Manufacturing multi-material articulated plastic products using in-mold assembly

Priyadarshi, Alok; Gupta, Satyandra K.; Gouker, Regina M.; Krebs, Florian; Shroeder, Martin; Warth, Stefan

doi:10.1007/s00170-005-0343-z

Cited by 36 publications

(29 citation statements)

References 11 publications

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“…In-mold assembly provides an effective alternate method for manufacturing miniature mechanical assemblies. These methods have been developed in the past for both macroscale [7] and mesoscale [8,9]. Using this method, a fully assembled articulating rigid body joint could be ejected from the mold.…”

Section: Background: In-mold Assemblymentioning

confidence: 99%

“…Hence, we need to develop methods to prevent bonding between the polymer and the metal inserts to allow for articulation after the insert molding process. This paper will address this challenge and demonstrate an innovative manufacturing approach based on the in-mold assembly process [7][8][9] to realize highly articulating mechanical assemblies. We will also present an analytical modeling based approach to select the optimum joint parameters which enable effective use of this process.…”

Section: Introductionmentioning

confidence: 99%

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

Ananthanarayanan

Ehrlich

Desai

et al. 2011

Journal of Mechanical Design

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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.

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Section: Background: In-mold Assemblymentioning

confidence: 99%

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

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“…A recent alternative, referred to as in-mold assembly process, performs molding and assembly steps concurrently inside the mold itself [Pirk98], [Plan02], [Good02], [Li04], [Gouk06], [Priy07]. This means that an entire assembly consisting of multiple components can be produced by a single set of molds, thereby eliminating the need for secondary assembly operations and the use of bolts, welds, glue, or other fasteners.…”

Section: Introductionmentioning

confidence: 99%

Generating Multi-Stage Molding Plans for Articulated Assemblies

Priyadarshi

Gupta

2007

2007 IEEE International Symposium on Assembly and Manufacturing

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Multi-stage molding is capable of producing better-quality articulated products at a lower cost. During the multi-stage molding process, assembly operations are performed along with the molding operations. Hence, it adds new constraints to the assembly planning problem. This paper introduces the problem of generating multi-stage molding plans for articulated assemblies. We present detailed algorithms for determining the molding sequence and intermediate assembly configurations.

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“…Such sequential injection molding techniques provide significant advantages in the manufacturing of complex and versatile parts, through the combination of primary shaping and assemblage in a single process step . Thus, the assembly costs can be significantly reduced, which leads to lower product costs …”

Section: Introductionmentioning

confidence: 99%

Process Influences on the Materials Interface of an Injection Molded Hard‐Soft‐Component

Frick

Spadaro

2018

Macromolecular Symposia

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Combining a soft thermoplastic elastomer with a hard polymeric material by multi‐component injection molding provides a novel and sophisticated alternative for mounting a vulcanized dynamic elastomeric seal part into a rigid housing. Such assembly injection molding is new and challenging, but promises several economic advantages. The main issue within such a development is the assurance of sufficient bond strength between soft and hard component, in order to withstand the service load conditions safely. This paper studies certain process influences on the interface condition between the materials. The strength of the adhesive bond of composite test specimens consisting of a hard outer ring and a soft inner ring with integrated rotary seal lip are evaluated. The injection molded and investigated composite parts consist of glass fiber reinforced polybutylene terephthalate (PBT‐GF30) as hard component and a thermoplastic polyurethane (TPU) as soft component. The required force to reach delamination between hard and soft component is monitored and correlated with the surface structure and properties of differently plasma pre‐treated hard components. Supposed a material combination and the contact temperature are defined the surface conditions of the hard component play the major role with respect to the adhesion bond strength.

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Manufacturing multi-material articulated plastic products using in-mold assembly

Cited by 36 publications

References 11 publications

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

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

Generating Multi-Stage Molding Plans for Articulated Assemblies

Process Influences on the Materials Interface of an Injection Molded Hard‐Soft‐Component

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