Castings Sustain Communities
A charity’s innovation helps HIV/AIDS survivors thrive in Africa.
Denise Kapel, Senior Editor
(Click here to see the story as it appears in March's Modern Casting.)
According to the latest report from UNAIDS, the the Joint United Nations Programme on HIV/AIDS, approximately 35 million people are known to be living with HIV, more than 25 million of them in Africa. In the early 1980s, just as the world was learning of the disease, a small group of engineers in Minnesota was working on designing innovative food and water tools to reduce hunger and poverty in the developing world.
Today, thousands of their food grinders, water chlorinators and grain processing tools are being used in dozens of countries to help communities improve their food production, raise their incomes and transform their lives. In Africa, a microenterprise in Malawi uses the group’s peanut processing equipment, with a cast ductile iron grinding burr developed in the U.S., to support its community of people living with HIV/AIDS.
Technical engineer George Ewing was among the group of volunteer engineers and scientists who founded Compatible Technology International (CTI), St. Paul, Minn., in 1980. With a background in chemical engineering, Ewing worked as a food processing research engineer for General Mills.
“[CTI] was an independent group, and General Mills donated use of its facility,” said Ewing. “Then, we outgrew that location and started our own operation. We got our nonprofit status in May 1981.”
The organization provides affordable, culturally appropriate tools to help families produce safe water, process their crops more efficiently and improve their nutrition. Its flagship technology is a hand-operated burr mill that grinds grain into flour and nuts into paste.
Without a reliable grinder, women and girls in rural Africa often spend several hours each day using rudimentary tools to grind their crops into edible food. With the CTI machinery, they are able to spend more time farming, selling their crops and attending school.
In addition to helping families reduce drudgery and improve food production in the home, CTI’s grinders are used for microenterprises. The Tikondane Support Group of people living with HIV/AIDS in Malawi uses CTI’s grinders to create peanut butter to eat and sell.
“Because of CTI’s grinders, our livelihoods have drastically changed for the better,” said Yonas Chonzi, who oversees the Tikondane Support Group. “Since the grinders came, we can afford peanut butter, a source of much needed protein. Before, we couldn’t dream of eating peanut butter because of its high price. Now, with the hand cranked grinders in our hands, we buy groundnuts and do the grinding on our own. Our health has improved greatly, and we have a thriving, income generating activity.” Chonzi offers the example of one Tikondane Support Group member, Joyce, whose health was deteriorating in 2012. Her weight decreased from 140 to 86 lbs. “[Antiretroviral drugs] were not making any difference to her until she began taking peanut butter,” he said. “She is now full of life and can do peace works and provide for her six children.”
“CTI’s grinders are often placed in communities in remote areas with few resources, so it is essential that they be reliable and low cost, which is a significant challenge,” said Alexandra Spieldoch, executive director, CTI.
The primary feature that sets CTI grinders apart from other hand-
operated mills is its burrs. These are the grinding plates that come in contact with the food being processed, and they must be not only food safe but extremely durable, because replacement parts and maintenance might not be available.
“We seek out fabricators and suppliers that can help us produce extremely high quality products at a rate that’s affordable,” Spieldoch said, “so we can impact more lives and provide tools to the families who need them most.”
The first generation of the product used stainless steel burrs that were CNC machined from solid metal at a machine shop in St. Paul, Minn.
“Not only was the product costly but the time consumed manufacturing it was expensive,” said Ewing. “So, a machinist and myself went over to Smith Foundry.”
Smith Foundry, Minneapolis, is an ISO9001:2008 registered green sand operation. It specializes in low and medium volume gray, ductile and austempered ductile iron castings ranging from several ounces to 250 lbs.
“[Ewing] came in with a couple of old castings and discussed with our staff what he had and what he was looking for,” said Neil Ahlstrom, president, Smith Foundry. “We discussed how we could put this together for him, what kind of material specifications it would require, and whether it could be cast or had to be machined. He had some basic issues he didn’t have answers to, which our engineering people helped him with.”
That collaboration resulted in patterns for the turning and fixed burrs, which CTI approved.
“He was grinding peanuts in a very simple and rudimentary way, and we discussed how close we could cast this to the near net shape of the part that was being produced through machining,” said Ahlstrom. “We were able to maintain the same profile, shape and size. Ductile iron was chosen for its wear properties.”
Smith Foundry made sample castings, tweaked the process where necessary, then went into production using ductile iron grade 80-55-06.
“After they are cast and the castings are cleaned, we put them in a machining process to cut the fine burrs on them,” said Ewing. “Then, the iron burrs are case hardened in a heat-treating process to about 55 or 60 Rockwell C so they are tough, reliable and affordable. The grinding burr is withstanding a lot of grinding force and use. Oxidation isn’t a problem because of the hardness of the metal, and we don’t run into any rusting or corrosion problems with it.”
The CTI Omega grinder is housed in a cast aluminum body produced by Modern Metals Foundry Inc., Bloomington, Minn. Its Ewing IV grinder is housed in sheet metal with a baked-on coating. The machines are assembled locally, packaged and sent to Africa, Asia and other locations.
“It’s been a tremendous boon for us to have Neil and the foundry people do this for us,” said Ewing. “They give us a good price on the product and meet our requirements whenever we need some. Now we can make large quantities at probably 25% the cost.”
Since Smith Foundry began casting the grinding burr 10 years ago, CTI has placed thousands of these machines around the world.