关于带式输送机的外文翻译@中英文翻译@外文文献翻译

Int J Adv Manuf Technol (2005) 25: 551559 DOI 10.1007/s00170-003-1843-3 ORIGINAL ARTICLE S.H. Masood B. Abbas E. Shayan A. Kara An investigation into design and manufacturing of mechanical conveyors systems for food processing Received: 29 March 2003 / Accepted: 21 June 2003 / Published online: 23 June 2004 Springer-Verlag London Limited 2004 Abstract This paper presents the results of a research investi- gation undertaken to develop methodologies and techniques that will reduce the cost and time of the design, manufacturing and assembly of mechanical conveyor systems used in the food and beverage industry. The improved methodology for design and production of conveyor components is based on the minimisa- tion of materials, parts and costs, using the rules of design for manufacture and design for assembly. Results obtained on a test conveyor system verify the benets of using the improved tech- niques. The overall material cost was reduced by 19% and the overall assembly cost was reduced by 20% compared to conven- tional methods. Keyword s Assem bl y Cost reduct i on Design DFA DFM Mechanical conveyor 1 Introduction Conveyor systems used in the food and beverage industry are highly automated custom made structures consisting of a large number of parts and designed to carry products such as food cartons, drink bottles and cans in fast production and assembly lines. Most of the processing and packaging of food and drink in- volve continuous operati ons where cartons , bottles or cans are re- quired to move at a controlled speed for lling or assembly oper- ations. Their operations require highly efcient and reliable me- chanical conveyors, which range from overhead types to oor- mounted types of chain, roller or belt driven conveyor systems. In recent years, immense pressure from clients for low cost but efcient mechanical conveyor systems has pushed con- veyor manufacturers to review their current design and assembly methods and look at an alternative means to manufacture more economical and reliable conveyors for their clients. At present, S.H. Masood (u) B. Abbas E. Shayan A. Kara Industrial Research Institute Swinburne, Swinburne University of Technology, Hawthorn, Melbourne 3122, Australia E-mail: .au most material handling devices, both hardware and software, are highly specialised, inexible and costly to congure, install and maintain 1. Conveyors are xed in terms of their locations and the conveyor belts according to their synchronised speeds, mak- ing any changeover of the conveyor system very difcult and ex- pensive. In todays radically changing industrial markets, there is a need to implement a new manufacturing strategy, a new system operational concept and a new system control software and hard- ware development concept, that can be applied to the design of a new generation of open, exible material handling systems 2. Ho and Ranky 3 proposed a new modular and recongurable 2D and 3D conveyor system, which encompasses an open re- congurable software architecture based on the CIM -OSA (open system architecture) model. It is noted that the research in the area of improvement of conveyor systems used in beverage in- dustry is very limited. Most of the published research is directed towards improving the operations of conveyor systems and inte- gration of system to highly sophisticated software and hardware. This paper presents a research investigation aimed at im- proving the current techniques and practices used in the de- sign, manufacturing and assembly of oor mounted type chain driven mechanical conveyors in order to reduce the manufactur- ing lead time and cost for such conveyors. Applying the con- cept of concurrent engineering and the principles of design for manufacturing and design for assembly 4, 5, several critical conveyor parts were investigated for their functionality, material suitability, strength criterion, cost and ease of assembly in the overall conveyor system. The critical parts were modied and redesigned with new shape and geometry, and some with new materials. The improved design methods and the functionality of new conveyor parts were veried and tested on a new test con- veyor system designed, manufactured and assembled using the new improved parts. 