Injection
`Molding
`Handbook
`
`Page 1
`
`MacNeil Exhibit 2076
`
`Yita v. MacNeil IP, IPR2020-01139
`
`Edited by
`Osswald / Turng /Gramann
`
`HANSER
`
`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 1
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`

`

`
`
`
`
`
`
`Injection Molding
`Handbook
`
`Edited by
`
`Tim A. Osswald,
`Lih-Sheng (Tom) Turng,
`and
`Paul J. Gramann
`
`
`
`
`
`
`
`
`
`with contributions from
`
`J. Beaumont, J. Bozzelli, N. Castafio, B. Davis, M. De Greiff, R. Farrell,
`P. Gramann, G. Holden, R. Lee, T. Osswald, C. Rauwendaal, A. Rios,
`M.Sepe,T. Springett, L. Turng, R. Vadlamudi, J. Wickmann
`
`HANSER
`
`Hanser Publishers, Munich
`Hanser Gardner Publications, Inc., Cincinnati
`
`MacNeil Exhibit 2076
`
`Yita v. MacNeil IP, IPR2020-01139
`Page 2
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`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 2
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`

`

`Tim A. Osswald, Department of Mechanical Engineering, Polymer Engeneering Center, Madison, WI
`53706, USA
`Lih-Sheng (Tom) Turng, Department of Mechanical Engineering, Polymer Engeneering Center,
`Madison, WI 53706, USA
`Paul IL. Gramann, The Madison Group: PPRC, Madison, WI 53719, USA
`
`We dedicate this handbook to Professor Kuo-King (K. K.) Wang
`whose vision and pioneering contributions propelled the
`advancement of injection molding technology.
`
`Distributed in the USA and in Canada by
`Hanser Gardner Publications, Inc.
`6915 Valley Avenue
`Cincinnati, Ohio 45244-3029, USA
`Fax: (513) 527-8950
`Phone: (513) 527-8977 or 1-800-950-8977
`Internet: http://www.hansergardner.com
`
`Distributed in all other countrics by
`Carl Hanser Verlag
`Postfach 86 04 20, 81631 Miinchen, Germany
`Fax: +49 (89) 98 12 64
`The use of general descriptive names, trademarks, ete., in this publication, even if the former are not espe-
`cially identified, is not to be taken as a sign that such names,as understood by the Trade Marks and Mer-
`chandise Marks Act, mayaccordingly be used freely by anyone.
`While the advice and information in this book are believed to be true and accurate at the date of going to
`press, neither the authors nor the editors nor the publisher can accept any leval responsibility for any errors
`or omissions that may be made. The publisher makes no warranty, ¢xpress Or implied, with respect to the
`material contained herein.
`
`T. Osswald, Tim A.
`
`IL.
`
`Tim A. Osswald, Paul J. Gramann, and Lih-Sheng (Tom) Turng
`
`Library of Congress Cataloging-in-Publication Data
`Injection molding hand book / edited by Tim A. Osswald, Lih-Sheng (Tom) Turng and
`Paul J. Gramann
`p. cm.
`Includes bibliographical references and index.
`ISBN 1-56990-318-2 (hardback)
`1. Injection molding of plastics—Handbooks, manuals, etc.
`Turng, Lih-Sheng.
`I. Gramann, Paul J.
`TP 1150.155 2001
`668.4712—de21
`Die Deutsche Bibliothek — CIP-Einheitsautfnahme
`Injection molding handbook / ed. by Tim A. Osswald .
`Cincinnati ; Hanser / Gardner, 2001
`ISBN 3-446-21669-3
`All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means,
`electronic or mechanical, including photocopying or by any information storage and retrieval system, without
`permission in writing from the publisher.
`
`2001039607
`
`.
`
`. - Munich : Hanser;
`
`© Carl Hanser Verlag, Munich 2002
`Production coordinated in the United States by Chernow Editorial Services, Inc., New York, NY
`Typeset in Hong Kong byBest-set Typesetter Ltd.
`Printed and bound in Germany by Késel, Kempten
`
`MacNeil Exhibit 2076
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`Yita v. MacNeil IP, IPR2020-01139
`Page 3
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`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
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`
`
`360
`
`Statistical Process Control
`
`[Refs. on p. 360]
`
`molding processes is to use x and Rm charts (individual measurement and moving
`range) for each individual stream. This method is recommended for cases where
`the CpK ofthe cavities is equal to or greater than 3 (CpK 2 3). When CpK <3, the
`x-bar and R chart (average and range) is recommended. This approach, however,
`tends to be complicated and time consuming.
`An alternative and more expedient appreach is to use the group chart. In this
`chart the highest and lowest values are plotted on the x-chart and the largest moving
`range on the R-chart. An example of a group chart is shown in Fig.8.30.
`Theprocess is running well as long as the high x-value is below the upperaction
`limit and the low x-value above the loweraction limit. The moving range chart shows
