Shape memory technology for active assembly ...

Assembly Automation Shape memory technology for active assembly/disassembly: fundamentals, techniques and example applications L. Sun W.M. Huang H.B. Lu C.C. Wang J.L. Zhang

Article information: To cite this document: L. Sun W.M. Huang H.B. Lu C.C. Wang J.L. Zhang , (2014),"Shape memory technology for active assembly/disassembly: fundamentals, techniques and example applications", Assembly Automation, Vol. 34 Iss 1 pp. 78 - 93 Permanent link to this document: http://dx.doi.org/10.1108/AA-03-2013-031 Downloaded on: 28 October 2015, At: 04:41 (PT) References: this document contains references to 50 other documents. To copy this document: [email protected] The fulltext of this document has been downloaded 304 times since 2014* Downloaded by 46.246.28.95 At 04:41 28 October 2015 (PT)

Users who downloaded this article also downloaded: Joseph Chiodo, Nick Jones, (2012),"Smart materials use in active disassembly", Assembly Automation, Vol. 32 Iss 1 pp. 8-24 http://dx.doi.org/10.1108/01445151211198683 Robert Bogue, (2014),"Smart materials: a review of capabilities and applications", Assembly Automation, Vol. 34 Iss 1 pp. 16-22 http://dx.doi.org/10.1108/AA-10-2013-094 Eujin Pei, (2014),"4D printing – revolution or fad?", Assembly Automation, Vol. 34 Iss 2 pp. 123-127 http://dx.doi.org/10.1108/ AA-02-2014-014 Access to this document was granted through an Emerald subscription provided by All users group

For Authors If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information.

About Emerald www.emeraldinsight.com Emerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services. Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. *Related content and download information correct at time of download.

Shape memory technology for active assembly/ disassembly: fundamentals, techniques and example applications L. Sun School of Civil Engineering, Shenyang Jianzhu University, Shenyang, People’s Republic of China

W.M. Huang School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore

H.B. Lu Center for Composite Materials, Harbin Institute of Technology, Harbin, China

C.C. Wang Nanjing Institute of Technology, Nanjing, People’s Republic of China, and

Downloaded by 46.246.28.95 At 04:41 28 October 2015 (PT)

J.L. Zhang School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore Abstract Purpose – This paper aims to present a review on utilizing shape memory technology (SMT) for active assembly/disassembly, i.e. assembly/ disassembly without physically touching. Design/methodology/approach – The fundamentals behind the shape memory effect (SME) in materials, in particular shape memory alloys (SMAs) and polymers, which are the cornerstones of SMT, are introduced, together with the possible approaches to implement this effect in active assembly/ disassembly. Example applications for not only active assembly/ disassembly, but also programmed active disassembly are presented. Findings – The advantages of utilizing SMT over conventional assembly/disassembly techniques are identified. Originality/value – The paper introduces the fundamentals behind the SME and the basic approaches to implement the SMT in not only active assembly/disassembly, but also programmed active assembly. Keywords Assembly, Disassembly, Design for assembly, Design for disassembly Paper type General review

applications, from surface patterning (Zhao et al., 2012) to novel medical devices (Huang et al., 2013). Figure 1(a) shows that a piece of polyethylene terephthalate (PET), which is one of commonly used engineering polymers for packaging and for water bottles, is impressed at high temperatures using a pin (top) to get a permanent impression. The impression can be fully removed upon heating (Figure 1(b)). The term of shape memory technology (SMT) was seemingly introduced in 1990s (Abrahamsson and Bjarnemo, 1994; Farzin-Nia and Inst Mech, 1999), and was promoted through the conference series of Shape Memory and Superelasticity Technologies (SMST). However, at that time, SMT was mainly focused on the applications of some particular metallic SMMs, known as shape memory alloy (SMA), and a couple so-called shape memory polymers (SMPs).

1. Introduction The shape memory effect (SME) is defined as the ability of a material, which has been severely and quasi-plastically predeformed, to recover its original shape at the presence of the right stimulus (Huang et al., 2010b; Otsuka and Wayman, 1998). Typical stimuli to trigger the SME include heating/ cooling (thermo-responsive) (in either direct or indirect manner), light (photo-responsive) (without involving much temperature fluctuation), chemicals (chemo-responsive) (e.g. water/moisture, ethanol, pH change), mechanical loading (mechano-responsive), etc. among others (Sun et al., 2012; Wang et al., 2012a, b). To date, the SME in a number of materials, which are traditionally known as shape memory material (SMM), has been utilized in a wide range of The current issue and full text archive of this journal is available at www.emeraldinsight.com/0144-5154.htm

The ABS/PC reported in Figure 29 was kindly provided by Nokia, Singapore. This project is partially supported by the National Natural Science Foundation of China (51178277), Program for New Century Excellent Talents in University (NCET-12-1013), People’s Republic of China, and the Fundamental Research Funds for the Central Universities (Grant No. HIT.BRETIV.201304), People’s Republic of China.

