Precision casting means the general term for the casting process of obtaining precise size castings. The precision casting process includes the sand casting of new sand molds such as water glass sand casting, ethyl silicate sand casting, silica sol sand casting, composite sand casting process; and other model casting processes such as investment casting, ceramic mold casting, metal mold casting, die casting, lost foam casting. Compared with the traditional sand casting process, the casting size obtained by precision casting is more accurate, and the surface finish is better.
Metal Mold Casting,
Precision castings are widely used in transportation, the home appliance industry, the communication industry, electromechanical industry, and other industries.
The size and accuracy of precision castings will be affected by the structure, material, mold making, shell making, baking, pouring, and other factors. The setting of casting production and any unreasonable operation in the production process will change the shrinkage rate of the casting, resulting in the deviation of the dimensional accuracy of the casting from the requirements. The following are factors that can cause dimensional accuracy defects in precision castings:
(1) Influence of casting structure:
a. If the wall of the casting is thick, the shrinkage rate is high; if the wall of the casting is thin, the shrinkage rate is low.
b. If the free shrinkage rate is high, the hindered shrinkage rate is low.
(2) Influence of casting material:
a. The higher the carbon content in the material, the lower the linear shrinkage, and the lower the carbon content, the higher the linear shrinkage.
b. The casting shrinkage rate of the common materials is as follows: casting shrinkage rate K=(LM-LJ)/LJ×100%, LM is the cavity size, and LJ is the casting size. K is affected by the following factors: wax mold K1, casting structure K2, alloy type K3, and pouring temperature K4.
(3) The influence of mold making on the linear shrinkage rate of castings:
a. Among the three processes of wax injection temperature, wax injection pressure, and pressure holding time during molding, the influence of the three processes on the size of the investment mold is the most obvious, the second influence is the pressure of wax injection, and the weakest is pressure holding time.
b. The linear shrinkage of wax (mold) material is about 0.9-1.1%.
c. When the investment mold is stored, it will further shrink, and its shrinkage value is about 10% of the total shrinkage, but after 12 hours of storage, the size of the investment mold is stable.
d. The radial shrinkage rate of the wax mold is only 30-40% of the longitudinal shrinkage rate, and the influence of the wax injection temperature on the free shrinkage rate is much greater than that on the hindered shrinkage rate (the optimal wax injection temperature is 57-59 ℃). , the higher the temperature, the greater the shrinkage).
(4) Influence of shell material: Different foundry sand and foundry powder will have different expansion coefficients.
(5) Influence of shell roasting: Due to the small expansion coefficient of the shell, when the shell temperature is 1150 °C, it is only 0.053%, so it can also be ignored.
(6) Effect of casting temperature: the higher the casting temperature, the greater the shrinkage rate, the lower the casting temperature, the smaller the shrinkage rate, so the casting temperature should be appropriate.
Different precision casting has different processes, so we should select the appropriate process according to the complexity of the casting, surface precision, mechanical properties, and other requirements.
Die Casting Process:
Investment Casting Process:
Lost Foam Casting Process:
Precision Casting Service is a process in which the foundry chooses the precision casting process to complete the order processing according to the complexity, mechanical properties, surface quality, and other precision requirements of the casting.
An excellent precision casting service supplier should have the following capabilities:
l Have a professional technical team that can optimize the process according to the demand and reduces the order's production cost.
l Have excellent production capacity, which can complete the production of precision castings faster.
l Have a complete quality control system to ensure that the product's performance can meet customer requirements.
l Have an experienced freight service team to provide lower freight prices and guarantee faster delivery of goods to you.
l Have a professional after-sales service team that can solve various after-sales problems faster and better.
HULK Metal has engaged in precision casting services since the second half of the 20th century. With the continuous integration of the supply chain, HULK Metal has established a complete precision casting service system. HULK Metal has provided thousands of customers with precision casting services using copper, aluminum, steel, and iron as raw materials. Precision castings manufactured by HULK Metal have been used in over 20 industries, such as automobile manufacturing, home appliance manufacturing, machinery manufacturing, and construction.