This thesis is focused on a production of injection molds. It contains some analyses of the various parts of the injection molds, a description of their functions and the possibility of structural design. A summary of existing technologies for the production of these molds, their advantages and disadvantages is included. This thesis deals with design of the component parts for injection of plastics, strategy of machining and a simulation of machining.

Currently, the plastics industry has a wide range of applications due to the possibility of a fully automated process or through increased production efficiencies. The reason for this choice of the thesis was to understand the whole issue of plastic injection molding process. The specified component is used to atach the sail, which serves to protect workers in the welding sector. A specified number of the series is 350 000. The work includes a theoretical problem of injection molding process, selection of technology, material selection and design of mold. An integral part of every design mold is a simulation of injection, which is also included. In conclusion of thesis is the calculation of the various stages of production and operation of the injection mold.

This master´s thesis addresses the design of technology manufacturing plastic parts. The first part deals with the study of theoretical properties of plastics and processing applicable to a given problem. In the second part is designed double injection mold with hot runners. The following authentication function by analyzing the injection solution and the work concludes technical and economic assessment of the project.

Das Fügen mehrerer Komponenten während des Spritzgießprozesses wird bei vielen Spritzgießsonderverfahren angewandt. Diese Arbeit beschäftigt sich mit der Verbundbildung zwischen einem kalten Einlegeteil und der einströmenden Kunststoffschmelze beim Spritzgießen, im Folgenden Stoffübertragung genannt. Ein Großteil der Untersuchungen findet an Zweikomponenten-Zugstäben statt, wobei erste und zweite Komponente aus dem gleichen Thermoplast gefertigt werden. Mögliche Einflussfaktoren auf die Verbundfestigkeit werden zunächst im Theorieteil vorgestellt und diskutiert. Eine Auswahl relevanter Prozess- und Materialparameter wird dann in praktischen Versuchen detailliert analysiert. Es wird nach korrelierenden Tendenzen sowohl zwischen unterschiedlichen Verfahren als auch zwischen verschiedenen Kunststoffen gesucht. Mittels statistischer Versuchsplanung werden die Spritzgießparameterkombinationen nach Größe des Einflusses auf die Verbundfestigkeit sortiert. Dies trägt zum Verständnis der bei der Stoffübertragung ablaufenden Grundmechanismen bei. Weiterhin werden die Einflüsse der Prozessparameter auf das neue Verfahren der In-Mold Oberflächenmodifizierung, bei dem ein funktionaler Modifikator während des Spritzgießprozesses übertragen wird, mit den Ergebnissen der Zweikomponenten-Verbundfestigkeit verglichen. Abschließend wird auf die Besonderheiten bei der selektiven Stoffübertragung eingegangen und das neue Verfahren des In-Mold Printing vorgestellt. / The joining of two components by the process of injection molding is state of the art, although adhesion phenomena are not fully understood yet. The formation of bonds between a cold material, which was inserted or applied onto the surface of the cavity before injection molding, and an injected polymer melt is studied in this work. Providing sufficient bond strength, the material is transferred from the surface of the mold to the injection molded part. Possibly influencing factors on the bond strength are first identified, theoretically discussed, later in experiments varied and finally analyzed. Thereby correlating tendencies between different polymers and different in-mold technologies are observed. The relevant material and processing parameters are put in order by their influence on the bond strength using design of experiments. This helps to understand the mechanisms of the formation of bonds. The majority of the experiments is concerned with two component injection molding by measuring the bond strength of two component tensile bars, produced under varying processing conditions. In each case, first and second components are made of the same thermoplastic polymer. The thermal energy of the melt can be used also to initiate chemical reactions. This permits bonding of a thin layer of a functional polymer, which is applied onto the surface of the mold before injecting the melt, to the surface of the molded part. In this way, process-integrated surface modification during injection molding becomes possible. In a further attempt, patterns of paint are printed onto the surface of the mold by pad printing. During injection molding the paint is transferred completely to the surface of the polymeric part. Using this new technology of In-Mold Printing, fully finished surface decorated parts can be produced by injection molding.

