rapid development of complex shaped customized products

TECHNICAL PAPER

Rapid development of complex shaped customized products

Mushtaq Ahmad • Nasir Hayat • Fiaz Hussain Shah

Received: 21 July 2013 / Accepted: 25 April 2014

� The Brazilian Society of Mechanical Sciences and Engineering 2014

Abstract In this work, two complex-shaped products

have been reverse engineered through rapid prototyping

(RP). First product is a single unit with a number of

complex features while the second product has sub-parts to

be assembled together. These sub-parts have various

complexities. One sub-part will frequently be in motion.

Target points are set on complex features of the scanned

3D point data to measure deviations of generated surface

models from scanned data and subsequently from physical

models. Two layer-by-layer manufacturing systems, i.e.

one employing ceramic powder-based 3D printing and

other fused deposition method have been used to develop

RP models of complex shapes. Suitability of the process for

complex-shaped prototypes has been discussed and rec-

ommendations have been made for parameter settings and

suitable process. Moreover, economic analysis has also

been performed with an objective to minimize the devel-

opment time and cost.

Keywords Reverse engineering � Rapid prototyping �Complex shapes � Product development cycle � Time-to-

market � Customized products

1 Introduction

The customized products are being developed and used in

the fields of automobiles, electronics and biomedical

implants. With the changing socio-economic scenario, the

demand for customized products is increasing. On one

hand, the customized products are expensive and on the

other hand, the product delivery time is excessively longer.

In the biomedical field, there is a pressing need to shorten

the product delivery time in case of emergency. This can be

achieved by minimizing the development time of the cus-

tomized implant. The developments in reverse engineering

(RE) and rapid prototyping (RP) may be helpful in mini-

mizing the development cycle time and lowering the fixed

cost, thus leading towards customized products at afford-

able price [1–4]. A large number of RP techniques are

available in the market but the most commonly used rapid

prototyping/rapid manufacturing techniques are stereo-

lithography (SL), fused deposition modeling (FDM),

selective laser sintering (SLS), three-dimensional printing

(3DP), laminated object manufacturing (LOM) and ink-jet

printing (IJP) [5–7]. Applications of RP techniques include

development of models for concept presentation, design

verification, rapid tooling (RT) and direct manufacturing of

parts [5–9]. The prototype models are being used as a

diagnostic aid in surgery [10]. The performance of above-

mentioned RP systems varies and the accuracy with which

the intricate details and complex features can be repro-

duced remains the focus of attention during the selection of

a process for particular application. The accuracy (or

dimensional error) in RP model depends upon a range of

technique-specific factors and needs to be investigated in a

systematic way [11–14]. There may be errors associated

with every stage during RP process from acquisition of

point cloud data till manufacturing and finishing processes

regardless of technique used.

Selective laser sintering (SLS) rapid prototyping is

dimensionally more precise technique in comparison to

3DP as concluded by Silva et al. [15] in their recent study

on dry skull. Reported mean dimensional errors for SLS

Technical Editor: Fernando Antonio Forcellini.

M. Ahmad � N. Hayat (&) � F. H. Shah

Faculty of Mechanical Engineering, UET, Lahore, Pakistan

e-mail: [email protected]

123

J Braz. Soc. Mech. Sci. Eng.

DOI 10.1007/s40430-014-0185-4

and 3DP models as compared to dry skull are 2.10 and

2.67 %, respectively. Also, the anatomical details were

reproduced more accurately with SLS technique. However,

3DP is advantageous for faster model build time and has

lower cost. An average dimensional deviation of 0.56 %

between original dry skull and RP model fabricated with

SL technique has been reported in [16]. To evaluate the

suitability of SL technique for surgical planning in dental

and craniofacial surgery, Nizam et al. [17] compared four

dry skull RP models with respective original dry skulls and

obtained an overall percentage difference of 0.08 % with a

standard deviation of 1.25 %. Comparison of three differ-

ent studies shows that SL technique, even with different RP

machines, has better dimensional accuracy as compared to

SLS and 3DP techniques, respectively. Ibrahim et al. [10]

compared SLS, 3DP, and PolyJet rapid prototyping tech-

niques based on dimensional accuracy and ability to

reproduce mandibular anatomy. They have reported SLS as

the most precise technique in dimensional perspective in

their particular study. The reported mean dimensional

errors are 1.79, 2.14 and 3.14 % for SLS, PolyJet and 3DP,

respectively. Ibrahim et al. [10] further highlighted that

anatomical details can more accurately be reproduced

employing PolyJet technique as compared to SLS and 3DP

techniques, respectively. In a similar study, Safira et al.

[11] obtained a mean discrepancy of 3.78 % for different

measurements made on dry mandibles and their respective

RP models fabricated with 3DP technique. This study

further strengthens the conclusion of Ibrahim et al. [10]

regarding the least dimensional accuracy of 3DP technique

as compared to SLS and PolyJet techniques. However, for

assisting in mandibular reconstruction 3DP has advantages

of greater accuracy, faster build time and lower cost over

SL technique as discussed by Cohen et al. [18]. For

auricular prosthesis, fused deposition modeling (FDM) RP

system showed better dimensional accuracy for larger

features as compared to ink-jet printing (IJP) system [19].

Nevertheless, IJP process showed greater dimensional

accuracy to capture fine details and acquire improved

surface finish. Subburaj et al. [19] further highlighted that

FDM is comparatively cost-effective system. Noy [20]

showed that FDM process results in higher average surface

roughness and delivers poor surface details as compared to

SL and IJP processes. However, FDM process delivered

better dimensional accuracy for simple and larger features

as compared to SL and IJP processes. Childs et al. [21]

compared the performance of four different RP techniques

[stereo-lithography (SL), selective laser sintering (SLS),

fused deposition modeling (FDM) and laminated object

manufacturing (LOM)] based on linear accuracies, geo-

metric tolerances, resolution, repeatability, ability to man-

ufacture free-form surfaces, filets and draft angles. Childs

et al. [21] ranked techniques based on their overall

performances with respect to the size of different features

and concluded that for features below than 5 mm, stereo-

lithography (SL) process performs better than SLS, LOM

and FDM techniques, respectively. For medium-scale fea-

tures (20–25 mm), the techniques showed similar perfor-

mance. For large-size features (up to 240 mm), selective

laser sintering (SLS) is better than the others.

It can be summarized that for the same part geometry,

different RP processes will yield different dimensional

accuracy, surface finish, build time, detailing and

mechanical properties. Also, for parts with different

geometries, same RP technique delivers different perfor-

mances with respect to various performance parameters.

Moreover, other than the process specific factors, layer

thickness is a factor that has an effect on the quality, build

time and cost of the prototype from all RP processes to

varying degree depending upon the RP process. Reduction

in layer thickness improves surface quality but increases

the prototype build time [22, 23]. Therefore, selection of

same layer thickness across different RP techniques being

compared will enhance the reliability of the results of the

study. However, the reported work mainly focuses on the

biomedical field. Also, only single-unit product was con-

sidered to evaluate the performance of various RP tech-

niques, except in [20]. Noy [20] considered the assembly of

two round hollow parts with internal and external threads.

No work has been reported in which assembly of a number

of curved geometry sub-parts and a part in motion through

slots, ribs, and protrusions has been considered. Thus,

assembly considered in the present work is relatively

complex and demands for more dimensional accuracy of

sub-parts as compared to [20].

In this work, an experimental investigation has been

carried out to compare FDM and 3DP and to select suitable

technique for intricate details, complex features and sub-

assembly having motion. The two techniques have been

compared by employing same layer thickness. Moreover,

linear measurements on landmark features have been made

to quantify the error. Furthermore, surface roughness of

produced models has also been considered.

