Stay current on the latest from America Makes.*
*Submission is for announcements only and does not include the bi-weekly members-only newsletter, AM Digest.
This project seeks to develop a software solution for the integration of additive and subtractive manufacturing and focuses on developing algorithms to determine optimal placement of sacrificial machining fixtures on AM produced parts.
Nearly all functional additive manufactured (AM) parts require secondary processing that in many cases can more than double the cost of the final part. Hybrid manufacturing systems that incorporate both additive and subtractive processes would enable mechanical parts to be “digitally manufactured” to meet the required final geometric accuracy.
Currently, there is no systematic software driven interface to combine additive and subtractive manufacturing allowances in the original STL file. There is also no integrated AM method for creating the sacrificial CNC chuck and bridging features that are predetermined based on a calculation of the CNC cutting tool forces. Finally, there is no current surface vision feedback system integrated with a CNC machining center for part orientation and validation of surface or feature tolerances.
The goals of this project were to:
The technical approach required considerable software “bridging” that could string together multiple existing software and mechanical techniques into a systematic sequence of relatively harmonized work steps. The AM software included the creation of surface allowances for subtractive machining as well as algorithms for optimizing material scaffolding and overall part orientation for subsequent machining. Subtractive machining would utilize sacrificial part features strong enough for cutting paths and integrated surface scanning technology to direct machining and validation operations.
A collaborative team from industry and academia worked together to:
As a result of this project, a Direct Additive and Subtractive Hybrid (DASH) manufacturing system was created using both additive and subtractive processing to create mechanical parts that are “digitally manufactured” to meet the final geometric accuracy required. Three project partners (John Deere, Kennametal, and Advanced Machining) verified the DASH system by producing commercial parts. Functional components were manufactured using the system by first producing a nearnet shaped part with additive technology. This part was then final machined in a 4-axis CNC machining center using automatically generated G codes. Additional accomplishments include: