STOPPING POWER

[Music] to move these 50-ton rigs requires engines with as much as 250 horsepower but to stop them safely takes 15 thousand horsepower brakes that calls for real stopping power the modern heavy-duty brake is a far cry from early efforts to stop vehicles at first automobiles had brakes only on the rear wheels since it was believed that front wheel brakes would throw the vehicle into a skid others had brake bands around the flywheel or on the prop shaft but as vehicle weights and speeds increased front wheel brakes not only appeared on the scene but took on more and more of the load until today they do about two-thirds of the work of stopping the car elaborate rod linkages have given way to cable actuation only to be replaced by four-wheel hydraulic brakes [Music] on heavy duty vehicles air brakes long since have taken over the field while vacuum power assists passenger car brakes [Music] the key to the whole breaking process friction materials had to keep pace with these developments or in the final analysis it is the brake lining that determines stopping power in order to stop any vehicle all the kinetic energy of its forward movement all of its momentum must be converted into heat the enormous heat which must be dissipated in stopping a loaded rig from high speeds is the subject of continuing engineering research in world bestest laboratories how fast this heat is dissipated is a measure of the power of a braking system since braking surfaces reach temperatures of more than a thousand degrees actually red-hot brake lining obviously must be made of a heat-resistant material more important it must maintain a satisfactory working friction over a wide range of temperature and moisture conditions in addition it must have a long life it must perform with a minimum of wear finally the lining must be soft enough gentle enough that it will not score the brake drum this is the problem of the brake lining manufacturer it's solution is the subject of this film to resist heat and provide body structure about half of a typical brake lining compound is asbestos fiber asbestos is a mineral made up of long flexible crystals of hydrated magnesium silicate most of the world's supply comes from the province of Quebec in eastern Canada from naturally occurring deposits south of the st. Lawrence River it is mined and separated from other rock by a series of so called been officiating operations these include crushing and screening classifying fluffing and drying the asbestos fibers are held together by means of a phenolic resin of thermal setting plastic material capable of polymerization of knitting together chemically when it is heated practically all of the other ingredients in a break lining formulation are designed to stabilize the friction of aligning some of these chemicals perform their chores only at high temperatures others pick up a load when the lining gets wet through experience in testing the chemist designs the compound to perform safely over a wide range of weather and operating conditions in the factory dry mix ingredients are weighed out and blended together in a cascade of specially designed conical mixers the formulas are supervised by world bestest chemists working in cooperation with company product engineers before each batch is released to production a sample is taken to the control laboratory where it is subjected to a variety of quality control tests in this room raw materials are also analyzed to be certain that they conform to specifications only after the batches approved by the control chemists is it released to production to form the heterogeneous brake lining mixture into heavy-duty brake blocks a prescribed amount of the mix is weighed into a preformed mold where it is pressed into a biscuit preform weights and press pressures are carefully controlled to assure proper density of the finished product the preformed biscuit is placed into a curing bowl where it is subjected to heat and pressure to form it into a block slab the temperature and time of this Precure operation are governed by automatic controls as is the periodic release of mould pressure to allow gases to escape after molding the block slab begins to look like brake lining the cure is completed overnight in an automatic oven where program controls automatically raise the heat to the required temperature in a series of prescribed gradual steps the cured slab is trimmed and then is cut into individual break blocks [Music] both the inside and outside surfaces of the block are ground volume break blocks are drilled and cutter board on highly accurate automatic drilling machines every finished block is visually inspected one out of every 25 is checked for drilling pattern accuracy as well as Gogan hardness before the batch is released to bulk storage or to the warehouse quality passenger car brake lining begins much like brake blocks pre-weighed dry mixed ingredients are first preformed into a large board the board is pre cured in a hot press and then chilled in a cold press to set the resin with the board in a flat true condition the semi cured board is cut into strips of the proper width the strips are ground to the required thickness then they are cut to the flat length of the segment and after reheating are formed to the prescribed drum diameter [Music] final cure takes place against heated fixtures of controlled diameter or in automatic ovens [Music] a final grind cleans up the friction surface before drilling grooving kamme grinding cementing or other special operations components are stored partially finished for maximum inventory flexibility while popular numbers are where housed as sets for immediate shipment rolled lining is made by calendaring doughy pre-mixed liquid and solid ingredients on a rolling or tape machine this material is cured and processed in rolls before being cut into segments after which processed in a manner similar to dry mix like some special kinds of lining are extruded through a steel die while industrial friction materials are formed by a variety of methods when world Vestas receives a customer order the required information is coded and punched into data cards for processing in the company's electronic computer Ram Act using its magnetic memory Remick looks up necessary data on each item and prices computes discounts and prints out an acknowledgment of each order then it checks its memory disc for the inventory on each item ordered allocates material for the order adjust the inventory figures in its memory and delivers a set of cards that constitute action notices for each line item so that the material will be withdrawn from the warehouse or assembled and packed for shipment as required the system automatically orders more material from the factory if the stock is running below prescribed minimum levels Packers are responsible for verifying that the lining selected is what the order calls for that it is correctly labeled and is visually ok when the material is ready for shipment RAM AK prints the shipping papers and bills the customer the friction materials which daily leave world bestest duck provides stopping power for virtually every brake application in the world all over the world from passenger cars to the earth movers that build new highways for them from golf carts to go-karts breaks for elevators and industrial machinery brakes and clutches for forging and stamping presses [Music] applications ranging from lawn mowers to chainsaws brakes for City Transit buses and highway cruisers as well for construction and off the road equipment for jeeps and military trucks brakes and clutches for mining equipment the biggest power shovels in the world and the hundred ton dump trucks that service for logging trucks in the Canadian Rockies tankers and fall colors in the Midwest and tractor-trailer rigs all over the continent world Vestas makes brake linings to support its friction material commitments world Vestas maintains a technical staff that is continuously engaged in a customer oriented product development program chase dynamometer x' precisely evaluate friction characteristics under conditions of high temperatures and controlled moisture input the inertia dynamometer duplicates Road conditions on an entire brake assembly and measures stopping power heat buildup and other factors on conventional drum brakes and modern disc brakes as well this same equipment is used for research projects seeking the cause of brake noise and involving such special techniques as the use of high-speed motion picture cameras taking over 3000 exposures per second resulting in ultra slow motion pictures such as these of paramount importance in its development program is world Vestas test car fleet in these highly instrumented vehicles brake linings for all types of cars are evaluated under actual road conditions using standard engineering test procedures as well as sae specifications instruments record deceleration hydraulic pressure the temperature at each brake shoe and the number of stops thus permitting evaluations of stopping ability high temperature fade recovery and overall performance one of the special test locations available to world Vestas is the famous Indianapolis Motor Speedway site of the annual 500-mile racing classic on this track stops can be programmed under conditions of maximum speeds and accelerations far in excess of any conditions ever encountered on the road [Music] [Music] another special testing location familiar to automotive engineers is the jennerstown road in the mountains of Pennsylvania here on a 30 mile test course laid out by Detroit brake specialists aligning really proves it's worth test procedures call for extended periods of brake dragging program snubs and Erie otic stops downgrades longer and more severe than are found anywhere else in the country under these conditions passenger car brake linings reach flash temperatures as high as 800 degrees only exceptional materials can survive this kind of punishment without undue pain [Music] [Music] stopping power then depends on break lining quality and brake lining quality depends on the technical skill and the integrity of the manufacturing you can depend on both when you order world Vestas [Music]