2 Design for manufacturing and assembly (DFMA) In recent years, research in the area of design for manufacturing and assembly has become very useful for industries that are con- 552 sidering improving their facilities and manufacturing methodol- ogy. However, there has not been enough work done in the area of design for conveyor components, especially related to the is- sue of increasing numbers of drawing data and re-engineering of the process of conveyor design based on traditional methods. Emphasise standardisation Use the simplest possible operations Use operations of known capability Minimise setups and interventions Undertake engineering changes in batches A vast amount of papers have been published that have investi- gated issues related to DFM A and applied to various methodolo- gies to achieve results that proved economical, efcient and cost effective for the companies under investigation. The main classications of DFMA knowledge can be iden- tied as (1) General guidelines, (2) Company-specic best prac- tice or (3) Process and or resource-specic constraints. General guidelines refer to generally applicable rules-of-thumb, relat- ing to a manufacturing domain of which the designer should be aware. The following list has been compiled for DFM guidelines 6. These design guidelines should be thought of as “optimal suggestions”. They typically will result in a high-quality, low- cost, and manufacturable design. Occasionally compromises must be made, of course. In these cases, if a guideline goes against a marketing or performance requirement, the next best alternative should be selected 7. Company-specic best practice refers to the in-house design rules a company develops, usually over a long period of time, and which the designer is expected to adhere to. These design rules are identied by the company as contributing to improved quality and efciency by recognising the overall relationships between Design for a minimum number of parts Develop a modular design Minimise part variations Design parts to be multifunctional Design parts for multiuse Design parts for ease of fabrication Avoid separate fasteners Maximise compliance: design for ease of assembly Minimise handling: design for handling presentation Evaluate assembly methods Eliminate adjustments Avoid exible components: they are difcult to handle Use parts of known capability Allow for maximum intolerance of parts Use known and proven vendors and suppliers Use parts at derated values with no marginal overstress Minimise subassemblies particular processes and design decisions. Companies use such guidelines as part of the training given to designers of products requiring signicant amounts of manual assembly or mainte- nance. Note that most of the methodologies are good at either being quick and easy to start or being more formal and quanti- tative. For example, guidelines by Boothroyd and Dewhurst 8 on DFA are considered as being quantitative and systematic. Whereas the DFM guidelines, which are merely rules of thumb derived from experienced professionals, are more qualitative and less formal 9. 3 Conventional conveyor system design Design and manufacturing of conveyor systems is a very com- plex and time-consuming process. As every conveyor system is a custom-made product, each project varies from every other project in terms of size, product and layout. The system design Fig. 1. Layout of conveyor sys- tem for labelling plasic bottles 553 is based on client requirements and product specications. More- over, the system layout has to t in the space provided by the company. The process of designing a layout for a conveyor sys- tem involve revisions and could take from days to months or in some instances years. One with the minimum cost and maximum client suitability is most likely to get approval. Figure 1 shows a schematic layout of a typical conveyor system installed in a production line used for labelling of plastic bottles. Different sections of the conveyor system are identied by specic technical names, which are commonly used in similar industrial application. The “singlizer” sec- tion enables the product to form into one lane from multiple lanes. The “slowdown table” reduces the speed of product once it exits from ller, labeller, etc. The “mass ow” sec- tion is used to keep up with high-speed process, e.g., ller, labeller, etc. The “transfer table” transfers the direction of prod- uct ow. The purpose of these different conveyor sections is thus to control the product ow through different processing machines. A typical mechanical conveyor system used in food and bev- erage applications consists of over two hundred mechanical and electrical parts depending on the size of the system. Some of the common but essential components that could be standard- ised and accumulated