What Is the Silver Standard?

Standard silver is also called international standard silver. The standard content is more than 92.5% silver, which is called international standard silver. It is a hypoallergenic material and can be worn safely by people with sensitive skin. Silver alloy containing 7.5% other metals (such as copper) to increase its hardness. British silver coins are made of this silver, so they are called standard. The mark is usually "925", or "92.5fine".

1 000 oz standard silver ingots are submitted to the London Bullion Market Association (LBMA)

Production logistics refers to raw materials, fuels, purchased parts, etc. that are put into production, and then sent to various processing points and storage points after being unloaded and sent out. Units are processed and stored in accordance with the prescribed technological process. With the help of certain transportation devices, the unit flows from a certain point and flows out from a certain point, which always reflects the physical material flow process [2]. The production logistics action and production process in casting are complementary and have already formed part of the production process. For example, for every 1 t of qualified castings produced in a foundry of a large machinery plant, the material is handled up to 110 t times. During the casting of automobile wheels in a foundry of a large automobile plant, only one step from falling sand to storage is required. Handled 16 times; the casting of a diesel engine is only the material in and out, which is 6 times the quality of qualified castings. In the existing 1 000 ounce standard silver ingot casting production, silver ingots need to constantly leave the previous process and enter the next process, and constantly occur logistics operations such as moving up and down, moving forward, and temporarily stopping. The entire process is too focused. Isolated production process, ignoring the connection and cooperation of each logistics action. In a production cycle, the logistics action takes much more time than the actual processing time ^[2]

The 1 000 oz standard silver ingot weighs (32 ± 1) kg. It is trapezoidal in overall shape. The size of the front side (marking side) is 300 mm × 127 mm, and the size of the bottom side is 280 mm × 100 mm. The electrolytic silver powder with a purity of 99.9% is the main raw material. After smelting, it is directly poured into the flat mold mold, and after cooling and molding, it is pickled, washed, coded, weighed, palletized, packed, palletized, etc. ^[2]

From the production process of the LBMA 1000 ounce standard silver ingot, it can be seen that the silver ingot needs to be repeatedly transported in each process and carried out in sequence. There are about 19 production logistics operations. Among them, there are about 7 logistics actions between melting and ejection. During this process, the temperature of the metal changes from liquid to solid. The temperature is high and there are hidden safety hazards. Therefore, this link is designed as a silver ingot casting vehicle, which completes logistics operations such as forming, heat preservation, slow cooling, mold release, and smoke mold, and performs signal feedback, interlocking, and issuing instructions through PLC. In the process of forming silver ingots, the production logistics operations are mainly moving. In order to shorten the time and distance of production logistics and achieve automatic operations, an industrial robot is used to replace labor and set it as the center of the logistics. The production logistics between the pallets are connected in series into a closed loop.

The silver ingot automatic casting line was tested in a precious state-owned metal smelter of a large state-owned enterprise. The operation process of the silver ingot casting car was smooth. The measurement accuracy of the weighing system under the manual and automatic operation processes met the technical standards, and all links could meet the process requirements. Trial production was carried out on the site for 3 days, of which 35 yuan were on the first day, and 49 yuan on the second and third days. The average is 7 pieces / h, working in a single shift for 8 hours. After the 7th furnace is poured, the smelting furnace stops working, and the industrial robot continues to work until the last process is completed.

The experimental results show that by optimizing the production logistics process and eliminating redundant logistics actions, the designed 1 000 oz standard silver ingot automated casting line can not only produce qualified products that meet the LBMA delivery standards, but also shorten the manufacturing time by 36.5% and the handling time by 94% , Shortening the carrying distance by 91.6%, reducing the operator by 40%, increasing the yield by 5.33%, and significantly improving production efficiency. This casting line has obtained national patent (patent number: ZL201420462946.5) ^[1]

Introduce production logistics to the 1,000-ounce standard silver ingot automatic casting line, developed an integrated silver ingot casting cart, and used industrial robots to tandem the production process, reducing redundant logistics actions in the production process. Experiments show that the production time can be shortened significantly, the transportation distance can be reduced, and the product quality can be improved. In order to inspire, introducing production logistics into the traditional manufacturing process, developing new equipment, developing new processes, and upgrading technology can significantly increase production efficiency and save production costs. It is a new means of technological innovation ^[2] .