2 Experimental procedures

Two complex-shaped products namely bald-headed doll

face (subsequently Compshprod-I) [24] and ergonomically

designed computer mouse (subsequently Compshprod-II)

[25, 26] have been selected (Table 1) for the present study

with an objective to develop customized complex products

with minimum time and cost. It is clear from Table 1 that

both products have varying degree of complex features, i.e.

rapid changes in contours, sudden thin sections, increased

number of features per unit surface area (ear, nose and lips)


123

and hollow sections. Compshprod-I as shown in Fig. 1 is a

single unit, whereas Compshprod-II has various sub-parts

to be assembled upon development. Moreover, Compsh-

prod-II also has a rotating sub-part and a part which will be

frequently pressed.

As a first instance, prototype models of Compshprod-I

were produced with fused deposition modeling (FDM) and

plaster powder-based 3D printing (3DP) methods. Subse-

quently, based on the findings of models of Compshprod-I,

prototype model of Compshprod-II was produced with

plaster powder-based 3D printing (3DP) method only.

2.1 Materials and methods

HTS-300 (subsequently Sys-I) and Spectrum Z-510 (sub-

sequently Sys-II), shown in Fig. 2b, c, have been employed

to develop prototype models. Both systems build products

layer by layer from a series of virtual cross-sections from

Table 1 Complex-shape

products and their featuresS. No. Complex-shape product

(Compshprod)

Features Remarks

1 Bald-headed doll face

(Compshprod-I)

Lips, nose, ears, facial features Single unit

Bald headed

No beard, no eye brow

2 Ergonomically designed computer

mouse (Compshprod-II)

Curves, steps, valleys, ridges,

rotating parts, minor impressions

on wheel-like knurling,

graduation, etc.

With sub-parts to be

assembled

Names of parts

(a) Bottom casing

(b) Main body

(c) Left-click cover and

right-click cover

(d) Top casing

(e) Scroll wheel

(a) (b) (c) (d)

(e) (f) (g)

Various curves

Fig. 1 Different views of physical model of Compshprod-I showing complex features: a front face, b left-side ear, c right-side ear and various

curves, d back head, e enlarged view of nose, f enlarged view of left ear, g enlarged view of right ear


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CAD models; however, they differ in the basic working

principles. Sys-I is based on fused deposition modeling

(FDM) technique in which filament of a thermoplastic

material such as acrylonitrile butadiene styrene (ABS) is

squeezed out a fine-heated nozzle (shown schematically in

Fig. 2a) that is deposited in layers to build the part. Quality

of the final product depends upon a number of factors such

as orientation of the part, size and complexity, layer

thickness, material, speed and feed rates. Sys-II is based on

powder-based 3D printing (3DP) technique in which a

liquid binder is printed into the powder through a head

containing multiple nozzles in a layer-by-layer fashion.

Accuracy of the prototype is affected by a number of

factors that include part orientation, size and complexity,

powder and binder materials, layer thickness, saturation

level and infiltration method. Materials employed along

with technique and specifications of both systems are

presented in Table 2. Specifications show the differences in

various parameters of two systems. The products devel-

oped with Sys-II were submerged in an infiltrant (Z-Bond

101TM) solution and cured for a sufficient time to enhance

strength and life.

(a) (b) (c)

Cooled Platform

Nozzle

liquifier

ABS FilamentDrive wheels

Fig. 2 RP systems employed during current study: a schematic of FDM process, b HTS-300 [27], c Spectrum Z-510 [27]

Table 2 RP systems, materials and methods used in present study

S.

