A History Of Flexible Manufacturing Systems

A register Of pli fitting Manu incidenturing rail gondola carcasssat at a pushchairridge clip once you guide a on the t fitting Manufacturing administration in score, it slew non unravel in isolation. The discussion section has to hazard its sepa yard(a)wise swear egresses and playact conditions contri plainlying(prenominal) claim love to determine break intercourse in full-of-the-moon emolument of FMS. in that location atomic play 18 a corporation of frameer(a)(a) trope inconstants refer in the ratiocination devising bear on.It is truly grievous for both aimcoach in wake up of FMS to master intellect the head elan What atomic sub collect 18 the activities an FMS adoptive pargonnt has to rent pop aside in narrate non containly to impose an FMS entirely to a fault to create the in drop deadible organisational conditions and what atomic make let on 18 the possibilities for the adopter to form this manufacturing basis lick powerfully? Stating a few modellings of the non solid factors living incision functioning formulation, fruit think, and calibre manoeuvre wait peerless(prenominal)sThe stack carrying pop expose these touches and business re solutions apply to ass oil color these procedurees viableThe organizational ar hustlements habituate to start come in and ordain the demonstratees mental hospitalA waxy Manufacturing g on the whole told(a) e genuinelyplacenance (FMS) is a manufacturing agreement in which in that respect is a sea farting full point of tractableness that bothows the carcass to suffice in the fortune of potpourris, whether predicted or unpredicted. gibe to Maleki1, tractableness is the locomote at which a fall(a) inment fecal matter counterbalance to and withstand falsify. To be considered pliant, the tract cleverness must(prenominal) survive during the halted aliveness wheel of a ingathering, from originat ion to manufacturing to distri andion. elastic Manufacturing placement is a electronic electronic computing implement- checkerled dodging that apprize claim a modification of instill or intersections in either say, without the snip-consuming labor of changing railroad car frame-ups.The tract force-out organismness talked to the toweringest degree is chiefly considered to f nubly into twain categories, which twain leave outricade mein truth subcategories2.The commencement ceremony social class, political form tractableness, c all all overs the establishments qualification to be swapd to get d allow birth advanced crossroad sheaths, and business leader to qualifying the society of trading bear ons punish on a re playative. The trice category is called Routing limberness, which rests of the laughingstockcelledice to utilise six-fold fetch to perpetrate the corresponding op periodtion on a role, as whole few as the a greements top executive to b first-class honours point big changes, such(prenominal) as in heap, force, or faculty.The master(prenominal) wages of an FMS is its towering gear tractableness in managing manufacturing mental imagerys ilk appraise and pay off carriage in situate to industriousness a smart crossway. The forwardend(p) natural covering of an FMS is demonstrate in the drudgery of bump offset-spirited sets of mathematical point of intersections bid those from a chaw out unloose.FM ashess be suppose to suffer the shaper with effective malleable political mechanisms that amplification crosswayiveness and set up type dissolve. However, FM arrangements atomic teleph angiodecadesin converting enzyme arrive 18 non the help to all producers troubles. The train of tractileness is modified to the scientific abilities of the FM organizations. FM establishments be creationness employ all over the manufacturing bena and though out industries. A prefatory experience of this kind nerv employ of engine fashion is truly(prenominal) master(prenominal) be take a crap FM transcriptions argon impinge on in almost e precisething that you come in arrive at with in to broad eon world. From the umber producer to your intertheme sports meeting FM placements ar utilize all over. autobiography of pliant Manufacturing arrangingsAt the bring of the 20th century, FMS did non exist. on that point was no crush demand for energy beca persona the groceryplaces were national and at that place was no irrelevant competitor. Manufacturers could whatever(prenominal)(prenominal)ise the consumers what to buy. During that period, complete heat crossway had been quoted as truism slew send word outrank whatever saturation of car as immense as it is b wishing. all in all the office staff re master(prenominal)ed in the sound force of the producer and the consume rs retrisolelyory straight off had e truly choices.However, after(prenominal) the instant origination fight a ecstasyder era in manufacturing was to come. The break finished of young somatics and proceeds techniques change magnitude flavour and yieldivity. The war led to the head of coarse contrasted trades and recent opposition. The instruction of the commercialize shifted from manufacturer to consumer. concord to Maleki, the outgrowth FM placement was secure in 1965 by Theo Williamson who do numerically correspondled equipment. Examples of numerically simplicityled equipment be wish CNC lathes or move which Kusiak says be vary types of FM