Assembly Automation 34/1 (2014) 78– 93 q Emerald Group Publishing Limited [ISSN 0144-5154] [DOI 10.1108/AA-03-2013-031]

78

SMT for active assembly/disassembly

Assembly Automation

L. Sun, W.M. Huang, H.B. Lu, C.C. Wang and J.L. Zhang

Volume 34 · Number 1 · 2014 · 78 –93


Figure 1 The SME in PET

(b)

(a)

Notes: (a) After impression; (b) after heating University, UK in late 1990s (Chiodo et al., 1997, 1998a; Chiodo and Jones, 2012). The main driving force behind active assembly/disassembly is to simplify the processing procedure, so that for instance, one sized screw/rod can be used for a range of sized holes and different components in obsolete devices can be automatically separated (Chiodo and Boks, 2002; Jones et al., 2004), instead of manually, which is labor and time intensive, or automatic disassembly, which requires large investments, for effective recycling (Koyu et al., 2003; Jones et al., 2003; Carrell et al., 2009; Tanskanen and Takala, 2001). Active disassembly is a promising technology, enabling high-speed, low cost and non-destructive dismantling process, allowing the reuse of parts in a next product life cycle (Chiodo and Boks, 2002; Chiodo et al., 1999a). Readers may refer to www. ActiveDisassembly.com for many demonstrations. The outline of this paper is following. Section 2 briefly discusses the fundamentals of different types of SME. Section 3 introduces the basic concept of SMT for active assembly/disassembly. Section 4 presents some example applications of SMAs for active assembly/disassembly, and Section 5 discusses the implementation of polymers in not only active assembly/disassembly, but also programmed active disassembly. Conclusions are presented in Section 6.

Despite some previous works (e.g. reported in Hussein and Harrison (2004)), on the contrary to conventional understanding, more and more recent studies reveal that the SME is actually not a unique characteristic of some particular materials, but a generic feature of a range of materials. For instance, as discussed in Huang et al. (2012b), most polymers and polymeric materials, if not all, are essentially thermo-/chemo-responsive SMM. Hence, the SMT has been expanded accordingly to include the following three groups of techniques (Huang et al., 2012b), namely: . The techniques to enable the SME in materials, such as those conventional engineering polymers (Hussein and Harrion 2004; Zhao et al., 2011a). . The techniques to design and produce a SMM with the required properties/functions for a particular application. For instance, to fabricate a shape memory hybrid (SMH) with the required cooling-responsive SME (Wang et al., 2012a) or behaving in a rubber-like manner at low temperatures and even with thermally assisted self-healing function (Wang et al., 2012c, d). Of course, conventional techniques of chemical/polymer synthesis are part of it. . The techniques to optimize the SME to achieve, for instance, high actuation stress or sharp shape recovery temperature range (Sun et al., 2011). The purpose of this paper is to discuss the potential applications of SMT in active assembly/disassembly, i.e. components/parts are firmly put together (assembly) or separated (disassembly) in a physically non-contact manner via altering the environmental conditions, mostly temperature. Folding/unfolding, which may be also considered as an extension of active assembly/ disassembly, is not discussed here. The research work on active disassembly of obsolete electrical devices, such as mobile phones, using SMAs/SMPs, was initialized by Dr J.D. Chiodo and his co-workers at Brunel

2. Fundamentals of SME As shown in Figure 2, a piece of silicone/wax hybrid ring is pre-expanded at high temperatures into a large size (left), and after heating the ring returns its original size (right). This is the traditional understanding of the SME. By means of selecting a polymer or polymeric hybrid for the right recovery temperature/stress, a shape memory micro tag as shown in Figure 3 can be mounted firmly onto the leg of an ant without any harmful effect. 79


Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93

Figure 2 The SME in a silicone/wax hybrid

one is permanent (A) and the other is temporary (B) as shown in Figure 4. If the energy barrier (H) is high, additional energy (via applying the right stimulus) is required to overcome the barrier for shape recovery. This is the SME. On the other hand, if the energy barrier is low (H’) or virtually none, the material is able to switch between these two shapes either gradually (e.g. visco-elastically) or instantly. Although the SME appears as a non-intrinsic material property, there are a number of approaches to enable the SME in materials. Generally speaking, a shape memory cycle includes two processes, one is the programming process to deform the material into the temporary shape; and the other is the shape recovery process to apply the stimulus to trigger shape recovery. For some materials and also depending on the required temporary shape, programming may be carried out without the presence of the right stimulus or at the presence of another stimulus. Bear in mind that there might be a couple of different stimuli for a material. For example, in addition to the thermo-responsive SME, water/moisture and ethanol are also stimulus to trigger the chemo-responsive SME in polyurethane (PU) (Wang et al., 2012b; Huang et al., 2010a). According to Huang et al. (2013), there are two basic categories of generic working mechanisms for the SME in materials, namely dual-phase (state) transition system and dual-component system (Figure 5). Under the category of dual-phase transition system, there are three sub-types. A typical example for Type A is thermo-responsive SMA, a typical example for Type B is magneto-responsive SMA, and a typical example for Type C is elastomer. Under the category of dual-component system, there are two sub-types. Type A refers to dual-segment/phase SMP/SMH. Type B is applicable to enable the SME in a wide range of materials (even for melting glue, wax and solder). In real practice, more than one mechanism may be involved. Readers may refer to Huang et al. (2013) for details. Above mentioned SME is meant for switching from the temporary shape back to the permanent shape. It cannot be operated in a cyclic fashion (hence, only with the one-way SME), unless a special mechanism (via an external force) is applied to automatically reset the temporary shape. The resulted cyclic operation in such a manner is called the mechanical two-way SME. On the other hand, in some

Notes: Left: after expansion; right: after heating Source: Reproduced with permission from Huang et al. (2013)


