Injection
`Molding
`Handb00k
`
`
`
`MacNeiI Exhibit 2076
`
`Yita v. MacNeiI IP, lPR2020-01139
`
`Page 1
`
`Edited by
`
`Osswald / Turng / Gramann
`
`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 1
`
`

`

`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`'
`
`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
`
`
`
`1'
`
`HANSER
`
`Hanser Publishers, Munich
`
`
`
`
`Hanser Gardner Publications, Inc., Cincinnati
`
`MacNeiI Exhibit 2076
`
`Yita v. MacNeiI IP, lPR2020-01139
`
`Page 2
`
`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 2
`
`

`

`Tim A. Osswald. Department of Mechanical Engineering, Polymer Engeneering Center, Madison, WI
`Lih-S/wng (Tom) Turng, Department of Mechanical Engineering, Polymer Engeneering Center,
`53706. USA
`Madison, WI 53706. USA
`Paul 1 Gramaim, The Madison Group: PPRC, Madison, WI 53719, USA
`
`We dedicate this handbook to Professor Kim-King (K K ) Wang
`Whose ”no" andpzoneermg contributions pmpelled the
`-
`-
`.
`.
`.
`.
`advancement of injection molding technology.
`
`Tim A. Osswald, Paul .I Gramann, and Lih—Sheng (Tom) Turng
`
`Distributed in the USA and in Canada by
`Hanser Gardner Publications, Inc.
`6915 Valley Avenue
`Cincinnati, Ohio 45244-3029, USA
`Fax: {513} 517-8950
`Phone: (513) 527—8911? or 17800-950-8977
`Internet: littpziiwwwhunscrgttrdnmzcom
`
`Distributed in all other countries by
`Carl Hanser Verlag
`Postfach 86 04 20, 81631 Mfinchen, Germany
`Fax: +49 (89) 98 12 64
`
`The use of general descriptive names. trademarks. etc, in this publication, even if the former are not espe—
`cially identlficd. is not to be taken ns :1 sign that such names, as understood by the Trade Marks and Mer-
`chandise Marks Act. may accordingly 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 In
`pl'L‘SS. neither the tLLtihUt‘S nor the editors nor the publisher can accept any legal responsibility For any errors
`or omissiom that may be made. The publisher makes no warranty. express or implied. with respect to the
`material contained herein.
`
`Library of Congress Cntztlogingein-Publication Data
`Injection molding hand book I edited by Tim A. Osswald, Lih—Sheng (Torn) 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.
`Turug. Liit-Sl‘teng.
`III. Gi'umunu. Paul J.
`TP 1150155 2001
`668.4’12—dc21
`
`I. Osswald, Tim A.
`
`II.
`
`Printed and bound in Germany by KOSei. Kemplcn
`
`2001039607
`
`Die Deutschc Bibliothek — Cll’-.Einhcitsautfnahme
`Injection molding handbook 1‘ ed. by Tim Ar Osswald .
`Cincinnati .‘ Hanseri Gardner. BUEJI
`ISBN 3-446—21669—3
`
`.
`
`. 7 Munich : Hanser;
`
`All rights reserved. No part of this book may be reproduced or transmitted in any form or by :my means.
`electronic or mechanical. including photocopying or by any information storage and retrieval system. without
`permission in writing from the publisher.
`
`-l"- Carl I-lunscr Verlag. Munich 3.002
`Production coordinated in the United States by Chernow Editorial Services, Inc., New York, NY
`Typeset in Hung Kong by BCSI-.‘-‘l Typesetter Ltd.
`
`MacNeil Exhibit 2076
`
`Yita v. MacNeil IP, |PR2020—01139
`
`Page 3
`
`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 3
`
`