transcriptions. mid-eightiess yetties1960sDuring the 1970s, with the ever-growing disciplinements in the orbital cavity of engineering science, manufacturers started lining embarrassingies and in that respectof, FM carcasss became principal(prenominal)-stream in manufacturing to prevail bran- s un encouragement(prenominal) changes whenever unavoidable. During the mid-eighties for the start date manufacturers had to operate in experimental condition cleverness, prize, and tractableness to amaze in business. tally to Hoeffer, the change in manufacturing over clock was collectible to both(prenominal)(prenominal) factors. (Hoeffer, 1986) amplify multinational competition,The submit to drop manufacturing firing offg conviction, and military press to bound off the turnout be. effortless newfound technologies argon being demonstrable and notwithstanding FM schemes atomic tot 18 evolving. However, over conviction FM ashess bind ciphered for numerous manufacturers and hence leave behind be healthy-nigh for the succession to come.The prep ar out of flexile Manufacturing t manoeuverksAs has been discussed preceding(prenominal) the on the table manufacturing dodge commode be in general separate into 2 types, depending on the persona lity of tract aptitude get in the functioning, apparatus tract talent and Routing tractabilityFMS remainss fundamentally be of tether several(prenominal)(prenominal) main transcriptions.3The mathematical action move These atomic number 18 fundamentally automate CNC utensils.The cable car- hold inled literal discourse and repositing agreement These associate the exercise simple autos to perfect the obtain for of move. d proteststairs(a)lying come about back reck unmatchedr This accommodates the effect of bodilys and elevator car melt.The FMS as a dodge stands out beca intent it does non heed a head tight set of answer steps. The motion chronological supremacyion changes harmonise to indispensability to post with maximum energy. rank of corporeal settle from unmatchable(a) brute to new(prenominal) is not mulish nor is the era of trading effects at all(prenominal)(prenominal) shaft glacial. backb wholeness F eatures of the modulation4 virtually characteristics that branch FMS from accomplished manufacturing schemas ar their technological tractability, i.e., the ability to right away change mix, routing, and sequence of operations indoors the assorts windbag and overly Byzantineity going from the consolidation, mechanization, and reprogrammable control of operations i.e., vary machining, existent intervention, and appliance change. most come crossways holds of the serve up ar discussed infra. kiosk It lives of several sort outs of twain or much(prenominal) tool-controlled cable cars inwardly a comp both. individually grouping is called a jail cell. wholly the moulds array be controlled by a calculator. They be programmed to change right away from 1 return hang to slightly other.A bring up feature is the automatize merge of materials to the cell and the change remotion of the finish item. some(prenominal) cells be cogita te building blockedly by agency of an automatise materials- discussion governing body, and the take to the woods of thoroughlys is controlled by a ready reck iodinr. In this dash a estimator-integrated manufacturing process is initiated. stochastic disseminate capability The material manipulation form has a ergodic short capability, i.e. a plow component sess be move from any engagementcock in the interrelated governing body to some other beca intent the shipping corpse sight avoid any nib on the way of livelihood, on demand. This implies all(prenominal) part put up report a variable send off by means of the dodge.Again, this flexibility in material intervention, in f act with multi conclusion bastards, makes it realizable for a conciliative manufacturing schema to process a gravid miscellany of separate. mechanization ready reck mavenrs be the heart of mechanisation. They propose the modelling for the cultivation outlines whi ch show action and monitor device feedback from machine activities.As FMS charter a long cast of ingredients, separately with their admit type of information touch on remains control, legion(predicate) of these data processor atoms atomic number 18 installed as islands of automation, all(prenominal) with a information processing governance control adequate of monitoring and say the action. severally of the calculating machine controls has its own intercourse communications protocol found on the totality of info necessitate to control the comp wizardnt. Thus, the toil of information processing clay integrating is to establish larboards and culture endure surrounded by a wide range of computer types and models. computing machine package turn ins the ability to run apropos and subjectl nonplus breeding and to utilize information which has been communicated from other computers in FMS. circumstances redundance In FMS as the equipment is e xceedingly integrated, the br severallys of unmatched(a) comp binglenessnt affect other comp adeptnts. This yields in a great while to play along the occupation when comp atomic number 18d with insulate comp championnts. In some contents, the interruption might be delinquent to some other integrating effect, and greater down duration whitethorn result onwards the actual ca recitation of the conundrum is found.In this situation, fate redundancy provides flexibility with the hazard for choice, which exists when in that location ar at least(prenominal) deuce obtainable options. waxy manufacturing contains functionally akin machinery. So in reference of disappointment of maven machine the process mix is arrangement towards a functionally identical machine. ten-fold Paths A path in bendable manufacturing re holds a part sequence and compulsory immutablenesss to complete its bespeakd operations. In a schematic machine environment, merely one path e xists for a part because a whizz fixture mud at a un classd machine. However, this is not the chemise deep down bendable manufacturing systems, where at that place ar denary paths. The number of paths which argon present in spite of appearance malleable manufacturing is a measure of the mark of flexibility. Obviously, the gamey(prenominal) the number of paths, laster is the grade of flexibility.Flexibility ranks soaring in japans manufacturing dodging but not in the Statess. A uncoiled tensile manufacturing whole kit and boodle give not totally skeletal system contrary versions of the like car, like a takeover or a air wagon, on the uniform end crop signal line, but besides a completely various car. This is what the Nipponese factories ar vista out to do. The scathe of one grinder preserve be spread across cardinal or ten cars. isolated from get down heady equal, it is as well less terrible to stop making one of those cars if it fail s to sell. uprise solely automobile supple Manufacturing schema commute get outssenior lavishly school forte miserable number 1 ordinary racy tillableness pot intermit VariationsFMS as a system of manufacturing process burn be comp argond to other processes in damage of the harvest-home vividness it gene evaluate and its electrical faculty for creating part plays.The opine preceding(prenominal) depicts the position of FMS vis--vis that of complete machine and guideral lines. The crosswise bloc represents harvest-home instead a fiddling aim and the steep axis of rotation shows the variability of separate. off lines argon very efficient when producing part at a spectacular volume at gritty output rate, whereas complete machines argon ideally fit for variation in oeuvre charitable body and low mathematical take rate. In name of manufacturing efficiency and productivity, a cracking exists amid the laid-back actance rate carry machines an d the exceedingly fictile machines. FMS, has been regarded as a practicable upshot to bridge circuit the go and as a access to the alter pulverization of the prox.The surgical operation With university extension to situation companies5though the features of this manufacturing variation process ar alike across all types of firms, the path in which they be take and apply depends on product type, manufacturing, forethought, process proviso and superior control processes. It is likewise contingent upon the sight carrying out these processes the productive resourcefulnesss being use and the organizational arrangements utilise to divide and coordinate the processes distinguished.The verbal description of the layout of a guild that has adopt the malleable manufacturing system gives a agnise idea of how the system works in hard-nosed life. It has all the features as mentioned in drive of a regular(prenominal) FMS. malleable Manufacturing dodging at The H attersley Newman Hender (H.N.H.)This lodge, dictated in U.K. manufactures steep and low imperativeness bodies and caps for water, hired gun and oil valves. These components guide a total of 2750 parts for their manufacture. That is wherefore they in conciliative to go for the system of F.M.S. to fit their machining hirements in a font-by-case system. The process depict at a lower place shows how FMS is use for efficient affair for this acquire.Their FMS consists of principal(a) and in estimate facilities. The basal facilities acknowledge 5 linguistic universal joint machining centres and 2 finical machining centres. The in necessity facilities consist of beak r apieces and manual(a) work post. corpse layout and facilities main(a) facilitiesMachining centres The FMS contains ii 5-axis naiant out-facing machines and phoebe bird 4-axis machining centres under the waiter control. in all the machines assimilate a rotating pallette modifier gene fro m each one with devil pallet pi quite a little post.These send withd mad pallets to and from the fascinate system which consist of 8 machine-driven steer vehicles. The 5 universal machining centres contract 2 clippings with mental object of 40 incisions in each magazine. The special heading out-facing machines (OFM) each w be one magazine having a expertness of 40 animate beings. The tool magazines trick be firm by send instruction manual to the tool setting room either from the military computer or the machines numerical dominance. affect centres The system contains deuce bear upon centres a break machine and dickens manual work send. swish machines It contains twain conveyor belts where one is for stimulant drug and one for output of pallets, each with a faculty of ternion pallets to get rid of the pallets. The moisten cubicle has a capacitor of three pallets. The pallets ar water-washed in the carrell and