In rapid manufacturing, ranking third in importance behind superior quality and accordance with specifications is time to market, according to Ron Jr. (Reg) Gustafson, Project Manager, Clinkenbeard.
Actually, “time to market” as a term to reflect a measure of performance is becoming obsolete, he said. It is rapidly being replaced by the term “speed to market,” which, he said, many customers of rapid-manufacturing companies think more accurately reflects the process that truly governs today’s product or prototype development cycles—and that gives rapid-manufacturing companies a real competitive edge.
Clinkenbeard recently employed its patented toolingless process on behalf of Hamilton Sundstrand Aerospace, which asked Clinkenbeard if it could develop two identical castings of a new fuel pump, plus do the finish machining and inspection so the product could be tested within three weeks. The answer was yes.
“Clinkenbeard’s experience and knowledge of the sand-casting process and tooling proved to be essential in the development design phase of this program,” said Hamilton Sundstrand senior engineering specialist Bob LaFurge. “They came in and worked directly with our engineering group.”
The casting needed to be designed first so that external details associated with the new pump could be added at a later date.
Once Clinkenbeard received the 3-D model, it performed the engineering work required for the sand-casting process. The fuel pump design incorporated a multiple core configuration, which Clinkenbeard split up so it could easily alter a single area of the casting if changes occurred during testing and development.
Clinkenbeard built a traditional “low-volume rapid pattern” for the exterior, which allowed for a gating system and easy-to-make modifications if additional castings and iterations were required. The interior was produced via the toolingless process, which involves the rapid production of cores and molds without the requirement to produce foundry tooling first.
“We developed this [toolingless] process when we realized American companies were going to Germany to obtain sand castings quickly from a process similar to stereolithography, which cures coated sand with a laser,” said Ron Jr. (Reg) Gustafson, Clinkenbeard Project Manager. “We searched in the U.S. and could not find any companies that had any processes that could produce sand castings without producing tooling first. We decided we needed to come up with a method so we could retain our customer base and grow.”
The company’s goal was to “develop a process where we could produce rapid sand castings that closely reflected the production process that would be used. We developed a process where we would first produce a block of sand for the molds and cores and then shape them in a subtractive method. Using this method, we are able to produce cores and molds using different sand binder systems.”
Hamilton Sundstrand could have gone to another rapid manufacturer, who, more than likely, would have had to produce a complete set of foundry tooling to pour the castings. This would have lengthened the process and added cost, according to Gustafson.
“One feature of the Clinkenbeard process our customers appreciate,” he said, “is the fact we can easily use different sands and binder systems that will most closely reflect their production casting process. This greatly minimizes surprises that may come up once the project has made it into the production process.”
“Using traditional CNC methods of producing tooling requires the production of patterns and core boxes, rigging and gating for the foundry,” said Gustafson. “Using our toolingless process saves the upfront pattern production time. This allows the process to go straight to the production of cores and molds. The amount of time and money saved is directly related to the complexity of the part. By using this method we have actually seen a 90% reduction in lead time in the most extreme cases.”
This was the case with Hamilton Sundstrand’s aerospace fuel pump. The project was a good candidate for the Clinkenbeard process due to the complexity of the internal core passages.
Making sand cores using its toolingless process and CNC processes was the only option Clinkenbeard had on the table to achieve the desired delivery dates.
CNC-machining the sand cores not only reduced the manufacturing time for the sand core, but it also opened the door for engineering change implementation right up until the time that the sand core was physically cut in sand.