`the maximum range from any stream to its own previous value, makingit sensitive
`to changes in any stream regardless of constant differences between streams. The
`group chart is most useful for day-to-day monitoring; however, a tabular report can
`be useful to identify consistently high or low stream. For instance, from a tabular
`report it may become obviousthat cavity 3 is running consistently high. If we use an
`M/I chart, we can denote the individual points with the cavity number. In this case,
`it will be immediately obvious from the chart when oneofthe cavities is running con-
`sistently low or high. Identifying the low and high X values with the cavity number
`will do the samein the group chart. This method is preferred becauseit is easier to
`identify problems from a chart than from tabular data.
`
`References
`
`. Shewhart, W., Economic Control of Quality of Product (1931), Van Nostrand Reinhold, New
`York.
`;
`. Grant, E. I, Leavenworth, R. S., Statistical Process Control, 5" ed. (1980), McGraw-Hill, New
`York,
`. van der Veen, J., Holst, P., Median/Individual Measurements Control Charting and Analysis for
`Family Processes (1993), Northwest Analytical, Inc.
`. Bajaria, H., Skog, F, Quality (1994), December.
`. Rauwendaal, C.J, Statistical Process Control in Injection Molding and Extrusion (2000), Hanser,
`Munich.
`
`*With a contribution from Mauricio Degreiff and Nelson Castafio on rubberinjection molding.
`
`Injection moldingis one of the most versatile and important operations for mass pro-
`duction of complex plastic parts. The injection molded parts typically have excellent
`dimensional tolerance and require almost no finishing and/or assembly operations.
`In addition to thermoplastics and thermosets, the process is also being extended to
`such materials as fibers, ceramics, and powdered metals, with polymers as binders.
`Amongall the polymer-processing methods, injection molding accounts for 32% by
`weight ofall the polymeric material processed [1]. Nevertheless, new variations and
`emerging innovations of conventional injection molding have been continuously
`developed to extend the applicability, capability, flexibility, productivity, and prof-
`itability of this process further. To be more specific, these special and emerging injec-
`tion molding processes introduceadditional design freedom, new application areas,
`unique geometrical features, unprecedentedpart strength, sustainable economic ben-
`efits, improved material properties and part quality, and so on, that cannot be accom-
`plished by the conventional injection molding process.
`This chapter is intended to provide readers with a general introduction of these
`special injection molding processes with emphases on process description, relevant
`advantages and drawbacks, applicable materials, as well as existing and/or potential
`applications. Referenceslisted at the end of this chapter provide detailed informa-
`tion for more in-depth studies. With this information, readers will be able to evalu-
`ate the technical merits and applicability of the relevant processes in order to
`determine the most suitable production method.It is also hopedthata collective pre-
`‘sentation of these various special molding processes, which descend from the same
`origin and yet mature with diversified creativity, will spark innovative ideas that lead
`to further improvementor new inventions.
`In addition, thanks to a well-focused research effort conductedat many research
`and educationalinstitutions(see, e.g., [2-20]), a solid scientific foundation for injec-
`tion molding and related special processes discussed in this chapter has been estab-
`lished. Based on the resulting findings and theoretical principles, computer-aided
`engineering (CAE) tools have been developed and are now widely usedin the indus-
`ty. As a result, the design and manufacturing of injection-molded parts haveliter-
`ally been transformed from a “black art” to a well-developed technology for many
`manufacturing industries. These CAE tools help the engineer gain process insight,
`Pinpoint blind spots and the problems usually overlooked, and contribute to the
`development and acceptance of many special injection molding processes discussed
`in this chapter.
`
`9 Special Injection Molding Processes
`
`L.-S. Turng*
`
`MacNeil Exhibit 2076
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`Yita v. MacNeil IP, IPR2020-01139
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`MacNeil Exhibit 2076
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`

