In relation to the fourth industrial revolution, traditional manufacturing methods cannot serve the flexibility demands related to mass customization and small series production. Rapid tooling provided by generative manufacturing has been suggested recently in the context of metal forming. Due to the high loads applied during processes to such tooling, a purposeful mechanical description of the additively manufactured (AM) materials is crucial. Until now, a comprehensive characterization approach for AM polymers is required to allow a sophisticated layout of rapid tooling. In detail, information on compressive and flexural mechanical properties of solid infilled materials made by additive manufacturing are sparsely available. These elementary mechanical properties are evaluated in the present study. They result from material specimens additively manufactured in the fused filament fabrication (FFF) process. The design of the experiments reveals significant influences of the polymer and the layer height on the resulting flexural and compressive strength and modulus as well as density, hardness, and surface roughness. As a case study, these findings are applied to a cup drawing operation based on the strongest and weakest material and parameter combination. The obtained data and results are intended to guide future applications of direct polymer additive tooling. The presented case study illustrates such an application and shows the range of manufacturing quality achievable within the materials and user settings for 3D printing.
While deep drawing of sheet metals is economical at high volumes, it can be very costly for manufacturing prototypes, mainly due to high tooling costs. Additively manufactured polymer tools have the potential to be more cost-efficient for small series, but they are softer and thus less resilient than conventional steel tools. This work aimed to study the dimensional precision of such tools using a standard cup geometry. Tools were printed with FFF using two different materials, PLA and CF-PA. A test series of 20 parts was drawn from each tool. Afterwards, the dimensional precisions of the drawn parts were analyzed using an optical measuring system. The achieved dimensional accuracy of the first drawn cup using the PLA toolset was 1.98 mm, which was further improved to 1.04 mm by altering shrinkage and springback allowances. The repeatability of the deep drawing process for the CF-reinforced PA tool was 0.17 mm during 20 drawing operations and better than that of the PLA tool (1.17 mm). To conclude, deep drawing of standard cups is doable using direct polymer additive tooling with a dimensional accuracy of 1.04 mm, which can be further improved by refining allowances incorporated to the CAD model being printed.