Statistical tolerance analysis of linkage mechanisms taking into account deviations from additive manufacturing
Third party funded individual grant
Start date : 01.09.2017
End date : 31.08.2019
Extension date: 31.12.2020
Project details
Scientific Abstract
Additive manufacturing finds increasing application in product development processes. In addition to prototypes and tools, additive processes are used more and more often for the manufacturing of end products, for example in the field of medical technology or aviation industry. Since no form defined tools are needed the resulting unit costs are independent from the lot size and only slightly depending on the component’s complexity. Furthermore conventional design rules are eliminated such as the avoidance of undercuts in cast components. Based on the layer-by-layer buildup, complex lightweight structures and complete movable assemblies can be produced in a single process step (instead of multiple single-item productions). This way, the previously required assembly steps can be avoided completely.
Despite these numerous possibilities of additive manufacturing the freedom of design is still limited and process-specific design rules are necessary. The current state of the art insufficiently offers adequate design rules for additive manufacturing. For example the anisotropic material behavior and geometric accuracy of the manufactured components are depending on the buildup orientations as well as on numerous manufacturing process parameters. These production-related deviations imply major challenges, especially concerning the design of linkage mechanisms which include necessary joint clearance to allow the movement between the components.
The statistical tolerance analysis offers great potential to early determine these influences in the design of additive manufactured products. So far, statistical tolerance analyses are solely applied to conventional manufacturing processes and allow the assessment of random and systematic deviations caused by production, assembly as well as operation. For this purpose no appropriate methods for additive manufacturing are currently available.
Therefore, the aim of the proposed research project is to enhance the statistical tolerance analysis to determine the movement behavior of additively manufactured linkage mechanisms with joint clearance. For this purpose a method is developed to determine the production-related deviations and the resulting joint clearance in linkage mechanisms and integrate them in statistical tolerance analyses. The evaluation of this methodology is carried out by capturing the path of movement of real manufactured linkage mechanisms. The focus is on linkage mechanisms produced by Fused Deposition Modeling.
Thus, the result of the proposed research project is an extended statistical tolerance analysis to early predict the movement behavior of additively manufactured linkage mechanisms and to avoid time and cost intense iterations in product development.