Food insecurity and nutrition are two of the biggest challenges facing our society. Urban agriculture can help address these challenges, though lack of awareness about opportunities for engagement and degraded soils are two barriers that could prevent people from realizing the benefits that these operations can provide. Soils in urban areas are often highly degraded due to development activities and lack the structure and microbial life needed to sustain healthy, productive plants. Many lifelong habits such as healthy eating and engagement in community gardening are best established during young adulthood. Graduate school is a particularly unique time period, as many students are living on their own for the first time with modest incomes and some have young families that are particularly vulnerable to food insecurity. Consequently, the first objective of this project was to identify which barriers, if any, Purdue graduate students face when purchasing and consuming fresh produce and participating in local urban agriculture initiatives as Purdue’s campus and much of the surrounding area are characterized as food deserts by the USDA. We also sought to determine how the COVID-19 pandemic influenced food access and motivations for healthy eating and community garden engagement. To answer these questions, we distributed a voluntary 33 question online Qualtrics® survey to all Purdue graduate students via mass email blast. Results indicate that many Purdue graduate students face individual and structural barriers to accessing fresh fruits and vegetables. International respondents, in particular, were particularly vulnerable to structural barriers. Not having access to a personal vehicle appears to be the primary predictor of who was most vulnerable, especially during the pandemic. Results also indicate that students are interested in participating in local urban agriculture initiatives, but most are unaware of their existence. Students indicated that e-mails were the best method for increasing awareness and engagement. The second objective of this study was to determine whether leaf mold compost could improve the health and productivity of degraded urban soils. In addition, we aimed to determine whether the leaf compost could better support a beneficial microbial inoculant to further enhance crop productivity, as well as the extent to which plant genotype moderates these beneficial plant-soil-microbial relationships. To answer these questions, leaf compost was obtained from a local grower and applied to experimental plots at the Purdue University Farm. Two tomato varieties, Wisconsin 55 and Corbarino, were inoculated with Trichoderma harzianum T-22 or a sterile water control, and transplanted into the field trials. 15 Survival following transplanting, vigor, disease ratings and the yield and quality of tomato fruit were quantified over the course of two growing seasons. Results indicated that several measures of soil health were significantly increased in compost-amended soils and the health and productivity of tomato plants greatly improved. The microbial inoculant dramatically reduced transplant stress, especially in Wisconsin 55. Other more subtle differences among the tomato varieties indicated that urban agriculture systems could be improved through varietal selection. These studies highlight the fact that graduate students are not immune to food insecurity and proper nutrition and they are interested in connecting with urban agriculture initiatives to address these challenges. Pairing of the two groups could prove to be a successful mutualistic symbiosis as graduate students provide the enthusiasm and manpower that urban gardens need while urban gardens offer access to low-cost fresh produce that many graduate students desire. Leaf mold compost can aid in these initiatives by providing a cost-effective approach to improve the health and productivity of urban soils and crops, while at the same time providing further benefits such as reduced accumulation of valuable carbon sources in municipal landfills. Results like these provide stark evidence that agriculture, particularly urban agriculture, can continue to improve access to nutritious foods through green initiatives and innovations.

Sand mold casting is a manufacturing method that has been used for thousands of years. In recent years additive manufacturing has, among other things, enabled production of sand molds with complex geometry resulting in castings with geometry that would have been very hard, if not impossible, to produce with conventional sand mold casting or machining procedures. Since this manufacturing method is relatively new, knowledge gaps exist regarding the benefits and drawbacks of the method as well as when it should be used. The purpose of this study has been to explore casting molds produced by additive manufacturing, how they can be used and what effect they have on the manufactured product. For this purpose, a existing product has been redesigned to be cast in one of these molds instead of traditionally being machined from large aluminium blocks. The design work has been supplemented with calculations on the parts structural integrity, interviews and material sample tests. The redesign was made on behalf of Vattenfall AB and the studied component was a part of a test rig for a hydro power plant called spiral casing. The result of the study is a new design of the spiral casing with a lower weight and volume, made with stainless steel instead of aluminium, and other improvements. Testing of cast samples have shown that the mechanical properties of steel cast in 3D-printed and conventionally manufactured sand molds do not differ significantly. The sample cast in a 3D-printed mold did have a finer surface finish however.  Production volume, product complexity, material and lead time are all factors that determine when additive manufacturing should be used in the creation of sand molds. Further studies are required to better determine where the breakeven points are.

