 millimeters in width, 2000 millimeters in length and 30 millimeters in thickness. The design was inspired by the shape of a traditional Japanese boat which is a cultural heritage of the town of Sakawa. The structure looks like an arch-shaped inverted boat. (Fig.3) The total length is six meters with the total height in 1.8 meters. The size of it is designed similarly to the actual height of the Kuroiwa/black stone which is a sacred figure in Sakawa. In addition, the overall structure can be disassembled into three parts. This is possible by the two joints fabricated by the CNC. The three parts were small enough to be transported by a small pickup truck which made is easy to relocate. (Fig.4) The beam s thickness is 100 millimeters which is strong enough for an adult to be on and for the thrust, we anchored down at both ends of the arch for stability. Essentially, this architectural project was placed for the children to communicate and connect to the heritage of Kuroiwa/Black Stone as they understand the historical townscape of Sakawa. (Fig.5) (Fig.6) 2 UIA 2017 Seoul World Architects Congress
Fig.3. Full perspective of the Structure / Fig.4. Being Transported by a Truck Fig.5. Children of Sakawa Playing / Fig.6. Children of Sakawa Resting 4. Fabrication To not damage the blade by cutting through the wood knots, we had a solution. Before cutting, we took a photo of the wooden material and uploaded into CAD to convert the wood. We place eight sheets of wood, 1200-millimeter-wide and 2000 millimeters long, at once. (Fig.7) Since the blade s diameter was 6.35 millimeter with the total length of thirty millimeters, we ran the cut five times to minimum the damage. Out of all the eighty sheets, sixty-two sheets were used and it took roughly 11.5 hours in total to fabricate. (Table.1) UIA 2017 Seoul World Architects Congress 3
Fig.7. Cutting Sheets Sheet 1 2 3 4 5 6 7 8 Time 01:31:49 01:44:00 01:25:02 01:38:13 01:18:20 01:22:47 01:06:40 01:21:38 Table.1. Each Sheets Cutting Time After we ran the all the cuts for all of the sheets, we crimped the two fabricated sheets and made a sixty millimeter-thickness sheet. (Fig.8) For the joints, we used what is called CNC-joint which is a method applying the traditional Japanese joint, and used M8 bolts as the dowels. (Fig.9) The mortise of the joint is keep the two parts together and the whole arch structure allows it to not break apart. (Fig.10) Assembling the parts was done by combining three pieces at a time upside down, and later on flipping them up with a couple of people. From a housewife to an office-worker, five volunteers helped us in this process. (Fig.11) It took two days and one person to fabricate all, and one day and three people to assemble it. After that it took half an hour and five people to install the structure without a carpenter. This installation was able to build because of the basic module structure with less man power in a short amount of time because of the use of the CNC milling machine. Fig.8. Wooden Components / Fig.9. The Mortise and Tenon Joints 4 UIA 2017 Seoul World Architects Congress
Fig.10. The Basic Module / Fig.11. Modules Put Together 5. Conclusion Ultimately, we succeeded in finishing the process of cutting, producing, fabricating, and assembling all parts of the design in a five-kilometer radius. (Fig.12) This was a significant result considering the fact that the calculated average of the timber transportation distance by the Woodmiles Forum is 7000 kilometers, with the suggested standard distance to be 700 kilometers. In detail, the total transportation distance was 24.7 kilometers: from the forest to the sawmill 12.2 kilometers, from the sawmill to the woodshop 5.9 kilometer, and from the woodshop to the installation space 6.6 kilometers. This is 1/280 of the average transportation distance, and 1/28 of the suggested distance. Even with the scale of the project taken into mind, this result definitely indicates a possibility of a sustainable future for not just the lumber industry but also for the study of architecture. In conclusion, by introducing low cost but high efficiency digital fabrication machines to small-scale and local lumber industries, architectural production can be born with minimum man-power and transportation distance. Since materials and machines are the town s assets, the raw material cost and the production cost can be considered as zero. In addition, the assembling could be done by volunteers which would make the labor cost close to zero as well. With that said, it is greatly possible to make the overall cost free. This can result in lowering the living cost and bringing change to the work life in Japan. Moreover, we might be able to bring back the old sustainable Japanese way of living with people cooperating together making their own communities and nurturing their environment on their own. UIA 2017 Seoul World Architects Congress 5
Fig.12. Networking Diagram 6. Future Work There are two projects that we designed after the research at Sakawa was conducted: the 16-meter-wide arch shaped installation (February 2017, Fig.13) and the roofed resting area. (June 2017, Fig.14) Both of these used local wood in production and the CNC milling machines. The highlight of these two projects was that by using more than one machine for fabrication, we were able to fasten the production. For the installation, such a big project was done only in two days because of the use of multiple CNC milling machines. For the second project, the cutting process was done by two machines in different locations. These projects were the first in history to connect and network within the small-scaled lumber industries, and further on, research and projects like these would be the next step. Fig.13. 6-Meter-Bridge / Fig.14. Roofed Resting Area References 1) http://woodmiles.net/071-kanren-shihyo-hyoka.htm 6 UIA 2017 Seoul World Architects Congress