Friday, June 22, 2018

World Cup 2018




The FIFA World Cup Trophy has become the most sought after and recognized sporting prize in the world and holds a universal appeal that is unique to the sport of football.
However, the current trophy is actually the second generation of the coveted prize. The first trophy – named the Jules Rimet Cup in 1946 in honour of the founding father of the FIFA World Cup™ – was commissioned from French sculptor Abel Lafleur by FIFA. The trophy was a depiction of the goddess of victory holding an octagonal vessel above her head, produced in gold with a base of semi-precious stones.

The Jules Rimet Cup had an eventful history, beginning with a period spent hidden in a box under a bed during World War II. It was later stolen in 1966 while on display in England. With the help of a dog named Pickles, the famed English detectives of Scotland Yard were able to retrieve the Trophy, which was hidden in a suburban garden.

At that time, FIFA regulations stated that any nation winning the FIFA World Cup three times would become permanent owners of the Trophy. Brazil did just that, taking home the Trophy in 1970 only to have misfortune follow in 1983, when the Trophy was stolen in Rio de Janeiro, only this time it was never to be seen again. It is widely believed that it was melted down by thieves.

In the early 1970s, FIFA commissioned a new trophy for the tenth FIFA World Cup™, which was to take place in 1974. Fifty-three designs were submitted to FIFA by experts from seven countries, with Italian artist Silvio Gazzaniga’s work ultimately winning the vote.

Gazzaniga described his creation thus: ”The lines spring out from the base, rising in spirals, stretching out to receive the world. From the remarkable dynamic tensions of the compact body of the sculpture rise the figures of two athletes at the stirring moment of victory.”

The original FIFA World Cup Trophy cannot be won outright anymore, as the new regulations state that it shall remain in FIFA's possession. Instead, the FIFA World Cup™ winners are awarded a replica which they get to keep as a permanent reminder of their great triumph. The gold-plated replica is referred to as the FIFA World Cup Winners’ Trophy.

The authentic, one-of-a-kind FIFA World Cup Trophy is 36.8cm (14.5 inches) tall, weighs in at 6.142kg (13.54 pounds), and is made of 18-carat gold. The base contains two layers of semi-precious malachite while the underside of the trophy is engraved with the year and name of each FIFA World Cup™ winner since 1974. Following the 2014 FIFA World Cup™, the vertical alignment of the champions’ engraved names needed to be redesigned to fit future title holders. The list of world champions since 1974 was therefore rearranged into a spiral to accommodate the names of the winners of future editions of the tournament.

Information courtesy and copyrighted by FIFA.com

Tuesday, April 3, 2018

Oil & Grease Lubrication for Made to Order Bearings

Oil & Grease Lubrication for Made to Order Bearings

          The importance of an oil depends mainly on its film forming ability which depends further on its viscosity.

         An oil of lowest viscosity is generally more suitable for an application since a higher viscosity oil will waste power to overcome the internal friction of the oil itself

          There are many ways to supply a lubricant to a bearing.  We will explore the different options below.

    

Pressure lubrication is probably the most positive and efficient means to provide lubricant to a bearing.
In addition to offering a more copious supply of oil lubricant, up to an average pressure of 50 PSI, it coats the bearing, maintaining a more stable viscosity range and it assists in flushing out dirt and wear debris from the bearing surface.



        


Oil bath lubrication is where the bearing is submerged in oil which makes it the next reliable method to the pressure-fed oil. The shaft speed should not be so great as to cause excessive churning of the oil.




Splash-fed lubrication involves the oil being splattered onto the bearing surface by movement of other adjacent parts. The housing should be reasonably oil-tight to prevent excessive loss and leakage of the lubricant.






         

Oil ring lubrication involves a revolving or processing ring on a shaft in contact with the oil sump. When the shaft is at low speed, sufficient oil may not be brought to the bearing surface or if the shaft speed is too great, the oil will be centrifuged beyond where it is needed. It also may not keep pace with the oil required.

For best results, it has been proposed that the peripheral speed should be in the range of 200 to 2000 feet per minute. The safe load based on full hydrodynamic lubrication mode should be reduced by one half of pressure lubricated bearings.




Wick or waste-pack lubrication delivers oil to a bearing surface by capillary action of a wick or waste-pack as done in many old railroad axles using bobbitted bronze backed partial sleeve bearings. The safe load when compared with pressure-fed full hydrodynamic load should be reduced to 1/4 of the load.


