An Investigation on Punching Process of Circular Hole on

Commercially Pure Titanium Sheet

Yani Kurniawan

, Muslim Mahardika

, Suyitno

, Muhammad Yaser

Department of Mechanical Engineering, Universitas Pancasila, Jakarta, Indonesia

Department of Mechanical and Industrial Engineering, Universitas Gajah Mada, Yogyakarta, Indonesia

Department of Electro Engineering, Universitas Pancasila, Jakarta, Indonesia

muhammadyaser@univpancasila.ac.id

Keywords: Titanium, Puching, Circular Hole

Abstract: In this study, an experimental study was carried out to the investigation on punching process of the circular

hole on commercially pure titanium sheet by a hydraulic punch machine. Sheared face geometry and hardness

distribution resulted from punching process were investigated. The commercially pure titanium sheet with

0.4, 0.5 and 0.6 mm thickness were used in the experiment. The diameter of the punch is 1.7 mm and clearance

of punch-die is 7.5%. In the experiment, punch speeds used were 1 and 6.5 mm/s. The results show that

punching process on the CP-Ti sheet can increase surface hardness, however hardness distribution on the

punched hole are uneven. Hardness distribution on punched hole shows as getting closer with a sheared edge,

the surface hardness is bigger. Punch velocity and material thickness increases, burnish height increases, while

fracture height decreases.

1 INTRODUCTION

The punch process on commercially pure titanium

sheets (CP-Ti) is developed to fabricate medical

components and equipment. One of the components

and medical devices that can be fabricated using a

punch process is a jawbone joint plate. In the

manufacture of jawbone joint plates, the punch

process is applied to fabricate bolt holes.

Characteristics of punched holes are influenced by

process parameters. Punch speed and material

thickness will influent the characteristics of punched

holes.

The punch speed increases, surface roughness of

the burnish decrease on commercially pure aluminum

material (M. Gotoh and M. Yamashita, 2001). In

brass material, increase punch speed with ∆v = 47.5

mm/s to decrease surface roughness of 0.16 µm and

increases burnish height of 28% (J. Xu, B. Guo,et all,

2012), while increase punch speed with ∆v = 2400

mm/minute to decrease burr height of 18.2% (I.

Ristiawan & M. Mahardika,2017) In copper material,

increase punch speed with ∆v = 2500 mm/minute to

increase burnish height of 7.3% (D. Z. Lubis & M.

Mahardika, 2016), while according to Meng et al.

(2015) increase punch speed does not always increase

surface hardness (B. Meng, M. W. Fu, C. M. Fu & J.

L. Wang,2015).

The material thickness increase of 0.5 mm

becoming 0.6 mm causing burr height decrease of

0.03% on stainless steel materials, but material

thickness increase of 0.5 mm become 0.6 mm on steel

material causing decrease of 0.05% burr height (E. A.

Momani & I. Rawabdeh,2015). The punching process

on double layer sheet with low temperature co-fired

ceramic (LTCC) and polyethylene terephthalate

(PET) material has been done, the results showed that

punch force in hole manufacture at 40 μm material

thickness smaller than at 100 μm material thickness

(S. H. Rhim, S. W. Baek & S. I. Oh, 2006) causing

the material thickness increase and burr height

decrease (S. H. Rhim, S. Y. Shin, B. Y. Joo & S. I,

2006).

The punch velocity and material thickness have an

influence on the characteristics of different punch

holes on each material. However, in the manufacture

of components and medical equipment especially

jawbone plate, the effect of punch velocity and

material thickness needs to be investigated to produce

the appropriate characteristics of the criteria in the

manufacture of jaw bone plates. This paper aims to

investigate the punching process of the circular hole

Kurniawan, Y., Mahardika, M., Suyitno, . and Yaser, M.

An Investigation on Punching Process of Circular Hole on Commercially Pure Titanium Sheet.

DOI: 10.5220/0009006500670071

In Proceedings of the 7th Engineering International Conference on Education, Concept and Application on Green Technology (EIC 2018), pages 67-71

ISBN: 978-989-758-411-4

on commercially pure titanium sheet. Effect of the

difference punch velocity and material thickness on

the characteristics of the punched hole in the

commercially pure titanium sheet was investigated.

2 MATERIAL AND METHODE

The testing material used was commercially pure

titanium sheet with hardness of 160 VHN. Material

thickness used were of 0.4, 0.5 and 0.6 mm. Punch

type used was a single shear angle with the shear

angle of 17° and punch diameter 1.7 mm. Punch

material used was high-speed steel (HSS) with

hardness of 63 HRC. Punch tool was manufactured

by grinding machine with a punch-die clearance of

7.5%. The schematic of the testing apparatus used as

shown in Figure 1. Punching machine used was

hydraulic drive with force capacity of 100 ton. Punch

speed for testing was 1 dan 6.5 mm/s.

Figure 1: The schematic of the testing apparatus.

Characteristic of punched hole shown in Figure 2.

Rollover, burnish, fracture and burr height were

measured using dino-lite digital microscope of

AM4515 series. Surface hardness was measured with

BUEHLER Vickers microhardness test with 100-

gram load and 15 s load time. The position of surface

hardness testing shown in Figure 3.

Figure 2: Characteristic of the punched hole.

Figure 3: The position of surface hardness testing,

with unit of µm.

