Mold Components Research Articles

Automatic recognition and suppression of holes on mold bases for finite element applications

As the required accuracy of mold flow analysis has recently increased, it has become necessary to consider all components of a mold base and to generate solid meshes for all of them. If holes on all mold components are kept in mesh generation, the mesh size near each hole must be adapted to maintain the shape accurately. This, however, not only increases the effort required to edit the meshes, but also increases the total amount of meshes tremendously. The objective of this study is to present a method for the recognition and suppression of holes on mold bases. A preliminary computation of the data required for hole recognition is described, which includes entity grouping, fillet recognition, and loop recognition. An algorithm for recognizing holes on all mold components can thus be implemented, which includes the recognition of all face compositions on various kinds of “ladder” structures that involve several holes connected to each other. All hole structures can then be suppressed automatically. The recognition and suppression of holes on two mold bases are presented to demonstrate the feasibility of the proposed technique.

Hard Coating for Cutting Tools and Die, Mold Components

Hard Coating for Cutting Tools and Die, Mold Components

Study of a additive device which measures the angled walls of injection mold components on a three axis CNC

The paper attempts to demonstrate an efficient on machine measurement system. During this study the authors will develop a measurement device, in order to accurately analyze the dimensional precision of the angled vertical walls used to center active cavities inside an injection mold, on a three axis CNC. The designed device will work in strong connection with a touch trigger probe. The final results will show an improved accuracy of the measurement system.

Study on surface defects in five-axis ball-end milling of tool steel

The AISI P20 tool steel is widely used for manufacturing the plastic mold components, while surface defects problem often arises during ball-end milling process, which can deteriorate the fatigue life of the plastic molds. Therefore, it is vital to reveal the formation mechanism of the surface defects. First, a surface topology predictive model is conducted which is verified by experimental results; in addition, according to the simulation and experimental results, tool wear, surface topology, and surface profile are analyzed. Secondly, the origin of the surface defects is analyzed on the basis of the scanning electron microscope (SEM) images, and the relationship between the chip and surface defects is also discussed. Based on the investigation, the cutting friction and heating rather than the carbide particles are the main reason for surface defects in milling AISI P20 steel. This research is beneficial for the understanding of surface topology and surface defect formation mechanism. Meanwhile, the results could provide a technical base for selecting cutting parameters in five-axis ball-end milling of AISI P20 steel.

Aiming for Improved Lifetime of Die and Mold Components through an Integrated Laser Hardening Operation, Combining Machining and a Selective Heat Treatment in One Setup

The growing use of fiber reinforced plastics in injection molding greatly reduces the lifetime of components in dies and molds. In this research, injection nozzles are machined within one set-up, combining machining and selective laser hardening operation. This allows the machining and hardening of die and mold components in one single setup. A thermal model is developed and experimentally validated in order to be able to select optimal hardening parameters and strategy. Hardness values exceeding conventional hardening techniques on tool steel are presented, aiming for a prolonged lifetime of dies and molds.

Nation-Based Occurrence and Endogenous Biological Reduction of Mycotoxins in Medicinal Herbs and Spices.

Medicinal herbs have been increasingly used for therapeutic purposes against a diverse range of human diseases worldwide. Moreover, the health benefits of spices have been extensively recognized in recent studies. However, inevitable contaminants, including mycotoxins, in medicinal herbs and spices can cause serious problems for humans in spite of their health benefits. Along with the different nation-based occurrences of mycotoxins, the ultimate exposure and toxicities can be diversely influenced by the endogenous food components in different commodities of the medicinal herbs and spices. The phytochemicals in these food stuffs can influence mold growth, mycotoxin production and biological action of the mycotoxins in exposed crops, as well as in animal and human bodies. The present review focuses on the occurrence of mycotoxins in medicinal herbs and spices and the biological interaction between mold, mycotoxin and herbal components. These networks will provide insights into the methods of mycotoxin reduction and toxicological risk assessment of mycotoxin-contaminated medicinal food components in the environment and biological organisms.

