Advances in Low Pressure Carburizing and High-Pressure Gas Quenching

Low Pressure Carburizing (LPC) in combination with High Pressure Gas Quenching (HPGQ) has been established as an advanced and robust technology for case hardening. The process can be applied with batches consisting of multiple layers as well as batches consisting of single-layers. The paper shows the latest progress in LPC and HPGQ for the heat treatment of automotive and aerospace components. Significant progress has been made by continuous improvements in the fields of- Fixturing / load densities,- Reduction of cycle times,- Control of distortion,- Digitalization / Automation,- Quality control and- Integration of heat treatment into the manufacturing line. Practical applications are shown for both multiple- and single layer treatment.

A framework and method for analysis of feed-forward industrial and manufacturing lines

PurposeThis modeling facilitates the determination of control responses (or possibly reconfiguration) upon such events and the identification of which segments of the pipeline can continue to function uninterrupted. Based on this modeling, an algorithm is presented to implement the control responses and to establish this determination. In this work, the authors propose using Message Queuing Telemetry Transport (MQTT), which is an integrated method to perform the system-wide control based on message exchanging among local node controllers (agents) and the global controller (broker).Design/methodology/approachComplex manufacturing lines in industrial plants are designed to accomplish an overall task in an incremental mode. This typically consists of a sequence of smaller tasks organized as cascaded processing nodes with local controls, which must be coordinated and aided by a system-wide (global) controller. This work presents a logic modeling technique for such pipelines and a method for using its logic to determine the consequent effects of events where a node halts/fails on the overall operation.FindingsThe method uses a protocol for establishing communication of node events and the algorithm to determine the consequences of node events in order to produce global control directives, which are communicated back to node controllers over MQTT. The algorithm is simulated using a complex manufacturing line with arbitrary events to illustrate the sequence of events and the agents–broker message exchanging.Originality/valueThis approach (MQTT) is a relatively new concept in Cyber-Physical Systems. The proposed example of feed-forward is not new; however, for illustration purposes, it was suggested that a feed-forward be used. Future works will consider practical examples that are at the core of the manufacturing processes.

Buffer allocation problem in a shoe manufacturing line: A metamodeling approach

Footwear production is subject to the variability inherent in any process, and producers often need to apply tools that allow them to make the right decisions. This work documents the process to optimize the buffer allocation in a shoe manufacturing line minimizing the cycle time in the system, applying a metamodeling approach. It was found that the Front sewing operation, and the interaction between the Lining sewing operation and the assembly operation have the greatest effect on the flow time of the product within the process; the optimum assignment of spaces follows a non-uniform arrangement on the line saturating the slower stations; the cycle time follows a non-linear behavior vs. the total number of spaces (N) in the line. For a certain value of N, the cycle time reaches a minimum value.

Kanban in Apparel Manufacturing: A Case Study

Pull system and Kanban are effective lean manufacturing tools. Though many companies in various manufacturing fields have successfully implemented pull manufacturing using Kanban systems, such studies in apparel manufacturing are rarely found. Kanban system was implemented in an apparel manufacturing company, which had implemented some of the lean manufacturing tools. The apparel manufacturing line was identified in four different sub sections and separate Kanbans were used in each sub section. The system was evaluated using two parameters: the number of Kanban cards in each point; the production output. Correct number of Kanban cards were found at all the time of the monitoring period of two weeks-the production efficiency has increased by 22%.