First, manufacturing plastic molding
Plastic mold production process is referred to as tapping, rubber mold is widely used commercial mass production, is because of its elasticity and can easily cut a variety of complex templates can be cut out and glue a careful use of die life up to 10 years. Tapping System a simple plastic mold is not difficult, but cutting a complex system of plastic mold requires patience, research and practice. Plastic mold making tools and materials:
1, the mold frame: usually made of aluminum, also made of other metallic materials such as steel, a variety of sizes.
2, raw rubber: the beginning of the production of plastic mold, without the use of glue is scheduled cooked raw rubber, then the rubber has excellent plasticity, it can be any combination of cut, shaped rubber mold after curing it fixed, have excellent toughness and flexibility, in addition to natural rubber, silicone rubber production in recent years began to use rubber mold.
3, scalpel: Tapping System main tools plastic mold, its blade may need to use, due to a very sharp knife, the operation should be careful.
4, repair mode pen: actually a special electric iron, used to repair defects on the plastic mold.
5, the nozzle holder: plastic mold for each outlet will not be too thick, in order to facilitate both at the edge of wax injection plastic mold to put an outlet of the nozzle to form a bell.
6, pressing machine: the plastic mold curing equipment, in upper and lower plate is equipped electric wire, adjustable temperature, the pressure plate and the screw connection to adjust the distance between the pressure plate two. Plastic mold curing temperature is generally 140 ℃ ~ 150 ℃.
Second, the production of wax
Wax casting out the use of plastic, the process referred to as wax injection. Making wax wax is used with a variety of properties of different waxes formulated. To give the desired melting point synthetic wax, hardness, strength and toughness. Regardless of wax, the total requirement is to have a certain strength, able to completely burn without leaving a residue, melting away the shorter the better, making wax models can be divided into the following three categories:
1, a wax injection: Injection good wax melting point should be low, good flow properties, rapid solidification, has appropriate elasticity, is easy to remove from the plastic mold. A commercially available product wax green, red and other colors to distinguish their properties. Green wax used most commonly, a good wax melt injection temperature between 63 ℃ ~ 74 ℃, the lower the temperature, the smaller the shrinkage wax, wax injection temperature is too high, the wax will flow into the plastic mold kerf, intake air, The formation of small bubbles wax upon cooling.
2, injection wax: The wax injection machine after the wax melt pressure of plastic injection mold, plastic mold injection wax to stand for 2 to 3 minutes. After cooling Carefully remove wax wax, wax injection melting wax when temperatures are adjusted according to the nature of the wax. While the air pressure according to adjust the thickness of wax, usually at 4 to 10 atmospheric pressure, thick wax mold using high pressure. Note wax, with two pieces of steel or aluminum plate or plexiglass plate clamped plastic mold, two armed with wax injection nozzle aligned depress footswitch, wax injection began. When the light is off, wax on a good note.
3, take the wax: the timing of wax removed from the plastic mold to be controlled, not completely solidified wax too early, not forming; too late, it has been hardened brittle, easily broken when removed. Note well and cooled rubber molding on the table with one hand under the mold, one hand slowly bend open the mold, and the wax is still lower die, and then you can pick up the lower mold slightly bent Remove the wax. Take off the wax as tiny surface defects, may be appropriate to repair, repair can be performed by complement wax and scratched.
Third, make plaster mold
1, seed wax: the so-called wax is a wax mold to a regularly welded together, make full use of the cavity space for mass production. Wax welded together we aptly called wax tree, because welding and metal casting outflow channel called outlet, outlet like tree trunks, like the wax linking wax hierarchically distributed branch dry top. For the outlet to be rough enough, no acute angle and bend, and wax, dry branches and trunk weld should be smooth. Complex shape of wax or a plurality of nozzle outlet help. Branch outlet should be as short as possible, usually not more than 15 mm, the main outlet can not be shorter than 7 mm, location and casting methods and other factors related to the outlet. Wax wax chess can be arranged according to shape, size, species distribution on branch dry, shape, weight and nozzle wax form different arrangements should be balanced on branch dry. Kind of good wax can not be separated by too close, or after making a plaster mold will be broken due to model thin cavity wall, kind of good wax tree must be cleansed of surface oil and impurities, and the like can be used organic carbon tetrachloride solvent wash. To wax tree weighed, and make a record in order to calculate the corresponding metal weight at the time of casting.
