The biggest impedance to progress on this project has been the available time of those working directly on it, and to be honest- I was the roadblock for about a year. But the seeds of labor over the last year have borne fruit!
Last fall my father built a pattern for the control valve body. The pattern itself is traditional in its wooden construction and the presence of core-prints, but the molding strategy is anything but. The valve body has a number of cavities and internal features of fairly complex geometry. Producing core boxes for these would have been an onerous and time consuming task, so we decided to skip them! Instead, I designed sand cores which were to be 3D printed using a foundry-specific printing machine and process. We also decided to utilize this process for the valve body cover casting as well, and Ron Ginger very kindly produced the pattern using his CNC router. The tradeoff for using 3D printed sand cores, is that they get very expensive compared to traditional cores and the cost increases by a cubic factor with the overall size. But when the expected casting quantity and core complexity align, it can be quite the tool.
While I worked at Enterprise Foundry, I had been looking for opportunities to bring 3D printed sand cores into the workflow, but we couldn't find the right job to pair with the technology. The vacuum brake controller proved to be just the project we were looking for. So when a critical machine went down around Christmas, I negotiated trade- I would come in during the holiday in my capacity as a WW&F volunteer and make the repair using the WW&F's mag drill. In exchange, Enterprise would pour 10 total molds containing 3D printed sand cores purchased by the WW&F. On Monday, the first two molds were made and poured, and we are thrilled with the results. I want to publicly thank Enterprise for their involvement and donation for this project. Between the value of the iron itself and the time spent in the plant, this constitutes a significant contribution and greatly aided in getting this project closer to the finish line. There were also some great lessons learned from this use of printed cores which will directly apply to a major casting project on the horizon.
Over the last few months, Gordon Cook and Ron Ginger have been producing the many machined components for the internals of the control valve assembly. I don't have any pictures to share of their work, but I look forward to seeing all of their work myself! Finally, three smaller patterns for parts which will be made using traditional foundry methods were completed and handed off to Wayne Laepple to be made at Cattail Foundry.
Finally, as some have noticed- my time spent on-site in Alna has decreased rather significantly from what it had been for the last last couple of years. I recently started a company focused on patternmaking and casting purchasing for the preservation industry- piggybacking off the skills which I first learned through my involvement with the WW&F and my time as the quality engineer at Enterprise Foundry. These patterns and castings are somewhat of a "launch" for Preservation Pattern, showcasing just some of technologies that a 21st century pattern maker has at their disposal now.
Moving forward, Jason and I are planning a day or two to complete the machining on the valve body and the rest of the castings which will allow everything to go together afterwards as we work towards our goal of testing and implementing the complete system.
It was pretty fun going back to Enterprise to supervise the production of these parts. I went in on Monday morning to check the molding, and then went back at 9PM on Tuesday during the night shift to shake out the molds and knock off the risers.
Ron's Pattern
The mold
Core installed
The raw casting after being cleaned
My dad's valve body pattern
Mold made and cores installed
The valve body and the cap after being cleaned with the risers still attached
Note the first use of a chaplet for a WW&F casting. This is exactly what we wanted to see. The chaplet is centered on the location where a pipe fitting will be installed, so it will end up being drilled out- negating any concerns of complete fusion.
Both castings in a very raw state. They both still need to be ground before any machining happens.
Showing just some of results of the printed cores.
And the patterns which were just handed off to Wayne.