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5. MASTER THESIS SCHOOL IN FOREST MACHINE TECHNOLOGY Magnus Thor 1 *, Björn Löfgren 1 & Jan Wikander 2 1 Skogforsk, Uppsala, Sweden 2 KTH Royal Institute of Technology, Dept Machine design, Stockholm, Sweden * magnus.thor@skogforsk.se The issue of productivity in forestry is getting more into focus. Skogforsk has initiated and reinforced the cooperation with technological R&D environments, such as The Royal Technical College (KTH) in Stockholm and The University of Linköping. So far, on our initiative some 250 university students at KTH have taken courses where forest machines have constituted the project examples. In addition, 12 master theses and 9 project works involving forest machines have been conducted. From this promising cooperation an idea about a strategic, knowledge-building ”Master Thesis School” has formed. During 2010 there was a call for a set of c. 5 master theses with the emphasis on forest machines. Each thesis contributes as one part of a larger picture, namely “carefulness” – towards the operator, the soil/water and the climate. Focal areas are chassis, drive train and operator’s environment. The intention is to build a generic, common knowledge base of value for machine manufacturers and for forestry. All projects are supervised by KTH, Dept. of Machine design. The Master Thesis School is financed jointly by the forestry sector, through Skogforsk, and by a group of leading machine manufacturers. These founders have established a scholarship fund, from which the students had to apply for scholarships. There is a prize for the best thesis in the school. The jury consists of representatives from the financing bodies and from KTH. A Master Thesis School aiming at forest technology builds bridges between forestry organizations, machine manufacturers and the technical universities. It creates a wider platform for forest technology. Furthermore, the school provides a great opportunity for marketing at the campus site, besides Scania, ABB, Ericsson, Siemens and other companies which are present there. More mechanical engineers with advanced knowledge about forest machinery will also create an increased base for recruitment. This project could be useful in the planning and establishment of larger R&D efforts involving public financing. Keywords: Chassis, drive train, innovation, operator’s environment, R&D cooperation, soil impact. 8
6. COST-EFFICIENCY OF A SYSTEM WITH ONE HARVESTER THAT LOADS TWO FORWARDERS IN COMPARISON TO A TRADITIONAL HARVESTER- FORWARDER SYSTEM Ola Lindroos 1 * 1 Swedish University of Agricultural Sciences, Umeå, Sweden * ola.lindroos@srh.slu.se In the cut-to-length system, some alternative machine systems have lately challenged the conventional harvester-forwarder system. In the so called “Beast-system”, manned forwarders take turns to remote control one un-manned harvester. In this system logs are loaded directly on the forwarder, and hence, less crane work is needed, logs are kept clean and do not risk to be forgotten. Moreover, each log is handled by only one operator and the unmanned harvester can be made cheaper than the cabin equipped manned harvester. The backside is that the system becomes completely integrated (“hot”), as the harvester cannot conduct work without a forwarder, and a forwarder cannot load without the harvester. Any numbers of manned forwarders could take turns in using the un-manned harvester, but two forwards were assumed in this study as other numbers of forwarders only rarely were more cost-efficient. Below this method of integrated cooperation between one harvester and two forwarders is called integrated forwarder loading (IFL). Because harvester productivity is mainly affected by tree size and forwarder productivity is mainly affected by forwarding distance, there are intrinsic difficulties to balance the work time required by the machine types. In the conventional harvester-forwarder system, this can be handled in such a way that it does not necessarily cause delay time on machines, through changes in work time or alternative work tasks. For the IFL-system, delay time is only avoided when it for one forwarder takes as long time to transport, unload and return to the harvester as it takes to fill the other forwarder. If the forwarding distance is to short in relation to the harvester productivity (loading time), the forwarder will return before the other forwarder is loaded and will, thus, have to wait for its turn to use the harvester (to be loaded). If the distance is too long, the harvester will be left unused. As a consequence, the margin for balance between machines is thin and delays occur for most combinations of tree sizes and forwarding