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Influence of Mechanical Press Dimensionson its Kinematic BehaviorIulian Taba ra and Constantin DogariuAbstract This paper analyzes the influence of the links dimensions on thekinematics of the knuckle joint press. At the same time, depending on the results ofthe analysis, is accomplished the selection of the manufacturing operation for eachconsidered structure. Modelling the knuckle joint press structures was performedusing SolidWorks application while their operation simulation and determinationof kinematic parameters variation diagrams of the ram was done using SolidWorksMotion model.Keywords Knuckle joint press mechanism?Motion simulation?Suitableoperation1 IntroductionTo achieve optimal technological conditions necessary for the development ofplastic deformation, kinematic assembly of the presses must respect the specificcharacteristics of different processing methods. During operation of the press, thematerial is deformed under the action of the kinematic machine assembly andtherefore the ram speed is obtained from the conditions imposed to its movement.Ram speed has to be maintained in accordance with specific technologicalrequirements of each operation, and towards the end of stroke race is necessary toensure the transition from v = vmaxto v = 0, the system occur without significantdynamic loads.I. Taba ra (&) ? C. DogariuUniversity Politehnica Bucharest, Bucharest, Romaniae-mail: iuliantabaraC. Dogariue-mail: cdogariuI. Visa (ed.), The 11th IFToMM International Symposium on Scienceof Mechanisms and Machines, Mechanisms and Machine Science 18,DOI: 10.1007/978-3-319-01845-4_22, ? Springer International Publishing Switzerland 2014217Processing procedures using mechanical presses are dependent on the tem-perature at which deformation occurs, the speed of the ram, thickness of materialsubjected to processing, dimensional and geometric characteristics of the shape ofthe finished piece, etc. (Al-Arifiet al. 2011; Osakada et al. 2011; Taba ra andTureac 1984; Taba ra et al. 1976; Strano and Albertelli 2011; Der et al. 2007; Reid1991; Oza and Patel 2011; Boerger 2000, 2012).Kinematic parameters variation characteristics of the ram are very important forobtaining a high quality of machined parts. Also, depending on desired operation isimposed a certain interval of rams kinematic parameters of variation as much as acertain aspect corresponding to the requirements of the imposed manufacturingprocess. In this paper it is determined which are the variants of the optimal structureof knuckle joint press depending on the operation which must realized by therespective machines. It will have in view the minimal constructive modification ofthe schemes knuckle joint press schemes but with maximal impact on obtainingsome diagrams of variation conform to the various imposed operations.2 ContentDesigning mechanisms for knuckle joint presses must be done taking into accountprocessing media which it is intended. In this way are taken into account pressesfor operations such as: punching, stamping, forging, pressing powders etc.Kinematics of knuckle joint presses mechanisms determines the choosing of theoptimal solution for each of the plastic deformation operations listed above.This paper addresses only mechanical presses which contain knuckle jointmechanism. Kinematics of these mechanisms depends on their structure, the sizeof its components and in a large measure by their position in space. Next, we insistonly on the last aspect, namely the influence of upper joint position on thekinematics knuckle joint mechanism.For this we consider joint D located at the top (Fig. 1a) in three positions bytranslating it horizontally.In the first version joints D and E are located on the same vertical and determinethe direction of movement of the press ram. This is considered the classicalstructure of the knuckle joint press mechanism.The second version (Fig. 1b) was made considering that D joint is movedopposite to the main shaft of the mechanical press with a distance.The third version (Fig. 1c) was accomplished considering that D joint is movedand placed in a symmetrical position to the one presented in the previous case(Fig. 1b).Kinematic analysis consisted in determining the displacement, velocity andacceleration of the ram of the mechanical press (specifically E joint).Results are represented in Figs. 2, 3 and 4. Figure 2 shows the variation ofdisplacement for a complete cinematic cycle in the three cases mentioned aboveand noted a, b, c.218I. Taba ra and C. DogariuFig. 