into families of the conveyor system are side frames, spacer bars, end plates, cover plates, inside bend plates, outside bend plates, bend tracks and shafts (drive, tail and slave). The size and quantity of these parts vary according to the length of conveyor sections and number of tracks correspond- ing to the width and types of chains required. The problems and shortcomings in the current design, manufacturing and assembly of mechanical conveyors are varied, but include: 4 Areas of improvement In order to identify the areas of cost reduction in material and labour, a cost analysis of all main conveyor parts was conducted to estimate the percentage of cost of each part in relation to the total cost of all such parts. The purpose of this analysis was to identify the critical parts, which are mainly responsible for in- creasing the cost of the conveyor and thereby investigate means for reducing the cost of such parts. Table 1 shows the cost analysis of a 50-section conveyor sys- tem. The analysis reveals that 12 out of 15 parts constitute 79% of the total material cost of the conveyor system, where further improvements in design to reduce the cost is possible. Out of these, seven parts were identied as critical parts (shown by an asterisk in Table 1) constituting maximum number of compo- nents in quantity and comprising over 71% of overall material cost. Among these, three components (leg set, side frame and support channel) were found to account for 50% of the total conveyor material cost. A detailed analysis of each of these 12 parts was carried out considering the principles of concurrent en- gineering, design for manufacture and design for assembly, and a new improved design was developed for each case 10. De- tails of design improvement of some selected major component are presented below. 5 Redesign of leg set assembly In a conveyor system, the legs are mounted on the side frame to keep the entire conveyor system off the oor. The existing design of conveyor legs work, but they are costly to manufacture, they Over design of some parts High cost of some components Long hours involved in assembly/maintenance Use of non-standard parts have stability problems, and cause delays in deliveries. The delay is usually caused by some of the parts not arriving from over- seas suppliers on time. The most critical specications required for the conveyor legs are: Table 1. Conveyor critical parts based on parts cost analysis Product description Leg set Side frame Support channel Bend tracks Rt. roller shaft Tail shaft Spacer bar Support wear strip Support side wear strip End plate Cover plate Bend plates Torque arm bracket Slot cover Inside bend plate Qty 68 80 400 8 139 39 135 400 132 39 39 8 18 97 8 Material used Plastic leg + SS tube 2.5 mm SS C channel SS Plastic 20 dia. SS shaft 35 dia. Stainless steel 50X50X6 SS 40 10 mm plastic Plastic 2.5 mm/SS 1.6 mm S/S 2.5 mm/SS 6 mm S/S plate Stainless steel 2.5 mm/SS Cost (%) 20.22 16.07 15.00 14.36 6.70 6.27 5.43 5.36 3.01 1.88 1.57 1.29 1.21 0.97 0.66 Improvement possible (Yes/No) Yes Yes Yes No Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Total Critical parts 100.00 554 Strength to carry conveyor load Stability Ease of assembly Ease of exibility (for adjusting height) 1 and part 3 in Fig. 2) was not rigid enough. The connections for these parts are only a single 6 mm bolt. At times, when the conveyor system was carrying full product loads, it was observed that the conveyor legs were unstable and caused mechanical vi- bration. One of the main reasons for this was due to a single bolt Figure 2 indicates all the parts for the existing design of the conveyor leg. The indicated numbers are the part numbers described in Table 2, which also shows a breakdown of cost an- alysis complete with the labour time required to assemble a com- plete set of legs. The existing leg setup consists of plastic leg brackets ordered from overseas, stainless steel leg tubes, which are cut into specied sizes, leg tube plastic adjustments, which are clipped onto the leg tube at the bottom as shown in Fig. 2. Lugs, which are cut in square sizes, drilled and welded to the leg tube to bolt the angle cross bracing and backing plate to support leg brackets bolts. The # of parts in Table 2 signies the number of components in each part number and the quantity is the con- sumption of each part in the leg design. Companies have used this design for many years but one of the common complaints reported by the clients was of the instability of legs. From an