Figure 3 Shape memory micro tag

Notes: The pre-expanded shape memory tag is heated slightly to 37°C for shape recovery; subsequently, the tag holds tightly on the leg of the ant without inducing any excessive stress Source: Reproduced with permission from Huang et al. (2006) It should be pointed out that in many occasions, the SME is confused with the other effect, namely the shape change effect (SCE), in the literature. The main difference between these two effects is that before applying the right stimulus, shape recovery in SMMs is limited, if there is any, while in the SCE, reversible shape change (either instantly or gradually) is dependent on whether the right stimulus is applied (Huang et al., 2012b; Sun et al., 2012; Lendlein, 2010). For instance, while a piece of thermo-responsive SMA requires heating to trigger the SME, an elastic spring extends/contracts in response to force (mechano-responsive SCE). Since a same piece of material may have either the SME or the SCE depending on the working conditions, further confusion is highly likely. Traditional definition even worsens the situation. A typical example is thermo-responsive SMA, which at low temperatures, has the SME, while at high temperatures, is superelastic (according to current definition, this belongs to the SCE). Fundamentally, the difference between the SME and SCE is due to the magnitude of energy barrier between two shapes,

Figure 4 SME and SCE

Shape memory effect

H B A

H’

Sha pe c

ffect hange e

Source: Reproduced with permission from Huang et al. (2012b) 80


Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93

Figure 5 Basic working mechanisms for the SME

(I) Dual-phase transition system

A

B

(II) Dual-component system


C

A

B

(1)

(2)

(3)

Notes: (I) Dual-phase transition, (II) dual-component; (1) original shape, (2) after programming, (3) after shape recovery Source: Reproduced with permission from Huang et al. (2013) Instead of introducing a temporary gradient transition temperature field into the material as shown in Figure 7, one can produce different transition temperatures at different parts in a few different ways. Utilizing the influence of water on the glass transition temperature (Tg) of PU (Yang et al., 2006), a piece of 1 mm diameter PU wire is pre-immersed into room temperature water for different periods of time for its different segments and then pre-bent into the shape as shown in Figure 8. Upon gradually heating, the bottom segment, which has been immersed into water for the longest period of time and has the lowest transition temperature, recovers first, followed by the middle segment, and finally the top segment, which has the shortest water immersion time. Since there are two intermediate shapes in this experiment, this may be called the quad-SME. Recent development reveals that it is possible to achieve the multiple-SME in both SMAs and polymers by programming (Sun and Huang, 2010; Tang et al., 2012). The procedure to program a piece of silicone/wax hybrid for the triple-SME is shown in Figure 9, in which a piece of straight hybrid is bent at

materials, it is possible to reduce the size of such a mechanism down to micro/nano level via a special process, and thus the material has the material two-way SME (Huang, 2002). In Figure 6, a piece of NiTi SMA, which originally has the oneway SME is trained to have the material two-way SME (Huang and Toh, 2000), so that it can open/close accordingly in response to heat. Bear in mind, according to above definition, strictly speaking the two-way SME should belong to the SCE. Via introducing a gradient recovery (transition) temperature field into a SMM, one can achieve the multiple-SME, i.e. the shape recovery sequence is in a step-by-step manner and can be pre-programmed. Figure 7 shows the shape recovery sequence in a piece of NiTi SMA, which originally has the oneway SME, and is pre-bent at two locations into different curvatures. Due to the influence of pre-strain on the transition temperature (Huang, 1998; Huang and Wong, 1999), upon heating the less bent section becomes straight first and the more bent section straightens at higher temperatures. Since there are three shapes involved (temporary shape, intermediate shape, and permanent shape), this is called the triple-SME. 81


Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93

Figure 6 Material two-way SME

(a)

(b)


Notes: (a) At room temperature; (b) upon heating Source: Reproduced from Sun et al. (2012) with permission

Figure 7 Triple-SME upon heating

Source: Reproduced from Sun et al. (2012) with permission 808C and then cooled to 248C. At 248C, it is straightened and then cooled to 2 58C. In the subsequent heating process for shape recovery (Figure 10), the hybrid bends downward upon heating to 248C and then bends upward. At 808C, it becomes straight again. From engineering application point of view, one can either select an existing material with the transition temperature at around the required range or design a material (for instance, following the concept of SMH (Sun et al., 2012)), and then select the programming temperature to tailor the exact shape recovery temperature for the requirement(s) of a particular application (Sun et al., 2011). In the case of multiple-SME, it is possible to pre-determine the individual recovery temperatures.

scope of this paper to explore the details of individuals. Instead, a brief introduction of the relevant ones when is needed will be presented. Although the term of SME was seemingly introduced only after the observation of the shape memory phenomenon in AuCd alloy in 1932 (Funakubo, 1987), the history of harnessing this interesting effect can be indeed traced back well before this term ever being coined. Heat shrink soft tubes made of ethylene-vinyl acetate (EVA) or polyethylene (PE), etc. to wrap around a bundle of wires for insulation/protection (Figure 11) has found a vast commercial market at least before 1906 (Litynski, 1987). Nowadays, even expensive polyether ether ketone (PEEK) has its niche in this field (e.g. PEEKshrinkw) for extreme harsh environmental conditions. Instead of flexible heat shrink tubes, stiff SMM (e.g. SMA) has been used for coupling to firmly bond two rigid tubes together in a convenient manner (Figure 12). SMA coupler has become a commercially successful product since 1990 (Funakubo, 1987).

3. SMT for active assembly/disassembly As mentioned above, the currently developed SMT includes three core groups of techniques, one for enabling the SME in materials; one for design a material with the required feature/ function; and one for optimizing the SME. It is not within the 82


Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93


Figure 8 Recovery in a 1 mm diameter PU SMP wire upon heating

Source: Reproduced from Huang et al. (2005) with permission

Figure 9 Programming process

(a)

(b)

(c)

Source: Reproduced from Sun et al. (2012) with permission

Figure 10 Shape recovery sequence upon heating to different temperatures

(a) At –5°C

(b) At 24°C

Source: Reproduced from Sun et al. (2012) with permission 83

(c) At 80°C


Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93

Figure 11 Heat shrink polymeric soft tube

(a)

(b)

Notes: (a) Before heating; (b) after heating


Figure 12 Heat shrink coupler (the middle short tube)

(a)

(b)

Notes: (a) Before heating; (b) after heating In addition to above traditional applications of SMMs in assembly, Figure 13 shows the concept of “one for all size” in using SMA for active assembly (Huang and Gao, 2001). As shown in Figure 13, a piece of raw SMA wire (normally being cold drawn into coiled shape and thus without the SME) is annealed into straight shape with the SME. After that, it is pre-stretched and then insert into the holes of two components. After heating to trigger the SME, SMA wire returns its original shape and hence, firmly bonds two components together. As compared with SMAs, which have a recoverable strain no more than 10 per cent (Huang, 2002), the recoverable strain in many polymers is often on the order of 100 per cent. As such, a number of engineering polymers, such as poly(methyl methacrylate) (PMMA), acrylonitrile butadiene

styrene (ABS) and propylene carbonate (PC), etc. have the intrinsic advantage. As shown in Figure 14, a piece of PMMA rod is pre-stretched to 200 per cent strain at above its Tg (which is around 1208C) into a much smaller diameter and then placed inside the hole of a shaft. Upon heating, the rod expands and hence firmly bonds to the shaft. The advantage of large recoverable strain not only widens the size range of holes (and even irregular holes) for active assembly, but also enables for thread formation on polymer rods. As shown in Figure 15, two PMMA rods are prestretched, placed into threaded holes and then heated to different temperatures. Formation of thread enables us to twist the rod (using a screw driver) to remove the PMMA rods as normal PMMA screws. This is an apparent advantage of using polymers other than SMAs in active assembly.

Figure 13 Illustration of active assembly using SMA wire

84



Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93

Figure 14 Assembly using one single sized PMMA rod for a range of sized hole

actively disassembled without any physical touching. Upon further heating, the cap shrinks back to its original shape, and thus it can be reused as a normal cap again. Such a concept can be applied as an alternative approach for anti-counterfeit (Huang et al., 2012a). In the early attempts for active assembly/disassembly, conventional SMMs were applied. For instance, the feasibility studies for active disassembly of various electrical devices conducted at Brunel University, UK, Katholieke Universiteit Leuven, Belgium and Nokia Research Center are based mainly on SMAs and SMPs (occasionally using engineering polymers around 2000-2002 at Brunel University) (Chiodo et al., 1998b, 1999, 2000, 2001, 2002; Tanskanen, 2003; Carrell et al., 2009; Duflou et al., 2006). By means of selecting a right material among commercially available ones in the market, such as among the existing engineering polymers, which have been accepted by the industry, and optimizing the programming parameters (e.g. programming temperature and deformation), the chance of success in real implementation of the SMT can be significantly enhanced (Hussein and Harrison, 2004; Purnawali et al., 2012).

4. SMAs for active assembly/disassembly In Figure 18(a) and (b), active assembly using NiTi SMA wires are demonstrated in two examples, one for an aluminum plate and the other for the read/write head of a hard disk. Figure 18(c) shows the feasibility for active assembly of the spindle of a hard disk using CuZnAl ring. As compared with polymers, SMAs have the advantage of high strength. However, limited by small recoverable strain, a key issue to achieve success in active assembly/disassembly is to ensure high precision in dimensions in the components to be assembled. Figure 19 shows a hole drilled by electrical discharge machining (EDM) in stainless steel. As revealed, the hole is not with a uniform size from one side to the other. Surface finish at the bottom side is not smooth. In Figure 20, two holes in a piece of aluminum are produced by milling machine (FJV-250), which again reveals the nonuniformity and imperfection in the resulted holes. Figure 21 plots a typical pulling force vs extension curve of a pulling out experiment conducted on a 0.5 mm diameter (nominal) NiTi wire after assembly with a 1 mm thick stainless steel plate (produced by EDM as shown in Figure 19). As shown, pulling load increases with the extension until reaching around 0.4 mm of extension. After that the load drops slightly and then maintains virtually constantly over a long displacement. At about 8 mm of extension, the load increases dramatically before drops to almost zero. The measured extension includes two parts. One is the extension of the NiTi wire upon stretching, and the other is due to the slip of the wire. It is obvious that before an extension of 0.4 mm, the extension of the NiTi wire is dominant. After that, slip occurs. In the last stage, dramatic load increase is due to imperfection (elliptical shaped cross-section) at the end of the NiTi wire, since it was cut out from a long wire using a vise. In assembly, our interest is within the stage before slip happens. Figure 22 plots typical experimental results of different pairs of measured nominal diameter of NiTi wire and nominal diameter of hole. All tests were carried out at a

Figure 15 Assembly using PMMA rod (resulting in PMMA screw with thread)

Furthermore, in a particular application, there are a range of engineering polymers to select for the required thermomechanical properties and shape recovery temperature, etc. In Figure 16, a piece of polystyrene (PS) is pre-compressed at 708C into the square shaped hole in an aluminum plate. This piece of PS shrinks upon heating to 708C and thus automatically opens the hole. The multiple-SME mentioned above provides a new dimension to achieve what is beyond our imagination in the past. As shown in Figure 17, a piece of polymeric cap is programmed for the triple-SME. Subsequently, it can be used as a normal cap. However, upon heating it expands, so that it can be 85


Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93

Figure 16 Automatic hole-opening upon heating

Source: Reproduced from Sun et al. (2012) with permission


Figure 17 Illustration of triple-shape memory cap

(a)

(b)

(c)

Notes: (a) Before heating; (b) after slightly heating for expansion; (c) after further heating for shrinking Source: Huang et al. (2012a) Figure 18 SMA for active assembly

(a)

(b)

(c)

Notes: (a) NiTi SMA wire (0.5mm diameter) and aluminum plate; (b) NiTi SMA wire (1mm diameter) and read/write head of hard disk; (c) CuZnAl ring and spindle of hard-disk Source: (a) and (b) Reproduced from Sun et al. (2012) with permission; (c) reproduced from Huang et al. (2002) with permission constant speed of 1 mm/min. Holes are produced by milling machine on 1 mm thick aluminum as in Figure 20. Figure 23 summarizes the maximum load before slip vs nominal hole diameter relationship in pulling and pushing tests with/without 80 thermal cycles between room temperature (about 228C) and 1008C. As revealed, the maximum load is virtually dependent only on the nominal hole diameter,

while the influence of exact wire diameter and thermal cycling is limited. The triple-SME in SMAs, which is achievable in some NiTi based alloys after programming (Tang et al., 2012), provides a practically feasible approach to achieve griping and then release. As shown in Figure 24, after programming, upon heating the NiTi coil is able to shrink first and then expand. 86


Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93

Figure 19 Hole (about 0.5 mm in diameter) drilled by EDM (material: 1 mm thick stainless steel)

(a)

(b)

Notes: (a) Top view; (b) bottom view

(a)

(b)

Notes: (a) Top view; (b) bottom view Figure 21 Typical result of pulling test 30 25 Load (N)


Figure 20 Holes (about 1 mm in diameter) produced by milling machine (material: 1 mm thick aluminum)

20 15 10 5 0

0

2

4

6 8 Extension (mm)

10

12

14

Note: Loading speed: 1 mm/min

5. Polymers for active assembly/disassembly

active assembly, and (c) is after stretching to fracture. It is clear that failure occurs at the junction point, which is more likely due to stress concentration. Figure 26(a) shows the result of tensile test on PMMA rod till fracture, and Figure 26(b) shows the result of stretching test after active assembly. A close look reveals that if considering the real dimension of PMMA at the junction point, the strength of PMMA is mostly unaffected.

High recoverable strain in polymers provides a more practically accessible solution for active assembly/disassembly. However, in order to be really applicable in industry, one important concern is strength and long-term stability. Figure 25 shows a study on the strength of PMMA rod based active assembly, in which (b) is right after heating, (a) is after slightly twisting PMMA to show the thread formed after 87


Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93

Figure 22 Typical experimental results of different pairs of nominal diameter of NiTi wire and nominal diameter of hole 30

35 0.992/0.988 0.990/0.988 0.995/0.992

0.991/0.988 0.993/0.988 0.991/0.988 0.994/0.992

30 Pushing Force (N)

Pulling Force (N)

25 20 15 10 5

25 20 15 10 5 0

0 0

2

4

6 8 10 12 14 16 18 Tension (nm)

–5 –1 0

1

2 3 4 5 6 7 Compression (mm)

8

9 10

(b)

(a)

Figure 23 Maximum load before slip vs nominal diameter of hole relationship in pulling/pushing with/without thermal cycling

50 Pulling without cycle Pulling after 80 cycles Pushing without cycle Pushing after 80 cycles Data-fitting

40 30 Load, N


Notes: (a) Pulling test; (b) pushing test

20 10 0 0.988

0.990

0.992 0.994 0.996 Diameter of hole, mm

0.998

1.000

Figure 24 Morphing of a NiTi coil upon gradually heating

Zhao et al., 2011a, b; Sun et al., 2011), appears to be more suitable material for this purpose. Figure 27 shows the shape change (disappearance of thread) upon heating to 1208C in a programmed PMMA screw. Figure 28 shows its application in active disassembly. Most of the casing materials for electrical devices are ABS, PC or a combination of them (ABS/PC). Using the same ABS/PC

Preliminary studies on some engineering polymers over one year of storage at room temperature and above reveal that high shape recovery ratio (over 85 per cent) is largely maintained. Shape memory screw has been previously investigated using conventional SMPs (e.g. in Koyu et al. (2003)). PMMA, which is one of the engineering materials for plastic screws, has Tg over 1108C, and has the excellent SME (Purnawali et al., 2012; 88


Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93

Figure 25 Strength test on PMMA screw

Figure 26 Experimental results of tensile test on PMMA rod (a) and stretching test after assembly (b) 250 30

200 Force (N)

Tensile Stress (MPa)


Notes: (a) Thread formed after active assembly; (b) right after heating for active assembly; (c) after stretching to fracture

20 10

150 100 50

0

0 0

2

4 6 8 10 Tensile Strain (%)

12

0.0

0.2 0.4 0.6 0.8 Tensile Extension (mm)

(a)

1.0

(b)

Figure 27 PMMA shape memory screw

(a)

(b)

Notes: (a) Left: original rod; right: after programming; (b) after heating for the case of Nokia’s E51 mobile phone, Figure 29 show the feasibility to achieve step-by-step active disassembly, i.e. programmed active disassembly as reported in Purnawali et al. (2012) where PMMA was used. Programmed

active disassembly enables us to use one material, instead of a few different materials, for step-by-step disassembly. Such a feature is made possible based on the intrinsic multiple-SME in polymers (Sun and Huang, 2010). By optimizing the programming 89


Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93


Figure 28 Demonstration of active disassembly using PMMA screw

Notes: (a) Tightening; (b) heating at 130°C for 30 min (insets: threads disengage); (c) removing (threads disappear) Source: Reproduced from Purnawali et al. (2012) with permission

