cetak plastik ok

7/21/2019 Cetak Plastik OK

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Cetak Plastik Cetak Plastik

Plastics Injection MoldingPlastics Injection Molding



Sejarah Plastik



Jenis

plastik/polimer

Thermoset Thermoplastic



Sifat Umum: tahan lama, keras, tangguh, ringan.

Thermoset

Contoh:

Polyester: lacquers, varnishes, perahu, furniture

Epoxy dan Resin: lem, coating untuk electrical circuits,

composite: fiberglass baling-baling helicopter, perahu



Elastomer

Sifat Umum: thermoset, seperti sifat karet

Contoh:

Polyurethan: matras, cushion, insulation, mainan

Silicon: sarung tangan medis, masker, seal



• umumnya thermosetting polymer

• mold dipanaskan dan ditutup dengan tekanan

• Plastik mengalir kedalam rongga

• perlu finishing

Peralatan makan, handel ketel, ski,

Casing untuk circuit breaker, sol sepatu,fiber-reinforced composite



Sifat Umum: suhu leleh rendah, lunak, flexible

Contoh:

Polyethylene: packaging, electrical insulation, milk and waterbottles, packaging film

Polypropylene: carpet fibers, automotive bumpers, microwavecontainers, prosthetics

Polyvinyl chloride (PV: electrical cables cover, credit cards, carinstrument panels

Polystyrene: disposable spoons, forks, !tyrofoam"!crylics (P""!: polymethyl methacrylate: paints, fake fur,

plexiglassPolyamide (nylon#: textiles and fabrics, gears, bushing andwashers, bearings

PET (polyethylene terephthalate: bottles for acidic foods like #uices,food trays

PT$E $polytetrafluoroethylene: non-stick coating, %ore-&ex"

$raincoats, dental floss

Thermoplastik



Proses Pen%olahan Plastik



Extrusion

pelletsopen cross-sections (channels) closed cross-sections (tubes, pipes) pelletsopen cross-sections (channels) closed cross-sections (tubes, pipes)



&lo' moldin%

heated glass

3-piece mold

(a) The hollow piece of heated glass (parison)

is first created by a blow mold

(see text-book Fig 1!"#)

(b) The mold is put together

(c) $lunger and hot air push the

glass up

(d) %ot air blows the glass out towards

the mold surface

(e) &old comes apart, bottle is remo'ed

heated glass

3-piece mold

(a) The hollow piece of heated glass (parison)

is first created by a blow mold

(see text-book Fig 1!"#)

(b) The mold is put together

(c) $lunger and hot air push the

glass up

(d) %ot air blows the glass out towards

the mold surface

(e) &old comes apart, bottle is remo'ed



Thermoormin%

Lembaran plastik Pemanasan (lunak) Dicetak sesuai bentuk



Vacuum thermoormin%



ompression and Transer "oldin%

compression molding

transfer molding

$bentuk lebih rumit



)njection "oldin%

- Paling banyak digunakan, penting, dan ekonomis.



Skematik ProsesSkematik Proses ** "esin"esin

+

' !ource: http:((www.idsa-mp.org(proc(plastic(in#ection(in#ection)process.htm

+

Skematik mesin )njection moldin% thermoplastik



Pen%aruh suhuPen%aruh suhu moldmold dandan

tekanan terhadap penyusutantekanan terhadap penyusutan

0.030

0.000

0.010

0.005

0.015

0.020

0.025

100 120 140 160 180 200 220 240

Mold Temperature (F)

LP! PP

"#lo$ 6%6

PMM&

&'etal

( ) r i $ k a *

e

0.030

0.000

0.010

0.005

0.015

0.020

0.025

( ) r i $ k a * e

6000

8000

10000

12000

14000

16000

Pressure o$ i$+e'tio$ plu$*er(psi)

&'etal

LP!

"#lo$6%6

PP

,it-o,

18000

PPa'ross

-o,

PMM&



)njection "oldin%:

&entuk/%eometri "old

*omponen utama:

mold pieces $menentukan bentuk(geometri produk,

sprue, gates, runners, vents, ejection pins,cooling system



)njection "oldin%: ,-piece and .-piece molds



)njection "oldin%:mold den%an core er%erak dan side-action cam

- +ila bentuk(geometri ada undercuts



Cait#Core

/ompo$e$ mold u$tuk /ompo$e$ mold u$tuk

produk 'a$*kir plastik produk 'a$*kir plastik

u$$erate

"ole

prue



u$$er

Part

Cait#

"ole

Part

Cait#

/$o

(tripperplate

u$$er

Part

Cait#

"ole

u$$er

Part

Cait#

"ole

u$$er

Part

Cait#

"ole

Part

Cait#

/$o

(tripperplate

Part

Cait#

/$o

Part

Cait#

/$o

(tripperplate

u$$er

Part

Cait#

"ole

u$$er

Part

Cait#

"ole

Perancan%an injection mold : mold in action

[source: Lec notes, Prof T. Gutosky, MT!



Perancan%an injection mold : itur-itur umum

[source: """.i#sa$mp.or%!



(a) hut-off hole

no side action re*uired

(b) +atch


(c) ,ngled +atch

ide action cam re*uired

(a) hut-off hole


(b) +atch


(c) ,ngled +atch

ide action cam re*uired

Perancan%an injection mold : itur-itur umum



0asar perancan%an produk injection moldin%

asar utama:$i aliran plastik ke seluruh bagian cavity sebelum mengeras$ii penyusutan plastik dalam lubang penyusut

Panduan (1#

sahakan penampang(ketebalan seragam seluruh bagian produk

ow: use of ribs(gussets

/source: %0 plastics: 1n#ection 2olding esign %uidelines3



Panduan (,# indari penampang yang tebal

/source: %0 plastics: 1n#ection 2olding esign %uidelines3




Panduan (.# 4okasi gate menun#ukkan weld line

weld lines

' !ource: http:((www.idsa-mp.org(proc(plastic(in#ection(in#ection)des




eld li$e i$k mark eld li$e i$k mark

& 'ource: ttp:""" i#sa mp or%procplasticin*ectionin*ection #esi%n tm

eld li$e

&lira$ kedalam Mold

ate

Produk #* suda +adi

i$k mark Pera$'a$*a$ ris u$tuk

memi$imalka$ si$k mark

cetak plastik ok

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