Grease-packed bearings: Grease is generally packed to surround the bearing and although is substantially less effective than oil, it is much more permanent but the bearing will generally operate in boundary conditions.







  Lubricant Selection

           The selection of a lubricant is based on various factors such as the type of operation, whether full hydrodynamic, mixed film or boundary film conditions in addition to the surface speed and bearing load involved.
 
          Various lubricant articles suggest some recommended viscosities for specific services.
 
          As a rule of thumb, the following suggested viscosities should be considered on the basis of surface speed with a qualified load.

                                Speed(fpm)                 Viscosity(sus)                   SAE Oil
                                 30 or less                       1200-1800                           80
                                 70                                    800-1200                           70
                                 150                                  500-800                             60
                                 300                                  300-500                             50
                                 600                                  150-300                             40
                                 1200                                120-150                             30
                                 2400                                  90-120                             20
                                 5000                                  40-90                               10
                                 over 5000                            5-40                                 5

          As a general rule of thumb, heavier oils are recommended for high loads and lighter oils for high speeds.
 
          In order to obtain a quick conversion of viscosity (sus) to centistokes (cSt), multiply the (cSt) value by 5. The multiple will be the approximate (sus) value.

         To obtain the (cSt) value, divide the (sus) value by 5.

         These results are reported to be accurate within 7% in the range of75 to 7000 (sus) and 15 to 1500 (cSt).

          But also be cautioned that this assumption should not be used below 75 (sus) or 15 (cSt).

          For more explicit lubrication data, we suggest you refer to the CBBI manual or to the Machine Design article of March 10, 1966.


I hope post wasn't too DRY for you and this helped you learn about lubricating methods with ease. 

Anyway, that's it for now.  Until next time my metal loving friends...

Thursday, January 25, 2018

Bearing Design Guide: Chapter Sixteen: Effect of the Casting Method on Bronze Alloys




          The casting method should not be ignored but given consideration of the type of service the bronze alloy will be subjected to.

           In particular, the type of load - whether steady and continuous, intermittent or with shock impact or pounding loads - the surface speeds to be encountered and other important features required to be met.

          The casting method has a definite impact on the bronze alloy such as the resulting grain size, density, hardness, mechanical and physical properties, soundness and structure.

          In general, the slower chilled or cooled casting will give rise to coarser and larger grain size. These have a profound effect on the surface qualities, coefficient of friction, wear rate or wear resistance and loads.

          The faster cooled or chilled castings result in greater density, hardness, finer grain size, improved soundness and structure.

           Referring to the illustrations on the following page, please note the finer grain sizes developed by each method of casting.

          Sand Casting: Since molten bronze is poured into a sand mold, the sand or silica having thermal insulating characteristics, will cause slow cooling or chilling of the casting in air. This slow cooling permits the grain size to grow larger, the density, the soundness and structure to be less than by other casting methods.

          Permanent Molded or Chill Casting: The thermal insulating sand is replaced by nickel steel or cast-iron dies. The metal mold quickly chills the casting and this faster solidification results in finer grain size, no interconnected porosity, finer surface finish and improved physical and mechanical properties.

          Centrifugal Casting: Molten metal is poured into a rotating steel or cast-iron die. The centrifugal force impacts the molten metal against the inside of the die, eliminating any porosity. the rotating or spinning die is then sprayed with water coolant to obtain a faster chill than the first two methods discussed the finer grain size further improves the physical and mechanical properties still further.

         Continuous Casting: The molten metal flows by gravity through a graphite die which is chilled
immediately by the cooling jacket surrounding the die. This faster cooling further reduces the grain size and results in still higher physical and mechanical strength.

          The average increase progressively in the tensile and yield strengths is about 5000 to 10,000 PSI and hardness is increased by 10 to 20 points of Brinell hardness.

          Remarks: To further enhances the physical and mechanical properties of the bronzes, extrusion and forging operations can reduce the grain size additionally. These are special processes and the four methods of casting described earlier in this chapter cannot achieve comparable mechanical and physical strength.


Casting Effect On Grain Size and Density


          So...as you can see above, things may look the same on the outside, but they can be very different on the inside.  It is always important to really understand the final application your part will be used in so you know which casting method would be best for you.

          Well...that's it for today. I say goodbye for now. Until next time my metal loving friends...