Design and validation of integrated clamping interfaces for post-processing and robotic handling in additive manufacturing

Additive manufacturing (AM), particularly laser-based powder bed fusion of metals (LPBF), enables the fabrication of complex and customized metallic parts. However, 20–40% of the total manufacturing costs are usually attributed to post-processing steps. To reduce the costs of extensive post-processing, the process chain for AM parts has to be automated. Accordingly, robotic gripping and handling processes, as well as an efficient clamping for subtractive machining of AM parts, are key challenges. This study introduces and validates integrated bolts acting as a handling and clamping interface of AM parts. The bolts are integrated into the part design and manufactured in the same LPBF process. The bolts can be easily removed after the machining process using a wrench. This feasibility study investigates different bolt elements. The experiments and simulations conducted in the study show that a force of 250 N resulted in a maximum displacement of 12.5 µm. The milling results of the LPBF parts reveal a maximum roughness value, Ra, of 1.42 µm, which is comparable to that of a standard clamping system. After the bolt removal, a maximum residual height of 0.067 mm remains. Two case studies are conducted to analyze the form deviation, the effect of bolts on build time, and material volume and to demonstrate the application of the bolts. Thus, the major contribution of this study is the design and the validation of standardized interfaces for robotic handling and clamping of complex AM parts. The novelties are a simple and clean interface removal, less material consumption, less support structure required, and finally an achievement of a five-side tool accessibility by combining the interfaces with a three-jaw chuck.

Design and Validation of Integrated Clamping Interfaces for Post-Processing and Robotic Handling in Additive Manufacturing

Additive manufacturing (AM), particularly laser-based powder bed fusion of metals (LPBF), enables the fabrication of complex and customized metallic parts. However, 20–40% of the total manufacturing costs are usually attributed to post-processing steps. To reduce the costs of extensive post-processing, the process chain for AM parts has to be automated. Accordingly, robotic gripping and handling processes, as well as an efficient clamping for subtractive machining of AM parts, are key challenges. This study introduces and validates integrated bolts acting as a handling and clamping interface of AM parts. The bolts are integrated into the part design and manufactured in the same LPBF process. The bolts can be easily removed after the machining process using a wrench. This feasibility study investigates different bolt elements. The experiments and simulations conducted in the study show that a force of 250 N resulted in a maximum displacement of 12.5 µm. The milling results of the LPBF parts reveal a maximum roughness value, Ra, of 1.42 µm, which is comparable to that of a standard clamping system. After the bolt removal, a maximum residual height of 0.067 mm remains. Two case studies are conducted to analyze the form deviation, the effect of bolts on build time and material volume and to demonstrate the application of the bolts. Thus, the major contribution of this study is the design and the validation of standardized interfaces for robotic handling and clamping of complex AM parts. The novelties are a simple and clean interface removal, less material consumption, less support structure required and finally an achievement of a five-side tool accessibility by combining the interfaces with a three-jaw chuck.

Tool accessibility with path and motion planning for robotic drilling and riveting

Robotic applications in aerospace manufacturing and aircraft assembly today are limited. This is because most of the aircraft parts are relatively small or have complex shapes that make tasks like robotic drilling and riveting more challenging. These challenges include tool accessibility, path planning, and motion planning. In this thesis, a process methodology was developed to overcome the tool accessibility challenges facing robotic drilling and riveting for aircraft parts. The tool accessibility was analyzed based on the Global Accessibility Area and the Global Accessibility Volume to determine the accessible boundaries for parts with zero, one and two surfaces curvatures. The path planning was optimized based on the shortest distance, least number of steps, and minimal tool orientation change. The motion planning was optimized based on the s-curve using the robot’s maximum velocity and acceleration for minimum cycle time and maximum production rate. A software application was developed to simulate the tasks.

Tool accessibility with path and motion planning for robotic drilling and riveting

Robotic applications in aerospace manufacturing and aircraft assembly today are limited. This is because most of the aircraft parts are relatively small or have complex shapes that make tasks like robotic drilling and riveting more challenging. These challenges include tool accessibility, path planning, and motion planning. In this thesis, a process methodology was developed to overcome the tool accessibility challenges facing robotic drilling and riveting for aircraft parts. The tool accessibility was analyzed based on the Global Accessibility Area and the Global Accessibility Volume to determine the accessible boundaries for parts with zero, one and two surfaces curvatures. The path planning was optimized based on the shortest distance, least number of steps, and minimal tool orientation change. The motion planning was optimized based on the s-curve using the robot’s maximum velocity and acceleration for minimum cycle time and maximum production rate. A software application was developed to simulate the tasks.

Engage for Equity: Development of Community-Based Participatory Research Tools

We developed a set of four community-based participatory research (CBPR) partnership tools aimed at supporting community–academic research partnerships in strengthening their research processes, with the ultimate goal of improving research outcomes. The aim of this article is to describe the tools we developed to accomplish this goal: (1) the River of Life Exercise; (2) a Partnership Visioning Exercise; (3) a personalized Partnership Data Report of data from academic and community research partners; and (4) a Promising Practices Guide with aggregated survey data analyses on promising CBPR practices associated with CBPR and health outcomes from two national samples of CBPR projects that completed a series of two online surveys. Relying on Paulo Freire’s philosophy of praxis, or the cycles of collective reflection and action, we developed a set of tools designed to support research teams in holding discussions aimed at strengthening research partnership capacity, aligning research partnership efforts to achieve grant aims, and recalling and operationalizing larger social justice goals. This article describes the theoretical framework and process for tool development and provides preliminary data from small teams representing 25 partnerships who attended face-to-face workshops and provided their perceptions of tool accessibility and intended future use.

A sequence planning method for five-axis hybrid manufacturing of complex structural parts

The concept of additive–subtractive hybrid manufacturing provides a new idea for the manufacturing of high-precision complex structural parts. Currently, under the five-axis additive–subtractive hybrid manufacturing mode, existing research work concerned with sequence planning issues have limitations. This article presents a sequence planning method for hybrid manufacturing of complex structural parts with high precision. The initial printing direction of parts was determined based on an iterative search method and the initial hybrid manufacturing sequence was constructed by part volume decomposition, which solved the coupling problem of printing direction decision and machinability calculation. Under the constraint of tool accessibility, the whole planning of the hybrid manufacturing sequence was realized based on greedy algorithm. This method has achieved highly effective planning of the alternative sequence in the process of hybrid manufacturing, thus greatly reduced the number of tool changes required and laid a foundation for the realization of highly efficient hybrid manufacturing.