`

`
`
`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 of the 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 approach 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.
`.
`The process is running well as long as the high x—value is below the upper action
`limit and the low x-value above the lower action limit. The moving range chart shows
`the maximum range from any stream to its own previous value, making it 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 obvious that 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 one of the cavities is running con—
`sistently low or high. Identifying the low and high X values with the cavity number
`will do the same in the group chart. This method is preferred because it 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. 1., Leavenworth, R. 8., Statistical Process Control, 5th ed. (1980), McGraw-l-lill, New
`York.
`.
`. van der Vccn, I, Holst, P., Median/Individual Measurements Control Charting and Analysts for
`Family Processes (1993), Northwest Analytical, Inc.
`_
`. Bajaria, H., Skog, F., Quality (1994), December.
`. Rauwendaal, C.J., Statistical Process Control in Injection Molding and Extrusron (2000), Hanser,
`Munich.
`
`*With a contribution from Mauricio Degreiff and Nelson Castafio on rubber injection molding.
`
`9 Special Injection Molding Processes
`
`L.-S. Turng*
`
`Injection molding is 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.
`Among all the polymer-processing methods, injection molding accounts for 32% by
`weight of all 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 introduce additional design freedom, new application areas,
`unique geometrical features, unprecedented part 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. References listed 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 hoped that a 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 improvement or new inventions.
`In addition, thanks to a well—focused research effort conducted at many research
`and educational institutions (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 used in the indus-
`try. As a result, the designand manufacturing of injection—molded parts have liter—
`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.
`
`MacNeil Exhibit 2076
`
`Yita v. MacNeil IP, |PR2020—01139
`
`Page 4
`
`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 4
`
`

`

`Special Injection Molding Processes
`
`[Refs on pp. 4604163]
`
`363
`
`Micro Injection Molding
`Thinrwoli Injection Molding
`
`'3"
`
`Structural Foam Molding
`[polymermelt + rooming agents]
`Powder Injection Molding
`[polymer melt + metoi/
`ceramic powders]
`l
`
`‘
`
`
`
`.
`
`.
`K
`.-
`
`'
`
`ln»moid Decoration
`ln-mold Lamination
`
`
`
`ticular engineering effects. 9.1 Coinjection (Sandwich) Molding
`
`Table 9.1 Categorization of Special Injection Molding Processes
`l. Incorporation of additional material(s) or component(s) into the molded part
`a. Adding or injecting additional plastics
`i. Coinjection molding
`ii. Multi-component injection molding (overmolding)
`iii. Lamellar (microlayer) injection molding
`b. Injection around (or within) metal components
`i.
`Insert/outsert molding
`ii. Fusible core (lost core) injection molding
`c. Injecting gas into the polymer melt
`i. Gas—assisted injection molding
`d. Injecting liquid or water into polymer melt
`i. Liquid gas-assisted injection molding
`ii. Water—assisted injection molding
`e. Injecting gas into the metal (or ceramic) powder-polymer mixture
`i. Gas-assisted powder injection 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-pressure injection molding
`2. Melt formulation
`
`f.
`
`a. Mixing polymer melt with super—critical fluids
`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 powder injection 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
`3. Providing vibration and oscillation 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
`
`3. Applying compression with mold closing movement
`i.
`Injection—compression molding
`5- Special part or geometry features
`a. Producing parts with miniature dimensions or relatively thin sections
`i. Micro-injection molding
`ii.
`Thin—wall molding
`
`MacNeiI Exhibit 2076
`
`Yita v. MacNeiI IP, lPR2020-01139
`
`Page 5
`
`Low-pressure Injection Moiuinq
`Microcellular injection Molding
`[polymer melt + superrcrmcal CO, or N,)
`.
`.
`.
`.
`Lamellar (MICIOIOWFJ Iniectlon MOldan
`Gos—ossrsted Injection Molding
`Water—assisted Injection Molding
`Liquid Gos-ossisted Injection Molding
`
`. _
`--
`-
`
`Overmolding
`Insert Ouiser’r l'.lolcl'|r'
`‘ Fusibl/e Core injecting Molding
`I
`l"
`.I'el S Rheomolding
`Push-pull Injection Molding
`Live-teed lnjeclion Molding
`.:2
`
`i -
`
`3
`
`#-
`i 3':
`
`
`
`Figure 9.1 Special injection molding processes for thermoplastics.
`
`It is very difficult to cover all special injection molding processes, not to mention
`those new processes that are being developed and field—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 umque
`characteristics of the process. Figure 9.1 illustrates some of the characteristlcs of those
`special injection molding processes for thermoplastics. It should be'noted that, for a
`special purpose or application, a new or viable special injection molding process could
`employ multiple specific techniques listed in Table 9.1 (e.g., gas-asSISted powder 1n-
`jection molding, multicomponent powder injection molding, gas—asmsted 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 compatlble
`“core” material into a cavity. This process produces parts that have a sandwich struc—
`ture, with the core material embedded between the layers of the skin material. ThlS
`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 par-
`
`'
`
`'
`
`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 5
`
`

