Michael Rosenthal, Markus Rüggeberg, Christian Gerber, Lukas Beyrich and Jeremy Faludi
The purpose of this study is to quantify the vertical shrinkage rates and the mechanical strength of three-dimensional (3D) printed parts for a variety of wood-based materials for…
Abstract
Purpose
The purpose of this study is to quantify the vertical shrinkage rates and the mechanical strength of three-dimensional (3D) printed parts for a variety of wood-based materials for liquid deposition modeling.
Design/methodology/approach
The overall hypothesis was that a well-chosen combination of binders, fibers and fillers could reduce shrinkage in the Z dimension and increase compressive and flexural strength (DIN 52185, 52186). To test this assumption, eight sub-hypotheses were formulated. Mixtures of the ingredients were chosen in different ratios to measure the performance of prints. For time efficiency, an iterative heuristic approach was used – not testing all variations of all variables in even increments, but cutting off lines of testing when mixtures were clearly performing poorly.
Findings
The results showed that some mixtures had high dimensional accuracy and strength, while others had neither, and others had one but not the other. Shrinkage of 3D printed objects was mainly caused by water release during drying. An increase of the wood as well as the cement, sand, salt and gypsum content led to reduced vertical shrinkage, which varied between 0 and 23%. Compressive and flexural strength showed mixed trends. An increase in wood and salt content worsened both strength properties. The addition of fibers improved flexural, and the addition of cement improved compression strength. The highest strength values of 14 MPa for compressive and 8 MPa for flexural strength were obtained in the test series with gypsum.
Originality/value
This paper is an important milestone in the development of environmentally friendly materials for additive manufacturing. The potential of many ingredients to improve physical properties could be demonstrated.
Details
Keywords
The purpose of this paper is to examine the competencies that US healthcare organizations require for quality and performance improvement positions.
Abstract
Purpose
The purpose of this paper is to examine the competencies that US healthcare organizations require for quality and performance improvement positions.
Design/methodology/approach
A US healthcare improvement job posting content analysis was conducted using the HQ Essentials competency framework.
Findings
The HQ essentials competencies most desired for improvement positions include project management, training, data analysis and applied performance improvement methods. Competency requirements varied somewhat by job focus area: performance, quality, or process improvement, and Lean and Six Sigma.
Practical implications
Healthcare leaders may use the author’s results to understand what competencies may be required for various improvement roles and to identify any gaps in required skills and knowledge areas that may need to be addressed. Educators and policy-makers should consider how these competencies align with employers’ needs and what resources or professional development may be needed to address gaps.
Originality/value
This is the first healthcare improvement competencies analysis based on job postings.