As for the sand castings, there are several moulding processes, which include manual moulding, machine molding (mechanical moulding), automatic machine molding. The automatic molding include horizontal molding and vertical molding. The famous brands include KW, disa, sinto, HWS, TOKYO, TOYO and luolamendi etc. The Japan sinto manufactured FBM-I, FBO-Ⅱ, FBO-III, FBM-IV, FBM-ⅢT automolding lines. The flask size ranges from 350*450, 480*360, 510*410, 550*450, 610*508 to 700*600.
Automatic molding line usually produces small to medium castings with weights from 0.5kg to 30kg. This line uses green sand as the sand material. They can use the oil sand core and precoated sand core.
What is the advantage of the auto molding line? Firstly, high production efficiency. One line can produce 100 boxes within 3 hours. Secondly, good surface quality and dimensions.
However, there are also some disadvantages for the auto molding line. The auto molding line needs metal patterns / molds. The metal patterns usually cost from 2000 USD to 4000 USD. Therefore, if you annual demand is small, we do not suggest you to use auto molding line. Secondly, they have size and weight limitation. Thirdly, since the cooling time is short, the castings will have some level of deformation during cooling. Therefore, if the figure or structure of the castings are easy for deformation, you can not make them by auto molding line. Fourthly, the sand cleaning is through the violent vibration. Therefore, the strong shake will damage the small buttons on the surface of castings. The castings will also damage each other during sand cleaning period.
According to the opinion of Mr. Galen Wang from Dandong Foundry. In the future, the automatic molding can not completely replace the traditional manual molding process. These molding processes can be a good supplement to each other.
Wooden patterns are also named wooden molds, wooden moulds, which are made in pattern workshops, the materials are wood. The wooden patterns should be made by skilled workers, and will be used for sand casting process.
The metal foundries usually use wooden patterns to make samples. Because of its cheap cost, easy modification and quick delivery. According to the different complex, one set of wooden patterns will use about 3 to 10 days to complete. The wooden pattern has a very short lifetime. They usually can make only hundreds of castings. However, you have to store them very carefully. Even so, they will have some kind of deformation after a period time. Therefore, they can not be used for batch production. In addition, their strength is limited, so they can not make some castings with very thin wall thickness and some special structures. The metal foundries usually make the resin patterns or metal patterns according to the approved wooden patterns.
The full name of resin patterns are resin epoxy fiber glass reinforced patterns, glass fiber reinforced plastic patterns, Fiber Reinforced Plastics (FRP) Patterns, which is green, and made by resin and glass fiber. The resin keeps good surface quality, and glass fiber will reinforce the inside strength. Therefore, resin patterns can form complex structure, low cost, good strength, easy modification, good resistance to deformation. So, resin patterns can make thousands of castings. Resin patterns have been widely used in the metal foundries in China, and there are many professional resin pattern workshops who are serving for the metal foundries.
The metal patterns are usually made by iron and aluminum. And machined by normal machined, digital milling machines or CNC centers. The advantages for the metal patterns are good surface quality, very long lifetimes, good strength and many others. The disadvantages are long delivery time, high cost, and can not make very large castings. The iron patterns are usually used on the automatic molding line, and aluminum patterns have lower cost, and widely used for auto molding lines and machine molding, manual molding process.
According to the opinion of Galen Wang from Dandong Foundry, the clients should choose the patterns according to your annual demand and quality requirements.
For the photos of these patterns, please check Dandong Foundry Blog .
For the photos of FBO automatic molding line, please check Dandong Foundry Blog