4
STEP 13
Process StaPgreocess Stage
SPwreitscsh onbuPMtotoownuelrdsiInuNgpJEMpClyaTcIoOhfiNnMeinoi Innjecmtioonnitor
display and set:
1.INJ: SETUP PRESS at 60 bar,
Position at 18
2. Set up Press at 30 bar,
Position at 5
3. HOLD PR: Set 20 bar,
HOLD TIME as 2.0 Sec
46
4
Smooth and
Creamy
STEP 14
Process StagPeroces
s Stage
Switch on Power supply of Mini Injection
Press buttonMINoJuElCdTinIOg NMasochtihnaet the
cylinder move to the m
inimum position
Make sure the process until smooth and
creamy material is achieved
47
4
STEP 15
Process Stage
PrSowcietcshs oSntaPgoewer supply of Mini Injection
Moulding Machine
Press button SEMI AU
TO to switch mode
machine to operate in semi auto.
This makes slow mould close, mould
clamping, barrel charge, inject, retract,
mold open and eject pin trigger.
48
4
Mould still open Mould Close
STEP 16 End Product
Key Chain Malaysia
Process Stage
ProceSswsitSchtaognePMoowuelrdsinugpMplyacohfinMeini Injection
Press both button
green colour 49
simultaneously and material melted
injected to barrel and mold to produce
POLITEKNIK MALAYSIA key chain.
4
Injection unit upward
STEP 17Process Stage
ProcSewsitscShtoangePower supply of Mini Injection
Moulding Machine
Press button SUCK BA
CK to pull the
injection unit upward
50
4
Remaining stick on sprue hole or nozzle
STEP 18
Process Stage
Process Stage
AreftmeremSwbcieotcrmhtpoolnertePinMmogowouveelrdpsiarnulolgpd
uMpunlcyautciosohefnidnM, eimniapItlneejraeisacetl,ion
open the hopper gate to collect all unused
material, perform purging until no material
left inside the barrel, clean/ clear out
remaining material stick on sprue hole or
nozzle, make sure nozzle is set back to
sprue of mold (downward), clamping the
mold and switch off machine.
51
4
FINAL PRODUCT
Compare your final product, what do you have? .
Show your Key Chain Malaysia in Lab Report.
52
4
i. What button to press if want to perform Mould Close?
ii. What are the buttons to press if want to produce a plastic Key
Chain (Product) after setting up manual parameters.
Student can check answer by peer review
53
5 MAINTENANCE OF MACHINE
On completion of this course, students should be able to:
i. Explain basic maintenance of machine
54
5 MAINTENANCE OF
MACHINE
1.Make sure hydraulic oil level is always within max level
(Check per week)
2.Lubricate each of the cylinder columns.
3.Clean each of the cylinder column as dust will accumulate
on the columns.
4.Make sure barrel is free of material before shutting down
machine
5.Remove any material that sticks to sprue of mold or nozzle
before shutting down machine.
6.Always keep the mold close and nozzle at mold to prevent
dust collected.
7.Connect cooling water to hydraulic unit, if any, to prolong
machine life.
55
5
Process Stage
Put oil along the cylinder column to make
sure the mould able to open by move up
and move down to close easily
56
5
Process Stage
Make sure to use the correct oil
viscosity for hydraulic system AWS 68
57
5
Process Stage
Make sure to use wood to lay unused
mould
58
5
Make sure the hydraulic tank oil level
AWS 68 or equivalent, reach until
indicator position for JT150 80L
59
5
Material Temperature setting
ABS 190-270 oC
ACRYLIC 220-250 oC
HDPE
o
210-270 C
LDPE 180-240 o C
POLYCARBONATE 280-320 oC
Polypropelne (PP) 200-280 oC
PLA 120-180 oC
Table 2: Types of material and range of melting temperature
Setting
Table 2 shows types of material and
range of melting temperature which is
recommended by vendor and for
references
60
5
Settingup Mold
MOVMOULD: current actual position
of mold open/close
LOWP: set 1-3 mm higher than MOVMOULD
position when mold clamp
CLOF: set 20-25 mm higher than LOWP;
rapid close mold until desire height
OSL: set 2-5 mm higher than LOWP; slow
opening to desire height other setting
unchanged 61
5
Figure 17 :Mechanical Properties and Chemical
Resistance of plastics
Figure 17 shows the Mechanical
Properties and Chemical Resistance of
plastics
62
5
i. What type of oil grade is this Mini-Injection Moulding used?
ii. Explain why to maintain/check always oil level before proceed
any injection.
Student can check answer by peer review
63
6 MOULDING DEFECTS
On completion of this course, students should be able to:
i. Recognize basic causes of moulding defects.
64
6 MOULDING DEFECTS
65
6
Process Stage
Moulding Defects:
1.Blister: causes Tool or material to hot, often caused
lack of cooling around the tool or faulty heater.
Alternative name: Raised or layered zone on surface of
the plastic part.
2.Burn marks: causes Tool lacks venting, injection speed
too high
Alternative name: Black or brown burn areas on the
plastic part located at furthest points from gate.
3. Short shot: causes lack of material, injection speed or
pressure too low.
Alternative name: Non fill/short mold.
4. Flash: causes Tool damage, too much injection
speed/material injected, clamping force too low, Can also
caused by dirt and contaminants around tooling surfaces
Alternative name: Burrs.
5.Warping/distorted part; causes cooling too short,
material too hot, lack of cooling around the tool, incorrect
water temperature or wrong setting up temperature
parameter.
Alternative name: Twisting part
66
6
Process Stage
Short shot/ non fill Short Mould
causes
Lack of material
injection speed or pressure too low
67
6
Process Stage 68
Warping/distorted part
causes
cooling too short, material too hot, lack of
cooling around the tool, incorrect water
temperature or wrong setting up
temperature parameter
6
i. List at least THREE(3) of moulding defects.
ii. Explain why moulding defects short shot occur in injection
Processes.
Student can check answer by peer review
69
REFERENCES:
1. A. Brent Strong (2006). Plastics, Third Edition, Pearson Prentice Hall.
2. John R. Wagner Jr. (2012). Handbook of Troubleshooting Plastics Processes: A Practical
Guide, Publisher: Wiley-Scrivener.
3. Laurence W. McKeen (2008). The effect of temperature and other factors on plastics and
elastomers, Publisher: Plastics Design Library/William.
4. Manual Mini Injection Molding.
5. V. Pacáková, J. Virt, 2005. Encyclopedia of Analytical Science (Second Edition), Science
Direct.
6. Canva Education.
7. Serope Kalpakjian (1997). Manufacturing Process for Engineering Material, Third Edition,
Addison Wesley Publishing Company.
8. Vanessa Godship, Bethany Middleton, Ruth Cherrington (2016). Design and
Manufacture of Plastic Components for Multifunctionality: Structural Composites,
Injection Molding, and 3D Printing, Publisher: William Andrew is an imprint of Elsevier.
9. https://www.3dsystems.com/quickstart/learning-center/injection-molding-basics.
70
Ts. Johnny Yakin Sinit
MME (System Design)
B. Tech and Edu (Mechanical Engineering)
Diterbitkan oleh:
POLITEKNIK KOTA KINABALU
No.4, Jalan Politeknik, KKIP Barat
Kota Kinabalu Industrial Park
88460 Kota Kinabalu, Sabah
© Politeknik Kota Kinabalu
Edisi Pertama, 2022
Credit: This presentation template was created using Canva.