Assembly Mistakes Research Articles

Automatic evaluation of the misplacement risk during manual assembly based on a CAD design

AbstractIn HMLV manufacturing, assembly mistakes by operators are common due to the ever increasing product variability and complexity. If mistakes can be detected early-on in the design process, product designers can reduce the possibility for mistakes. We present an algorithm to automatically detect and evaluate potential misplacements of parts that need to be fastened. Evaluation starts from a product CAD and returns the risk of misplacement as well as visual feedback on possible misplacements. An implementation with FreeCAD of our algorithm is illustrated on different use cases.

Off-axis telescope misalignment correction based on defocus spot moment features

Optical mirror misalignments, which are caused by assembly mistakes and changes in the surrounding environment (such as gravity, temperature, and atmosphere), degrade the system’s imaging performance. Therefore, active misalignment correction is essential for ensuring the image quality of the off-axis telescope. In this paper, a novel misalignment correction method without wavefront sensors is proposed. The point spread functions (PSFs) of the system are analytically related to the optical mirror misalignments. On this basis, a fully connected neural network (FCNN) is used to establish the mapping relationship between the misalignments and the discrete orthogonal unbiased finite impulse response (UFIR) moment features, which can effectively characterize changes of intensity and geometric of the spot image. The simulation and experimental results in this paper justify the effectiveness and practicality of the proposed method. This approach offers a low-cost and straightforward technical method for achieving high imaging quality throughout the alignment and observation phases. This approach can prevent the accumulation of errors caused by wavefront detection and the high delay of multiple iterations.

Voltage withstand tests and PD measurements on cable accessories with assembly mistakes

Voltage withstand tests and PD measurements on cable accessories with assembly mistakes

Using stories to battle unintentional injuries: Narratives in safety and health communication

After 14 years of rising death rates due to unintentional injuries in the U.S., it is time to ask how safety messages can be redesigned to have a greater impact on risky behavior. To this end, many researchers have called for a new, narrative approach to prevention messages-based on persuasive stories about people who have suffered injuries and illnesses in the past. Still, there is scant evidence that story-based communications are more effective than equivalent non-narrative messages at changing actual (rather than self-reported) safety and health behavior. Our research examined the impact of injury stories on actual safety behavior in a controlled experimental setting at a US university. Teams of participants assembled a product (a child's swing) using written instructions. The instructions contained safety messages targeting assembly mistakes that have been linked to serious injuries in children who play on swings. Participant teams were randomly assigned to three conditions: assembly instructions containing story-based safety messages, instructions with concrete (but non-anecdotal) safety messages, and instructions with traditional abstract safety messages. After adjustment for covariates, story-based messages resulted in a 19 percent improvement in safety behavior, compared with non-narrative communications. Importantly, injury stories did not create undue fear of the message object, demonstrating that brief anecdotes about accident victims can convince people to take reasonable precautions without creating unwarranted alarm about risks.

Assembly mistakes of steel structures

Steel structures have plenty of advantages, which decide on their usage in many buildings. At the same time require they great precision in the design stage as well as during the building phase. Indispensable precision is oft a reason for design and assembly mistakes. In the paper there are presented the assembly mistakes, which occur the most often during the realisation stage.

Basics of Quality Improvement in Health Care

Basics of Quality Improvement in Health Care