Development of a Reliable Vibration Based Health Indicator for Monitoring the Lubricating Condition of the Toggle Clamping System of a Plastic Injection Molding Machine

Plastic injection molding has become one of the most widely used polymer processing methods due to its ability to viably produce large volumes of complex parts in a short time frame. Most of the plastic injection molding machines currently used in industry possess a toggle clamping mechanism that undergoes a repeated clamping and unclamping cycle during operation. This toggle must therefore be properly lubricated to avoid catastrophic failure and eventual machine downtime. To overcome this limitation, the industry currently relies on the experience of a skilled operator, paired with a fixed empirical value, to determine the timing for re-lubrication. This method often leads to the machine operator either wasting lubricant by over-lubricating the toggle, or damaging the toggle by failing to re-lubricate when needed. Herein, we explore the use of vibration analysis to perform real-time condition monitoring of the lubrication condition of the toggle clamping system. In this study, our novel structural response analysis out performed both traditional time domain and frequency domain analyses in isolating the vibrational signatures indicative of lubricant degradation. Additionally, this study confirms that the vibration generated during the unclamping period of the toggle, proved to contain more valuable information relevant to the instantaneous lubricant quality than provided by its corresponding clamping period.

RESIN FLOW SIMULATION DURING THE RTM METHOD OF COMPOSITES PRODUCTION

Processes of plastic injection molding are often under analyzes in industry and science. Many of these considerations apply to epoxy resins with additional reinforcement, often with glass or carbon fiber inside the closed mould. The simulations of injection molding processes in the production of composite elements is not as common, as thermoplasts. Hence the idea to carry out the work described in this article. The RTM (Resin Transfer Molding) method is dedicated to serial production with the possibility of producing visual carbon fiber elements for aesthetic reasons. Simulations can help to better refine the products. This allows to take appropriate precautions and solve many issues before implementation. The article presents possible situations that could occur in real conditions. Various shapes models were prepared as basis of the numerical calculations. The analyses highlighting the possible issues were performed. The influence of resin pressure and flow rate on the final product was also considered. The aim was to present the characteristic phenomena and their causes that often occur in reality to technologists working with the RTM. Conclusions related to the work carried out are included. Based on the analyzes and conclusions drawn, it is possible to improve the quality of production processes.

Development of a Novel Design Strategy for Moving Mechanisms Used in Multi-Material Plastic Injection Molds

Plastics injection molding is a sector that is becoming increasingly competitive due to the environmental issues it entails, pressuring consumers to reduce its use. Thus, plastics processing companies attempt to minimize costs, with the aim of increasing competitiveness. This pressure is transmitted to the mold manufacturers, as the mold conditions the equipment that it is used for, which may have significantly different amortization costs. The present work aimed to design a novel mechanism able to deal with the necessary movements in 2K injection molding in a more compact way. A novel hybrid mechanical and hydraulic movement was developed. More compact movements lead to smaller molds, which can be used on smaller injection machines, leading to reduced costs. This methodology consists of multiplying a disproportionate movement to the mold through several movements, which results in a slightly more complex, but much more compact, system for molds devoted to multi-material injected parts.

Bonding Integrity of Hybrid 18Ni300-17-4 PH Steel Using The Laser Powder Bed Fusion Process For The Fabrication of Plastic Injection Mould Inserts

Laser powder bed fusion (LPBF) is a metal additive manufacturing (AM) process for fabricating high-performance functional parts and tools in various metallic alloys, such as titanium, aluminium and tool steels. The process can produce geometrically complex features such as conformal cooling channels (CCC) in plastic injection mould inserts to improve cooling efficiency. A recent attempt using a hybrid-build LPBF AM technique to fabricate aluminium mould inserts with CCC attained a substantial reduction in processing time, making it an attractive alternative method to the mould-making industry. Also, the successful bonding of aluminium powder with wrought aluminium alloys proved the practicability of this concept. This study further investigates whether a similarly successful outcome could apply to tool steel since tool steel is the preferred material for constructing high-grade high-volume plastic injection moulds. In this investigation, hybrid 18Ni300 powder-wrought 17-4 PH steel parts were additively fabricated using the hybrid-build LPBF technique, followed by various post-build heat treatments. The mechanical and metallurgical properties of the samples’ bonded interface were examined. Microstructure analysis revealed homogenous powder-substrate fusion across the interface region. Results from tensile tests confirmed strong powder-substrate bonding as none of the tensile fractures occurred at the interface. A direct post-build one-hour age-hardening treatment achieved the best combination of hardness, tensile strength, and ductility. The overall result demonstrates that hybrid-built 18Ni300-17-4 PH steel can be a material choice for manufacturing durable and high-performance injection mould inserts for high-volume production.

Processing and Testing of Reinforced PA66 Based Composites

The new requirements in different sectors, such as aerospace, automotive and construction, for lightweight materials have led to an increase in demand for composite materials suitable for use in high rate production processes, such as plastic injection. This makes it necessary to look for matrices and reinforcements that, in addition to being compatible with each other, are also compatible with the injection process. It is in this area of research where the work presented here arises. To meet the two requirements mentioned above, this study contemplates a battery of composite materials obtained by combining PA66 and fiberglass, in different proportions and configuration, both for the preparation of the matrix and for reinforcement. For the elaboration of the matrix, two options have been evaluated, PA66 and PA66 reinforced at 35% with short glass fibre. To obtain reinforcement, six different options have been evaluated; two conventional fiberglass fabrics (each with different density) and four hybrid fabrics obtained from the previous ones by adding PA66 in different configurations (two over-stitched fabrics and two other fabrics). The different composite materials obtained were validated by means of the corresponding adhesion, peeling and resistance tests.