No

RP system Materials used Techniques Specifications

1 HTS-300

(Sys-I)

Acrylonitrile butadiene styrene (ABS)

(Mat-I)

Fused deposition modeling (FDM)

prototype technique

Max. Speed = 100 mm/s,

Accuracy = ±0.2 mm,

Layer thickness = 0.1 mm

Auto generate support

Slicing software

Power = 6 A

2 Spectrum

Z-510

(Sys-II)

Plaster Powder(ZP-131) Binder (Zb-60) and

Infiltrant (Z-Bond-101TM)

(Mat-II)

Powder-based 3D printing (3DP)

technique

Build speed = 2–4 layers/

min

Layer thickness = 0.089-

0.203 mm

Resolution = 600 9 540 dpi

No. of print heads = 4

No. of jets = 1,216

Power = 6.2 A


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2.2 Procedure

Procedure adopted to develop rapid prototype (RP) models

of complex-shaped products through reverse engineering

(RE) has been outlined in Fig. 3. 3D point cloud data have

been obtained with 3D laser scanner FARO Platinum

FaroArm (V3 ScanArm 6ft) which has an accuracy of

±0.061 mm. The complex features as depicted in Fig. 1

are identified and target points are set on different features

in 3D point cloud data for alignment and statistical analysis

to ensure the accuracy of 3D surface model to be gener-

ated. The point cloud data are filtered and sampled to

reduce noise and number of data points. The surface

models are generated by employing polygonal surface and

curved surface for Compshprod-I and Compshprod-II,

respectively. After ensuring that deviation in the complex

features is within acceptable range, i.e. no loss of feature

and no change in shape, *.stl files are generated. All above

steps including target points setting, data filtering, data

sampling, polygonal and curved surface generation, post

Fig. 3 Methodology adopted for reverse engineering of complex-shape products


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processing and statistical analysis for both of the products

have been performed with Geomagic Studio12 Software.

However, curved surface model of Compshprod-II was

imported into Pro/ENGINEER software to extrude parts to

the desired thickness, create protrusions and other such

features. Necessary changes to the size of different parts

were made to ensure proper assembly. To explore the

suitability of method and material keeping in view the

functional requirements for complex-shape products, two

materials ABS and plaster powder employing FDM and 3D

printing system (powder based) respectively have been

utilized.

Preliminary experiments were carried out to select the

suitable parameter settings. During the preliminary exper-

iments it was revealed that different parameters are needed

for intricate parts, i.e. minimum layer thickness with lowest

feed rate for both part and support. The parameter settings

are shown in Table 3.

3 Results and discussions

It is evident from Fig. 3 that same procedure has been

adopted for both products except methodology adopted for

surface model generation. Figures 4 and 5 show the 3D point

cloud data obtained with 3D laser scanner. It is evident from

Fig. 4 that there are clusters of noise present in the complex

features of Compshprod-I. However, point cloud data of

Compshprod-II have relatively low noise with noise in main

body (Fig. 5b) and left- and right-click cover (Fig. 5c) at

edge holes. The scroll wheel (Fig. 5e) of Compshprod-II has

intricate impressions, i.e. knurling with noise at some inner

Fig. 4 3D point cloud data of Compshprod-I showing noise clusters in complex features: a front face, b left-side ear, c right-side ear and various

curves, d back head

Table 3 Parameter settings

Name of product Parameters Remarks

Sys-I (HTS-300) Sys-II (Spectrum Z-510)

Compshprod-I Layer thickness = 0.1 mm

Maximum

acceleration = 1420 mm/s2

Maximum speed = 45 mm/s

Feed rate for part = 34

Feed rate for support = 27

Layer

thickness = 0.1 mm

Bleed compensation

feature not enabled

Saturation level = 85 %

Layer thickness is set same for both processes to

make true comparison for the two RP models. This

is minimum layer thickness for FDM process

Compshprod-II

(a) Bottom casing

(b) Main body

(c) Left-click cover

and right-click cover

(d) Top casing

(e) Scroll wheel

– Bleed compensation

feature not enabled

Saturation level = 85 %

(a) Layer

thickness = 0.1 mm

(b) Layer

thickness = 0.1 mm

(c) Layer

thickness = 0.1 mm

(d) Layer thickness = 0.1 mm

(e) Layer

thickness = 0.089 mm

Minimum layer thickness for scroll wheel is set due

to intricate features (knurling/graduations) on the

part


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Fig. 5 Point cloud data of different parts of Compshprod-II: a bottom casing, b main body, c left- and right-click covers, d top casing, e scroll