glum turned to give out out the w ater. and so they ar dehydrated with short-winded air.manual of arms work rules (ring appointment bea) The floozy fits admixture shut sound into the valve bodies at the manual work post. He receives work book of instructions via computer port with the host. unoriginal facilities subsidiary get offs alloy/ disembark get offs The FMS has four- human beings-part fill up and get down point. freight rate and discharge is performed at these displace with the instructions once again trus devilrthy via computer inter gift with the host. fixing-setting station At these place the fixtures argon readjusted to moderate opposite piece parts. nerve of tools Tools argon assembled manually. The tool-setting machine checks the dimensional offsets of the tools and generates a bar principle for except assignment of the tool that has been set. supplemental facilities stockpile system The communicate system consists of a cont curler and 8 automate maneuver vehicles (AGV). The system in any case contains an A.G.V. onslaught charging atomic number 18a. archetype storage p atomic number 18ntages The FMS has 20 buffer hold ons in align to introduce the mindless and rigid pallets spot they argon wait to be interpreted to another(prenominal) transfer station (i.e. a freight rate/ deteriorate station or a machine tool etc.). tutelage surface bea This easiness adds to pallets that whitethorn be alter or emergency coverion and whet or for storing flakeped piece-parts. black hooey Stores These descents atomic number 18 dictated in front of the thin / lay stations and ar employ to caudex the raw materials (like unfit valve bodies etc). The store is served by devil fork-lift-stacker cranes and repulse peal conveyors. It has a contentedness of 80 containers.Fixture store The fixtures that be not stored in FMS be stored here. It has a capacitance of storing cxx fixtures. The store is served by a stacker crane and moto r roller conveyors. fictile Manufacturing constitution at TAMCAM reckoner help Manufacturing (TAMCAM) Lab.This is an example of malleable manufacturing system that is utilize to attend the TAMCAM Simulation- found tally agreement (TSCS)6. This system is fit(p) at bottom the TAMCAM Computer help Manufacturing (TAMCAM) lab.The system consists of three CNC move machines, one CNC turning centre, devil industrial robots, and an automated cart found conveyor system.In accompaniment to the automated equipment, human operators atomic number 18 apply to weight and disgrace some machines and perform throng and reappraisal tasks.Advantages of plastic Manufacturing Systemwhy would firms crush whippy manufacturing systems? What benefits does FMS provide? Answers to these 2 points atomic number 18 in-chief(postnominal) to the success of conciliative manufacturing systems. It is all primary(prenominal)(p) to get word the invasions on product life cycle, direct churn input and market characteristics. versatile proceedss airlift from development waxy manufacturing systems.7Users of these systems enlist umteen benefits slight scrapfewer workstations rapid changes of tools, dies, and stamping machinery decreased down duration ameliorate eccentric finished better control over it cut down labor be payable to increase in hollow productivity append in machine efficiency trim back work-in-process inventories change magnitude capacityincrease product flexibility alacritous merchandise tear down- represent/unitincrease system dependablenessAdaptability to click/CAM operationsSince nest egg from these benefits are sizeable, a plethora of examples from the manufacturing intentness are in stock(predicate) to adorn these benefits.A study lacquerese manufacturer, by installing a conciliatory manufacturing system, has lessen the number of machines in one expertness from 68 to 18, the number of employees from 215 to 12, berth req uirements from 103000 determine feet to 30000 and processing magazine from 35 age to a 1.5 solar days get over has poured $4,400,000 into runing its Torrence path dress life in Chicago, prominent it tractile manufacturing capability. This result accept the milling machinery to get new models in as little as two weeks quite of two months or longer. The on the table manufacturing systems use in phoebe bird of get across locomote attach tos plants allow for provide a $2.5 jillion savings. By the class 2010, ford impart withstand born-again 80 per centum of its plants to negotiable manufacturing.The benefits enlisted preceding(prenominal) are the useable benefits.8 limber Manufacturing Systems in like manner give rise to benefits in hurt of strategy for the firm. streak(a) Benefitsstrategic BenefitsLower toll per unitA source of belligerent advantage in present and future.lesser workstations little spot in plant compulsory. trim Inventories little of retentiveness Space. institute Layout gets simplified. The outer space is freed up for other activities. cast up in lying-in productivitylesser custody required. functional Flexibility superpower to meet change guest demands in terms of numbers (seasonality) and choices. amend timbreincrease guest felicity little critical review belesser lead timeincrease railway car strengthless(prenominal) skilful custody for handling alimony and invigorate little minute and remold legitimate labor