tech tech - PDF

Document Sample
tech tech - PDF Powered By Docstoc
					                                                                                                                                                                                                                                Guide Elements

     NG gy
   LIhnolo                                  in the guidepost or by a retaining           Production of quality metal stamp-                                                   Upper           Anatomy of a Die
                                            washer that secures to the end of the
                                            guidepost. These components come
                                                                                      ings relies heavily on properly in-
                                                                                      stalled wear plates that have the
                                            in commercial or precision grade.         proper clearance for the type of die
                                            For lubrication, stampers should          where they are used. Wear plates in-                    block                                                                                                Ball-bearing
     On those jobs that do impart sig-      apply a lightweight spindle oil.          stall in the heel-block area of the die                                                                                                                      guide pin
  nificant loads onto the bushings,                                                   set and guide the pad between the                                                                                                                            Ball-bearing
  toolmakers can use a composite to         Wear Strips and Plates                    upper and lower die shoes. With the                                                                                                                          retainer
  line a steel bushing or bearing. Some        Wear strips, of aluminum bronze        tremendous amount of energy that a
  composites can be used in clean-          or bronze-plated steel, typically get     stamping press can produce, the           Bump                                                                                                               Ball-bearing
  room applications where no trace of       the call when the application re-         plates help to avoid die crashes due      cam                                                                                                                bushing
  lubricants or dust can be left behind     quires side-to-side or up-and-down        to misalignment of pad travel.
  to contaminate the end product—           movement, for guidance in metal-                                                                                                                                                                       Upper heel
  medical products or food containers,      stamping applications as well as for      Gibs and Cams                                                                                                                                                block
  for example, or where the next pro-       machine ways in punch presses. The           For heavy-load applications, gibs
  cedure would require a clean part,        natural lubricity of the bronze sur-      made from steel with bronze often                                                                                                                            Wear plates
  such as a painted surface.                face resists wear, abrasion and de-       are specified as guide elements. For
     Sintered materials often are used      formation under high compressive          less-demanding applications, the                                                                                                                            Lower heel
  as guiding elements—bearings,             loads. Wear strips can be provided        gibs can be of aluminum bronze                                                                                                                              plate
  washers and wear plates—due to            with graphite plugs for mainte-           with graphite plugs for constant
  their self-lubricating properties.        nance-free operation.                     lubrication.
                                                                                                                                  Lower shoe
  Ball Bearings for Speed
      Die builders and maintenance
  personnel prefer the use                                                                                                        U blocks, V blocks, center keys,            What’s Next                                cants. These materials can be mold-
  of ball-bearing com-                                                                                                            cam-dwell wear plates and guide                In the future, manufacturers of         ed or formed to suit a particular ap-
  ponents because they                                                                                                            rails primarily are used in the con-        tooling components will be relied          plication and are composed of as
  ease die construc-                                                                                                              struction of custom and standard            on to supply products that give utili-     much as 80 percent oil, which is im-
  tion. High-speed ap-                                                                                                            cams used in automotive and home-           ty, maintenance freedom, absolute          parted at a controlled rate under the
  plications require                                                                                                              appliance applications. V blocks and        interchangeability between a family        influence of external forces, elevat-
  ball-bearing guide                                                                                                              center keys are of hardened alloy           of parts and off-the-shelf availability,   ed temperatures or capillary action.
  components. These consist of                                                                                                    steel or aluminum bronze with self-         with globally competitive pricing.            • Guide bushings, bearings, lin-
  three parts: a steel guide bushing, a                                                                                           lubricating graphite plugs. Center-            The following exemplify the             ers, wear plates and wear strips of