wheel

Fig. 6 Finished surface model of generated after polygonal surface for Compshprod-I: a front face, b left-side ear, c right-side ear and various

curves, d back head

Fig. 7 Finished surface model generated after curved surface for Compshprod-II: a bottom casing, b main body, c left- and right-click covers,

d top casing, e scroll wheel

Fig. 8 Target points and

deviation in Compshprod-I:

a target points, b deviation


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portion but remaining part is almost noise free. The noise

needs to be carefully reduced to ensure the accuracy of

complex features. Compshprod-I is without hair (no beard,

no eye brow and bald headed). This was selected to avoid

unnecessary shape. Moreover, due to restriction in layer

thickness hair are difficult to reverse engineer.

Figures 6 and 7 show the surface models obtained from

polygonal surface and curved surface for Compshprod-I

and Compshprod-II, respectively. As a result of close

visual comparison of actual Compshprod-I and Compsh-

prod-II with the respective finished surface model it can be

said that complex features have been reproduced with a

reasonable degree of accuracy. Moreover, no feature is lost

during this process.

The curved surface model was generated for Compsh-

prod-II to compensate for size variation which might result

due to noise reduction. The sub-parts of Compshprod-II are

thin with curved features and some have holes as well. This

led to the formation of saw-toothed shape at edges and

holes due to the presence of noise. To remove saw tooth

shapes, the edges might be smoothened via creating

boundary around the part which in turn would result in

reduction of size of sub-parts. Variation in sizes of sub-

parts could be problematic during the final assembly and

fitting. The problem was overcome by generating patches

on polygonal model and then curves were created (Fig. 7).

These curves can be easily modified as per scale to ensure

proper assembly of sub-parts. In the case of holes, all holes

were filled and created again as per required size.

Figure 8a, b shows the set target points on different

features for alignment and statistical analysis, respectively,

for Compshprod-I. Similar procedure was used for the

statistical analysis of the surface model of Compshprod-II.

Deviations of the surface models from the original 3D

scanned data are presented in Table 4. It is clear from

Fig. 8b that the regions that deviated more are those where

corrections have been made to remove dents and other

imperfections in the model. All other regions deviated

within a range of ±0.339 mm. Such an analysis is helpful

in making early decisions for the acceptance or rejection of

the surface model and for taking necessary actions to

improve the product quality.

Figures 9, 10 and 11 show reverse-engineered models of

Compshprod-I developed through Sys-I and Sys-II and

Compshprod-II developed through Sys-II, respectively. For

the same layer thickness (0.1 mm), Compshprod-I devel-

oped through Sys-I by employing Mat-I has rough surface

as compared to Compshprod-I developed through Sys-II by

employing Mat-II. The reasons behind better surface finish

generated through Sys-II lie with the material as well as

nature of the process itself. There is a room for further

improvements in surface finish and strength as the layer

thickness can be further reduced to the lowest value of

0.089 mm as per specifications of Sys-II. The roughness

values taken with surface texture meter (Surtronic S 25,

Taylor Hobson Precision) for both models of Compshprod-

Table 4 Deviations between surface models and original 3D data

S. No. Product Max.

deviation

(mm)

Average

deviation

(mm)

Standard

deviation

(mm)

1 Compshprod-I ?5.703/

-6.787

?0.056/

-0.040

0.195

2 Compshprod-II

Main body ?1.685/

-3.089

?0.009/

-0.009

0.020

Top casing ?0.040/

-3.024

?0.006/

-0.003

0.006

Bottom casing ?0.162/

-2.605

?0.014/

-0.006

0.020

Left-click cover and

right-click cover

?0.182/

-0.072

?0.018/

-0.006

0.030

Scroll wheel ?2.680/

-1.785

?0.072/

-0.020

0.153

Fig. 9 Different views of RP model of Compshprod-I with Sys-I: a front face, b left-side ear, c right-side ear and various curves, d right ear