initial investigation, it became clear that the connec- tion between the stainless steel tube and plastic legs bracket (part Fig. 2. Existing leg design assembly with part names shown in Table 1 Table 2. Cost analysis for old leg design assembly connection at each end of the lugs in part 3 and part 7. The sta- bility of the conveyor is considered critical matter and requires rectication immediately to satisfy customer expectations. Considering the problems of the existing conveyor leg de- sign and the clients preferences, a new design for the conveyor leg was developed. Generally the stability and the strength of the legs were considered as the primary criteria for improve- ment in the new design proposal but other considerations were the simplicity of design, minimisation of overseas parts and ease of assembly at the point of commissioning. Figure 3 shows, the new design of the conveyors leg assembly, and Table 3 gives a description and the cost of each part. Figure 3 shows that the new design consists of only ve main parts for the conveyors leg compared to eight main parts in the old design. In the old design, the plastic leg bracket, the leg tube plastic adjustment and the leg tube were the most expensive items accounting for 72% of the cost of leg assembly. In the new Part no. 1 5, 6 4 7 2 3 8 Part description Plastic leg bracket Leg tube plastic adjustment Lug Angle cross bracing Backing plate Leg tube Bolts # of parts 2 4 2 1 2 2 6 Qty 2 2 2 1 2 2 6 Cost $ 30.00 $ 28.00 $ 4.00 $ 5.00 $ 4.00 $ 25.00 $ 3.00 Source Overseas Overseas In-house In-house In-house In-house In-house Total assembly cost (welding) $ 15.00 In-house Total 19 17 $ 114.00 555 Fig. 3. New design for leg assembly with part names in Table 3 Table 3. Cost analysis for new design leg assembly Part no. 1 3 4 5 2 Part description Stainless steel angle (50 50 3 mm) Leg plastic adjustment Cross brassing Bolts Backing plate # of parts 2 2 1 8 2 Qty 2 2 1 4 2 Cost $ 24.00 $ 10.00 $ 7.00 $ 4.00 $ 4.00 Source In-house Overseas In-house In-house In-house Total assembly cost $ 10.00 In-house Total design, those parts have been replaced by a stainless steel angle and a new plastic leg adjustment reducing the cost of leg assem- bly by almost 50%. Thus the total numbers of parts in the leg have been reduced from 19 to 15 and the total cost per leg setup 15 11 Size of side frame (depth) Strength of the material Ease for assembly Ease for manufacturing $ 59.00 has been reduced by $ 55 in the new design. The new conveyor leg design, when tested, was found to be more secure and stable than the old design. The elimination of part number 1 and 5 from old conveyor design has made the new design more stable and rigid. In addition, the width of the cross bracing has also been increased with two bolts mount instead of one in old design. This has provided the entire conveyor leg setup an additional strength. 6 Redesign of the side frames The side frame is the primary support of a conveyor system that provides physical strength to conveyors and almost all the parts are mounted on it. The side frame is also expected to have a rigid strength to provide support to all the loads carried on the conveyor. It also accommodates all the associated conveyor components for the assembly. The critical considerations of side frame design are: Figure 4 shows the side frame dimension and parameters. The side frame used in existing design appears to be of rea- sonable depth in size (dimension H in Fig. 4). From the initial investigation, it was found that the distance between spacer bar holes and return shaft (dimensions G and F in Fig. 4) could be reduced, as there was some unnecessary gap between those two components. The important point to check before redening the design parameters was to make sure that after bringing those two closer, the return chains would not catch the spacer bar while the conveyor is running. The model of the new side frame design was drawn on CAD to ensure all the specications are sound and the parts are placed in the position to check the clearances and the ts. Using the principle of design for manufacturing the new side frame design was made symmetrical so that it applies to all types of side frames. This change is expected to reduce the size of side frame signicantly for all sizes of chains. Table 4 shows a comparison of dimensions in the old design and the new design of side frames for the same chain type. It 556 Fig. 4. Side frame dimensions Table 4. New and old side frame dimension parameters Old design Chain