`Special Injection Molding Processes
`
`[Refs. on pp. 460-463]
`
`9.1 Coinjection (Sandwich) Molding
`
`Micro Injection Molding
`Thin-wall Injection Molding
`
`Structural Foam Melding
`(polymer melt + foaming agents)
`PowderInjection Molding
`(polymer melt + metal/
`ceramic powders)
`
`|
`
`In-moid Decoration
`In-mald Lamination
`
`
`
`Table 9.1 Categorization of Special Injection Molding Processes
`1. Incorporation of additional material(s) or component(s) into the molded part
`a. Addingor injecting additionalplastics
`i. Coinjection molding
`ii, Multi-componentinjection molding (overmolding)
`iii, Lamellar (microlayer) injection molding
`b. Injection around (or within) metal components
`i,
`Insert/outsert molding
`low-pressure Injection Molding
`Pe
`ii, Fusible core (lost core) injection molding
`
`rametcose|MicrocellularInjection Molding
`c. Injecting gas into the polymer melt
`
`=|Overmolding (polymer melt + super-ciitical CO, or N,)
`iS Inser/QuisertMolding
`al
`i. Gas-assisted injection molding
`Lameliar(Microlayer) Injection Molding
`Fusible Core Injection Molding
`LATA
`d, Injecting liquid or water into polymer melt
`i. Liquid gas-assisted injection molding
`= i live-eedInjectionMolding
`ii, Water-assisted injection molding
`Injecting gas into the metal (or ceramic) powder-polymer mixture
`i, Gas-assisted powderinjection molding
`Incorporating reinforced fiber mats inside the cavity
`i. Resin transfer molding
`ii. Structural reaction injection molding
`g. Incorporating film,foil, fabric, or laminate to be back-molded by polymer melt
`i.
`In-mold decoration and in-mold lamination
`ii. Low-pressureinjection molding
`2. Melt formulation
`a. Mixing polymer melt with super-criticalfluids
`i. Microcellular injection molding
`b. Mixing polymer melt with chemical or physical blowing agents
`i. Structural foam injection molding
`c. Mixing polymer melt with metal or ceramic powders
`i. Metal/ceramic powderinjection molding
`d. Mixing prepolymer (monomers or reactants) prior injection
`i. Reaction injection molding
`ii. Structural reaction injection molding
`iii. Resin transfer molding
`iv. Thermoset injection molding
`3. Melt manipulation
`a. Providing vibration andoscillation to the melt during processing
`i. Multi live-feed injection molding
`ii. Push-pull injection molding
`iii. Rheomolding
`iv. Vibration gas(-assisted) injection molding
`b. Using screw speed and back pressure to control melt temperature
`i, Low-pressure injection molding
`4. Mold movement
`a. Applying compression with mold closing movement
`1,
`Injection-compression molding
`5. Special part or geometry features
`a. Producing parts with miniature dimensions or Telatively thin sections
`i. Micro-injection molding
`
`i. Thin-wall molding MacNeil Exhibit 2076
`
`
`
`(= Rneomoiding
`— j
`Push-pull Injection Molding
`Pas
`
`Gas-assisted Injection Molding
`Water-assisted Injection Molding
`Liquid Gas-assisted Injection Molding
`
`Figure 9.1 Special injection molding processes for thermoplastics.
`
`Z
`ed
`-—
`
`€.
`
`f.
`
`
`
`It is very difficult to cover all special injection molding processes, not to mention
`those new processes that are being developed andfield-tested. Furthermore, due to
`the diversified nature of these special injection-molding processes, there is no unique
`method to categorize them. As a preliminary attempt, Table 9.1 classifies the various
`processes based on the specific techniques employed by the process or the unique
`characteristics of the process. Figure 9.1 illustrates someof the characteristics of those
`special injection molding processes for thermoplastics. It should benoted that, for a
`special purpose or application, a new orviable special injection molding process could
`employ multiple specific techniques listed in Table 9.1 (e.g., gas-assisted powderin-
`jection molding, multicomponent powder injection molding, gas-assisted push-pull
`injection molding, coinjection molding with microcellular plastics, etc.). Detailed
`description of these processes can be found in the following sections dedicated to
`each individual process.
`
`9.1
`
`Coinjection (Sandwich) Molding
`
`Coinjection molding (sometimes called “sandwich molding”) comprises sequential
`and/or concurrent injection of a “skin” material and a dissimilar but compatible
`“core” material into a cavity. This process producesparts that have a sandwich struc-
`ture, with the core material embedded between the layers of the skin material. ‘This
`innovative process offers the inherent flexibility of using the optimal properties of
`each material to reduce the material cost, injection pressure, clamping tonnage, and
`residual stresses to modify the property of the molded part, and/or to achieve pal-
`ticular engineering effects.
`
`*
`
`°
`
`Yita v. MacNeil IP, IPR2020-01139
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`