`

`364
`
`9.1.1
`
`Special Injection Molding Processes
`
`[Refs on pp. 460—463]
`
`9.1 Coinjection (Sandwich) Molding
`
`365
`
`Process Description
`
`
`
`
`
`0:208sz“0&me
`
`
`
`3550089..030032
`
`.m.m.mfl
`
`tS
`
`ep
`
`.nm7dwatm
`
`smwmfl:1
`
`S
`
`inMW0ph75
`
`mom
`
`eamu
`
`0/I\6mg
`
`SfDOma;
`
`.momwamm.eem.m.UCdrea
`
` aw.nlae.nB
`
`.nmwe
`
`tilmmhr.
`
`oartwmnHWeewmfl
`
`1.t
`IMC3mmmd
`.mm
`Hmh.n
`rsW8
`8V».
`
`
`
`$08.50000m
`
`
`
`
`050V053.03590003m90:00:30.3303003.00E@0503
`
`
`
`@098onmm<5000536530:0
`828%:<0HE”macaw:
`
`9:8EM
`
`mfinofifl<n~ANH¢~n~
`
`
`
`0020nan—0000.530500“.20300mm
`
`
`
`
`
`
`
`0:050:mE0080:0m800003500
`
`
`
`02m9E0fiammcmbEmu4:95.50
`
`
`
`902.50noon
`
`033can004093200found—boo000
`
`00%inE030820mzfifinn
`
`
`
`warm£03EBOQEvans—W:
`
`
`
`3:30.38885::me
`
`unofififiwe
`
`when
`
`
`
`Coinjection is one of the two-component or multi—component injection molding
`processes available today (see Table 9.2). Unlike other multi-component molding
`processes, however, the coinjection molding process is characterized by its ability
`to encapsulate an inner core material with an outer skin material completely. The
`process mechanics rely on the sequential and/or concurrent injection of two differ—
`ent materials through the same gate(s). Figure 9.2 illustrates the typical sequences of
`the co-injection molding process using the “one—channel technique” and the result—
`ing flow of skin and core materials inside the cavity. This is accomplished with the
`use of a machine that has two separate, individually controllable injection units and
`type of
`a common injection nozzle block with a switching head. The principle of this
`process is relatively simple: Two dissimilar polymer melts from their injection units
`7
`in stage (a) of Fig.
`are injected one after the other into a mold cavity. In particular
`9.2, a short shot of skin material (shown in black) is injected into the mold. Due to
`, a frozen
`the flow behavior of the polymer melts and the solidification of skin material
`.1CmVJ10pmSnaW:01OmIed1OCehtm0fiWm0tEratSremy11OpfOreyal
`.mgn.m0fl
`C
`mS
`t
`f
`l
`6
`mmCGmmhf60he
`
`h.nmm-m
`.02m9.3ma.
`tu
`6.
`.1
`WOhSWtnO”HHemehtt.al.aH
`
`
`
` 10mmnst.mdmmC05r.mCWnVaa.mHaemm
`
`A0.mm(
`
`the central region to the bounding walls), the skin mate
`up at the region adjacent to the mold walls. This process continues until the cavity is
`nearly filled, with skin material appearing on the surface and the end of the part as
`
`Figure 9.2 Sequential coinjection molding process [18] (Adapted from Ref. [21]. Reprinted by per—
`
`uoom03m3008850555%000.5050.”A0032;
`000%050v009000.000Emngflm
`
`
`
`
`23000080080582:530003
`
`
`:08canbEnEaann.5:602
`
`
`00320%:2:9?3:00.08
`
`E0330500330>580?
`
`
`00:30:09mE00354.53007:Uubmmaum
`
`
`25:00.55.uubeEgi.50.02.“...03.5.0005SEEEEE..:0E05weEms—5:50
`
`
`
`
`
`
`2E0...300%5:50Ezumfino_50_.EoU
`
`1020:000555:»
`
`RISES5M0E03bfimuwaom
`02050325000bfiunosgm
`
`00Am3:00.250.500:0A<
`ES3300058EBow
`
`
`
`
`
`U080?“.3000:03—.
`
`
`
`
`
`“£332ceauoni3.:063H
`
`
`
`
`
`Um.mm<>309:ӣ30302
`
`
`
`00005.:.5mnEu”9.300E06500002
`
`
`
`30000:.—02288000006.0500
`
`25239nwda05$3Emonfivfi
`
`
`3:053:52bflflfimfino30A
`
`
`
`cum—0:90E02:002083008300:55
`”00:308.:UnamEoE
`
`BEOEEE<5300Sub"—EouummE00003EEgomfig
`
`
`05£15003331.05...:05one
`
`
`
`
`3E:H8300?0000300025HE?0:3an
`
`
`
`
`
`mEEoEE50050200.9393029.:
`
`
`
`005250van082:5:05
`
`
`
`052°:55035
`
`
`
`030E005m0033505502
`
`
`
`noumfiomfiew0fim~
`
`
`
`
`
`
`
`
`
`ES00000095mum—03.55500?::5555333525.2.3Ndusafi
`
`
`
`
`
`
`
`@53035500?—.MiEoS5:607:EgonEoOéE—Em=_Ee:—._0>O
`
`mission of the ASME International).
` 0000M
`
`
`
`
`
`0%30%3$000505200:05
`
`
`Emma.mufimwowteam308.350#006500E”0002»
`
`
`
`ng001...$053930NHam00SEEbagswflw
`
`BEES—02
`
`
`9:0:2005“onawemEEEEQE«1.50m
`05505$32050can3080E305
`
`2033.050:00:Bmsgmfiugummmfl
`
`HE:902?05300.50»5:250208
`SE:«8300?02230005£9»
`
`
`:2:one05:.2350£508060SEwfifidmamufi
`
`
`
`
`0300305005
`
`
`
`0.5%:503.34....
`
`
`
`an53580.0#32023003.335
`“0wnEoEwom3.5afirm00:50:00
`
`
`BahamaEawningflfiE0.80
`
`
`mam—038.5505.2:0E_wmomEma
`
`
`moH0955080.0%900500.330
`
`0::E03058.2500000:0500qgg
`
`
`
`@00033:010Hobnou:wE£20002
`Bob:0805”SE:20:02.5
`
`
`.0503?00:5:025b85030
`0SE0005Amfiam95502“a
`
`
`bmfirnmfig85.602
`
`032F55020083009550535003
`EoBflE000:0895H.
`002%.85039505
`
`N035
`
`MacNeil Exhibit 2076
`
`Yita v. MacNeil IP, |PR2020-01139
`
`Page 6
`
`”0330mm08.8
`
`mmEgomfioo00EoE0E<
`
`
`
`5300.0an—wnoo0maE@0003
`
`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 6
`
`
`