type 3.25 LF/SS STR/LBP/MAG A 31 B 92 C 71 D 196 E 65 F 105 G 211 H 241 I 136 J 58 K 85 L 196 TAB 22 83 62 187 56 96 202 232 127 New design Chain type 3.25 LF/SS STR/LBP/MAG/TAB A 31 B 100 C 73 D 173 E 67 F 107 G 167 H 199 I 92 J 58 K 85 L 152 is noted that the overall size (depth) of the conveyor has been reduced from 241 mm to 199 mm (dimension H), which gives a saving of 42 mm of stainless steel on every side frame manu- factured. Thus, from a stainless steel sheet 1500 3000 mm, the old design parameters allowed only six 3 m long side frames but with the new design parameter now it was possible to produce seven side frames of 3 m long from the same sheet size. The amount of material used for side frames was also re- viewed for further investigation. It is estimated that about 55% of the total cost of the conveyor system is spent on materials. The current material used for side frames is 2.5 mm thick stain- less steel food grade 304. Currently, there are other materials available in the market with alternative thickness that could be considered as an option. For this, a deection analysis has been conducted to estimate if there was any other type of material suit- able to replace the existing material so that it does not fail its strength criteria. 6.1 Deection analysis for side frames Figure 5 shows the experimental setup to determine the deec- tion of new side frame in X and Y direction under different loading conditions. With the new design parameters a set of side frames were manufactured to investigate the deection on 1.6 mm thick stainless steel side frames. A section of side frame bolted with spacer bar and return shaft was assembled for test- ing with the experiment. The results for deection were obtained by applying variable loads on a section of the side frame via a hydraulic press. As shown in Fig. 5, the deection gauges are placed on vertical (Y ) and horizontal (X ) axes to measure any reading observed on the side frames. The loads are applied on side frame via the hydraulic press in downward direction. The side frames are supported by stands from the same position where the legs are mounted on the side frames. Three sets of experiments are conducted on four, six and eight tracks of conveyor sections to observe any abnormalities under big loads. The loads applied on the experimental conveyor sections are over estimated and are higher than actual load con- ditions for conveyor system in real applications. The conveyors are usually designed to carry load under one tonne per metre for industry application in the food and beverage industry. The pur- pose of applying a big load was to estimate the point of deection for side frame under high loads. Figures 6 and 7 show the results of the experiments for the conveyor sections of four tracks and six tracks, respectively. From the results obtained, it is observed that under 2 KN of loads, the deection values are almost under 2 mm for all Fig. 5. Experimental set up to investigate deection on new side frame design 557 Table 5. Cost analysis for side frame Side frame cost analysis for old design Product/process description Material Side frame (3000 241 mm 2.5 mm $ 360 per sheet) Slot (50 cent per slot punch) Holes (20 cent per hole punch) Fold Total cost Side frame cost analysis for new design Product/process description Material Side frame (3000 199 mm 1.6 mm $ 162 per sheet) Qty 1 8 30 2 Qty 1 Cost $ 60.00 $ 4.00 $ 6.00 $ 3.00 $ 73.00 Cost $ 23.00 Fig. 6. Deection results for 4-track 1.6 mm stainless steel side frame Slot (50 cent per slot punch) Holes (20 cent per hole punch) Fold Total cost 8 30 2 $ 4.00 $ 6.00 $ 3.00 $ 36.00 6.2 Side frame cost analysis The material review and deection analysis has shown that the existing 2.5 mm stainless steel sheet was an over design for side frame for the food and beverage conveyor application. The an- alysis also showed that 1.6 mm thick stainless steel sheet can be used as an alternative material for the side frame, which will perform its function satisfactorily. Table 5 shows a comparison of the costing of the old and new design of side frames, which shows that the saving per side frame on the new design is ex- pected to be $ 37 (i.e., a savings of 50.1%). Fig. 7. Deection results for 6-track 1.6 mm stainless steel side frame types of sections. Under the given circumstances, the 1.6 mm stainless steel side frame design can be a possible alternative to the existing conveyor side frame design. It is expected that with wider conveyor sections, the deections on side frame