`

`364
`
`Special Injection Molding Processes
`
`[Refs. on pp. 460-463]
`
`9.1 Coinjection (Sandwich) Molding
`
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`Process Description
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`Coinjection is one of the two-component or multi-component injection molding
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`MacNeil Exhibit 2076
`
`Yita v. MacNeil IP, IPR2020-01139
`Page 6
`
`
`
`
`
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`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 6
`
`
`

`

`366
`
`Special Injection Molding Processes
`
`.
`
`[Refs. on pp. 460-463]
`
`9.1 Coinjection (Sandwich) Molding
`
`367
`
`Skin
`
`Co-injection
`Nozzles
`Gates
`Cavities
`
`Figure 9.4 Multi-gate coinjection hot runner system with separate flow channels for skin and core
`materials, which join at each hot runnernozzle [23].
`
`Material Cost Reduction and Recycling
`High-performance and exotic engineering materials can be expensive but necessary
`for someapplications. Coinjection provides the opportunity to reduce the cost of the
`product byutilizing lower-cost materials wherever the high-performance materialis
`not necessary, perhaps in the core. Thatis, it permits the use of low-cost or recycled
`plastics as the core material, invisibly sandwiched within thin, decorative expensive
`skin surfaces typically made of virgin plastic material. An example of this is a gear
`wheel (cf. Fig. 9.5) whoseouterskin consists of a fluoropolymer or carbonfiberfilled
`polyamide (nylon). Asthe recycling of postservice plastics becomes necessary by law
`in many countries, coinjection molding offers a cost-effective manufacturing tech-
`nique to consume 100% recycled materials in high content.
`
`
`
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` (a)
`
`Figure 9.3 (a) Two-channel and (b) three-channel techniques [22].
`
`shownin Fig. 9.2(c). Finally, a small additional amount of skin material is injected
`again to purge the core material away from the sprueso thatit will not appear on
`the part surface in the next shot [cf. Fig. 9.2(d)].
`injected prior to the injection of
`When there is not enough skin material
`core material, the skin material may sometimes eventually be depleted during the
`filling process and the core material will show up onportionsof the surface and the
`end of the part that is last filled. Such “core surfacing” or “core breakthrough”is
`generally undesirable, although it may depend on the design requirement andfinal
`application.
`There are other variations to the sequential (namely, skin—core-skin, or A-B-A)
`coinjection molding process described earlicr. In particular, one can start to inject
`the core material while the skin material is being injected (i.e, A-AB-B-A). Thatis,
`a majority of skin materialis injected into a cavity, followed by a combination of both
`skin and core materials flowing into the samecavity, and then followed by the balance
`of the core materialto fill the cavity. Again, an additional! small amount of skin injec-
`tion will “cap” the end of the sequence, as described previously. In addition to the
`one-channeltechnique configuration, two- and three-channel techniques(cf. Fig. 9.3)
`have been developed that use nozzles with concentric flow channels to allow simul-
`taneousinjection of skin and core materials [22]. More recently, a new version of co-
`injection molding process that employs multi-gate coinjection hot-runner system has
`become available. Such a system moves the joining of skin and core materials into
`the mold, as shownin Fig. 9.4. In particular, this hot-runner system has separate flow
`channels for the skin and core materials. The two flow streamsare joined at each hot
`runner coinjection nozzle. In additiontoall the benefits associated with conventional
`hot-runner molding, this system allows an optimum ratio of skin and core in multi-
`cavity or single-cavity molds[23].
`
`9.1.2
`
`Process Advantages
`
`
`
`Coinjection molding offers a numberof cost and quality advantages, as well as design
`flexibilities and environmental friendliness as describedlater.
`
`i
`di
`in
`Figure 9.5 Gear wheel (101.6mm
`.
`6mm in diameter) with PTFE-filled while polyamide (nylon) 66 ski
`and glass-filled solid black polyamide 66 core made by coinjection molding[21],
`(nylon)
`"
`
`MacNeil Exhibit 2076
`
`Yita v. MacNeil IP, IPR2020-01139
`Page 7
`
`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 7
`
`

