Document 3eEx59yj1X5nk0Ng3vbLZzaG0

possibility of breakage, especially where multiple impressions or nesting methods are employed Preliminary or breakdown operations must be designed so that they accomplish the specific purpose and must be systematically arranged so that they do not create a hazard for the operator as he completes the forging cycle Radical bends or severe reductions in vol ume that might tend to jerk the tongs from the hands of the operator should be avoided Such operations should be modified or com pleted in additional operations The thickness and width of flash, gutter, and sprue should be ample so that flash or tong holds are not sheared off The size of the gates is important They should be de signed m relation to the size of the stock and the tongs used Cates should have enough width, depth, and clearance to allow safe handling Some dies, especially for smaller hammers, are designed with cutoffs which shear the completed forging from the end of the bar If possible, such cutoffs should be placed on one of the rear comers of the die for the operator's safety If cutoffs are placed on the front of the die and are used by placing the stock across the knife portion at an angle, enough clearance must be provided between the die and the hammer frame or gib Hammer die maintenance is important be cause of the nature of forging work and the abnormal abuse to which the dies are sub ject For example, fillet and comer radii in the impressions may be enlarged or sharpened by impact pressures, scale, abrasion, and wear It is therefore necessary to inspect these radii and correct any alteration that may be hazardous Sometimes the face of a forging die may be welded either to correct some defect or to maintain specifications A hard, brittle, or thin-skinned weld can become a flying hazard under impact The rod and the pre heating and postheating methods should be selected with extreme caution Provisions for storing dies, such as racks and rails, are essential to safety, good house keeping, and efficiency Dies preferably should be stored in an area separate from the forge shop and away from vibration Dote BOARD HAMMER MAINTENANCE CHECK Hummer No targfmw item CHECKED TIE BARS 8 SPRINGS NAME STUDS A SPRINGS DU KEYS A SKIMS SOW BLOCK KCT A SHUNS RAM CLEARANCE GUIDE BOLTS A ADJ MOTOR MOUNTS MOTOR COUPLING ROUSHAFT BEARINGS WIRING A CONTROLS FLYWHEEL A BEARINGS DRIVE GEARS ROU ADJUSTMENT LUBRICATION STEAM LINES BOARDS A WEDGES Alt LINES AIR FOOT SWITCH AIR CU A LINKAGE TREADLE A LINKAGE BOARD CLAMPS A LINKAGE DOGS A STOPS KNOCKOUT ARM FRICTION RODS SAFETY RODS REMARKS CONDITION TYPE OP REPAIR EST HRS TO REPAIR Fig 28-24 (upper left) -- Maintenance checklist for board drop hammers Maintenance and inspection A well-planned preventive maintenance program for forging hammers will help to reduce the number and seventy of accidents by minimizing part breakage and wear Reg ular inspections will disclose production units which are not operating up to standard so that repairs or adjustments can be made The results of a good maintenance pro gram can be measured in reduced operating costs which include 1 Cost of machine downtime, breakage, and lost production 2 Cost of replacement parts and labor 3 Cost of accidents due to faulty equipment Maintenance checklists for hammers (Figs 28-24 and 28-25) can be the basis for formulating a definite, planned inspection program A written checklist avoids the errors resulting from verbal reports that are often forgotten or misunderstood 843