Part Buyers Authority Issue #1

that particular casting by cutting the mold into several sections to allow for easier cleaning and handling or even removing mold material in areas that are unneeded to reduce cost and weight on the final mold. Once a final mold package is designed and assembled into a build file printing can begin. Printing is simple, with the slicing software provided with the computer doing all of the hard labor this part of the process is plug and play. The build file is imported into the software and centered on the build table, once centered printing can start. The 3D printer can run autonomously with very limited outside action needed by an operator. The operator is limited to occasional maintenance and cleaning on the print heads, as well as ensuring the sand is properly supported as the build progresses in height. With Viridis3D’s current printer technology the rate of printing is at 2.25in/hr on average and a curing time of 30 minutes to 2 hours depending on the size of the mold printed. It is typical to print a mold and pour it the next day with the time inbetween utilized by the operator, during another print cycle, to clean all the non-printed sand from the mold and add a mold wash to the casting cavity. This mold wash that is applied increases the quality of the surface finish. The unprinted sand can be easily removed by vacuum or hand without worry of disrupting the mold surface. The clean and washed mold can be assembled the same as existing foundry molds. If the foundry engineer designed the mold right rebar can be utilized to aid in lifting the pieces and in closing the mold. Figure 2 shows a partly assembled mold, in the picture internal riser sleeves can be seen as well as an intricate core. THE ADVANTAGES This technology in regards to sand casting gives several advantages to the foundry that are passed along to the customer. The biggest advantage to 3D printing is reduced lead times. 3D printing was created with rapid prototyping in mind and printing with sand is no different. The foundry can utilize 3D printing to produce a casting in the time it would take to even receive the pattern. The foundry is looking to print low volume orders for prototyping or replacement parts. The low volume orders translate to cost savings for the foundry and customer as no expensive pattern or major rework are needed. The rapid prototyping nature of 3D printing allows quick modification to any design or casting material changes with no downtime since there is no pattern that needs to be worked on for what may amount to several days. The modifications can be implemented within minutes of the results from the previous mold being seen, however with the utilization of solidification analysis there is a 90% confidence in the first iteration. Lastly, there is an abundance of cost savings for the customer as there is no hard tooling, no need for storage, and no repair/upkeep. Everything can be stored on a flash drive to be used again in short notice if that particular casting is needed within a couple weeks. Contact: ETHAN EDWARDS [email protected] 19 Figure 2: Partially assembled 3D printed mold Click here to SUBSCRIBE or CONTRIBUTE as an author.