3 RESULTS AND DISCUSSION

The relationships between material thickness and

punch velocity on the rollover, burnish, fracture and

burr depth are given in Fig. 4. As the material

thickness increases, burnish and fracture depth

increases. As the punch velocity increases, rollover,

fracture and burr depth decreases while burnish depth

increases on the material thickness of 0.4 and 0.5 mm.

However on the 0.6 material thickness, punch

velocity increases, rollover and fracture depth

decreases while burnish and burr depth increases.

This result occurs due to impact load on the 1 mm/s

punch velocity smaller than 6.5 mm/s punch velocity,

where low impact load cause longer elastic

deformation and shorter plastic deformation. As the

elastic deformation increases, rollover depth

increases. As the plastic deformation increases,

burnish depth increases. Thus to increase burnish

depth can increase punch velocity.

The relationships between material thickness and

punch velocity on the surface hardness are given in

Figure 6-7. The result of the punching process on

material thickness 0.4 to 0.6 mm shows the punching

process on the CP-Ti sheet can increase surface

hardness, however hardness distribution on the

punched hole are uneven. Figure 5 shows the

relationships between material thickness and punch

velocity on the surface hardness on 0.4 mm material

thickness. Hardness distribution on punched hole

shows as getting closer with a sheared edge, the

surface hardness was got bigger. As burnish region

experienced the largest increase in surface hardness

compared with rollover and fracture region. The

highest hardness in the rollover region at a distance of

50 µm from the sheared face of 173.96 VHN on the 1

mm/s punch velocity and 243 VHN on the 6.5 mm/s

punch velocity. The highest hardness in the burnish

region at a distance of 50 µm from the sheared face

of 226.7 VHN on the 1 mm/s punch velocity and

266.5 VHN on the 6.5 mm/s punch velocity. The

highest hardness in the fracture region at a distance of

50 µm from the sheared face of 225.13VHN on the 1

EIC 2018 - The 7th Engineering International Conference (EIC), Engineering International Conference on Education, Concept and

Application on Green Technology

mm/s punch velocity and 231.8 VHN on the 6.5 mm/s

punch velocity.

Figure 6 shows the relationships between

material thickness and punch velocity on the surface

hardness on 0.5 mm material thickness. As burnish

region experienced the largest increase in surface

hardness compared with rollover and fracture region.

The highest hardness in the rollover region at a

distance of 50 µm from the sheared face of 165.73

VHN on the 1 mm/s punch velocity and 178.30 VHN

on the 6.5 mm/s punch velocity. The highest hardness

in the burnish region at a distance of 50 µm from the

sheared face of 227.51 VHN on the 1 mm/s punch

velocity and a distance of 100 µm from the sheared

face of 248.82 VHN on the 6.5 mm/s punch velocity.

The highest hardness in the fracture region at a

distance of 50 µm from the sheared face of 222.03

VHN on the 1 mm/s punch velocity and 223.57 VHN

on the 6.5 mm/s punch velocity.

Figure 7 shows the relationships between material

thickness and punch velocity on the surface hardness

on 0.5 mm material thickness. As burnish region

experienced the largest increase in surface hardness

compared with rollover and fracture region. The

Figure 4: The relationships between material thickness and punch velocity on the: (a) rollover, (b) burnish, (c)

fracture and (d) burr depth.

Figure 5: Hardness distribution on the rollover, burnish and fracture region on 0.4 mm material thickness with

punch velocity: (a) 1 mm/s dan (b) 6.5 mm/s.

An Investigation on Punching Process of Circular Hole on Commercially Pure Titanium Sheet

highest hardness in the rollover region at a distance of

50 µm from the sheared face of 165.73 VHN on the 1

mm/s punch velocity and 178.30 VHN on the 6.5

mm/s punch velocity. The highest hardness in the

burnish region at a distance of 100 µm from the

sheared face of 243.44 VHN on the 1 mm/s punch

velocity and a distance of 50 µm from the sheared

face of 260.12 VHN on the 6.5 mm/s punch velocity.

The highest hardness in the fracture region at a

distance of 50 µm from the sheared face of 213.81

VHN on the 1 mm/s punch velocity and a distance of

100 µm from the sheared face of 200.66 VHN on the

6.5 mm/s punch velocity.

4 CONCLUSION

Punching process on the CP-Ti sheet can increase

surface hardness, however hardness distribution on

the punched hole are uneven. The biggest increase of

surface hardness occurs in the burnish region. Punch

velocity increase, surface hardness and burnish

height increase on the other hand fracture height

decreases. Material thickness increase, burnish height

and fracture height increase.

ACKNOWLEGMENT

This research was supported by Government,

Universitas Gadjah Mada and University of

Pancasila. The machine components were fabricated

in Gadjah Mada laboratory, PT. YPTI and supported

by many staff there. Their help are gratefully

acknowledgment

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Figure 6: Hardness distribution on the rollover, burnish and fracture region on 0.5 mm material thickness with

punch velocity: (a) 1 mm/s dan (b) 6.5 mm/s.

Figure 7: Hardness distribution on the rollover, burnish and fracture region on 0.6 mm material thickness with

punch velocity: (a) 1 mm/s dan (b) 6.5 mm/s.

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Application on Green Technology

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An Investigation on Punching Process of Circular Hole on Commercially Pure Titanium Sheet