`

`366
`
`Special Injection Molding Processes
`
`[Refs 0n pp. 460—463]
`
`9.1 Coinjection (Sandwich) Molding
`
`367
`
`Skin
`
`#
`
`Co-injection
`Nozzles
`Gates
`Cavities
`
`Figure 9.4 M'ultijgate coinjection hot runner system with separate flow channels for skin and core
`materlals, which jom at each hot runner nozzle [23].
`
`Material Cost Reduction and Recycling
`
`High—performance and exotic engineering materials can be expensive but necessary
`for some applications. Coinjection provides the opportunity to reduce the cost of the
`product by utilizing lower-cost materials wherever the high-performance material is
`not necessary, perhaps in the core. That is, 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) whose outer skin consists of a fluoropolymer or carbon fiber filled
`polyamide (nylon). As the recycling of postservice plastics becomes necessary by law
`in many countries, coinjection molding offers a costreffective manufacturing tech-
`nique to consume 100% recycled materials in high content.
`
`
`
`_iIJ_
`
`
`
`
`
`
`
`(a)
`
`(b)
`
`Figure 9.3 (a) Two—channel and (b) three—channel techniques [22].
`
`shown in Fig. 9.2(c). Finally, a small additional amount of skin material is injected
`again to purge the core material away from the sprue so that it 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 on portions of 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 and final
`application.
`There are other variations to the sequential (namely, skin—core—skin, or A—B—A)
`coinjection molding process described earlier. In particular, one can start to inject
`the core material while the skin material is being injected (i.e., A—AB—B—A). That is,
`a majority of skin material is injected into a cavity, followed by a combination of both
`skin and core materials flowing into the same cavity, and then followed by the balance
`of the core material to 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—channel technique configuration, two— and three-channel techniques (cf. Fig. 9.3)
`have been developed that use nozzles with concentric flow channels to allow simul-
`taneous injection 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 shown in Fig. 9.4. In particular, this hot-runner system has separate flow
`channels for the skin and core materials. The two flow streams are joined at each hot
`runner coinjection nozzle. In addition to all 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 number of cost and quality advantages, as well as design
`
`flexibilities and environmental friendliness as described later.
`
`
`'
`'
`'
`Figure 9 5 Gear wheel (101 6
`.
`. mm in diameter) With PTFE-filled white polyamide n ion 66 sk'
`and glassfilled solid black polyamide 66 core made by coinjection molding [21].
`( Y
`)
`m
`
`MacNeil Exhibit 2076
`
`Yita v. MacNeil IP, |PR2020-01139
`
`Page 7
`
`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 7
`
`

`

`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`368
`
`Special Injection Molding Processes
`
`[Refs on pp. 460463]
`
`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 expens1ve. 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. Cornjection
`molding with foamed material also features an excellent weigh t—to—strength ratio and
`produces better performance than gas—assisted injection molding for senSitive/iragile
`polymer materials. For thin—wall parts, 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 resm. 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, eomjection
`offers a solution that combines the aesthetic and property attributes of an unrem—
`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 (cg... computer housings] with electro-
`magnetic shielding (EMI) properties and grounding characteristics (cf. Fig. 9.6) [24].
`
`9.1 Coinjection (Sandwich) Molding
`
`369
`
`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 development for 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 employed for 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 material in front of it, 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 examine the 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 should be paired in order to reduce
`stresses in the joining layers.
`
`9.1.5
`
`Typical Applications
`
`
`
`
`Figure 9.6 Section of a molding housing with an outer skin of ABS and a core of the same Tesm
`filled with 35 wt% of electrically conductive carbon black [24].
`
`Coinjection molding offers a technically and economically viable solution for a wide
`range of commercial applications in the emerging markets, which include automo—
`the, buSiness machines, packaging, electronic components, leisure, agriculture, and
`
`MacNeil Exhibit 2076
`
`Yita v. MacNeil IP, |PR2020-01139
`
`Page 8
`
`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 8
`
`