enlarged


123

I are given in Table 5. The roughness tests are performed at

three different angles and it is clear from data given that

Compshprod-I (Mat-II, Sys-II) is more smooth than

Compshprod-I (Mat-I, Sys-I). The variations in roughness

values at different angles are because of layered structure

of RP models. As reported in [20], the average roughness

(Ra) values are 26.675 (lm) and 31.25 (lm) measured at

two different angles for Prodigy Plus machine (Stratasys

Inc.) with minimum layer thickness 178 lm based on FDM

technique using ABS material. Surface finish also depends

upon the part orientation, part geometry and measuring

direction. Subburaj et al. [19] concluded that InVision RP

system (polymer-based 3D printing) with acrylic plastic

material gives better surface finish than FDM 1650 system

(Stratasys Inc., USA) using ABS material. The 3D printing

system used is not directly comparable with the powder-

based 3D printing system used in the present work;

Fig. 10 Different views of RP model of Compshprod-I with Sys-II: a front face, b left-side ear, c right-side ear and various curves, d right ear

enlarged

Fig. 11 Different views of RP models of Compshprod-II with Sys-II: a bottom casing, b main body, c left- and right-click covers, d top casing

Table 5 Comparison of roughness of Compshprod-I (Mat-I, Sys-I)

and Compshprod-I (Mat-II, Sys-II)

S. No. Complex-shape product Average roughness values at three

different angles (lm)

Ra Rp Rsm Rz

1 Compshprod-I 20.06 30.6 683 109

Mat-I 4.2 13 265.6 22.3

Sys-I 22.8 32 900 107

2 Compshprod-I 3.9 11.6 314.6 18.6

Mat-II 6.7 22.3 230 39.3

Sys-II 10 25.3 147 54.6

Ra Arithmetic mean of the absolute departures of the roughness

profile from the mean line, Rp maximum profile peak height, Rsm

mean spacing between profile peaks at the mean line, measured

within the sampling length, Rz maximum peak to valley height of the

profile within a sampling length [28]


123

however, both techniques are very close. Thus, it can be

said that FDM process gives higher roughness values than

3D printing system.

Feature details in regions of rapid changes in contours and

increased number of features per unit surface area (ear, nose,

lips and eyes) have not been captured properly in RP model

of Compshprod-I manufactured on Sys-I by employing Mat-

I. Some features even cannot be distinguished as shown in

upper part of right ear (Fig. 9c, d) where curved features are

not visible due to excessive accumulation of fused material.

Experimental results reported in [19, 20] using FDM and

ABS material show an increase in error with a reduction in

size of the features. Moreover, Noy [20] concluded that the

FDM process is not adequate for generating slots below

0.4 mm and ribs below 0.4 mm. Similar trend is apparent in

the present work. The RP model of Compshprod-I developed

through Sys-II by employing Mat-II with binder closely

resembles the actual object with clear feature details.

Moreover, Compshprod-I produced by Sys-I by employing

Mat-I (based on fused deposition method) showed lack of

continuity (disjointed) in layers whenever there is a

D1

D2

D3

D4

D5

D6

Fig. 12 Various dimensions of Compshprod-I

Table 6 Comparison of RP

models with original physical

model (Compshprod-I)

Dimensions

(Fig. 8)

Original physical model

(mm)

Sys-I Sys-II

RP model

(mm)

Difference

(%)

RP model

(mm)

Difference

(%)

D1 62.68 60.71 3.14 60.68 3.19

D2 10.12 9.54 5.73 9.86 2.57

D3 76.83 74.94 2.45 75.00 2.38

D4 60.11 62.21 3.49 62.30 3.64

D5 17.94 17.07 4.85 17.49 2.51

D6 13.56 12.86 5.16 13.24 2.36

Fig. 13 Assembly of Compshprod-II developed with Sys-II


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considerable change in circumference during upward

movement along vertical direction. No such shortcoming was

observed in Compshprod-I RP model developed through

Sys-II by employing Mat-II with binder. Due to this reason,

RP model of Compshprod-II was developed through Sys-II

by employing Mat-II only. It can be attributed to slicing

limitation in FDM process.