Figure 29 Programmed active disassembly using ABS/PC

Notes: (a) and (b) Upon heating at 115°C, A separates from B (mainframe); (c)-(e) upon heating at 127°C, B opens; (f)-(k) upon heating at 140°C, B opens further and eventually flattens

parameters (Sun et al., 2011; Huang et al., 2012b), one can tailor the shape recovery temperatures for different components/parts. The programming procedure for active disassembly shown in Figure 29 is illustrated in Figure 30.

feasible approaches to utilize the SMT for active assembly/ disassembly. As the SME has been proved to be a generic feature of many conventional materials, in particular in many engineering polymers, SMT is expected to bring forward even bigger impact to reshape product design (Toensmeier, 2005) in many ways, including in active assembly/disassembly. Here, we present some example applications and hope to inspire more ideas on SMT based active assembly/disassembly.

6. Conclusions In this paper, we briefly introduce the fundamentals behind various shape memory phenomena, and summarize practically 90


Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93


Figure 30 Programming procedure for programmed active disassembly

Notes: (a) Original shapes of A and B; (b) step-by-step programming; (c) after programming

References

Chiodo, J.D., Billett, E.H., Harrison, D.J. and Harry, P. (1998b), “Investigations of generic self disassembly using shape memory alloys”, Proc. of the IEEE Int. Symp. on Electronics and the Environment, pp. 82-87. Chiodo, J.D., Jones, N., Billett, E.H. and Harrison, D.J. (2002), “Shape memory alloy actuators for active disassembly using ‘smart’ materials of consumer electronic products”, Materials & Design, Vol. 23, pp. 471-478. Chiodo, J.D., Mclaren, J., Billett, E.H. and Harrison, D.J. (2000), “Isolating LCD’s at end-of-life using active disassembly technology: a feasibility study”, Proc. of the IEEE Int. Symp. on Electronics and the Environment, pp. 318-323. Chiodo, J.D., Anson, A.W., Billett, W.H., Harrison, D.J. and Perkins, M. (1997), “Eco-design for active disassembly using smart materials”, in Pelton, A., Hodgson, D., Russell, S. and Duerig, T. (Eds), Proceedings of the Second International Conference on Shape Memory and Superelastic Technologies, SMST, Kharagpur. Duflou, J.R., Willems, B. and Dewulf, W. (2006), “Towards selfdisassembling products – design solutions for economically feasible large-scale disassembly”, Innovation in Life Cycle Engineering and Sustainable Development, pp. 87-110. Farzin-Nia, F. and Inst Mech, E. (1999), “Orthodontic applications of shape-memory technology”, Medical Applications for Shape-Memory Alloys. Funakubo, H. (Ed.) (1987), Shape Memory Alloys, Gordon and Breach Science Publishers, New York, NY.

Abrahamsson, P. and Bjarnemo, R. (1994), “The need for product design tools in shape memory technology”, in Yamamoto, R. (Ed.), Advanced Materials’ 93, V-a&B:A: Ecomaterials; B: Shape Memory Materials and Hybrids, Vol. 18, pp. 1171-1174. Carrell, J., Zhang, H.C., Tate, D. and Li, H. (2009), “Review and future of active disassembly”, International Journal of Sustainable Engineering, Vol. 2, pp. 252-264. Chiodo, J.D. and Boks, C. (2002), “Assessment of end-of-life strategies with active disassembly using smart materials”, The Journal of Sustainable Product Design, Vol. 2, pp. 69-82. Chiodo, J.D. and Jones, N. (2012), “Smart materials use in active disassembly”, Assembly Automation, Vol. 32, pp. 8-24. Chiodo, J.D., Billett, E.H. and Harrison, D.J. (1998a), “Active disassembly”, Journal of Sustainable Product Design, October, pp. 26-36. Chiodo, J.D., Billett, E.H. and Harrison, D.J. (1999), “Preliminary investigations of active disassembly using shape memory polymers”, Proc. 1st Int. Symp. on Environmentally Conscious Design and Inverse Manufacturing, pp. 590-596. Chiodo, J.D., Harrison, D.J. and Billett, E.H. (2001), “An initial investigation into active disassembly using shape memory polymers”, Proceedings of the Institution of Mechanical Engineers Part B – Journal of Engineering Manufacture, Vol. 215, pp. 733-741. 91



Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93

Huang, W.M. (1998), “Effects of internal stress and martensite variants on phase transformation of NiTi shape memory alloy”, Journal of Materials Science Letters, Vol. 17, pp. 1843-1844. Huang, W.M. (2002), “On the selection of shape memory alloys for actuators”, Materials & Design, Vol. 23, pp. 11-19. Huang, W.M. and Gao, X.Y. (2001), “Simulation of novel micro-assembly using shape memory alloy”, in Sood, D.K., Lawes, R.A. and Varadan, V.V. (Eds), Smart Structures and Devices, The International Society for Optical Engineering, Bellingham, WA. Huang, W. and Toh, W. (2000), “Training two-way shape memory alloy by reheat treatment”, Journal of Materials Science Letters, Vol. 19, pp. 1549-1550. Huang, W.M. and Wong, Y.L. (1999), “Effects of pre-strain on transformation temperatures of NiTi shape memory alloy”, Journal of Materials Science Letters, Vol. 18, pp. 1797-1798. Huang, W.M., Lee, C.W. and Teo, H.P. (2006), “Thermomechanical behavior of a polyurethane shape memory polymer foam”, Journal of Intelligent Material Systems and Structures, Vol. 17, pp. 753-760. Huang, W.M., Wu, X.L. and Tianlang, L. (2012a), “Multiple-step anti-counterfeit label, its fabrication and application method”, PR China Patent Application 201210512085.2. Huang, W.M., Yang, B., Zhao, Y. and Ding, Z. (2010a), “Thermo-moisture responsive polyurethane shape-memory polymer and composites: a review”, Journal of Materials Chemistry, Vol. 20, pp. 3367-3381. Huang, W.M., Yang, B., An, L., Li, C. and Chan, Y.S. (2005), “Water-driven programmable polyurethane shape memory polymer: demonstration and mechanism”, Applied Physics Letters, Vol. 86, p. 114105. Huang, W.M., Ding, Z., Wang, C.C., Wei, J., Zhao, Y. and Purnawali, H. (2010b), “Shape memory materials”, Materials Today, Vol. 13, pp. 54-61. Huang, W.M., Gao, X., Ng, Q., Liu, Q., Kung, H. and Liu, X. (2002), “Hard disk drive assembly using copperbased shape-memory alloy”, Materials Science Forum, Vol. 394-395, pp. 95-98. Huang, W.M., Zhao, Y., Wang, C.C., Ding, Z., Purnawali, H., Tang, C. and Zhang, J.L. (2012b), “Thermo/chemoresponsive shape memory effect in polymers: a sketch of working mechanisms, fundamentals and optimization”, Journal of Polymer Research, Vol. 19, p. 9952. Huang, W.M., Song, C.L., Fu, Y.Q., Wang, C.C., Zhao, Y., Purnawali, H., Lu, H.B. and Tang, C. (2013), “Shaping tissue with shape memory materials”, Advanced Drug Delivery Reviews, Vol. 65, pp. 515-535. Hussein, H. and Harrison, D. (2004), “Investigation into the use of engineering polymers as actuators to produce ‘automatic disassembly’ of electronic products”, in Bhamra, T. and Hon, B. (Eds), Design and Manufacture for Sustainable Development, The Cromwell Press, Trowbridge. Jones, N., Harrison, P.D., Hussein, H. and Billett, P.E. (2003), “Towards self-disassembling vehicles”, The Journal of Sustainable Product Design, Vol. 3, pp. 59-74. Jones, N., Harrison, P.D., Hussein, H., Billett, P.E. and Chiodo, J. (2004), “Electrically self-powered active disassembly”, Proceedings of the Institution of Mechanical

Engineers Part B – Journal of Engineering Manufacture, Vol. 218, pp. 689-697. Koyu, S., Hideo, O., Masanobu, T. and Takeo, Y. (2003), “Study of auto-disassembly system using shape memory materials”, Proc. 3rd Int. Symp. on Environmentally Conscious Design and Inverse Manufacturing – Ecodesign, pp. 504-509. Lendlein, A. (2010), Shape-Memory Polymers, Springer, Berlin. Litynski, G.S. (1987), “Profiles in laparoscopy: Mouret, Dubois, and Perissat: the laparoscopic breakthrough in Europe (1987-1988)”, JSLS, Vol. 3, pp. 163-167. Otsuka, K. and Wayman, C.M. (Eds) (1998), Shape Memory Materials, Cambridge University Press, Cambridge. Purnawali, H., Xu, W.W., Zhao, Y., Ding, Z., Wang, C.C., Huang, W.M. and Fan, H. (2012), “Poly(methyl methacrylate) for active disassembly”, Smart Materials and Structures, Vol. 21, p. 075006. Sun, L. and Huang, W.M. (2010), “Mechanisms of the multishape memory effect and temperature memory effect in shape memory polymers”, Soft Matter, Vol. 6, pp. 4403-4406. Sun, L., Huang, W.M., Wang, C.C., Zhao, Y., Ding, Z. and Purnawali, H. (2011), “Optimization of the shape memory effect in shape memory polymers”, Journal of Polymer Science Part A: Polymer Chemistry, Vol. 49, pp. 3574-3581. Sun, L., Huang, W.M., Ding, Z., Zhao, Y., Wang, C.C., Purnawali, H. and Tang, C. (2012), “Stimulus-responsive shape memory materials: a review”, Materials & Design, Vol. 33, pp. 577-640. Tang, C., Huang, W.M., Wang, C.C. and Purnawali, H. (2012), “The triple-shape memory effect in NiTi shape memory alloys”, Smart Materials and Structures, Vol. 21, p. 085022. Tanskanen, P. (2003), “A new life for old electronics”, Nokia Research Center Report. Tanskanen, P. and Takala, R. (2001), “Concept of a mobile terminal with active disassembly mechanism”, Nokia Research Centre Report. Toensmeier, P.A. (2005), “Shape memory polymers reshape product design”, Plastics Engineering, Vol. 61, pp. 10-11. Wang, C.C., Huang, W.M., Ding, Z., Zhao, Y. and Purnawali, H. (2012a), “Cooling-/water-responsive shape memory hybrids”, Composites Science and Technology, Vol. 72, pp. 1178-1182. Wang, C.C., Zhao, Y., Purnawali, H., Huang, W.M. and Sun, L. (2012b), “Chemically induced morphing in polyurethane shape memory polymer micro fibers/springs”, Reactive & Functional Polymers, Vol. 72, pp. 757-764. Wang, C.C., Ding, Z., Purnawali, H., Huang, W.M., Fan, H. and Sun, L. (2012c), “Repeated instant self-healing shape memory composites”, Journal of Materials Engineering and Performance, Vol. 21, pp. 2663-2669. Wang, C.C., Huang, W.M., Ding, Z., Zhao, Y., Purnawali, H., Zheng, L.X., Fan, H. and He, C.B. (2012d), “Rubber-like shape memory polymeric materials with repeatable thermal-assisted healing function”, Smart Materials & Structures, Vol. 21, p. 115010. Yang, B., Huang, W.M., Li, C. and Li, L. (2006), “Effects of moisture on the thermomechanical properties of a 92