Automatic process planning of mold components with integration of feature recognition and group technology

The machining process of plastic injection mold components is complex and continuously changing, and traditional practices rely on the experience and technique of professionals. In order to avoid the impact on business operations and losses, the geometric information of computer-aided design (CAD) systems should be converted into the manufacturing system required for computer-aided process planning (CAPP) and computer-aided manufacturing (CAM) systems through the integration of automatic feature recognition and group technology, thereby eliminating manual planning and shortening the planned lead time to realize CAD/CAPP/CAM integration and application. As part design is feature-based, each processing step can be regarded as a feature. This study applied hybrid recognition technology integrating the graph-based approach, rule-based approach, and hint-based approach to analyze and identify injection mold component shape features. Then, it established classification coding for data description according to the injection mold components before searching for the corresponding manufacturing processes in the database using the group technology. The case proved that the CAPP in this study could reduce about 90 % of the working time needed. It could accelerate the component planning process and integrate with the mold manufacturing scheduling to realize automated design and manufacturing.

Coated Composite Crosstie Mold Structure Design Used for Experiment with Inventor, Moldflow and Ansys

Coated crosstie products and counter mold components are created in 3-D model using Inventor software, preparing for CAE analysis. By using Moldflow software , to determine products gate location, filling, packing, cooling, push-out processing, as well as the injection process conditions optimization of simulation analysis to find possible defects, modify and optimize the design, determine the best processing parameters and conditions. Binding using Ansys11.0 software to analyze rail sleeper mold cavity deformation, structure stress, get distribution of property of von Mises stress and displacement vector sum, in the mold cavity on the contact surface. By changing the cavity wall thickness, and other factors to improve the force which it is subjected, providing references to structure optimization of injection mold design. It has been proven that in collaborative application of these three softwares, the design of the injection mold is a very efficient and easy.

Integrative Approaches for Mechanical Mold Design in Injection Molding

The injection mold faces a number of different loads during the injection molding process for plastic parts. The effect on the mechanical behavior of the mold, inserts, and adjacent processes can be complex and may cause bad final parts. By using an integrative simulation approach it is possible to take the process influence into account when calculating the solid body behavior of the mold in a structural simulation. A newly developed approach at IKV uses the advantages of the integrative approach and extends it by an automatic back coupling of deformation results during the filling simulation. This way the interaction of the melt flow and the deformation of inserts or mold components can be considered during the filling phase.

In-Place Repair of Worn or Damaged Mold Components

Portable, high-speed process reduces repair costs and downtime.

The Effect of Harvest Moisture and Bale Wrapping on Forage Quality, Temperature, and Mold in Orchardgrass Hay

Effects of harvest moisture and bale wrapping on forage quality and mold formation in orchardgrass ( Dactylis glomerata L.) hay have not been investigated. The objectives of this study were to determine the effects of initial bale moisture and plastic wrapping on temperature, forage quality (protein, fiber components, and digestible energy), and mold formation in large round-baled orchardgrass hay. In all, 40 round bales of mature orchardgrass hay measuring 1.2 × 1.5 m 2 were baled at three different moisture ranges (eight bales per treatment): 124 to 166 g/kg (low moisture); 180 to 232 g/kg (intermediate moisture); and 259 to 337 g/kg (high moisture). Selected bales within each moisture range were individually wrapped in plastic (16 bales), and temperature sensors were placed in each bale for up to 10 weeks. The lowest ( P ≤ .01) maximum temperature and heating degree-day accumulations were observed when initial bale moisture content was 124 g/kg or when hay was wrapped, regardless of initial moisture content. In 2008 and 2009, all wrapped hays resulted in similar forage quality ( P ≤ .14) and mold counts ( P = .94) compared with 124 g/kg moisture hay. Hay baled at 166 g/kg resulted in fiber ( P ≥ .82) and mold ( P = .21) components similar to higher moisture bales. Mold counts for hay baled at 166 g/kg and 124 g/kg moisture were 24.8 × 10 6 and 2.7 × 10 4 CFU/g, respectively, demonstrating that large round bales are prone to molding at relatively low moisture concentrations. Maintenance of forage quality and reduction in mold growth were achieved by baling dry (124 g/kg moisture) or wrapping round bales of orchardgrass hay up to 337 g/kg moisture.