2, irrigation system, plaster molding: Preparations kind of good wax tree irrigation system, first put on the cast of steel tube, basic categories of steel tube is not perforated centrifuge casting cylinder, vacuum machine pouring Tao with shoulder pads and holes cylinder. Making plaster mold with plaster powder dust is not entirely composed of, in addition to the 25% -30% of plaster powder, other ingredients are calcite, quartz sand, a reducing agent and solidification additives.
Commercially available mainly imported Romen-Vest, Kerr Scurin, Last R & R, Ulterc-Vest and domestic Guangzhou, Shanxi, Shaanxi, and other varieties, comprehensive manufacturer product data is generally gouache ratios are by weight of water to gypsum powder weight of 40 % modulation slurry should be operated at room temperature 21 ℃ -26 ℃ for. The gouache mixing gypsum slurry begins to solidify time is called operating time, usually 9 minutes. During this time, only powder extinguishers filling good standing.
3, pulp and filling tube: pulping tools used, weighing machines have a glass or plastic cylinder sets that mix slurry with stirring spoon and mixing bowl, vacuum pumps used in pulping.
4, dewaxing and baking mold: the cured powder extinguishers to go through the dewaxing and baking mold can be used for casting. Dewaxing general use electric steam, temperature-controlled. When the plaster mold was introduced to make the nozzle down, baking mold with the requirements of the electric furnace temperature is adjustable up to 900 ℃, the actual baking mold temperature should not exceed 760 ℃, when the heating temperature should be gradually increased, reaching the highest temperature After 3 hours to heat, the inner temperature of the oven after all uniform plaster mold plaster mold temperature was lowered to allow the optimum temperature.
Four, melting, casting
Jewelry casting can be divided into two categories: First, melting; one casting. However, due to smelting operating time consuming, difficult to control the temperature, mass production is limited, and is using a centrifuge casting and vacuum casting machine.
After weighing up the required metal and mending, the two metals are uniformly mixed into the melting pot of molten gold, mixing directly after casting the melting. A key issue is casting casting temperature. Casting a metallic material different temperature differs depending on the melting point and the properties of the metal. The melt can flow into jewelry molds have four basic areas. Cause different results in different regions. In order to make the cast blanks to achieve the desired effect, we must first understand the characteristics of the melting point and the metal used, saying called master the furnace.
Melted into a semi-liquid metal melt flow seems very good, in fact Lueqian furnace, heat it contains the inertia weight, not enough to make the two share split hydrothermal flow at the confluence of molten one, semi-liquid metal the consequences are cooling pitting, less serious is the lack of limb legs. Suitable temperature of the metal melt to maintain its optimum mobility, merged into a complete liquid, excellent operating personnel to follow this principle, the consummate operating point gallop freely cast out the best products.
Since the metal melt superheat, the active ingredient volatile, metal hair dry, overheating pitting, sometimes worse than the consequences of inadequate melting point.
(1) centrifugal casting machine is the most widely used machines, using centrifugal force principle of operation is completed.
(2) high vacuum casting machine for plaster mold and die spool requirements, processing trouble blocking the crucible bottom outlet, and unpopular. New automatic vacuum casting machine, although the use of type casting pour, but bulky and expensive, but also affect the vacuum casting machine in the market applications.
Five hollow electroformed
In recent years, the jewelry production process, hollow electroformed been developed, due to the development of a new additive to make this technology matures. In fact, the preparatory work and electroforming lost wax casting process is almost the same, but do not make a plaster mold, only the wax surface sensitization process, the wax mold surface conductivity, and then in a special electroforming plating solution, complete After the wax mold to melt, it morphed into a hollow jewelry.