`

`370
`
`Special Injection Molding Processes
`
`
`
`SW0d "“318
`. 3‘ "c K x
`’
`t
`‘
`"
`fldDIPU‘IH
`XXVK
`
`d.L
`r-
`J-
`
`nsad
`
`l
`‘
`
`|
`
`3‘”
`m
`
`MOM
`nar
`
`4;
`x x
`
`xx
`
`x x x x
`
`><
`M>€K><
`
`i
`
`
`l
`
`1E
`
`‘3
`E
`"‘
`0
`,
`2
`5
`g
`:"3
`.1:
`"5
`<
`"‘
`.g
`E
`2
`m
`”z
`‘9
`"
`a
`
`[Refs on pp. 460—463]
`5 ET“:
`" E
`‘7 ‘
`9 u
`5‘5 5 53 3';
`h
`-u
`° 5 TJE 5
`QTEh'U
`L7
`5"
`_
`E '75
`El ;» ii
`9
`.31‘ 5-.”-
`”a _ .0 m .I
`+3. E. fi-g 3:
`‘
`:
`[A
`b
`'
`”M
`.
`3r:
`EE 3, g E
`S :-
`.
`I: I:
`dlEld
`g
`3% i E. T3.
`
`'
`=
`fl
`5 E" sE -;
`5-.
`.
`A m ‘5 33—9
`§
`§ E E a C:
`E
`g E E E a
`'5
`E:
`l, E E “3
`3 E 331 9' E
`i
`
`.
`= " u — 'r:
`“3
`5' 4.: 1:
`—.
`521712;:
`7;
`'
`- a 'E :1 :2»
`='
`C"
`3 a a E. .E' e
`E
`(‘5
`u)
`I
`~-
`,
`F.“
`5
`3 agagé.T
`dLSd
`vex
`xxxx
`0
`.. '4 d .i o. 0
`fi
`x x g
`L}
`T} Q E E; a; e:
`IH'Sd >< 5: x
`x x >< x x x >< x
`x x- x
`
`-
`.
`2
`‘E. y 0 E 3‘ 5'
`4
`a
`fiifieé3
`H
`g EEUEEJ‘
`'
`'
`:7 Til F *'. g E
`E E gin—1:2 “:5
`i g
`E"): E T,-
`‘2 "a
`m
`- 0
`E
`a
`E 5 E
`a ‘I1
`2.
`a; 3. e, =— 9
`N
`i
`.
`‘- r
`.4
`E E
`a if 35 {15-3
`.§
`- “
`4 3‘
`2:
`i? I
`5‘0 8 m
`2 2 ' e
`3
`
`vwwa
`>< ’4
`'
`I: 'g g 4,. E“ Q E a '—;'
`x g x R
`x '-
`x K E E a E I E“;
`L-
`‘
`K
`'3
`/7
`_.
`5 4:
`,2 E
`m ad K K x
`g E B
`if; E E; h;
`_ —L
`(IH'Eld a: x x
`>c
`:4 a: E >< ;:
`E E E: If: a;
`”We £E#=.:"_
`3d
`
`:4 C ' s
`50.3 E
`éI
`"Easé‘ié‘a‘fi’fi
`Q ~ 3 I E ex-m 5
`
`x g m E o u a ".‘-.
`.-
`2+,-
`si a. go 5 E- L f: - 4.-
`:3
`
`’ 2
`G ; 3° as? E
`
`T E ETC; : r
`5
`
`g § § 5 -_E_ E‘. d
`2
`E '5 S E '5' 8' §
`'3.
`t 8 “~ E i; = a
`5
`E:
`in E E a; a E
`g.
`"' i
`5‘:
`L'.
`_
`.
`a
`_,
`E”. 2:; .g E g
`i-
`E E .2 i E 2 E
`2
`
`at 3:3 “ 3 2:
`-
`E
`3w EE-EE'EE—F-zd'é
`3'} E § % E 3 E4; :7: f: ‘é-
`U D (5:- E E E E E“; E52 5.; E 3
`a
`E a
`D D <
`==Em5:~g—:..a__=
`05“- Oz
`:45;
`'3
`< m 2 2
`o
`= = r u a = :
`0 -
`.
`-
`I E“ D
`< ° °
`m <
`m
`
`apéixéEBEEEgfifiEEEfiKEE—‘EifimmEggafiggag;
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`do-dexx xxxxxxxx
`,
`W" oaa X K :4
`
`—
`
`dd *- >< *'
`woa
`
`" "
`
`><><
`x x
`
`x >< "i 7"
`..
`,c ,4
`
`be
`
`K”
`
`><
`X
`
`>< >< >< a:
`“5‘
`
`__!
`L
`
`x
`
`I
`
`K "“
`“H”
`.
`I
`R :4 K ><
`>< >2
`'
`-
`x x
`x K >e x
`
`>< x
`x ,4 x g
`
`99 W
`
`i
`
`V“
`v3
`
`vsv
`sav
`
`I
`
`371
`9.2 Fusible (Lost, Soluble) Core Injection Molding
`“soft touch” products. Example applications include canoe paddles, toilet seats and
`.
`.
`.
`.
`.
`.
`Clsterns, computer housmgs, copier parts, cash reglster covers, telev1s1on escutcheons,
`.
`.
`.
`.
`.
`audio cabinets circuitr
`and electronics enclosures, arden chairs, boxes and con-
`7
`y
`.
`.
`.
`.
`tainers, shoes and soles, palnt brush handles, metal hand-rims on wheelchalrs, thm—
`wall contalners and bevera e bottles automotlve
`arts such as exterlor mlrror
`g
`’
`.
`.
