This page contains a Flash digital edition of a book.
Diecast Zinc


North American Die Casting Association, Wheeling, Illinois Henry Bakemeyer, Die Casting Design & Consulting, Milwaukee


W


hile traditionally fo- cused in au- tomotive, ha r d- war e


and plumbing markets, diecast zinc alloys are used in some consum- er product industries, such as communications, electronics and home ap- pliances. Often at the expense of thermoplastic parts, this growth is due primarily to zinc’s ability to produce: • complex shapes—The complex shapes produced with diecast zinc alloys are the closest any metallic alloy system can come to equaling thermoplas- tics. The ability exceeds that of sheet stamping, extrusion or machining. In addition, extra shape complexity comes at a small cost compared to other processes;


• fine surface finish—The surface fi nish on a diecast zinc component is unsurpassed by any other diecast metal. In addition, electroplated and painted fi nishes can equal or exceed the aesthetic qualities of similar fi n- ishes on molded thermoplastics while providing an engineered structure only possible with metal;


• high mechanical properties at low cost—Zinc is not an inexpensive material, but the diecasting process


Zinc is capable of being cast in small complex shapes with a fi ne surface fi nish, making the material ideal for toy cars.


uses a minimum amount of metal to produce components. In addition, the ability to produce complex shapes allows for the consolidation of several components into a single zinc die cast- ing, eliminating product and assembly costs down the road. Zinc die castings also can be made to a 0.02-in. wall thickness, which allows for a conver- sion from thermoplastic parts that has a reduced weight and cost and a su- perior structure. In addition, zinc die casting dies cost less than those used for other alloys because zinc produces less wear and tear due to its lower heat content per unit volume and its lower casting temperature. Table 1 compares some of the me-


chanical properties of zinc alloys with other materials. Zinc alloys most often are diecast—a


process in which molten metal is inject- ed into metal molds at high pressure— because it provides the material with optimum surface finish and an ability to produce complex parts at a reduced cost. The alloys also can be sand cast to produce a prototype component; how- ever, alloy control is critical in achieving similar properties to those achieved via diecasting. Zinc components range in size from less than an ounce (termed miniature zinc casting) up to 6 lbs.


Alloys Zinc alloys are assigned to three alloy


Table 1. Comparison of Zinc Alloy Properties With Other Materials Material


Tensile


Die Cast Alloys Zinc Alloy 3 ZA-8


ZA-27 380 Aluminum AZ91 Magnesium


Sheet Steels Draw Quality HSLA


Powdered Iron


Plastics ABS


Polycarbonate


Nylon 6 (30% glass reinforced) PET (30% glass reinforced) PBT (30% glass reinforced)


Pictured is a miniature zinc casket arm that weighs less than 6 oz. 40 Metal Casting Design & PurChasing


35 43 52 45 34


40 60 —


8 9


22 21 18


Strength (ksi) Strength (ksi) (psi x 106 —


32 46 23 23


25-35 60 70


— — — — —


6.3


12.4 11.3 10.3 10.3


29.5 29.5


17.5-19.5


1.0 1.0 1.5 2.0 2.5


Source: Engineering Properties of Zinc Alloys, International Lead Zinc Research Organization Inc. 2010 Casting sourCe DireCtory


Yield Young’s Modulus, ) (ksi)


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164  |  Page 165  |  Page 166  |  Page 167  |  Page 168  |  Page 169  |  Page 170  |  Page 171  |  Page 172  |  Page 173  |  Page 174  |  Page 175  |  Page 176  |  Page 177  |  Page 178  |  Page 179  |  Page 180  |  Page 181  |  Page 182  |  Page 183  |  Page 184  |  Page 185  |  Page 186  |  Page 187  |  Page 188  |  Page 189  |  Page 190  |  Page 191  |  Page 192