Simple Solutions That Work! Issue 15

OPTIMIZING YOUR FOUNDRY OPERATION VIA OPTIMIZED RISERING PRACTICE E xothermic and insulating feeding systems (or feeders) are common practice in our industry. With the development of modern high production molding equipment, we have accepted the challenges in developing feeding aids for these new systems. Innovative rigging systems have also helped foundries improve productivity by increasing the number of castings per mold. Although this is a positive economic change, it limits positioning, sizing and feeder contact area on the pattern plate, making it challenging for the foundry engineer to produce shrink-free castings. Advancements in manufactured feeding aids are trying to meet the challenges foundries face by balancing improved processes, productivity demands and costs while maintaining high quality castings. In the past, foundries operated with as low as a 30% yield, resulting in additional personnel requirements and higher after-cast processing costs. The pain point in many North American foundries today is the lack of manpower. By optimizing casting yield and having the ability to easily remove feeders from the casting, you can reduce cleaning time and handling of castings and returns, as well as ergonomic improvements. These improvements can result in reduced staffing requirements in the foundry after-cast operations. This is one of many ways that improved risering can improve the bottom line of a foundry business. Few topics in foundry operation are equally as unique to our industry as the need to feed castings through the solidification of cast metals. JONATHAN ERMAN Territory Manager, Chemex Feeding Systems HA International LLC ARTICLE TAKEAWAYS: • You need to consider volume, modulus and location for successful risering practices • Rigging castings manually is simple and generates good results • Chemex Tele-Feeders should be considered for better yield, efficiency, and profitability Many terms are used to describe the products which supply the feed metal: • Risers • Feeders • Feeding aids • Riser heads • Sleeves Whatever you call it, we are talking about the need to accurately provide an adequate volume of liquid metal to the solidifying casting. The widespread growth and implementation of solidification software in our industry has improved optimizing feeder sizing, placement, and design. It has also given foundry personnel insights into how castings solidify as well as the parameters and criteria which lead to solid, defect-free castings. It’s hard to quantify the impact solidification software technology has had to our industry. Unfortunately, the available software packages can be costly and time consuming. That makes it unrealistic to do simulations for every casting in production or as a means to troubleshoot every casting issue. We can’t rely on solidification software alone. We need to make accurate feeding recommendations as timely and efficient as possible. The following process illustrates an alternative methodology to quickly achieve reliable results. VOLUME CONSIDERATION The volume of the casting multiplied by the known volumetric shrinkage of a given alloy will tell you what amount of feed metal is required to generate a solid part. If the 16