Waupaca铸造 is running a 50% reduced scrap rate in 2015 at Plant 1 located in Waupaca, Wisconsin. Read how continuous improvement, employee ingenuity and an investment in quality made this happen.

Molten metal filters are used in the iron casting process to prevent slag and other harmful inclusions from entering the mold and ending up in the final casting. 有几种类型的熔融金属过滤器可供选择. 然而, 保证任何过滤器的最佳性能, it is critical to have an understanding of the physical characteristics of the slag or inclusions specific to your foundry application.

大约三年前, 威尼斯注册送38元位于沃帕卡, 威斯康星州设置选择正确的熔融金属过滤器. 在所有的灰铸铁铸造线上, Waupaca introduced a more expensive filter into the iron casting pouring process after a year's worth of trials.

Waupaca铸造 was noticing a sizable increase in scrap on one of its lines. The line would be run for 2-3 hours and then the scrap rate would start to increase. At a Waupaca Way Production System level 4 meeting with its process engineering team, 一群致力于持续改进的工程师, 模具工头, Dave Peterson recommended changing the filter type to decrease the melt contaminants and reduce the scrap rate. The process engineering team took this suggestion to heart and received permission to run trials after some convincing arguments were presented. 在第一年的试验结束时, Waupaca铸造 had increased the filtration of the melt to decrease the inclusions which resulted in a 40% reduction in scrap. 2015年至今, the scrap rate is now running 50% lower than before the filter switch was implemented. 所有 vertical molding lines are running with the new filter type based on the foreman's initial recommendation. 更换过滤器需要大约12万美元的投资.00 that Waupaca铸造 felt they had to make to increase casting quality. The reduction in scrap helped to offset rising material and other operational costs.

Although a great deal of promising research on improving molten metal filtration technology and efficiency continues in both industry and academia, the vast majority of currently available molten metal filters rely on their relative "sieving" or "screening" ability to remove slag and other inclusions from the base metal as it passes through the body of the filter. It is worth noting that there really is no "perfect" or one-size-fits-all molten metal filter. Each has its own strengths and weaknesses that need to be considered carefully.

选择正确的过滤器

The surface area of the molten metal filter should be at least six times the cross sectional area of the ingate. 孔径以每平方英寸(ppi)的孔数来衡量。. Three main pour sizes can be used – 10 ppi (course), 15 ppi (medium) and 25 ppi (fine). Pore size selection is slightly different for each type of metal cast, 但在选择孔径之前要考虑的主要因素包括:

• 过滤前的熔体清洁度;
• 铸件洁净度要求;
• 可用空间或样板设备，以及
• 金属流量要求.

对于大多数灰口铸铁铸造应用，15 ppi过滤器是足够的. Ductile iron melts tend to have a significant amount of dross due to metal treatment. 10 ppi or 15 ppi filters satisfy most ductile iron casting applications.

The important characteristics of filters are filterability and freeze avoidance. “可过滤性”意味着过滤器必须完成它的工作.e. take out from the melt inclusions which would otherwise result in scrap castings or castings which would require substantial and costly reworking. 'Freeze avoidance' means that the filter must allow the passage of liquid steel through the filter without allowing the molten metal to freeze in route, 造成误铸.

The best filter is the one that meets or exceeds your application requirements and is reasonably priced. 一般来说，要求的过滤器越多，成本越高. In instances where the end-casting will be a critical high-performance item such as a medical implant or a turbine blade, 即使是微小的瑕疵也是不可接受的, the cost of the filter becomes far less important than its ability to remove inclusions.

With molten metal filters, the following needs to be taken into consideration:

• 去除有害夹杂物.
• 这些包裹体的物理特性.
• 浇注温度.
• 端部铸件在现场的关键性质.

选择合适的熔融金属过滤器需要反复试验. 这些试运行既耗时又昂贵, and in most cases the resulting best molten metal filter will also add cost to the overall manufacturing process in the long run. With all of these obstacles being a challenge to both plant and upper management, setting out on a journey of this scale takes a great deal of thought and commitment.

This change in Waupaca铸造's molten metal filtration process ultimately helped both the gray iron casting foundry and its customers by:

• 提高效率
• 降低制造成本
• 提高铸件质量
• 帮助按时交付产品.

It is this type of continuous improvement that drives Waupaca铸造 to be a high quality gray iron and ductile iron casting manufacturer.