Assembly Automation


Volume 34 · Number 1 · 2014 · 78 –93

polyurethane shape memory polymer”, Polymer, Vol. 47, pp. 1348-1356. Zhao, Y., Huang, W.M. and Wang, C.C. (2012), “Thermo/ chemo-responsive shape memory effect for micro/nano surface patterning atop polymers”, Nanoscience and Nanotechnology Letters, Vol. 4, pp. 862-878. Zhao, Y., Wang, C.C., Huang, W.M. and Purnawali, H. (2011a), “Buckling of poly(methyl methacrylate) in stimulus-responsive shape recovery”, Applied Physics Letters, Vol. 99, p. 131911.

Zhao, Y., Wang, C.C., Huang, W.M., Purnawali, H. and An, L. (2011b), “Formation of micro protrusive lens arrays atop poly(methyl methacrylate)”, Optics Express, Vol. 19, pp. 26000-26005.

Corresponding author


W.M. Huang can be contacted at: [email protected]

To purchase reprints of this article please e-mail: [email protected] Or visit our web site for further details: www.emeraldinsight.com/reprints

93


This article has been cited by: 1. Abhijit Vijay Salvekar, Ye Zhou, Wei Min Huang, Yee Shan Wong, Subbu S. Venkatraman, Zexiang Shen, Guangming Zhu, Hai Po Cui. 2015. Shape/temperature memory phenomena in un-crosslinked poly-ɛ-caprolactone (PCL). European Polymer Journal 72, 282-295. [CrossRef] 2. Haibao Lu, Yongtao Yao, Long Lin. 2015. Temperature sensing and actuating capabilities of polymeric shape memory composite containing thermochromic particles. Pigment & Resin Technology 44:4, 224-231. [Abstract] [Full Text] [PDF] 3. Zhibin Wen, Tianhao Zhang, Yan Hui, Wanli Wang, Keke Yang, Qian Zhou, Yuzhong Wang. 2015. Elaborate fabrication of welldefined side-chain liquid crystalline polyurethane networks with triple-shape memory capacity. J. Mater. Chem. A . [CrossRef] 4. Shaojun Chen, Funian Mo, Florian J. Stadler, Shiguo Chen, Zaochuan Ge, Haitao Zhuo. 2015. Development of zwitterionic copolymers with multi-shape memory effects and moisture-sensitive shape memory effects. J. Mater. Chem. B 3, 6645-6655. [CrossRef] 5. Huilong Guo, Yinwen Li, Jian Zheng, Jianqun Gan, Liyan Liang, Kun Wu, Mangeng Lu. 2015. High thermo-responsive shape memory epoxies based on substituted biphenyl mesogenic with good water resistance. RSC Adv. 5, 67247-67257. [CrossRef] 6. Ye Zhou, Wei Min Huang, Shu Feng Kang, Xue Lian Wu, Hai Bao Lu, Jun Fu, Haipo Cui. 2015. From 3D to 4D printing: approaches and typical applications. Journal of Mechanical Science and Technology 29:10, 4281. [CrossRef] 7. Li Sun, Wei Min Huang, Haibao Lu, Kok Jiak Lim, Ye Zhou, Tao Xi Wang, Xiang Yang Gao. 2014. Heating-Responsive ShapeMemory Effect in Thermoplastic Polyurethanes with Low Melt-Flow Index. Macromolecular Chemistry and Physics 215:10.1002/ macp.v215.24, 2430-2436. [CrossRef] 8. Wen Yang, Haibao Lu, Wei Huang, Hang Qi, Xue Wu, Ke Sun. 2014. Advanced Shape Memory Technology to Reshape Product Design, Manufacturing and Recycling. Polymers 6, 2287-2308. [CrossRef] 9. Nikolaus Fritzsche, Thorsten Pretsch. 2014. Programming of Temperature-Memory Onsets in a Semicrystalline Polyurethane Elastomer. Macromolecules 140715154816002. [CrossRef]

Shape memory technology for active assembly ...

Shape memory technology for active assembly ...

Suggest Documents

Super-active shape-memory alloy composites

Shape-memory properties of magnetically active triple-shape ...

Shape-memory properties of magnetically active triple-shape ...

Component assembly with shape memory polymer fastener for ...

A shape-memory scaffold for macroscale assembly of functional

Regularized Active Shape Model for Shape Alignment

Shape-memory polymers as a technology platform for ...

Exploring Shape Memory Alloys

Shape-memory NiTiNb foams

Shape-Memory Polymers

Fractal Active Shape Models

Multi-Shape - Hierarchical Active Shape Models

Regularized Active Shape Model for Shape Alignment - Google Sites

Regularized Active Shape Model for Shape Alignment - Google Sites

MATERIAL TESTING OF SHAPE MEMORY POLYMERS FOR ...

SmartFlex NiTi Wires for Shape Memory Actuators

Shape Memory Alloy Resetable Spring Lift for

Mechanically Strong Shape Memory Polyurethane for

Shape Memory Materials for Biomedical Applications - Research

Shape Memory Polymer Foams for Biomedical

Polymer Assessment for Magnetic Shape Memory

Industrial Applications for Shape Memory Alloys - Memry

Phase Transformation Temperatures for Shape Memory ... - CiteSeerX

Combining Active Shape Models and Active Appearance Models For