Various dimensions (Fig. 12) were measured on original

physical model and then comparison was made with RP

models (Table 6). It is clear from Table 6 that dimensional

accuracy of RP model with Sys-II and Mat-II is within

acceptable limits.

It is clear from Fig. 13 that sub-parts can be easily

assembled which indicates dimensional accuracy of the

produced sub-parts. The knurling/graduation on the scroll

wheel to facilitate grip and avoid slippage has been produced

with minimum layer thickness (0.089 mm). Thus, it can be

said that powder-based layer-by-layer manufacturing method

is more appropriate for reverse engineering of complex-

shape products of small size with low weight. Features can be

modified during surface model generation to customize the

products. In this way, development cycle of customized

complex-shape products can be shortened. Finally, virtual

model can be developed and after analysis RP system can be

used to make a mold. However, this is limited to material and

one such example has been reported by [19].

It is evident from Table 7 that layer-by-layer manufac-

turing through fused deposition method (FDM) took longer

time (20� h) as compared to ceramic powder-based layer-

by-layer manufacturing (5� h) to produce same complex-

shape product. On the other hand, variable cost (material and

electricity) as well as fixed cost (initial cost of machine) are

higher for ceramic powder-based layer-by-layer manufac-

turing to produce customized complex-shape products.

4 Conclusions

The present study was carried out to explore the suitable

method and material for the development of complex-shape

products with the dual objectives of minimization of product

development cycle time and cost. The speed of fabrication

processes, reproduction of intricate features, incorporation of

customized features, surface quality of produced models,

material and method selection and process shortcoming/

limitations have been discussed in detail. Following con-

clusions can be drawn from the present study.

1. Time-to-market plays a crucial role in the successful

marketing of customized products. This can be

successfully reduced by minimizing the product

development time.

2. Setting of target points accompanied by statistical

analysis of generated surface models is helpful in

improving product quality by ensuring dimensional

accuracy within acceptable limits.

3. RE of complex shapes can be accomplished if suitable

material and method are selected. Ceramic-based layer-

by-layer manufacturing is appropriate method to produce

customized complex-shape products with small size. FDM

cannot capture complex feature details like rapid changes

in contours, increased number of features/area, etc.

4. The results of roughness tests show that ceramic-based

layer-by-layer manufacturing has better surface finish

as compared to fused deposition method.

5. The parameter settings play a significant role in the

reproduction of intricate features, rotating parts, parts

to be assembled and surface finish during RE of

complex-shape products.

6. Fixed and variable costs are higher for ceramic-based

layer-by-layer printing as compared to FDM layer-by-

layer manufacturing; however, time consumed is

considerably low in case of earlier system.

Acknowledgments The authors acknowledge the support of

Department of Industrial and Manufacturing Engineering, UET La-

hore in carrying out the experimental work.

References

1. Hosni YA, Harrysson OLA (2002) Design and manufacturing of

customized implants. IERC 2002, Orlando, Florida, USA, May 19–21

Table 7 RP models and economic analysis

S. No. Complex-shape product Material Method Materialconsumed (g)

Time (h)

1 Compshprod-I Acrylonitrile butadiene styrene (ABS)

(Mat-I)

Layer-by-layer manufacturing through FDM

Sys-I

140 g 20�

2 Compshprod-I (i) Plaster Powder (ZP-131)

(ii) Binder (Zb-60)

(iii) Infiltrant (Z-Bond-101)

(Mat-II)

Layer-by-layer manufacturing through powder-based printing 3DP

Sys-II

(i) 230 gm

(ii) 65.7 ml

(iii) 5 g

5�

3 Compshprod-II (i) 122 g

(ii) 43 ml

(iii) 6 gm

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