Purpose: The purpose of this study is to examine the problems that occur due to moist in the workplace, as well as the measures that can be taken and which measures are most effective. The study will examine the material storage and how it is being handled in the workplace, exploring what directives the insurance companies have, so the insurance is valid. Lastly the study will compare the different measures based on an economic perspective, time perspective as well as material savings. Method: This study is based on a literature study and a case study. The case study is based on both an interview and a site visit. Information has been gathered from various sources such as books, previously made thesis and various governments websites. The case study for this thesis is conducted at Emausskolan in Västerås. Results: To ensure that the moisture management in the production is good a certified moisture expert is hired. Moisture on materials can be prevented by using just-in-time deliveries and the most optimal solution a weather protection. Directives from the insurance companies regarding moisture management at the workplace and what the entrepreneur is obligated to do after moisture damage has occurred. To minimize moisture and mold growth the workplace should be clean and dry. Self-monitoring and samples were carried out throughout the project to ensure that the work has been performed correctly. Conclusions: The conclusion for this thesis is that challenges for moisture depends on the weather, carelessness, and time pressed schedules. Solutions would be to have a tight climate shell, usage of weather protection and surface treatment on materials. Handling of materials is to a certain degree taken care of in terms of palletized and packaged but not always.

The outdoor logistics in wood industry is an interesting research area since many factors need to be taken into consideration for an efficient process. However, little research can be found specifically in term of the outdoor logistics within wood industry. The purpose of this study is to design a model for streamlining outdoor logistics in the wood industry. Additionally, what important factors for more efficient outdoor logistics are also to be investigated.  According to Institute for Transport Research (2002), the material handling is defined as all physical handling, movement, storage and packaging of materials. To make the study scope clear, the outdoor logistics is specifically defined as the outdoor material handling in this study, and the outdoor refers to the local area outside the production buildings. A major part of this investigation work has been performed at one case company called Valbo Trä. The research is done through literature review, interviews, site observations at case company, and has generated a broad and deep understanding of the operations at the case company and the theoretical basis for the model development.  This study shows that the demand for different products is very different as well as the lengths and quantities of the products. Such fluctuating demand generally occurs in the wood industry, not only at the case company. The unpredictability of the demand for raw materials makes it complex for the case company to meet the customer's demands for finished products. On the other hand, the material handling becomes complex when the inventory levels increase. The inventory levels create, among other things, tied up capital, obsolescence, tighter handling space and poorer visibility for the truck drivers. Obsolescence that occurs can be traced to material handling. Damage occurs during internal transport and the wood suffers from damage due to weather conditions during outdoor handling. When handling materials outdoors, there are also risks in the form of obscured visibility during transport with loaders. Violation of speed limits and varying compliance with safety rules also occur. High inventory levels also affect the possibility of applying FIFO. Flows, obsolescence, and safety have been identified as the most important factors for more efficient outdoor logistics within the wood industry. Based on the identified factors a model could be designed and applicable within the wood industry.

The current and forecasted global consumption of plastic packaging and products through the 21st century combined with the already reported and growing negative impact of plastics on the environment due to plastics being synthesized from nonrenewable resources that do not biodegrade is of serious concern. However, recent advances in starch technology including the development of thermoplastic starch (TPS) materials —polymers that are both renewable and biodegradable—have brought hope to reducing this impact. The mechanical properties of thermoplastic starch have often been improved by blending with synthetic polymers. One issue that arises with blending is volatilization of the melt from moisture in the TPS materials. Ecostarch™ a proprietary, pelletized thermoplastic starch resin formulated from potato starch, was processed and tested to observe injection molding processability at various moisture levels, in pure TPS as well as various blend ratios with high-density polyethylene (HDPE) and polypropylene (PP). This study evaluated and analyzed the effects of the TPS pellet moisture content on void formation in the plastic pre-injection melt and subsequent molded part mechanical properties. Statistical analysis of the test results showed that moisture had a significant effect on void formation in the plastic melt. In TPS/HDPE blends, voids percent (as measured by cross section area) increased by 300-350% from 0.6% to 1.4% moisture levels. In unblended TPS, void percent increased by 150% from 0.4% to 1.4% moisture levels. In the unblended TPS parts, impact strength (energy in ft-lb) was decreased by 1% from 0.6% to 1.4% moisture level. In the TPS/HDPE and TPS/PP blends, there was no significant effect on impact strength due to the moisture percent levels of the TPS. Modulus decreased by 25% from 0.4% to 1.4% moisture level in unblended TPS parts. From 0.6% to 1.4% change in TPS moisture content, the modulus of the TPS/HDPE blend decreased by 9% at a 30% TPS/70% HDPE blend and decreased by 14% at a 70% TPS/30% HDPE blend. Though the moisture of TPS did not have a significant impact on the tensile strength of TPS/HDPE blends, the tensile strength of TPS/PP blend samples were significantly affected: a change from 0.6% to 1.4% moisture increased tensile strength 34% at a 70% TPS/30% PP blend and increased tensile strength by 22% at a 30% TPS/70% PP blend. Thus the results of this study highlight the relationships between moisture, voids, and mechanical performance of TPS and TPS/Polymer blends.

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