1 Considered configurations of knuckle joint press mechanism770.9771.5772.2772.8773.4Linear Displacement14 (mm)759762766769772Linear Displacement15 (mm)0.000.200.400.600.801.001.201.401.601.802.00Time (sec)0.000.200.400.600.801.001.201.401.601.802.00Time (sec)0.000.200.400.600.801.001.201.401.601.802.00Time (sec)767769771773775Linear Displacement13 (mm)(a)(b)(c)Fig. 2 Ram displacement function of timeInfluence of Mechanical Press Dimensions219Analyzing the diagrams of ram displacement variation depending on time isshown that the shortest stroke is done in the second case (Fig. 2b) and longest ispresented in the first case (Fig. 2c). These schemes allow the selection of optimalkinematics depending on the operation to be executed by the mechanical press andthe thickness of material to be deformed. Processing characteristic of each oper-ation requires a certain size of the work stroke (deformation stroke) which is notidentical with the entire descendent stroke of the mechanical press.For a same active stroke length, it is found that the contact time between tooland material for processing is the longest in the second case and the shortest in thethird case. Although the duration of contact between tool and work piece is higherin the second case, in this situation there is a noticeable reversal of the ram afterreaching end of the stroke.Note that speed limits vary between low limits (Fig. 3b) but with multiplevariations during the same cycle cinematic which is another reason why thisstructure is recommended to press the pressing powders. 0 5 91419Velocity5 (mm/sec)02579Velocity6 (mm/sec) 0 8152330Velocity7 (mm/sec)0.000.200.400.600.801.001.201.401.601.802.00Time (sec)0.000.200.400.600.801.001.201.401.601.802.00Time (sec)0.000.200.400.600.801.001.201.401.601.802.00Time (sec)(a)(b)(c)Fig. 3 Ram velocity function of time220I. Taba ra and C. DogariuThis solution can be adopted for presses that make pressing powders becausethe specificity of pressing powders consists in the fact that the speed should be lowand the tool return allow stress relaxation and air removal from material particleswhich are pressed followed by a new compaction aimed to give the final shape ofthe product.The third variant (Fig. 3c) show that the contact between tool and work pieceoccurs in a very short time, in this situation, in this situation the press meant to beused for punching operations where displacement and speed are higher than in theprevious case. Unlike the last version, the first version allows contact between tooland work piece over a longer period of time.At the same time the range of velocities and accelerations is reduced withgentle changes of in velocity (Fig. 3a) and acceleration (Fig. 4a) in the first versionin comparison with the third one (Figs. 3c and 4c). Smooth variation of acceler-ation leads to reduced dynamic shock, one of the most important goals pursued inthe operation of mechanical presses. Therefore, this structure is suitable fordrawing and assembly operations by plastic deformation.0.000.200.400.600.801.001.201.401.601.802.00Time (sec)0.000.200.400.600.801.001.201.401.601.802.00Time (sec)0.000.200.400.600.801.001.201.401.601.802.00Time (sec) 223446586Acceleration5 (mm/sec*2) 113263851Acceleration6 (mm/sec*2) 4 34 64 94124Acceleration7 (mm/sec*2)(a)(b)(c)Fig. 4 Ram acceleration function of timeInfluence of Mechanical Press Dimensions2213 ConclusionsIt is noted that using very small changes of position of a joint are obtained importantinfluence upon displacement, position, velocity and acceleration of the workingram. For this reason it is necessary for each project a detailed analysis to determinethe optimal variant to satisfy the requirements of the machining process by plasticdeformation. The press configuration modelling was fulfilled using SolidWorkssoftware and their running simulation and determination of kinematic parametersvariation diagrams of the ram was achieved using SolidWorks Motion model,which allow the selection of the optimal structure according to the kinematicrequirements imposed by each operation performed by plastic deformation.ReferencesAl-ArifiN, Zamani A, Khan J (2011) Billet optimization for steering knuckle using Taguchimethodology. Int J Comp Theory Eng 3(4)Boerger D (2000) The use of link motion on mechanical presses, AIDA-Tech. AIDA-AmericaCorporationDer MT, Hsin PC, Wei CS, Chun YH, Tzuen LC (2007) Performance improvement of a punchingmechanism for flexible printed circuit boards. In: Proceedings of the 13th world congress inmechanism and machine science, Guanajuato, A724, Besancon, France, pp 1821 June 2007Flexible on the