Don’t look at the copper handicraft ornaments that look very simple, but the manufacturing process of modern copper handicraft ornaments is by no means a simple process of splicing and stacking, but requires professional casting skills and multi-faceted and complex process operations such as sculpture and mold opening. , run-in, through the use of copper alloy material suitable for casting sculpture, high temperature, hot melt casting.
Metal plastic deformation method for copper processing to process copper ingot billets into copper sheets metal fabrication, strips, foils, pipes, bars, profiles and wires. The most important metal plastic processing methods are rolling, extrusion and stretching, and forging, deep drawing, spinning and other processing techniques can also be used for copper foil. The following will introduce the manufacturing process of copper cnc machining technology.
Remanufacturing mould
According to specific requirements such as the size of the sculpture shape and the level of refinement, different reproduction processes are adopted. For larger sculptures, those with relatively low level of refinement require gypsum and fiberglass molds; for those with smaller sculptures and relatively high levels of refinement, silicone molds are used. Under normal circumstances, the combined method of the two copper manufacturing processes is used to overturn the mold. The large-area shapes with relatively simple turns, undulations, lines and details in the same sculpture are made of plaster and fiberglass, and the shapes of local details and complex lines are made of silicone.
The hanging shell
The goal of shell hanging is to form a casting cavity outside the wax mold. Generally use water glass hanging shell. This is compared to traditional craftsmanship. Put the prepared wax film in the water glass tank for a certain period of time, and then use fine quartz sand to hang the manufactured wax pattern with fine sand and wrap it up layer by layer. Every time you hang it, let it dry. Then hang up again. The sand shell is made of 9mm (5-7 layers) thick, and the number of times the sand is hung has a certain relationship with the size of the sculpture. The bigger ones need to hang up ten to twenty times. Takes a relatively long time. Form a relatively hard casting cavity.
The benefit of this craft is that the surface treatment of the artwork is delicate and does not damage the brushstrokes made by the sculptor. The original appearance of the sculpture prototype is basically adhered to, but the defect is that the cycle is long and the cost is high.
Casting Material selection
At present, the commonly used copper for casting is mainly brass, tin bronze and pure copper.
Brass is copper containing a certain amount of zinc. Generally, brass with a zinc content of about 30-40% is often used for artistic casting. Brass has good mechanical properties, good plasticity in hot state and cold state, easy machinability, easy brazing and welding, and corrosion resistance. Glossiness, fineness, and artistic expression are abundant. In addition, the price of brass is relatively cheap, and it is a material of modern copper carving craftsmanship.
Copper alloys other than brass and cupronickel are collectively referred to as bronze. Tin bronze is the oldest alloy in use. In ancient my country, it was often used to make tripods, bells, weapons, Beryllium copper mirrors and other utensils. Tin bronze has good corrosion resistance, good toughness, easy processing, high hardness, small compression, good durability, and is also a commonly used art casting material.
Process castings
The casting process of bronze sculpture is complicated and involves all aspects of professional operation knowledge and steps, so I won’t go into details here. A brief introduction is as follows.
Prepare the sintering spare hollow cavity. Weigh an appropriate amount of copper, zinc, tin and other metals in proportion, put them in a crucible, and heat to 1100-1500°C. Until the copper and other metals in the crucible are completely melted and mixed. Then, the melted copper liquid is immediately injected into the cavity, and after cooling, the outer sand shell is shattered, and the rough copper and brass casting product is peeled off.
It should be specially pointed out that because individual manufacturers are seeking low cost and vicious competition, they often use impure miscellaneous copper, inferior scrap copper and other unqualified raw materials. Various casting defects occur.
