it,” said the casting buyer’s mechani- cal engineer. “T ey then let me know what was possible and if you could pour metal into something of that shape. I wanted Pier to add draft angle and handle the other require- ments for castings.” Pier Foundry relied on its simula-
tion software to provide verifi cation that the casting’s gating and riser design would lead to sound castings. Pier then produced the necessary tool- ing for the coreless green sand mold. After passing Pier Foundry’s internal testing for soundness, the castings were shipped to a local contractor for machining and painting before the customer received hubs that were ready to be assembled, balanced and installed in the ventilation system.
Realizing the Benefi ts T e casting conversion reduced
overall manufacturing costs 30% by simplifying the component from 34 pieces of steel that required sawing, rolling, machining, fi t-up and welding to a single casting. Such a savings is signifi cant, but the benefi ts extended beyond the bottom line. “It’s not just about saving money,
it’s also about freeing up time to do more value-added things, like add- ing assembly capacity and selling the product,” Dulaney said. T e casting also performed above
expectation when the customer’s engi- neers put the component through an intense series of tests. “It’s supposed to last forever and
that’s what our customers expect,” said the customer’s engineer. “I did a lot of destructive testing when we received the castings. We built the hub into an impeller and fi red steel rods at it. We couldn’t break the thing. We haven’t had them in the fi eld for 10 years yet, but from our testing we believe they are plenty capable.” T e casting conversion also improved
performance related to the adjustable blades on the outside of the hub. T e original weldment had a fl at outer edge, which created a gap between the blade base and hub when the blades were ro- tated. With the casting’s spherical outer surface, now the blades can rotate while remaining tight to the hub.
The original hub was a 34-piece steel weldment that required substantial labor. “In the weldment, where the hub
was cylindrical, you had a big gap when the blades are at a low angle,” the customer’s mechanical engineer explained. “Now we can curve the blades’ tails to match the outside of the hub, which helps with the perfor- mance of the fan.” Because the manufacturer produces
ventilation systems in a wide range of sizes, the two fi rms have started to ex- plore changing more hubs from weld-
ments to castings. In addition to the lessons learned in this case, Pier’s time spent instructing the customer on the casting process continues to pay off . “Now that they’ve been through
this first casting design, it will open a lot of doors for them,” Rice said. “They are looking at upcoming proj- ects to see if there are casting op- portunities right off the bat. It has opened their minds to a completely new process for their product.”
Pier Foundry and the fan manufacturer are discussing converting other ventilation system hubs to cast ductile iron.
Jul/Aug 2014 | METAL CASTING DESIGN & PURCHASING | 39
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60