  ball cage or retainer and steel guide                                                                                           key guides and U blocks are of hard-        processes and products that have           graphite-fiber composites. These
  pin. The precision balls incorporat-                                                                                            ened alloy steel; all other blocks are      been pioneered by tooling-compo-           materials can be molded or formed
  ed in the cage run tightly between                                                                                              of hardened alloy steel with self-lu-       nent manufacturers:                        to virtually any shape. The material
  the pin and bushing, ensuring close       U blocks and V blocks find use in special slide applications and as actuating         bricating graphite plugs.                      • Bronze-plated products that           is comprised of polyamide resins
  tolerances and smooth action.             devices, primarily used in the construction of cams for automotive and home-             Quality guiding components are           combine the strength of the steel          with carbon-graphite fibers distrib-
      Guide pins for high-speed appli-      appliance applications.                                                               imperative in cam manufacturing,            backing with the lubricity of bronze;      uted throughout the section. The
  cations are of hardened chrome-                                                                                                 whether purchased as a standard                • Oil-impregnated plastic bear-         unique aspect of the material is a
  alloy steel and come as straight pins          The length of travel, speed, load       Manufacturers produce gibs to            off-the-shelf unit or when building a       ings and bushings;                         network of 1-in.-long carbon fibers
  or demountable pins. Demountable          and mating component that the             exacting standards, important for           custom cam for a specific applica-             • Sintered bearings and bushings;       dispersed throughout the resin. The
  guide pins and guide bushings offer       wear strip will be subjected to helps     use in linear slide applications that       tion. Cams employ mechanical die               • Base-metal alloys plugged with        material imparts tensile, flexibility
  all of the advantages of straight pins    to determine the right thickness,         require extreme accuracy. They typ-         springs, rubber springs, nitrogen gas       graphite for self-lubrication;             and compressive strength as well as
  and straight-sleeve bushings, with        width and length of the wear strip.       ically come in lengths to 48 in., with      springs or air cylinders to assist in re-      • Bushings with liners made of          dimensional stability and controls
  the convenience of simple assembly        These parts function best where the       mounting holes for standard appli-          turning working slides to their prop-       self-lubricating materials;                thermal expansion. Self-lubricating,
  and disassembly.                          mating surface is hardened and            cations or without holes so the tool-       er location after each press stroke.           • Wear plates incorporating lay-        the composites can be used in wear
      Ball-bearing guide-assembly           ground. Wear strips typically are         maker can drill and mount them for          Cam-dwell wear plates are of hard-          ers of self-lubricating material and a     components subjected to tempera-
  bushings also are of hardened             1
                                             ⁄8- to 1-in. thick, 1- to 12-in. wide    custom tooling. Gibs can withstand          ened alloy steel or aluminum bronze         metal backing;                             tures reaching 550 F. The materials
  chrome-alloy steel; ball-retainer         and as long as 96 in.                     temperatures to 400 F, and may              with or without graphite plugs.                • Ball-bearing components.              tend to ingest contaminants present
  cages are of heat-treated aluminum             Wear plates primarily find use in    come in square, V and L shapes to              Complex multi-angular mecha-                Some of the processes and prod-         in hostile environments without
  alloys or polymers that combine           automotive tooling that produces          meet specific criteria.                     nisms, cams require very accurate           ucts for use as guiding elements           detriment to the wear surface.
  light weight and high strength. The       medium-sized to large stamped parts.         Gib assemblies consist of a base         guidance to perform piercing, flang-        being considered or under develop-            • Aramid fibers that incorporate
  ball bearings inserted into the retain-   The plates typically are constructed      plate with two L-shaped gibs                ing and trimming operations. They           ment include:                              high-temperature resin systems are
  er cages, and held in place by stak-      of steel, steel with graphite plugs, or   screwed and doweled to the base.            mount to the upper or lower die                • Guide bushings, bearings and          being considered for bushings and
  ing, are manufactured to the quality      aluminum bronze with graphite             These assemblies find use in special        shoes—those that mount to the               plates constructed of microporous          bearings. This material possesses excel-
  AAA1 grade (25-millionth accuracy         plugs. Wear-plate thickness ranges        slide applications and as actuating         upper shoe are called aerial cams,          polymer lubricants—solid polymeric         lent mechanical strength and dimen-
  class). Ball-retainer cages attach to     from 0.08 to 1 in., width from 0.20 to    devices.                                    those that mount to the lower shoe          materials containing interconnecting       sional stability when immersed in water,
  the guidepost by a setscrew and slot      8 in., and length from 0.20 to 12 in.        Guide blocks, keeper blocks,             are called die-mounted cams.                microscopic pores filled with lubri-       acids and chemical solutions.       MF
 50                                                            MetalForming/March 2002     March 2002/MetalForming                                                                  51

Shared By: