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Design and fabrication of a low-volume, high-temperature injection mould leveraging a ‘rapid tooling’ approach

DOI:10.1007/s00170-019-03799-8
Authors:
Hamed Kalami at University of Windsor
Hamed Kalami
Ruth Jill Urbanic at University of Windsor
Ruth Jill Urbanic
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Abstract and Figures

The costs for low-volume production moulds (1–200 production components) are related to the mould material, the process planning time and the fabrication costs. Researchers have explored using additive manufacturing (AM) processes to fabricate moulds directly from their digital models as this reduces the process planning time and some fabrication costs, but there are issues with directly employing an AM solution. Material costs are high for metallic AM processes, and there are thermal conductivity and material compatibility issues when using plastic-based AM processes. Both the metal- and plastic-based AM processes have surface finish issues; so post processing activities must be part of the fabrication plan. In this research, a methodology is found to fabricate low-volume production moulds using a high-temperature moulding material. A general solution is provided, with a case study focusing on an over moulding process in which the injection material being moulded is Technomelt-PA 7846 black. A hybrid mould fabrication is applied where a material extrusion–based process is used to make a sacrificial product-shaped pattern. This pattern is used to form a resin-based insert which is to be assembled into a mould base frame. Customised inserts can be readily built and exchanged to provide a rapid response to a customer request. An assessment of the digital model, the manufacturing, assembly and the final validated assembly model is provided.
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ORIGINAL ARTICLE
Design and fabrication of a low-volume, high-temperature injection
mould leveraging a ‘rapid tooling’approach
Hamed Kalami
1
&R. J. Urbanic
1
Received: 15 August 2018 /Accepted: 17 April 2019
#Springer-Verlag London Ltd., part of Springer Nature 2019
Abstract
The costs for low-volume production moulds (1–200 production components) are related to the mould material, the process
planning time and the fabrication costs. Researchers have explored using additive manufacturing (AM) processes to fabricate
moulds directly from their digital models as this reduces the process planning time and some fabrication costs, but there are issues
with directly employing an AM solution. Material costs are high for metallic AM processes, and there are thermal conductivity
and material compatibility issues when using plastic-based AM processes. Both the metal- and plastic-based AM processes have
surface finish issues; so post processing activities must be part of the fabrication plan. In this research, a methodology is found to
fabricate low-volume production moulds using a high-temperature moulding material. A general solution is provided, with a case
study focusing on an over moulding process in which the injection material being moulded is Technomelt-PA 7846 black. A
hybrid mould fabrication is applied where a materialextrusion–based process is used to make a sacrificial product-shaped pattern.
This pattern is used to form a resin-based insert which is to be assembled into a mould base frame. Customised inserts can be
readily built and exchanged to provide a rapid response to a customer request. An assessment of the digital model, the
manufacturing, assembly and the final validated assembly model is provided.
Keywords Additive manufacturing .Mould fabrication .Low volume .High-temperature moulding materials .Process
planning .Rapid tooling .Assembly
1 Introduction
The competitive landscape in the manufacturing domain is
increasing in our global economy for both mass production
and customised product fabrication; hence, developing new
approaches to address wage and wage disparity issues, econ-
omies of scale and mass customisation, virtualisation and dig-
ital manufacturing, and self-optimisation are research areas
associated with Industry 4.0. The Industry 4.0 approach is
applicable to a wide variety of manufacturing domains, and
applications could leverage the Internet and cloud resources,
digital models (or twins), data analytics, smart sensors, 3D
printing or additive manufacturing, and so forth to allow pro-
ducers to better react to customer demands profitably. The
plastic mould–making industry, which is a multi-billion indus-
try consisting of typically small- and medium-size enterprises
(in Canada, there are 502 establishments with 5,300 em-
ployees and $926 million in shipments [1]), is actively pursu-
ing opportunities to reduce tooling costs and processing time.
The design solutions depend on the production volumes and
planning horizons, and different mould materials and fabrica-
tion strategies are required for low-volume, medium-volume,
and high-volume production. The introduction of digital
manufacturing and assembly strategies introduce new oppor-
tunities, especially for complex specialty production applica-
tions. However, to enable mass customisation, lower product
introduction cycles, and so forth, domain-specific detailed
product and process realisation knowledge need to be cap-
tured, and included in the company’s design standards or pro-
prietary knowledge base, complementing the digital models.
The objective of this research is on low-volume production,
where the production quantities vary between 1 and 200
A shorter version of this paper was presented at the CSME 2018,
May 2018 (Kalami and Urbanic 2018).
*R. J. Urbanic
jurbanic@uwindsor.ca
Hamed Kalami
kalami@uwindsor.ca
1
Department of Mechanical, Automotive, and Materials Engineering,
University of Windsor, Windsor, Ontario N9B 3P4, Canada
https://doi.org/10.1007/s00170-019-03799-8
The International Journal of Advanced Manufacturing Technology (2019) 105:3797–3813
/ Published online:
2019
21 May
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... One study conducted by Eiliat et al [9] demonstrated that the existence of voids is unavoidable in an FDM process and these voids can create failure points in FDM-built products. Additionally, using FDM technologies to directly build a tooling is not feasible due to the high pressure and temperatures involved in an IM process [11]. As a result, a new tooling method is needed to accommodate low to medium (10-5000) production volumes. ...
... Besides, they reported that even though their tool had a lower quality in composition and tool life compared to other conventional tools, it could manufacture the final product as accurately as other conventional tools. Kalami et al. [11] designed and fabricated a low volume injection mold and followed a rapid tooling approach that was suitable for a hightemperature material. In their research, they reported that material costs are high for metallic AM technologies and plastic based AM technologies will not be suitable for a tooling solution due to thermal conductivity and material compatibility. ...
... To conduct the injection simulation, the injection temperature (200 ℃), initial mold temperature (18 ℃), and material properties were selected (Technomelt-PA 7846). [11]. ...
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... One of the RT options to increase competitiveness is using metal epoxy composite (MEC), which provides greater heat conductivity as mould inserts in RT application and lowers tooling production costs and lead times by 25% and 50%, respectively [3,6]. Using optimisation methods to determine the optimal composition for materials, as recommended in the linked literature, can be considered for future research, such as determining the best amount of Al or Cu to mix with epoxy resin for desirable mechanical properties [27][28][29][30][31][32][33][34][35][36][37]. The use of MEC mould inserts for RT in the injection moulding process, which uses pure metal filler particles combined with epoxy resin, has attracted the attention of many researchers [20,29,[38][39][40]. ...
Potential of New Sustainable Green Geopolymer Metal Composite (GGMC) Material as Mould Insert for Rapid Tooling (RT) in Injection Moulding Process
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The investigation of mould inserts in the injection moulding process using metal epoxy composite (MEC) with pure metal filler particles is gaining popularity among researchers. Therefore, to attain zero emissions, the idea of recycling metal waste from industries and workshops must be investigated (waste free) because metal recycling conserves natural resources while requiring less energy to manufacture new products than virgin raw materials would. The utilisation of metal scrap for rapid tooling (RT) in the injection moulding industry is a fascinating and potentially viable approach. On the other hand, epoxy that can endure high temperatures (>220 °C) is challenging to find and expensive. Meanwhile, industrial scrap from coal-fired power plants can be a precursor to creating geopolymer materials with desired physical and mechanical qualities for RT applications. One intriguing attribute of geopolymer is its ability to endure temperatures up to 1000 °C. Nonetheless, geopolymer has a higher compressive strength of 60–80 MPa (8700–11,600 psi) than epoxy (68.95 MPa) (10,000 psi). Aside from its low cost, geopolymer offers superior resilience to harsh environments and high compressive and flexural strength. This research aims to investigate the possibility of generating a new sustainable material by integrating several types of metals in green geopolymer metal composite (GGMC) mould inserts for RT in the injection moulding process. It is necessary to examine and investigate the optimal formulation of GGMC as mould inserts for RT in the injection moulding process. With less expensive and more ecologically friendly components, the GGMC is expected to be a superior choice as a mould insert for RT. This research substantially impacts environmental preservation, cost reduction, and maintaining and sustaining the metal waste management system. As a result of the lower cost of recycled metals, sectors such as mould-making and machining will profit the most.
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... Typically, a metal die accommodates polymeric AM inserts of dies for IM that can be used to produce end components. Kalami and Urbanic [95] highlighted the contribution of such 'soft tooling' or 'temporary moulds', fabricated to produce a limited number of parts (1-200 production components), with the main advantage being that problems with the mould or design modifications can be easily rectified by re-printing the mould [96]. Conversely, the main issue is the lower thermal conductivity of polymeric RT materials, which may negatively affect the warpage, shrinkage, and mechanical properties of moulded end parts, and cause slower cooling rates, therefore resulting in longer packing and cooling times [73,97]. ...
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In the Industry 4.0 scenario, additive manufacturing (AM) technologies play a fundamental role in the automotive field, even in more traditional sectors such as the restoration of vintage cars. Car manufacturers and restorers benefit from a digital production workflow to reproduce spare parts that are no longer available on the market, starting with original components, even if they are damaged. This review focuses on this market niche that, due to its growing importance in terms of applications and related industries, can be a significant demonstrator of future trends in the automotive supply chain. Through selected case studies and industrial applications, this study analyses the implications of AM from multiple perspectives. Firstly, various types of AM processes are used, although some are predominant due to their cost-effectiveness and, therefore, their better accessibility and wide diffusion. In some applications, AM is used as an intermediate process to develop production equipment (so-called rapid tooling), with further implications in the digitalisation of conventional primary technologies and the entire production process. Secondly, the additive process allows for on-demand, one-off, or small-batch production. Finally, the ever-growing variety of spare parts introduces new problems and challenges, generating constant opportunities to improve the finish and performance of parts, as well as the types of processes and materials, sometimes directly involving AM solution providers.
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... Generally, the AM can produce prototype with complex geometries. Injection mold can be manufactured in a short time and at low cost by RT because RT can shorten the time to the market compared to conventional machining approaches [2][3][4][5][6][7]. It is widely known that computer numerical control (CNC) machining is the most effective method to manufacture components or molds with excellent surface quality, good dimensional accuracy, and microstructures [8]. ...
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... This has an advantage regarding conventional metal molds which is the freedom of structural construction of 3D printing that can provide unparalleled flexibility in designing the geometry of molds (Dizon et al. 2019). Nevertheless, there are some issues concerning the surface finish of the mold and its dimensional accuracy; this can affect the final molded part (Kalami and Urbanic 2019). There also are some risks that may compromise the mold durability; this is the layer delamination due to the warping stress which is caused by the repeated thermal contraction of a hot layer plastic on top of a cold layer plastic during the material extrusion (Dizon et al. 2019). ...
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Mold injection is an expensive manufacturing method; it involves several engineering-design hours and expensive alloys. Enabling the use of low-cost mold tooling can turn low-run productions economically and sustainably viable. There is a low-cost and more environmentally amicable alternative to injection molding for low-run productions based on epoxy resin molds. However, one drawback is the polymeric nature of the epoxy material, which possess low thermal conductivity, negatively affecting the injection process and thus quality of the molded pieces; as well as its low degradability rate. An opportunity arises for improving the performance of epoxy resin molds by studying the effect of embedding thermally conductive fibers in the matrix. The methodology used in this work consisted in the computational evaluation of a series of molds of composite material models built up from epoxy resin and copper fibers in different geometrical shapes and orientations. Injection simulations were carried out using the software Moldflow and the “effectiveness” of the injected parts was assessed (i.e., injection cycle time, percent volume shrinkage, and injected part deflection). Results suggest that embedding copper fibers within the epoxy matrix resin molds lowers the injection cycle time and reduces volumetric shrinkage while maintaining the deflection amplitude of the injected parts; optimum effectiveness results were obtained when copper is embedded as long fibers oriented along the principal heat flow direction. Moreover, epoxy resin can be replaced by up to a 70% volume of copper fibers, depending upon wall thickness and geometry complexity, thus lowering the impact this resin has on the environment.
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... Unfortunately, the characteristics of plastic physical models printed by AM machine do not usually match the requirements of the end product with the material needed. Thus, rapid tooling technology (RTT) [6][7][8][9][10][11] was then developed. Generally, RTT is considered as a nature extension of AM technology because molds [12] or dies [13] can be manufactured by AM technology for small-volume production. ...
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... Currently, the mold or die industry continued to suffer pressure since time and production costs are two major concerns that are needed to develop a new product in the industry. To overcome this obstacle, additive manufacturing (AM) [1] and RT [2] was developed to meet this requirement. RT is cost-effective method for small volume production since it has been proved to a great impact on product development cost [3]. ...
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View
... Prototype molds also appear in specific injection molding applications [16]. Kalami et al. [17] created a low-volume injection mold for the production of a cable bundle by overmolding. They applied a hybrid mold fabrication methodology, where they extruded a sacrificial product-shaped pattern. ...
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View
... Jahan et al. [18] proposed an optimal cooling channel in 3D-printed dies for plastic injection molding to produce 1.5-mm-thick plastic parts. Rapid tooling technology is an alternative method for batch production because it has proved to a great impact on product development cost [19][20][21][22][23]. The wax injection molding (WIM) is one of the most widely used methods for producing wax patterns [24][25][26]. ...
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... AM technology can provide the mold or die designers to verify a design in a matter of hours. Rapid tooling (RT) technology [5][6][7][8] is divided into soft or hard tooling. Tooling for low volume manufacturing runs is known as soft tooling (ST). ...
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