Job (2012) Knuckle-joint presses for the Non-Automative Industry, ShulerBrochure, Netphen-WerthenbachOsakada KV, Mori K, Altan T, Groche P (2011) Mechanical servo press technology for metalforming. Elsevier Editorial System(tm) for CIRP, Annals 2011, vol 60/2Oza R, Patel SP (2011) Analysis and optimization of drive shaft in eccentric mechanical press. IntJ Eng Res Appl (IJERA) 1(2):055058Reid D (1991) Fundamentals of tool design, Society of manufacturing engineers. Publicationsdevelopment departmentStrano M, Albertelli P (2011) Eco-design of forming machines. Polytechnic University of Milan,Department of MechanicsTaba ra V, Catrina D, Ganea V (1976) Calculation, design and adjustment of presses. TechnicalPublishing House, BucharestTaba ra V, Tureac I (1984) Machines for plastic deformation. Didactic and PedagogicalPublishing House, Bucharest222I. Taba ra and C. DogariuMechanical Pressing DEAN K. BREDESON, The French Oil Mill Machinery Co., Piqua, OH ABSTRACT The major current movement of screw presses into the U.S. vegetable oil field is as prepresses. Except for highly industrialized nations outside the U.S., the screw press retains a major part of the oilseed processing market. The three essential requirements for efficient extraction are discussed, including operating parameters for various oilseeds. The trend is toward larger capacity screw presses. From the emphasis placed on solvent extraction one would almost assume that screw presses were obsolete in the United States. In spite of the great number of medium and large solvent plants, there are still over 100 mills in the U.S. using screw presses for extracting vegetable oil. There is a cotton seed crushing mill in Little Roch, AK, that employs ten screw presses, each equipped with a 100 HP drive motor crushing 450 tons of seed a day to a residual oil of 3.5%. There are many more mills, mostly of smaller size, but using screw presses with 200 and 300 HP, that con- tinually crush seed in competition with the solvent plants. However, in the United States there is no trend to installing new screw press mills for cottonseed, soybeans, flaxseed, etc., except in very special situations. Occasionally a processor who has a good market situation with screw press meal will replace small worn out screw presses with modern large presses (Fig. 1). Screw presses are still being purchased and installed in the United States for the full extraction of oil from special high oil content nuts, for corn germ, for chocolate extrac- tion, for coffee oil extraction, and for use in extracting grease and tallow in packing house and rendering use. The major current movement of screw presses into the vegetable oil field in the U.S. is as prepresses to pre-extract high oil bearing materials prior to solvent extraction. For years the trend in the industry was to speed up an old full press screw press, change the shaft and screen bar spacing, and utilize this equipment for the prepress operation. Now the press manufacturers have designed efficient large presses with features and prices in relation to tonnage capabilities that make it a better investment to purchase new prepress equipment (Fig. 2). With the exception of the highly industrialized nations outside the U.S., the screw press retains a major part of the market for the extraction of oilseeds. Many of the less developed countries, or undeveloped countries, have large, efficient screw press mills employing the latest types of high horsepower screw presses presently designed and manufactured. And if the infrastructure of a country makes it feasible to utilize solvent extraction, the latest in high capacity prepresses are employed with modern solvent extraction plants. No brief summary of the utilization of screw presses would be complete without saying that the fast expanding oil palm industry is just graduating from the hydraulic press stage to the screw press era, and special screw presses are having wide accePtance in Africa and the East Indies. A decade ago we were all talking about higher capacity presses; longer drainage cages, which were preceded by extension cages; the importance of rolling seed to rupture oil cell walls; and the importance of a proper cook. With our equipment, the cottonseed meats from 45 tons of whole cottonseed per press per 24 hr can be processed to a residual oil of 3 to 3.5% with good quality oil and bright cake because of the water cooled cages and shafts. Not too much has changed except we, as well as many of our competitors make larger roils, larger cookers, larger screw presses with more sophistication. Before