Removal of the α‐Case Layer from Precision‐Cast Cellular TiAl6Nb7 to be Used for Biomedical Applications

The present work deals with the chemical removal of the α-case layer formed during precision casting of cellular TiAl6Nb7 sponges for biomedical applications. The major part of the brittle α-case layer can be attributed to chemical reaction between titanium and the investment mold components. To improve the ductility of the cell struts by eliminating the brittle surface, a pickling-vibration treatment was developed by which the α-case layer is chemically removed.

Pro/ENGINEER를 이용한 사출금형의 표준부품 및 몰드베이스 자동생성 3D CAD 프로그램 개발

Automated design system of injection mold was developed in this study. Shapes of mold parts and mold base were defined according to standards of mold components and database modules of mold components were built. And then an automation program of mold design was developed by the user definition features, family table and Pro/Program of Pro/Engineer. The automatic production divided into mold base and standard parts was manipulated to manufacture parts meeting the design requirements and the selected parts were changed in size and shape to meet the design goals. The mold design was also carried out to have organic relations and be easy in case of a change to the mold part or mold base.<BR> As a result, it is possible to design the mold efficiently and conveniently modify the designed mold parts and base by using the developed automated design system in this study.

Clara Cell Secretory Protein Is Reduced in Equine Recurrent Airway Obstruction

Horses are prone to recurrent airway obstruction (RAO), an inflammatory lung disease induced by repeated exposure to environmental mold, dust, and bacterial components. Active disease manifests with mucus hyperproduction, neutrophilic inflammation, bronchoconstriction, and coughing. Chronically affected animals have lung remodeling characterized by smooth muscle hyperplasia, collagen deposition, lymphoid hyperplasia, and impaired aerobic performance. Clara cell secretory protein (CCSP) counters inflammation in the lung, hence we hypothesized that CCSP depletion is a key feature of RAO in horses. Recombinant equine CCSP and specific antiserum were produced, and percutaneous lung biopsies were obtained from 3 healthy horses and from 3 RAO-affected horses before and after induction of RAO. CCSP relative gene expression in tissue, as well as protein concentration in lung lavage fluid, was determined. Immunocytochemical analysis, using both light and immunogold ultrastructural methods, demonstrated reduced CCSP staining in lung tissue of animals with RAO. Immunogold label in Clara cell granules was less in animals with chronic RAO than in normal animals, and absent in animals that had active disease. Median lung lavage CCSP concentration was 132 and 129 ng/ml in healthy horses, and 62 and 24 ng/ml in RAO horses before and after challenge, respectively. CCSP lung gene expression was significantly higher in healthy animals than in animals with chronic RAO. Together, these preliminary findings suggest that reduced production of CCSP and subcellular changes in Clara cells are features of chronic environmentally induced lung inflammation in horses.

Levels and determinants of β(1 → 3)-glucans and fungal extracellular polysaccharides in house dust of (pre-)schoolchildren in three European countries

Background Mold growth is believed to be one causative factor underlying the association between dampness in buildings and increased respiratory morbidity. Measurements of β(1 → 3)-glucans and fungal extracellular polysaccharides (EPS) are used as markers of mold exposure in field studies. Little is known about their levels and determinants in homes. Objective To study levels and determinants of β(1 → 3)-glucan and EPS levels in mattress and living room floor dust in three European countries. Methods Mattress and living room floor dust was collected in the homes of 1065 German, Dutch, and Swedish (pre-)school children. All samples were analyzed for β(1 → 3)-glucans and EPS in one central laboratory. Determinants were assessed by questionnaire. Results Amounts of dust, EPS and β(1 → 3)-glucan levels differed between countries. Amounts of dust, β(1 → 3)-glucan and EPS levels for mattresses were only weakly correlated with those for living room floors. Floor dust β(1 → 3)-glucan loads, EPS loads and EPS concentrations were strongly correlated with the amount of dust sampled, which is largely determined by the type of floor that was sampled (carpeted floors had 5–20 higher amounts of dust). None of the other determinants was consistently and statistically significantly associated with amounts of dust, β(1 → 3)-glucan and EPS concentrations on floors and mattresses. Conclusion Mattress dust and floor dust are two different measures of exposure to the investigated mold components. Living room floor β(1 → 3)-glucan and EPS loads and EPS concentrations are largely determined by the type of floor sampled. Differences between countries can only partly be explained by the determinants studied.

