Foundry sand mixers are an important element in the foundry industries. Sand mixer is a hallow device with a motor and paddle blades that when rotated facilitates the refining of green sand to make it flexible enough to be formed into a molded cast. Today’s technology has made sand mixing a less taxing chore in a foundry because of the invention of the high speed continuous sand mixers. The function of this device is to continually mix the sand that needs to be bonded chemically. The principle is very identical to an electric egg beater where two or more set of blades rotate inside the container and continuously mix the sand ingredient until it is ready for casting.
The old system is called sand batch mixing. The difference of sand batch mixing and continuous mixing is in the latter, sand input needs to be constantly fed into the machine. Furthermore, the output in a continuous mixing is lot less consistent as compared to that of the batch mixing process. Also, the output is measured in grams per hour; thereby making voluminous project less difficult because of the continuous mixer’s high and variable speed. However, if the desired result needs to be more consistent or unadulterated, it is safer to opt for the batch mixing process.
It is very economical to use high speed continuous sand mixer because the equipment is so compact it uses little space. Second there is no problem in refilling the equipment, third, little manpower is needed to operate the system and the system is very cost efficient. Lastly, the maintenance is so simple that in-house engineers or maintenance crew can easily do the job.
Relative to the above, core making system is the result from the output of sand mixing. The core is a molded sand insert that is used to mold and create a void in the interior area of the iron casting and to do this a device called the core box is needed. A clear example of this process is a cast iron water pipe. The hollow portion of the pipe is created by the use of the core box and by the core making system already discussed.
There are three basic systems used in core making and they are isocure cold box, warm box and shell type processes. Depending on the need of the client, the foundry will decide which system is best for the customer and which is more economically viable for the foundry and the end user.
Introduction to Sand Mixing and Core Making System