`

`368
`
`Special Injection Molding Processes
`
`[Refs. on pp. 460-463]
`
`9.1 Coinjection (Sandwich) Molding
`
`369
`
`Quality Surface with Foamed Core Material
`In the case of thick-wall products, coinjection is preferred to conventional structural
`foam because of its superior cosmetic surfaces. Structural foam parts are often
`sanded, primed, base painted, and texture coated,all of which is expensive. A solid
`skin combined with a foamed core provides the advantages of structural foam, such
`as reduced part weight, low molded-in stresses, straight sink-free parts, and design
`freedom, yet without the objectionable elephant-skin surface defects. Coinjection
`molding with foamed material also features an excellent weight-to-strength ratio and
`producesbetter performance than gas-assisted injection molding for sensitive/fragile
`polymer materials. For thin-wallparts, such as food packaging and bottles, coinjec-
`tion also offers additional benefit in terms of physical and mechanical properties of
`the part and cost saving with foamed core.
`
`Modification of the Part Quality and Property
`With coinjection, one can obtain a combination of properties by joining different
`materials in one part, which is not available in a single resin. For instance, an elas-
`tomeric skin over a rigid core will provide a structure with soft touch, Another
`example includes a combination of a brittle material with a high-impact-resistant
`material, which provides excellent material properties. In applications where the per-
`formance of the components demands the use of reinforced materials, coinjection
`offers a solution that combines the aesthetic and property attributes of an unrein-
`forced skin material with the benefits of a highly reinforced core material. Additional
`performance and cost improvements can be made by combining the conductive
`plastic with a more impact-resistant and less-expensive grade of plastic through co-
`injection molding. Such an application includes using either a skin or core polymer
`filled with a conductive material(e.g., aluminum flakes, carbon black, or nickel-coated
`graphite fibers) to provide the molded part (e8., computer housings) with electro-
`magnetic shielding (EMI) properties and grounding characteristics (cf. Fig. 9.6) [24].
`
`9.1.3
`
`Process Disadvantages
`
`Despite all the potential benefits of coinjection molding, the process has been
`slow to gain widespread acceptance for several reasons. First of all, the coinjection
`machine usually costs 50 to 100% higher than standard injection molding equipment
`[25]. This high investment cost offsets the benefits of developing unique processing
`techniques, improving part quality, and permitting the use of recycled materials. In
`addition, the developmentfor a coinjection mold takes longer time than a conven-
`tional injection mold.This is also true for process set up, as the process requires addi-
`tional control parameters for timing and controlling the injecting core material.
`
`9.1.4 Applicable Materials
`
`Coinjection molding can be employedfor a wide variety of materials. Although most
`of the materials used are thermoplastic, there are some promising developments with
`using thermosetting materials, which are coinjected with thermoplastic materials.
`Because two materials are used in coinjection molding processing, the flow behavior
`(Fig. 9.2) and the compatibility of material properties are very important. In consid-
`ering the material selection, the most important properties are viscosity difference
`and the adhesion between the skin and core material. Because the core material
`needs to penetrate the skin materialin frontofit, it is desirable to have a skin mate-
`rial with a viscosity lower than that of the core material. Using low-viscosity mate-
`rial in the core may cause the core flow front to travel too fast relative to the skin,
`which results in undesirable core surfacing. Experimental studies of coinjection
`molding have been conducted to examinethe effect of relative viscosity ratio of skin
`and core materials on their spatial distribution within the part [26].
`Because the materials are laminated together in the part, an effective adhesion
`of skin and core material is desirable for optimum performance. Table 9.3 provides
`some basic guidelines on a wide range of material combinations [27]. It should be
`noted that this information should only be used as a guide or benchmark. The actual
`performance must be determined by the application because the molding conditions
`and the operation/service conditions will influence the final performance. The other
`material property that needs to be of concern is material shrinkage. The rule of thumb
`is that materials with similar molding shrinkage shouldbe paired in order to reduce
`stresses in the joining layers.
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
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`
`
`filled with 35 wt% of electrically conductive carbon black [24].
`
`Figure 9.6 Section of a molding housing with an outer skin of ABS and a core of the same rest
`
`9.1.5
`
`Typical Applications
`
`Coinjection molding offers a technically and economically viable solution for a wide
`lange of commercial applications in the emerging markets, which include automo-
`lve, business machines, packaging, electronic components, leisure, agriculture, and
`
`MacNeil Exhibit 2076
`
`Yita v. MacNeil IP, IPR2020-01139
`Page 8
`
`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 8
`
`

