Single Minute Exchange Die Approach for Optimising Setup Time in Labelling Printing Company

The concept of “make-to-order” (MTO) type companies is to produce the products just-in-time and improve the customer satisfaction. These types of company produce a high variety with low volume requiring a frequent setup operation. The shorter setup time will reduce the manufacturing lead time and hence increase the productivity. Unfortunately, most of the MTO type companies suffer with high setup time. Thus, single minute exchange die (SMED) concept is developed which consist of four stages: internal and external setup are not distinguished, separating internal and external setup, converting internal into external setup and streamlining all aspects of the setup operations. The main objective of using SMED concept is to accomplish setup time in less than 10 min. In this case study, the SMED concept being applied to convert internal setup to external setup which involves the activities of ink preparation and test printing. In the stage three of SMED concept, feasible solutions has been applied to fulfilled the objective. The result of implementing SMED concept in MTO type companies is the improvement in the productivity and reduction in the setup time. The improvement of productivity for this case study was 29.15%.

A study of anti-cavitation properties of propellant-feeding systems of oxygen/hydrogen engines operating on boiling hydrogen

The paper presents results of studies on anti-cavitation properties of propellant-feeding systems of advanced oxygen/hydrogen engines when they operate on boiling hydrogen. It provides a description of an algorithm for conducting cyclic cavitation tests on booster turbopump assemblies. It also provides a schematic of a test setup developed at CADB. Test runs of the setup were preceded by prolonged analytical effort which included profiling of new versions of axidiagonal impellers, CFD flow simulations to evaluate the efficiency of the proposed profilings, constructing a non-stationary model and writing the software that can simulate the operation of the setup. The software made it possible to evaluate the effect of regime parameters on the test setup operation. The final part of the effort was running tests on the setup using hydrogen. The tests provided cavitation characteristics of three booster turbopump assemblies at various flow rates and temperatures of liquid hydrogen. The test results made it possible to update the math model taking into account special profiling features of the axidiagonal impellers. Key words: LOX-LH2 rocket engine, booster turbopump assembly, cavitation, vapor content.

Greedy heuristics for identical parallel machine scheduling problem with single server to minimize the makespan

This paper considers the problem of scheduling a set of n independent jobs on m identical parallel machines with setup times constraints. Immediately before processing, each job must be loaded on a common server to perform the setup operation. During the loading operation, both the machine and the server are occupied. Two greedy heuristics are developed for (m ≥ 2) in order to minimize respectively the server waiting time and the machine idle time. These heuristics generalize those proposed in the literature for the case of two machines. The computational results show the efficiency of the proposed heuristics.

Multi-period disassembly levelling and lot-sizing for multiple product types with parts commonality

Disassembly levelling is to determine disassembly structures that specify components to be obtained from end-of-use/life products, and disassembly lot-sizing is to determine the timing and quantity of disassembling end-of-use/life products to satisfy the demands of their components. As an extension of the previous studies that consider them separately, this study integrates the two problems, especially in the form of multi-period model. Particularly, this study considers a generalized integrated problem in which disassembly levels may be different for the products of the same type. To describe the problem mathematically, we develop an integer programming model that minimizes the sum of setup, operation and inventory holding costs. Then, due to the problem complexity, a heuristic algorithm is proposed that consists of two phases: (a) constructing an initial solution using a priority-based greedy heuristic and (b) improving it by removing unnecessary disassembly operations after characterizing the properties of the problem. To show the performance of the heuristic algorithm, computational experiments were performed on various test instances and the results are reported.

SLS Setup and its Working Procedure

The given paper presents the flowchart of the worked out SLS print setup. The setup consists of a laser source, a reactor tube, a laser sweeping system (scanatory system), a control unit, a gas supply and pumping-out system, a melting process visual review system. The paper covers the results of the given setup operation, introduces a sample made with the use of SLS printing and some of its parameters.

Mixed Integer Programming Models for Two Identical Parallel Machines with a Single Server

This paper addresses the problem of scheduling jobs on two identical parallel machines with a single server such that the makespan is minimized. Each job can be processed by either one of the two parallel machines, but before processing, a setup operation must be done by a single server. Two mixed integer programming models for the considered scheduling problem are developed using time indexed variable and sequence indexed variable respectively. To evaluate the performance of the two models, CPLEX is used to test instances generated randomly. The results show that the sequence indexed model outperforms on the number of variables and computational time, which can be used to solve the instance of 20 jobs.