will stay within the allowable limits, that is, 5 mm. The main rea- son why this experiment was conducted is to ensure that the side frames do not buckle under high loads. Thus there was no evidence of buckling occurrence for any of the types of con- veyor sections used. It is also expected, based on the experiences of engineers and the investigation during the current research, that after the complete assembly is made, the conveyors will conceive additional strength, which will further reduce the possi- bility of deection on the side frame. The deection, for instance, was measured for each set of experiments outwards. With the leg mounted on the side frame, the forces will act in opposite direction that will push the side frame inwards. The full obser- vation of this assumption can be concluded when a complete test conveyor is manufactured and tested based on new design parameters. With all the results obtained from the experiments, it is con- cluded that 1.6 mm stainless steel grade 304 side frames can be manufactured for conveyors for food and beverage industry under the specied guidelines for loads. The cost saving made in this area is expected to be signicant since 80% of material used in a conveyor system is made of stainless steel. In addition to this cost saving, the reduction of side frame size from 241 mm to 199 mm will also allow the production of one extra side frame out of the 3000 1500 mm stainless steel sheet. New design improvements were also carried out in several other critical parts such as support channel, return roller shaft, spacer bar, support wear strip and support side wear strip, which resulted in further cost and labour savings and also ease of manu- facturing and assembly. For example, the new design of support channel assembly (including support wear strip and side wear strip) required reduced number of processes, reduced wear strip thickness, use of a new M section channel and provision for use with different types of chains giving a cost saving of 33.7% in this improved design. The new design of return roller shaft of- fered a cost savings of 44.5% and a 50% reduction in labour time. The new design of the spacer bar offered an estimated cost saving of 25% from the old design. 7 Design implementation in a test conveyor system The implementation of design improvements of individual criti- cal parts and components was carried out in the design, manufac- turing and assembly of a full-edged test conveyor system. This new and improved test conveyor was then tested and veried for performance with actual products (plastic bottles). A cost analy- sis was also conducted to compare the overall cost savings in this 558 test conveyor with the costs involved with an identical conveyor based on old design 7. The new test conveyor is a singleiser type (Fig. 8), comprises of three different sections with a total length of 5 m. Section C1 is a six-track conveyor section joined to section C2, which is a six-track 90 bend conveyor. This is connected to conveyor section C3, which is an eight-track conveyor section with combi- nation of two different types of chains, TAB and STR. The test conveyor contains a total of 26 major parts. Figure 9 shows the test conveyor used for testing of product ow at the collaborating company. The performance and efciency of the new test conveyor and its critical new parts were tested for smooth, noiseless perform- ance by observing the product ow of empty plastic drink bottles on the conveyor. All the parts and the conveyor system were found to show fully functional satisfactory performance. A complete cost analysis on the test conveyor was conducted to measure the difference between old and new designs and also to evaluate the ease in assembly and reduction in labour expendi- ture. Quantity of parts, the material used, and the manufacturing Fig. 8. A singliser test conveyor Fig. 9. Test conveyor assembly: product ow test costs were calculated for each part and percentage savings of each part and the overall system were determined. 