`housings and interior door handles and knobs, components for high-end ovens, audlo
`.
`.
`.
`.
`-
`speaker housings, and music center mainframes.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`Cost-reductlon opportumties and the desne and mandated requlrements to use
`rec cled materials w1ll dr1ve more a
`lications to com ection 1n new and exrsting
`y
`.
`-
`markets. More refined technology and a broader experience base among des1gners,
`processors and or1g1nal equipment manufacturers (OliMs) Will also expand the
`sporadic current use of the process. Useful de51gn gu1dehnes for COIIljeCthIl molding
`and other multicomponent injection molding processes can be found in Ref. [28].
`
`.
`.
`u
`.
`Fusrble (Lost, Soluble) Core Injection Molding
`
`9.2
`
`.
`.
`.
`.
`.
`,
`The fusible (lost, soluble) core 1n]ection molding process producescomphcated,
`hollow components with complex and smooth mternal geometry in a smgle molding
`.
`.
`.
`n
`.
`.
`n
`.
`n
`-
`-
`o erat10n.Th1s
`roces51s a form of insert moldm 1n wh1ch lastic IS Injected around
`p
`p
`,
`.
`.
`.
`.
`_
`.
`.
`.
`.
`a temporary core of low meltlng-pomt material, such as tin—blsmuth alloy, wax, or a
`therrno lastic. After moldm , the core W111 be
`hysrcally melted (or chemically
`.
`.
`.
`dissolved), leaving lts outer geometry as the internal shape of the plastlc part. ThlS
`process reduces the number of components required to make a final assembly or
`.
`.
`.
`.
`.
`substitutes plastic for metal castlngs to boost performance (e.g., corrosmn resrstance)
`while saving weight, machining, and cost.
`
`9.2.1
`
`,_
`Process Description
`
`_
`
`.-
`
`Different techniques are available to produce single—plece components featurlng
`complex, smooth internal geometry and a high dimensional stability, whlch cannot be
`obtained through the conventional 1n]ection moldmg process [1,30,31]:
`.
`.
`. Fuslble core technlque
`.
`.
`I Soluble core technique
`I Salt core techmque
`All of these techniques employ the same principle: the production of Injectlon
`molding with a lost core that gives the internal contour of the molded part. Among
`.-
`.
`.
`.
`.
`these lost core rocesses fuslble core techni ue IS the most ener
`~1ntensrve method.
`P
`u
`q
`gy
`Nevertheless, this drawback is offset by the low core losses, smoother internal surface
`
`‘I
`
`‘
`
`'l
`I
`H
`
`I
`|
`‘
`
`|
`
`I
`I
`
`.
`'
`
`|
`
`i
`i
`
`l
`
`I
`‘
`
`MacNeil Exhibit 2076
`
`Yita v. MacNeil IP, |PR2020-01139
`
`Page 9
`
`
`
`MacNeil Exhibit 2076
`Yita v. MacNeil IP, IPR2020-01139
`Page 9
`
`

`

`
`
`[Refs on pp. 460-463]
`
`9.2 Fusible (Lost, Soluble) Core Injection Molding
`
`373
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Figure 9.7 A eutectic bismuthrtin (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: BASF. (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 o