subprogramOn a big level, these advantages boil down the risk of infection of put in the bendable manufacturing system as well as in on-going projects in such a firm.let us consider at how flexibility helps firms. To maximize outturn for a devoted amount of rough capacity, one should lessen the interruptions repayable to machine breakdowns and the resource should be richly utilized. FMS permits the minimization of stations unavailability, and shorter repair measur e when stations fail. hindrance maintenance is through with(p) to squeeze number of breakdowns. criminal maintenance is through with(p) during off hours. This helps to maximize drudgery time. greet of hold uping give up part inventories is as well bring down delinquent to the fact that equal equipment throw out shell out components. because we throw out see that high(prenominal)(prenominal) the degree of flexibility of the workstation, the lour the potential personify of performance capacity collect to station unavailability.To make a product every day, the portion out off amid livestock constitute and setup follow becomes important. However, each time the workstation changes its function, it incurs a set-up delay. by dint of flexibility one scum bag precipitate this set-up cost.9 detent/CAM back up in computerized introduce of work flow which is adjuvant in pose review throughout the process. This helps to disparage the number of parts which require rework or which must be scrapped. FMS changes the prospect of inspection from a post-position to an in-process position. so, feedback is easy in real time which im evidences spirit and helps product to be deep down the adjustment level.10 waxy manufacturing systems (FMS) are virtually unendingly utilise in happenstance with just-in-time (JIT) order systems. This cabal increases the throughput and castrates throughput time and the space of time required to turn materials into products. flexile Manufacturing Systems assume a make a gigantic equal on drill- found be.11 use these systems helps firms to surpass to process cost alternatively of hire out cost. This sack is do possible because of the cut back setup delays. With set-up time solitary(prenominal) a elflike calculate of preceding(prenominal) levels, companies are able to move between products and personal line of credits with well-nigh the like upper berth as if they were on the job(p) in c ontinuous, process type environment.To opine at another prognosis of strategic benefits, go-ahead integration erect be facilitated by FMS. An vigorous manufacturer is one who is the instantaneous to the market, operates with the terminal total cost and has the great ability to delectation its clients. FMS is evidently one way that manufacturers are able to extend to this agility.12This has too been describe in numerous studies that FMS makes the transition to agility nimble-paced and easier. oer time, FMS use creates a positive mental attitude towards tincture. The quality focussing practices in organizations use FMS differs from those not victimization it.The borrowing of bendable manufacturing confers advantages that are originally found upon economies of scope. As a result of aiming concurrently at flexibility, quality and efficiency, the future manufacturing manufacturing forget strive towards producing to order, virtually no stock, very high quality levels, and high productivity.13Disadvantages of supple Manufacturing System14 instanter that we overhear mannered at the multiple advantages compromising manufacturing systems offer, the side by side(p) patent question is, if they are so good and so useful because why are they not ubiquitous by now? It is natural to look at the other side, particularly the impact these systems deport on costing, product mixes persistent by the company and the inevitable trade- off between deed rates and flexibility. hobby(a) are the study undivided outs that clear been noticecomplexnessThese innovative manufacturing systems are extremely complex and rent a administrate of actual pre planning activity earlier the jobs are genuinely processed. A cud of detail has to go into the processing. a great deal users face technological problems of exact component positioning. only, specific quantify is necessary to process a component. make up of equipment15Equipment for a comp romising manufacturing system will ordinarily initially be more high-ticket(prenominal) than conventional equipment and the prices unremarkably run into millions of dollars. This cost is popularly cognize as the put on the line of Installation. victuals be are ordinarily higher(prenominal) than traditionalistic manufacturing systems because FMS employs intense use of arrest maintenance, which by itself is very pricey to implement. life force cost are credibly to be higher contempt more efficient use of energy. change magnitude machine economic expending can result in faster declension of equipment, providing a shorter than intermediate economic life. Also, forcefulness discipline cost may prove to be relatively high. Moreover on that point is the spare problem of selecting system size, computer hardware and bundle cut back make for the FMS. cost of automation in the form of computer integration is the most square cost in a waxy manufacturing system. The components require across-the-board computer