Thesis (M.E.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / This report involves the overall design of a closed loop computer control plastic injection molding system and detailed design of the inspection portion of the system for a specific part. This project is concentrated on the inspection portion of the system. A part and its print specifications were provided. Design requirements called for 100% inspection of the critical part dimensions which were most subject to change. The main system constraints influencing the design were inspection accuracy and speed. The system also had to be designed using available hardware. A gaging system was designed to be used in conjunction with a Digital Equipment Corporation (DEC) PDP-8/I computer to inspect plastic parts produced by an Allrounder 100 injection molding machine. The design of a gage system that allows fast and automatic checking of the part requires sensitive instruments. Linear transducers were used in order that fast checking would be accomplished and allow the gage to be paced with the plastic molding machine. After the checking fixture design was completed and components ordered, a work station design was made in order to fully utilize the check fixture. Two designs were completed with one under an inspector's control and the other completely mechanized for future hookup with a computer controlled robot. A computer program was written to accept voltage signals from the transducers, convert them to part deviations, compare them to specified tolerances, and make an accept/reject decision on each part. The design is limited to one specific part, but that does not decrease the importance of the project because the parameters worked with are measured in all parts. The checking method may vary somewhat for different parts, but the basic concept will not change. The design phase is complete. It was planned that the building of the system should be completed in two successive phases and a third phase used for a critical evaluation of the system. In phase 1 the system should be completed, the computer software developed and tested, the checking fixture completed and checked out, and the manual work station designed in detail. Phase 2 would involve a balance of the work and decision making between the computer and the operator. The necessary computer hardware and software would be developed and debugged and the work station changed to allow automatic operation, thus saving an inspector's time. The final stage will be an analysis of phases 1 and 2 and possible further extension of the system to other parts so that it is more universal. The analysis will be directed at determining the economic feasibility of the system for industrial applications. / 2031-01-01

Lean production has become a widespread production system to address the need of being more productive. Since three decades ago that some big automotive manufacturers started to adopt lean, many SME’s has adopt it and enjoy the outcomes. Literature have investigated the successful implementation of lean in these organizations, yet, very few papers have addressed the challenges toward adopting lean. In this thesis research a plastic package manufacturer is chosen as the case of study to implement some initiatives of lean production and study the challenges and outcomes of lean adoption. The efforts during the making the changes were focused on adopting the SMED and Root-Cause Analysis techniques, and also to reduce defect rate in one of the products. The findings indicate before any effort to implement lean production techniques, some social issues must be considered to reduce the risk of failure. The Rosti AB case indicated that promoting motivation among operators and resolving mistrust between managers and operators is essential to encourage them to participate in improvement changes. In order to promote motivation and eliminate mistrust to encourage operators to participate in improvement changes it is necessary to empower them in decision makings in improvement implementations.

This diploma thesis deals with assessment of environmental load by selected plastic molding technology. The first part is focused on the ecological legislation in the field of mechanical engineering, which also includes the production of plastics, and describes various methodologies for assessing the environmental load. Another chapter is an overview of polymers and their properties as well as the possibilities of plastics processing with description of individual types of production methods. The practical part of this work describes the composition of the produced piece and the injection molding process of plastic production. Its two methods (direct gating and hot sprue method) are analyzed and then the environmental load evaluation is performed using the LCA method – product life cycle assessment. The environmental load of both production methods is assessed.

The aim is to design a single purpose machine for drilling and slotting plastic molding and then pressing the internal mechanics. First is described the current product technology, according to which the defined parameters of the basic units of the machine. Then described two possible design concepts devices whose suitability is then evaluated multi-criteria method.

This diploma thesis deals with the development, disign and manufacturing inspection device that is able to detect the presence of components in the assembly of the plastic molding. Evaluation of information are indicated by the operator device and sent for further processing. Rechecked product will be marked with a uniquemark.