`

`Special Injection Molding Processes
`
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`9.2 Fusible (Lost, Soluble) Core Injection Molding
`
`371
`
`“soft touch” products. Example applications include canoe paddles, toilet seats and
`:
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`cisterns, computer housings, copier parts, cash register covers, television escutcheons,
`audio cabinets, circuitry
`and electronics enclosures,
`garden chairs, boxes and con-
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`7
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`.
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`housings and interior door handles and knobs, components for high-end ovens, audio
`speaker housings, and music center mainframes.
`:
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`Cost-reduction opportunities and the desire and mandated requirements to use
`.
`=
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`recycled materials will drive more applications to coinjection in new and existing
`markets. Morerefined technology and a broader experience base among designers,
`processors and original equipment manufacturers (OEMs) will also expand the
`sporadic current use of the process. Useful design guidelines for coinjection molding
`and other multicomponentinjection molding processes can be foundin Ref. [28].
`
`.
`
`e
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`=
`
`9.2
`
`Fusible (Lost, Soluble) Core Injection Molding
`
`.
`a er
`:
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`The fusible (lost, soluble) core injection molding process produces complicated,
`7
`7
`D
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`hollow components with complex and smooth internal geometry in a single molding
`operation. This process is a form of insert molding in whichplastic is injected around
`a temporary core of low melting-point material, such as tin-bismuth alloy, wax, or a
`:
`:
`7
`.
`>
`thermoplastic. After molding, the core will be physically melted (or chemically
`.
`oe
`.
`.
`:
`dissolved), leaving its outer geometry as the internal shape ofthe plastic part. This
`:
`process reduces the number of components required to make a final assembly or
`a
`.
`.
`.
`.
`substitutes plastic for metal castings to boost performance(e.g., corrosion resistance)
`while saving weight, machining, and cost.
`
`9.2.1
`
`Ae
`Process Description
`
`
`
`
`3
`
`ze5
`
`oes
`:
`All of these techniques employ the same principle: the production of injection
`:
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`.
`thee with a lost core —— the cco contour or the aa part. ani
`ese lost core processes,
`fusible core technique is the most energy-intensive method.
`P
`q
`By
`Nevertheless, this drawback is offset by the low core losses, smootherinternal surface
`
`i
`
`|
`
`
`
`
`MacNeil Exhibit 2076
`
`Yita v. MacNeil IP, IPR2020-01139
`Page 9
`
`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 9
`
`

`

`
`
`372,
`
`Special Injection Molding Processes
`
`
`
`
`
`
`
`
`
`
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`
`
`
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`
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`
`
`
`I
`
`[Refs. on pp. 460-463]
`
`9.2 Fusible (Lost, Soluble) Core Injection Molding
`
`373
`
`
`
`Figure 9.7 A eutectic bismuth-tin (BiSn 138) alloy core for an intake manifold [30]. Source: BASF.
`(From innovation in Polymer Processing—Molding, Stevenson,J. F., (Ed.) (1996), Hanser, Munich,
`p- 159, Fig. 4.7.)
`
`Figure 9.8 A eutectic bismuth-tin (BiSn 138) alloy core secured in the mold for an intake manifold
`[30]. Source: BASE. (From Innovation in Polymer Processing—Molding, Stevenson, J. F., (Ed.)
`(1996), Hanser, Munich, p. 164, Fig. 4.12.)
`
`requiring low finishing cost, faster heat dissipation by using a stronger and highly con-
`ductive metal core. Fusible core injection molding basically comprises the following
`steps:
`
`2.
`
`1. One or more core pieces are prefabricated at a separate station from the injec-
`tion molding machine(cf. Fig. 9.7).
`If more than one core piece is needed,