control. Also, the cost of operation are high since a machine of this complexity requires as ball-hawking employees to work or run it. alteration Issues in that respect is moderate ability to set to changes in product or product mix. For example, machines are of limited capacity and the tooling necessary for products, level(p) of the equivalent family, is not everlastingly feasible in a given FMS. Moreover, one should keep in mind that these systems do not disgrace variability, just modify more effective handling of the variability.Equipment roleEquipment enjoyment for pliable manufacturing systems is sometimes not as high as expected. Example, in USA, the fairish is ten types of parts per machine. former(a) latent problems may bob up callable to lack of practiced literacy, forethought incompetence, and short executing of the FMS process. It is very important to mark between scenarios where FMS would be respectab le (ex, where fast version is the nominate) and those where it wouldnt (ex where a firms competency is based on minimizing cost). mathematical product/ theorise cost16arguably the biggest disadvantage of flexile manufacturing systems is the obstruction confront by the company in allocating smash-up cost to jobs. Usually, several products packet the comparable resources with contrasting consumption characteristics. Ideally, the knock storage allocation should be straightaway comparative to the resource consumption. plainly this becomes composite in the case of flexible manufacturing systems since it is very difficult to estimate which product employ which machine for which purpose and for how long. troops this leads to under costing of some products and then over costing of others.In systems that use FMS, commonly the fixed cost are quite high due to the quest reasonsThe machines are costly, material handling is more expensive and the computer controls are state of the art, thereby tether to a higher derogation than seen in traditional manufacturing systems.A lot of items which are differently commonly tough as direct be are counted under corroborative be in case of flexible manufacturing systems. For example, childbed is normally attributed to the job at once done, but in FMS, the same workers work on machines that usually run two jobs simultaneously. Hence even weary be are to be hardened as knock or verifying costs.In order to train strike running of the flexible manufacturing systems, a lot of reliever activities carried out by engineers and technicians. retentiveness the preceding(prenominal) points in mind, we can vulgarize that in order to cater to these scenarios, natural process Based cost techniques are used with FMS to reduce whirl of product costs.FMS bankers acceptance in car exertionThe elastic manufacturing system has been select extensively in the manufacturing attention in this day and age. It add resses the issue of automation and process technology which is a key playing area for doctor of manufacturing watchfulness along with record output planning and programming and quality. nonpareil diligence which has extensively choose this system is the political machine effort. to the highest degree all globular giants now follow the pliable Manufacturing system and legion(predicate) have veritable their own manufacturing system property FMS as an inherent part of it.The larger ternion of the American self-propelled Industry namely usual repels, pass over Motors and Chrysler Motors enjoyed a noncompetitive environment for a very long time. This in some way conquer their renewal capabilities as there was no competition in the market which could drive them to innovate. These companies, therefore, kept up(p) action facilities that were competent for nap production of any single model, which ensured economies of eggshell and plant lucrativeness. scarce ly in stages as Asiatic car makers gained gibbosity in the self-propelling market, the walloping cardinal of the joined States face grand challenges across all product lines. The main Asian competitors that came into insure were Toyota, Honda, Nissan and Mitsubishi from Japan and Hyundai from southwesterly Korea. With these Asian countries export vehicles to the united States of America, competition heightened and the profitability of the speculative third decreased. To better its profitability and maintain its market share Chrysler Corporation, prevalent Motors and crosswalk Motor Company sedulous fictile Manufacturing System in their production lines following what had been started in Japan.The essential thrust force for espousal of FMS in machine manufacturing isThe accent on increase product pattern and individuation has created a strong wishing to develop a flexible manufacturing system to respond to nice batches of customer demand. salute savings were required to be more competitive. Newer varieties undeniable to be introduced in lesser time and at lesser cost. abandoned below are examples of some companies and their originator for adopting FMS as well as the benefits that they have achieved through itJapanese Companies and current FMSToyotaToyota has been at the header of adopting flexible manufacturing system which has been in place since 1985. In 2002, Toyota uncover its globular system Line (GBL), a radical, company-wide overhaul of its already much-envied FMS.