The Hybrid Manufacturing Line – Where Does AM Fit Into Traditional Manufacturing?
In a traditional manufacturing world full of accepted regulatory hurdles and requirements, it is tough to see a path where additive manufacturing will play a prominent role. Organizations such as the American Welding Society are working with companies and industry leaders to develop industry-wide standards on additive manufacturing. Standards such as these will pose as the starting point for integrating AM processes into traditional manufacturing.
The hybrid manufacturing line, focused on the output of a product rather than a prototype, will include the use of 3D printers in order to reduce and isolate processes while moving previously outsourced processes in-house. This is a gamechanger for lean manufacturing, where the cost effective gap between small batch production runs and large batch production runs is dramatically reduced.
Additive Manufacturing: Design, Methods, and Processes -- 1st Edition -- Published 10/31/2017 -- Author: Steinar Westhrin Killi
Additive Manufacturing Supply Chain
Economy of scale in a traditional manufacturing industry relies on the development of tooling and fixtures along with adequate demand for the production. Additive manufacturing removes the necessity to revolve around economies of scale for any product and provides a scenario where low-volume parts can be produced for the same cost as high volume parts. For certain jobs, the supply chain can be brought completely in-house, removing the reliance on supplier time-lines and allowing procurement to guarantee delivery dates for internal and outbound products.
By understanding and vetting the complete manufacturing line on a job-to-job basis, manufacturing can be translated from a fragmented webbed framework into an internal and predictable operation. The question – how quickly and how costly is the consideration of additive manufacturing for a specific job? – is the first of many when considering the cost impacts of AM within a manufacturing line.
By bringing the supply chain in-house, it is important to consider the removal of powder, removal of part, and removal of bi-products while designing a production build. In order to prove the effectiveness of additive manufacturing and any new process, the benefits must outweigh the negatives.
Therefore, AM must remove or combine processes, reduce effective build time, broaden design capabilities, or increase reliability at a scale that qualifies the burdens of bringing parts of the supply chain in-house.
Hybrid Manufacturing Process
The designation of additive manufacturing as a component in a manufacturing line removes the assumption of an “all-in-one” MFG unit. The current state of AM forces design attention to areas that are not necessarily reasonable for the use-case of the production part. For example, certain piping designs, turbine designs, and piston designs may require surface finish of 32 Ra on critical surfaces, but a much more lenient finish on less critical features.
Therefore, from the onset of manufacturing line design and component design, it is important to determine the end-product specification requirements prior to considering AM’s cost effectiveness. The hybrid manufacturing process will incorporate AM and machining/finishing processes to accurately print production parts with complex or required intricate interior features and adequate external surface finishes and feature design.
The end-to-end additive manufacturing environment includes the below number tree and their respective sub-processes.
Determine the appropriate material for the end product specification requirements. How well will this material react to post process treatment? Will there be potential complications in the printing process for certain material makeups? 3D printable metal powder has been engineered to be comparable to currently available extrusion standards, although due to a scattered marketplace, many products are proprietary to the inventing company.
The setup time required to move from a completed design to a fairly optimized printing process that will output material shape with expected physical properties can take a reasonable amount of time. Using AM as a process for a custom designed product for a customer, it is likely that customer will require certification of compliance documentation for material make-up and functionality per physical specification requirements. Including cleanup and transitions, this process will include prototyping on a smaller scale, material testing, and orientation/support structure design.
The build process is straight forward, although it should be monitored by a machine operator at least through the first product run. A test specimen shall be printed alongside each printing process and tested using nondestructive or destructive testing methods.
The part must then be removed from the base plate using a horizontal or vertical saw or EDM machine. This process will also require the breaking and removal of support structures and the removal of any excess metal powder inside hollowed sections.
5. Post processes
Machining to complete part formation, heat treatment to bring the part up to it’s expected physical properties, bead blasting and polishing to bring the surface finish into compliance, additional welding to repair or complete sections of part. In the desired order, these are some potential post processes necessary in order to move the part from freshly printed into a completed product.
6. Facility management
Keeping the AM machine clean and separate from machining, grinding, and other post processing that will create potential contamination is important in order to maintain consistent quality. The base plate must be chosen correctly for the material used during the printing process and must be resurfaced between printing processes.
7. Disposal of waste
Although the printing process will be self-contained, excess powder should be sifted and reused for future printing processes. Waste metal powder and other byproducts should be disposed of in a manor applicable to regulatory organizations and government.
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