8 Results and discussion The most critical area of consideration was to check if the new support channel setup and the drip tray joining were carried out with less labour consumption. Attention was also paid to make sure that the labourers have been working effectively on the job. The times used for the assembly of conveyor system are expected to vary depending on the mood of workers and other external fac- tors. But efforts were made to achieve the closest possible time to manufacture the conveyors. A study of cost analysis reveals the following facts: A manufacturing cost saving of 40% or more was achieved in eight out of 12 of the improved design parts. A cost saving of 26% to 34% was achieved in other three parts. Among the high cost parts, the maximum savings were achieved for the side frame, return roller shaft, leg set and support wear strips. The overall cost of the conveyor was reduced by 19%. The overall cost of labour in the assembly of the conveyor was reduced by 20%. It is observed that the savings accomplished are mainly achieved for the conveyor parts that had been over designed or are not professionally designed. One of the major changes that affected the design of conveyor system was the revision of the side frame design parameters, which also affected the changes in other parts that were allied with it. Secondly, the development of new M prole support channel along with the standard wear strips added to major achievement in the new conveyor design. The accomplishment from the new design reduced the labour cost and also made signicant impact on the assembly line for improved design and manufacture. It was also noticed that by categorising the spacer bars for different number of tracks im- proved the selection procedure for the design. The new conveyor system became more economical and cost effective and the need to use extra strength materials was eliminated. 9 Conclusions In the design and manufacturing of mechanical conveyor sys- tems, there is a considerable dearth of research work in conveyor design optimisation and especially a lack of application of mod- ern techniques to the design improvement in such systems. In order to improve the costs and lead times in the conveyor sys- tem, a complete breakdown analysis of a test conveyor has been conducted to evaluate the high spending areas in conveyor manu- facturing. The analysis was supported by applying principles of design for manufacturing and design for assembly for improving the design without sacricing the functionality and operation of the system. A new conveyor design was proposed based on all the recommended modications of conveyor components. The 559 recommendations were veried on a test conveyor system and adopted by the collaborating company. The results proved suc- cessful with a 19% overall savings in cost and 20% reduction in total labour cost. The research results conrm that by applying the rules of DFMA, the cost of design and assembly of a complex system like the mechanical conveyors for food processing can be drastically reduced. References 1. Anderasen MM, Ahm T (1986) Flexible assembly system. Springer, Berlin Heidelberg New York 2. Ho JKL, Ranky PG (1994) The design and operation control of a recon- gurable exible material handling. Proceedings of 1994 Japan-USA Symposium of Flexible Automation, vol. 2, Kobe, Japan, pp 825828 3. Ho JKL, Ranky PG (1997) Object oriented modelling and design of recongurable conveyors in exible assembly systems. Int J Comput Integr Manuf 10(5):360379 4. Kusiak A (1990) Intelligent manufacturing systems. Prentice Hall, New York 5. Corbett J, Dooner M, Meleka J, Pym C (1991) Design for manufactur- ing: strategies principles and techniques. Addison-Wesley, UK 6. Mize JH, Glenn P (1989) Some fundamentals of integrated manufac- turing. International Industrial Engineering Conference Proceedings, Washington, DC, pp 546551 7. Mize JH (1987) CIMa perspective for the future of IEs. IIE Integrated Systems Conference Proceedings, Nashville, TN, pp 35 8. Boothroyd G, Dewhurst P (1988) Product design for manufacturing and assembly. Manuf Eng April:4246 9. Bedworth DD, Henderson MR, Wolfe PM (1991) Computer integrated design and manufacturing. McGraw-Hill, Singapore 10. Abbas B (2001) An investigation into design and manufacturing of mechanical systems for food processing and beverage industry. Disser- tation, Swinburne University of Technology, Hawthorn, Australia 10 译文： 对输送机用于食品输送系统的调查设计和制造 S.H. Masood B. Abbas E. Shayan A. Kara 收稿日期： 2003 年 3月 29 日 /接受日期： 2003 年 6 月 21 日 /线上发表于： 2004 年 6 月 23普林格出版社伦敦有限公司 2004 摘要 :本文介绍食品饮料行业的研究调查结果和进行开发的方法技术，在设计制造和使用的系统装配机械输送中缩短时间和成本。该输送机部件在设计和生产材料的基础上改进技术来最小化零部件和成本，利用装配设计和制造的设计规则。最终获得一个测试验证了改良技术的传送系统。相比传统的方法整体材料成本下降了 19，整体组装成本降低 20。 关键词 :装配 降低成本 设计 DFA DFM 机械输送机 1 引言 食品和 饮料业中使用的输送系统是高度自动化定制结构部件组成的，并进行线路设计的产品，如食品箱，饮料瓶，罐快速组装生产。大部分饮料食品的加工包装涉及到组装业务持续经营情况，瓶或罐需移动或控制的速度。它们的移动需要高效率和可靠的机械输送机， 从哪个范围的类型到地板镶嵌链子、路辗或者皮带传动的输送机系统的类型。 近年来，巨大的机械压力输送系统向客户提供低成本而高效率的输送机，制造商倾向审查其目前的设计和装配方法，看看另一种制造手段，可靠的输送机为他们的客户提供更经济的生产。目前， 大多数材料处理设备，包括硬件和软件， 成本高，安装和维护不灵活 1。 输送机是固定的地点和传送带有条件地根据自身的同步速度，使得任何输送系统非常困难和昂贵。在今天彻底变化的工业市场，有需要实施新的制造策略，新系统业务概念和新的系统控制软件和硬件开发的概念，即可以应用于材料设计的，灵活的新一代开放处理系统 2。侯和峦琪两人提出了一种新的模块化和可重构的二维和三维输送系统，该系统包括一个开放的可重构软件体系结构的基础上的 11 CIM - OSA 的（开放系统）模型。据指出，在饮料行业研究领域的改善输送系统中使用的是非常有限的。大多数已发表的研究是针对提高 系统的运行输送机一体化系统和高度复杂的软件和硬件。 本文提出的研究调查是旨在改善目前的技术和实践中使用的设计，制造和装配式链式输送机驱动机械，以降低制造所需的时间和输送成本等。部分应用并行工程的概念和几个重要的输送机制造的设计原则和设计组装 4， 5，为它们的功能进行了研究。材料的适用性，强度准则，成本和装配用于在整个运输系统。关键部件进行了修改和重新设计新的形状和几何形状，材料和一些新的。改进后的设计方法和部分新功能进行了核实。输送机上测试新的考验输送系统设计，制造和组装使用新的改进的部分。 2 制造和装配的设计（ DFMA） 近年来，研究关于在图纸面积上和设计制造，已成为非常有用的方法，为了产业，必须考虑改善其设施和制造业。然而，没有足够的相关工作做了特别的研究，输送配件的设计在方法问题上越来越多的传统的数据处理和重新绘制的工程设计输送机的基础。大量的论文已发表有相关的问题进行调查 DFMA 和应用各种方法，以实现经济的结果，证明，有效率和有效的公司根据成本调查的。 DFMA 知识的主要分类，可确定为：（ 1）一般准则，（ 2）公司特定的最佳实践（ 3）具体过程和或资源的困难。其中设计人员应该知 道 ,一般准则是指普遍适用的规则的，涉及到制造业领域。下面已经编制准则对于 DFM 的清单 6. 设计最低数量的零件 开发一个模块化设计 尽量减少部件的变化 设计部件是多功能 为多用途设计零件 为简化设计，零件制造 避免单独紧固件 最大化遵守：为简化设计，装配 尽量减少处理：处理演示设计 12 评估装配方法 消除调整 避免弹性元件：他们是难以操作 已知部分功能的使用 允许零件的最大的不容忍现象 使用已知的和经过验证的厂商和供应商 在强制降级的值使用部分无边际过度紧张 尽量减少部件 着中标准化 使用最简单的操作 已知 使用行动能力 尽量减少设置和干预 分批承接的工程变更 这些设计准则应被看作是最优的“建议”。他们通常会导致高品质，低成本的设计和制造。有时必须作出妥协，当然。在这种情况下，如果一个准则替代违背了市场营销或性能要求，下一个最好应选择 7。 公司具体的最佳实践是指在内部设计规则。公司的开发，通常在一个较长时期，而设计者将坚持自己的信念。这些设计规则，确定由该公司为促进特定工艺和设计决定，以全面提高质量和效益之间的关系通过承认。公司使用的培训等指导方针的一部分给予设计师或维修产品的手工装配需要相当数量的。注意这 些方法大部分是定量善于要么被快速方便地启动或更加正式和。例如，准则由 Boothroyd 和杜赫斯特 8 DFA的 就被视为是定量化，系统化。鉴于 DFM 指导方针，这仅仅是从经验丰富的专业经验法则推导，更不正式的定性和 9。 13 Fig. 1. Layout of conveyor system for labelling plasic bottles 3 传统的输送系统的设计 系统的设计和制造输送机是一个非常复杂和耗时的过程。由于每种输 送系统是一种特制的产品，每个项目都有各个不同的项目规模，产品和布局。该产品系统的设计是根据客户的要求和明确说明 .此外，系统布局应适应公司提供的空间。在修订过程中的输送系统的设计布局，可以采取包括从几天到几个月，或在某些情况下的几年。一个适宜的最低成本和最大限度满足客户的要求是最有可能得到批准。 图 1 显示了一条生产线，示意图中是一个典型的输送系统中安装使用的塑料瓶的标签。输送系统的不同部分被确定具体的技术名称，它通常用在类似的工业应用。该“ singlizer”一节使产品形成一个小巷里从多个。在“减速表”降低产 品的速度，一旦退出从填料，贴标机等的“流量”部分用于处理与保持高速，例如，填料，贴标机等的“转移表”转移的方向，产品流通。各节的目的，因此，这些不同的输送机控制加工机产品流经不同。 一个典型的机械输送系统应用用于食品和饮料包含超过 200 机械及零件根据系统的大小。体系中的一些共同输送的重要组成部分，但可以统一的，积累到家庭侧架，间隔棒，端板，盖板，弯板内，外弯板，弯轨和轴（驱动器，尾部和奴隶）。零件的大小和数量，这些根据所输送机的长度和数量节轨道相应的宽度和链类型的需要。存在的问题和缺点在目前的设计 ，制造和装配输送机械是多方面的，但包括： 14 对一些部件的设计 一些部件成本高 在装配的 /维修时间长 使用非标件 4 区改善 为了确定该地区的主要输送机零件。进行成本分析，降低材料的成本和一切劳动，以估计这种百分比在相对于总成本的所有各部分的成本。分析这样做的目的是找出关键部件，主要负责零部件的成本增加了输送机等调查手段，从而为降低成本。 表 1 显示了输送系统的成本分析 50 节。分析结果显示， 12 件在 15 个构成 79的成本降低总材料成本的，在输送系统进一步改进设计是可能的。在这些，确定了 7个部分，如表 1 星号的关键部分一（表现出）构成的最大数量的元件数量和成本，包括材料 71以上的整体。其中，三个组成部分（腿组，侧架和支持渠道）被发现 50的费用占了总输送材料。其中一名 12 件详细分析每进行审议大会的各项原则并行设计工程，设计和制造，以及一个新的改进设计，开发的每一个案件 10。组件的主要设计改进的细节部分选定如下。 5 重新设计一套装配小腿 在输送系统中，安装在腿的侧架，是以保持整个输送系统离地。现有输送工作设计的腿费用昂贵。他们有关于稳定方面的问题，并导致交货延误研究。该延迟时间通常是 由一些对供应商的零部件来自海外尚未到位。在输送中双腿所需最关键的规格是： 输送带负荷强度足够 15 稳固 易于组装 好的灵活性（调整高度） 图 2表示输送站所有设计的零件现有的。这表明数字是一部分腿数字表 2中描述，这也显示了一套完整的分类，以组建一个完整的成本分析与所需时间的劳动。现行体制包括塑料腿腿从海外订购括号，不锈钢管腿，这是图切割成指定大小，腿管塑料调整，这是在管腿夹到底部，如图所示。 2。片，这是大小切成正方形，钻孔和焊接管的腿交叉角螺栓支撑板，以支持和后盾腿支架螺栓。 2表中反映出的零件数目的 每个部件和组件的数量是设计消费的腿在每一部分。对于许多客户通过几年常见的投诉举报公司已经改进使用了这种设计，但其中一个是腿部的不稳定。 从初步调查后，很明显，该图连接之间的不锈钢管和塑料脚支架（第一部分和第三部分。二）未严格不够。这些部件的连接的只是一个 6 毫米的螺栓。有时，当输送系统进行完整的产品负载，有人指出，在输送的腿，造成不稳定的机械振动。一个主要的原因，这是由于在 3 月底单螺栓连接各表耳部分和第 7 部分。该输送机被认为是稳定的关键问题，并要求立即整改，以满足客户的期望。 考虑到设计问题，对现有客户喜好的 输送腿，开发一输送腿的新设计。一般来说，稳定和腿部力量的被视为点通车的主要标准，在新设计的改进建议，但其他的考虑是最小化的设计简洁，集会在海外部分缓解。图 3 显示了，腿装配新设计的输送的，而附表三则显示的说明和各部分的成本。 16 Fig. 2. Existing leg design assembly with part names shown in Table 1 Fig. 3. New design for leg assembly with part names in Table 3 17 图 3 显示，新设计腿只包含 5 至 8 个输送机的主要部件。在旧的设计，塑料腿支架，腿管塑料管的调整和腿是最昂贵的项目向大会占 72的腿部的成本。在新的设计方案，这些地方已经取代不锈钢的角度和新的塑料腿调整减少了近 50，装配成本的腿。因此，在小腿部分的总数已经减少 19 至 15 日，每站的总安装成本降低了55 美元的新设计。 新的输送站的设计，测试时，发现更安全和稳定的设计，比旧的。 1 消除零件编号和 5 岁的输送机设计，使新的 设计更稳定和僵化。此外，设计宽度交叉支撑，也增加了两个螺栓安装，而不是老一英寸这提供了整个输送站安装额外的力量。 6 重新设计的侧架 侧架是输送系统的主要部件，提供输送机和几乎所有的安装部分。侧架也将有一个刚性的力量，提供支持所有的负载进行输送。它也容纳输送配件为大会所有关联的。侧架设计的关键考虑因素是： 侧架（深度尺寸） 强度的材料 易于装配 易于制造 图 4 显示了侧架尺寸和参数。侧架设计用于现有似乎是合理的深度的大小（尺寸图的 H。 4）。从最初的调查，发现该图之间的间隔距离，并返回轴杆洞（尺寸 的 G 和F。四）可以减少，因为有一些不必要的两个组成部分之间的差距。重要的一点，检查前重新设计参数，以确保将那些经过两个紧密，返回连锁店将赶不上间隔栏，而输送机运行。设计模型是新的侧架民航处开出，以确保所有的规格是健全和部分放置在适合的位置，以检查和许可。使用框架的设计原理设计制造了新的一面对称，使其适用于所有类型的侧架。这一变化预计将减少边尺寸链框架的各种规模的显着。 Fig. 4. Side frame dimensions 18 表 4 显示了一个比较旧的设计尺寸和新设计的侧架为同一链条的类型。据指出，总体规模（深度输送机）的生产已经减少），从而使储蓄 42 毫米不锈钢侧面由 199 二百四十一毫米每到毫米（尺寸 H 牌照的时间表。因此，从不锈钢板 1500 3000 毫米，旧设计参数只允许 6 个 3 米长的侧架，但与新的设计参数现在有可能产生同样的纸张尺寸 7 侧架的 3 米长的。该材料使用量的帧侧也进行了审查作进一步调查。据估计，约有 55的输送系统的总费用是花在材料。目前框架材料用于一边是 2.5 毫米厚的不锈钢食品级 304。目前，有一个选择，因为其他材料认为可以在市场上与其他被厚度可能。为此，一挠度进行了分析估计，如果有任何其 他类型的合适的材料，以取代现有的材料，以便它不会失败的强度准则。 6.1 侧架挠度分析 图 5 显示确定偏转新框架方面的条件不同载荷下的 X 和 Y 方向的实验装置通过。使用新的设计参数的框架集制造，被调查方侧架的偏转上 1.6 毫米厚的不锈钢。阿方条架螺栓与垫片是酒吧和回报轴实验测试与组装的。为偏转的结果，得到了运用液压机上的可变负载侧架条通过。如图所示。 5，挠度测量仪是垂直放置（ Y）和水平（ X）轴来衡量任何阅读观察到侧框。上应用的负载侧架通过向下方