Characterization of a reverse molding sequence at the mesoscale for in‐mold assembly of revolute joints

Ananthanarayanan, Arvind; Gupta, Satyandra K.; Bruck, Hugh A.

doi:10.1002/pen.21709

Cited by 3 publications

(4 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Strength properties of the weld line area depend on the type of material being processed. It was shown that amorphous polymers are characterized by higher strength than semicrystalline ones . The viscosity of the polymer at the processing temperature plays a significant role.…”

Section: Introductionmentioning

confidence: 99%

The influence of the type of polypropylene and the length of the flow path on the structure and properties of injection molded parts with the weld lines

Bociąga

Kaptacz

Duda

et al. 2019

Polymer Engineering & Sci

View full text Add to dashboard Cite

Weld lines, created in the areas of collision of two flow fronts of plastic in the injection mold cavity, are the reason of lower mechanical properties and a worse surface condition of molded parts. In the weld line area, the V‐shaped notch is formed and its shape and size depend on injection molding conditions and properties of processed polymer. Addition of the foaming agent to the polymer can be one of the way to improve conditions of melt streams welding due to the higher velocity of the colliding streams of unfilled polypropylene (PP) and PP filled with talc. The examinations of mechanical properties showed, however, lower tensile strength of porous parts compared to solid ones, but in the microscopic observation and measurements of the geometric structure of moldings, in the weld lines area, better surface conditions were achieved for samples made of the foamed polypropylene. The size of V‐notch, determined by the total height of the raw profile Pt, depends also on the length of polymer flow path from the gate to the weld line area. The values of Pt parameter increase with the length of the flow path, but this increase is smaller for foamed polypropylene. POLYM. ENG. SCI., 59:1710–1718 2019. © 2019 Society of Plastics Engineers

show abstract

Section: Introductionmentioning

confidence: 99%

The influence of the type of polypropylene and the length of the flow path on the structure and properties of injection molded parts with the weld lines

Bociąga

Kaptacz

Duda

et al. 2019

Polymer Engineering & Sci

View full text Add to dashboard Cite

show abstract

“…The room temperature to which the polymers cool was assumed to be 28 C. We then calculated the interfacial frictional torque using Eqs. (1) and (2). These results are shown in Fig.…”

Section: Resultsmentioning

confidence: 52%

“…These methods, although highly inefficient, are popular processes for making macro scale mechanical assemblies. However, for fabricating miniature mechanical assemblies (joint dimensions < 1 mm) [1], manual assembly operations become very tedious and, in some cases infeasible. This is because, owing to the individual part sizes, it is difficult for a skilled human operator to assemble the parts.…”

Section: Introductionmentioning

confidence: 99%

Design of Revolute Joints for In-Mold Assembly Using Insert Molding

Ananthanarayanan

Ehrlich

Desai

et al. 2011

Journal of Mechanical Design

Self Cite

View full text Add to dashboard Cite

Creating highly articulated miniature structures requires assembling a large number of small parts. This is a very challenging task and increases cost of mechanical assemblies. Insert molding presents the possibility of creating a highly articulated structure in a single molding step. This can be accomplished by placing multiple metallic bearings in the mold and injecting plastic on top of them. In theory, this idea can generate a multi degree of freedom structures in just one processing step without requiring any post molding assembly operations. However, the polymer material has a tendency to shrink on top of the metal bearings and hence jam the joints. Hence, until now insert molding has not been used to create articulated structures. This paper presents a theoretical model for estimating the extent of joint jamming that occurs due to the shrinkage of the polymer on top of the metal bearings. The level of joint jamming is seen as the effective torque needed to overcome the friction in the revolute joints formed by insert molding. We then use this model to select the optimum design parameters which can be used to fabricate functional, highly articulating assemblies while meeting manufacturing constraints. Our analysis shows that the strength of weld-lines formed during the in-mold assembly process play a significant role in determining the minimum joint dimensions necessary for fabricating functional revolute joints. We have used the models and methods described in this paper to successfully fabricate the structure for a minimally invasive medical robot prototype with potential applications in neurosurgery. To the best of our knowledge, this is the first demonstration of building an articulated structure with multiple degrees of freedom using insert molding.

show abstract

“…Furthermore, IMAs of various thermoplastic components to be assembled, for example, for joints , were investigated using adapted process techniques. These should make it possible to prevent the bending of the insert by the melt pressure . The insert injection molding with fiber inserts and high‐density polyethylene (HD PE) as encapsulation material to single polymer composites was investigated regarding to the interface properties in the literature [26].…”

Section: State Of Researchmentioning

confidence: 99%

Thermoplastic encapsulations of a sensor platform by high‐temperature injection molding up to 360°C

Werner

Krumpholz

Rehekampff

et al. 2019

Polymer Engineering & Sci

View full text Add to dashboard Cite

For bioprotective encapsulated Internet of Things (IoT) electronics for the medical market, especially for cost‐effective, single or multiple use, injection molding will be of major importance. The stresses from the production process pose special challenges for electronics. The aim of the study was the simulative and experimental characterization of the load spectrum from the injection molding process and its effects on electronics. General recommendations for the encapsulation of IoT electronics in polymer matrices were derived. A microcontroller‐controlled temperature sensor board and a suitable injection mold were developed. Eight circumferential NTC‐sensors measured the prevailing thermal load directly on the component during overmolding. A simulation model allowed statements on the loads to be made about individual components, validated in experimental tests. In addition to PP and PMMA, PSU with a melt temperature of 360°C was tested. The temperature influence of the melt could be described as a function of the component position. The loss of adhesion, shrinkage, distortion, cavities, and delamination were analyzed using micrograph analysis. Complete functionality of the electronics was ensured after encapsulation. Optimization strategies were developed for the design of both IoT electronics and the injection mold. Novel concepts such as interlayer or backfill vias could be derived for future research approaches. POLYM. ENG. SCI., 59:1315–1331 2019. © 2019 Society of Plastics Engineers

show abstract

Characterization of a reverse molding sequence at the mesoscale for in‐mold assembly of revolute joints

Cited by 3 publications

References 15 publications

The influence of the type of polypropylene and the length of the flow path on the structure and properties of injection molded parts with the weld lines

The influence of the type of polypropylene and the length of the flow path on the structure and properties of injection molded parts with the weld lines

Design of Revolute Joints for In-Mold Assembly Using Insert Molding

Thermoplastic encapsulations of a sensor platform by high‐temperature injection molding up to 360°C

Contact Info

Product

Resources

About