distances. Moreover, delays will occur due to machine down-time and unplanned interruptions even with perfect balance. Such delays happen to both conventional and IFL-machines, but in the IFL-system the delays to one machine affect also other machines. Thus, the level of machine availability will be considerably lower in the IFLsystem. In this study of theoretical potentials, the work method of an IFL-system with two forwarders was compared with a conventional harvester-forwarder system in final felling. The analysis shows that the integrated work method used by the IFL-system is considerably less cost-efficient than what has been previously estimated. When assuming the unrealistic mechanical availability of 100% (i.e. all main work time is productive work time), the IFL-system was the most cost-efficient system when the mean tree size was larger than 0.6 m 3 at a mean forwarding distance of 100 m when harvesting 300 m 3 /ha. At 700 m forwarding distance, the trees had to be larger than 0.3 m 3 . However, when assuming more realistic levels of mechanical availability, the IFL-system became less cost-competitive. At 100 m forwarding distance the trees had to be at least 0.9 m 3 , and at 700 m at least 0.4 m 3 . The analysis of suitable combination of mean stand characteristics was applied to data on harvested stands in different Swedish regions. The results show that the volume of final felling on which the IFL-system is the most cost-efficient system is very limited, especially if also the system’s extra cost for road transport of machinery is included (three machines to transport instead of two). The results showed that less than 15% of the volume of final felling is costefficiently harvested with the IFL-system under the conditions assumed in the analyses. 9
Page 1 and 2: Rapport 12/2010 fra Skog og landska
Page 3 and 4: FOREWORD In attracting such a large
Page 5 and 6: TABLE OF CONTENTS Keynote 1. Forest
Page 7 and 8: Session 2.3 32. Impact of Extractio
Page 9 and 10: 1. FOREST OPERATIONS RESEARCH IN TH
Page 11 and 12: 2. SIMULATING THE EFFECT OF STRIP R
Page 13 and 14: 3. A LOW-INVESTMENT FULLY MECHANIZE
Page 15: 4. EFFICIENCY AND ERGONOMIC ADVANTA
Page 19 and 20: 7. ADAPTIVE TREE BUCKING SYSTEM USI
Page 21 and 22: 9. THE COST-EFFICIENCY OF SEEDLING
Page 23 and 24: 10. THE EFFECT OF WOOD PROCESSING C
Page 25 and 26: 12. STUMP EXTRACTION WITH A STUMP D
Page 27 and 28: 13. HARVESTING POTENTIAL OF FOREST
Page 29 and 30: 14. THE IMPACT OF TIMBER HAULAGE ON
Page 31 and 32: 15. STUMP LIFTING PRODUCTIVITY WITH
Page 33 and 34: 16. COMPARISON OF WORKING TECHNIQUE
Page 35 and 36: 18. FOREST OPERATIONS - FROM DOING
Page 37 and 38: 19. DEVELOPING PROFESSIONAL ENTREPR
Page 39 and 40: 20. GREAT POTENTIAL IN CORRIDOR THI
Page 41 and 42: spruce, 12,61 - 17,42 % for birch,
Page 43 and 44: 23. HARVESTING STUMPS FOR ENERGY IN
Page 45 and 46: 24. SCRUTINIZING THE WOOD SUPPLY CH
Page 47 and 48: Table 1. Results of a principal-com
Page 49 and 50: 27. AN EXTRACTION TRAIL GENERATOR U
Page 51 and 52: 29. ASSESSMENT OF VÄSTERBOTTEN CAS
Page 53 and 54: • Cost calculation method • Met
Page 55 and 56: 31. TESTING OF REVOLUTIONARY ROUND
Page 57 and 58: 32. IMPACT OF EXTRACTION CONDITIONS
Page 59 and 60: 33. EVALUATION OF DIFFERENT APPROAC
Page 61 and 62: 34. ESTIMATING POTENTIALS OF SOLID
Page 63 and 64: 35. PRODUCTIVITY OF SINGLE GRIP HAR
Page 65 and 66: 36. ANALYSIS OF LARGE-SIZE AND MEDI
Page 67 and 68:
37. FELLING HEADS VS HARVESTER HEAD
Page 69 and 70:
39. COMBINING ADAPTED DUMP TRUCKS A
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40. THE DRYING OF WOOD CHIPS WITH S
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Figure 2. Development of profitabil
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Table 1. Total economic output from
Page 77 and 78:
44. COMPARATIVE SHELTER-WOOD HARVES
Page 79 and 80:
45. EFFECT OF BOGIE TRACK AND SLASH
Page 81 and 82:
46. NECK MUSCLE ACTIVITY PATTERNS A
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47. BOOM AUTOMATION Löfgren Björn
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Keywords: Mechanized seeding, cost-
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from the time studies shows that th
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52. PRODUCTIVITY OF HARVESTERS AND
Page 91 and 92:
53. PRODUCTIVITY AND COSTS OF WHOLE
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54. A PROCESS-PERSPECTIVE ON TIMBER
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56. SIMULATION OF SKYLINE SYSTEMS I
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57. VOLUME AND COST CALCULATOR FOR
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onwards did ground reinforcement wi
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