looking at todays screw presses it might be well to review a few basics. There are three steps to good full extraction, all of major importance. The first is thorough and complete rolling of oilseed meats to uniformly rupture the greatest number of oil cells and to present a homoge- nous flake to the cooker conditioner. The second is a leisurely complete cook in a cooker that agitates the meats a minimum but insures no scorching, burning, or short cycling, and ruptures all of the remaining unruptured oil cells as well as coagulates the protein. The cooker must quickly increase the temperature above 180 F to inhibit destructive enzymes and then dry to pressing moisture at a minimum temperature. The third step is to have an efficient screw press. A screw press for full pressing usually has a high speed feed screw to compact the cooked meats, eliminate entrained air, and exert low pressure on the cooked meats. The first low pressure screw will press out 40 to 50% of the oil which can be removed in the press. In French presses this high speed feed screw usually starts with a 6 in. pitch and ends with a 4%in. pitch. It usually turns three to four times faster than the main shaft. The feed screw and the main screw rotate in a cage which is lined with case hardened FIG. 1. C3300 Full press screw press. 10?88 in. inside diameter, two speed shaft, 102 in. drainage, driven by 300 HP. J. AM. OIL CHEMISTS SOC., June 1977 (VOL. 54) FIG. 2. B2100 Prepress. 12 in. to 10?88 in. inside diameter, 50 in. to 72 in. drainoge, driven by 200 HP. 489A FIG. 3. H2-6600 Prepress. 16 in. to 14 in. inside diameter, 102 in. drainage, driven by 600 HP. tool steel screen bars ! in. thick, ?89 in. wide and 11-1/16 in. long and mounted around the periphery of a cage with spacers of from .020 to .005 between the bars. This small space or slot permits the drainage of the oil as the pressure is increased on cooked meats. After the slightly pressed meats leave the feed screw section, they pass into the slower speed high pressure section which is usually about six times longer than the low pressure section. The pitch of the pressing worms decrease from 6 in. to 3 in. and the body diameters increase from 75% of the inside diameter of the cage to 95% of the inside diameter. The pressing worms are reversible and are interrupted by tapered collars between the worms. Breaker bars extend to within 1/16 in. of the surface of the tapered collars from the ID of the cage to inhibit rotation of the pressed meats. At the discharge end of the shaft a moveable cone or choke permits the establishment of a restrictive orifice to control the final pressure. The pressure in full pressing ranges up to the 14,000 to 15,000 psi range. This great pressure gradually increasing through the length of the cage squeezes out the remaining recoverable oil after the low pressure section and results in residual oil in cake of 3 to 3%. Of course the great pressure results in the generation of heat and the tendency to wear, so most worms and collars are hard coated with various types of stellite to resist abrasion and establish the proper coefficient of friction. The excess heat generated is dissipated through water cooled cages and a water cooled shaft. Today in a new installation for the full extraction of the meats from cottonseed we would recommend a large 5 ft high 60 in. wide crushing roll to thoroughly roll the meat to the equivalent of .007 to .009 in. thick. We would furnish one cooker/conditioner of 100 in. or 132 in. in diameter with sufficient kettles to furnish a residence time of 50 or more min. The cooker would quickly increase the tempera- ture of the meats in the top rings to 190 F, the moisture would be increased by a steam/water spray to the 10% to 13% range, and the meats would be held at this temperature and moisture content for about 20 min. The meats would then be dried to a pressing moisture of about 3% and 250 F at the feeder to the screw press. Our screw press might be driven by a 200 HP electric motor, have an 8% in. diameter low pressure feed section and a 7 in. diameter high pressure cage. The drainage cage would be eight sections of 11-1/16 in. long screen bars. The cages would be held together with quick removable clamps rather than dozens of heavy hard-to-remove bolts. The cages and shaft would be water cooled. This 200 HP screw press would have the capacity of 70 metric tons, whole seed basis, and would produce a bright cake with 3 to 3% residual oil. Or the press might be driven by a 300 HP motor, have a 10?88 in. inside diameter cage, of nine or ten s