Medial surface generation using chordal axis transformation in shell structures

This paper describes the generation of chordal surfaces for various shell structures, such as automobile bodies, plastic injection mold components, and sheet metal parts. After a single-layered tetrahedral mesh is generated by the advancing front method, the chordal surface is generated by cutting the tetrahedral mesh. One or more shell elements are generated at each tetrahedral element, and the chordal surface is constructed with triangular or quadrilateral shell elements. This algorithm has been tested on several models with rib structures.

An ALE‐FEM approach to the thermomechanics of solidification processes with application to the prediction of pipe shrinkage

PurposeThe present paper addresses the computer modelling of pipe formation in metal castings.Design/methodology/approachAs a preliminary, a brief review of the current state‐of‐the‐art in pipe shrinkage computation is presented. Then, in first part, the constitutive equations that have to be considered in thermomechanical computations are presented, followed by the main lines of the mechanical finite element resolution. A detailed presentation of an original arbitrary Lagrangian‐Eulerian (ALE) formulation is given, explaining the connection between the Lagrangian and the quasi Eulerian zones, and the treatment of free surfaces.FindingsWhereas most existing methods are based on thermal considerations only, it is demonstrated in the current paper that this typical evolution of the free surface, originated by shrinkage at solidification front and compensating feeding liquid flow, can be effectively approached by a thermomechanical finite element analysis.Research limitations/implicationsFuture work should deal with the following points: identification of thermo‐physical and rheological data, automatic and adaptive mesh refinement, calculation of the coupled deformation of mold components, development of a two‐phase solid/liquid formulation.Practical implicationsAn example of industrial application is given. The proposed method has been implemented in the commercial software THERCAST® dedicated to casting simulation.Originality/valueThe proposed numerical methods provide a comprehensive approach, capable of modelling concurrently all the main phenomena participating in pipe formation.

Improved sand surface element for residual stress determination

A method has been developed to efficiently predict residual stresses in castings whose molds include steel chills and other high stiffness mold components. Mold elements are replaced by surface elements that apply an equivalent normal force to the surface of the part. A special contact condition, consisting of two separate functions, was developed to handle a large range of mold stiffnesses. Solidification of several geometric shapes was simulated and the solutions using the new element were compared with solutions computed using a mesh for the full mold. The surface element was found to provide a good estimate for the displacement and equivalent plastic strain for the casting models. The time necessary to compute the solution was also significantly decreased when using this new technique.

Generating sacrificial multi-piece molds using accessibility driven spatial partitioning

This paper describes an algorithm based on accessibility-driven partitioning approach to automate the design of sacrificial multi-piece molds. Sacrificial multi-piece molds are used for producing geometrically complex gelcast ceramic parts. The algorithm presented in this paper analyzes the accessibility of the gross mold shape and partitions using accessibility information. Each partitioning step improves accessibility of decomposed mold pieces. By performing successive decomposition, this algorithm finally produces a set of mold components that are accessible and therefore can be manufactured using milling and drilling operations. Using the algorithm presented in this paper, mold design steps can be significantly automated for making geometrically complex parts and facilitating the creation of physical part from the CAD model in a matter of hours.

912 複合表面改質による硬質膜の密着性とトライボ特性

While dry coating has attracted attention as surface treatment in late years, coating film has been applied as cutting tool, metal mold, and mechanical components. Also, durability in the dasher conditions in required. Duplex surface treatment using the synergetic effect of various properties by combining surface treatment to deal with the diversified needs attracts attention. In this report, nitriding treatment and dry coating were combined to evaluate the adhesion and tribology of coating film.