EXPERIMENTAL ANALYSIS ON
POLYPROPYLENE MOULDED PART FOR
PERFORMANCE OF LASER PRINTING
Ajay L. Dumanwad
PG Student, Department of Mechanical Engineering, JSPM Narhe Technical
Campus, Savitribai Phule Pune University, Pune – 411041, India
ajaydumanwad143@gmail.com
Manoj A. Kumbhalkar
Associate Professor, Department of Mechanical Engineering, JSPM Narhe
Technical Campus, Pune, India
manoj.kumbhalkar@rediffmail.com - https://orcid.org/0000-0003-2289-6373
Jaswindar Singh
Director, Ecorea & Kuroda Electric India Pvt. Ltd., Ranjangaon, Pune, India
Reception: 04/12/2022 Acceptance: 20/01/2023 Publication: 16/02/2023
Suggested citation:
L. D., Jay, A. K., Manoj and S. Jaswindar (2023). Experimental Analysis on
Polypropylene Moulded Part for Performance of Laser Printing. 3C
Tecnología. Glosas de innovación aplicada a la pyme, 12(01), 366-384. https://
doi.org/10.17993/3ctecno.2023.v12n1e43.366-384
https://doi.org/10.17993/3ctecno.2023.v12n1e43.366-384
3C Tecnología. Glosas de innovación aplicadas a la pyme. ISSN: 2254-4143
Ed.43 | Iss.12 | N.1 January - March 2023
366
EXPERIMENTAL ANALYSIS ON
POLYPROPYLENE MOULDED PART FOR
PERFORMANCE OF LASER PRINTING
Ajay L. Dumanwad
PG Student, Department of Mechanical Engineering, JSPM Narhe Technical
Campus, Savitribai Phule Pune University, Pune – 411041, India
ajaydumanwad143@gmail.com
Manoj A. Kumbhalkar
Associate Professor, Department of Mechanical Engineering, JSPM Narhe
Technical Campus, Pune, India
manoj.kumbhalkar@rediffmail.com - https://orcid.org/0000-0003-2289-6373
Jaswindar Singh
Director, Ecorea & Kuroda Electric India Pvt. Ltd., Ranjangaon, Pune, India
Reception: 04/12/2022 Acceptance: 20/01/2023 Publication: 16/02/2023
Suggested citation:
L. D., Jay, A. K., Manoj and S. Jaswindar (2023). Experimental Analysis on
Polypropylene Moulded Part for Performance of Laser Printing. 3C
Tecnología. Glosas de innovación aplicada a la pyme, 12(01), 366-384. https://
doi.org/10.17993/3ctecno.2023.v12n1e43.366-384
https://doi.org/10.17993/3ctecno.2023.v12n1e43.366-384
ABSTRACT
Now a day plastic injection molding is widely used process to manufacture
engineering product and consumer goods typically thermoplastic is combined with
rubber or another thermoplastic like RM master batch is used to add color to the
Molded part also the laser marking on plastic part and their printing cut, faint issue
observed. The aim of the study was to Optimize the injection parameters and
processing condition for the laser performance on polypropylene part. To achieve
enhanced dark laser marking on polypropylene, the process parameter of plastic
injection molding and the Raw material master batch mixing parameter successfully
prepared this laser–sensitive composite consisted of a high Laser induced
carbonization rate.in plastic injection molding use of raw material and mixing of master
batch is considerable factor for faint laser marking. Because of laser does not respond
well on carbonization added material, it was evident that master batch having the
carbon properties is much more responsible for faint laser marking issue on
polypropylene material part.
The effect of laser beam interaction (Nd: YVO4) with selected operational parameters
on the Quality of graphical features obtained on the surface of polypropylene-molded
pieces with different surface Textures (variable parameters of the surface layer).
Polypropylene test specimens were injection molded using original injection molds
Products with variable end parameters determined by the position of the cavity circle
can be identified. The layout of the laser function, the beneficiary texture of the
molded piece, the molded color and the support of the marking piece allow the
evaluation of the graphic symbol performance by means of laser marking of the type
of master back in their rendering relationship. Marked evaluation criteria were adopted
for the project.
KEYWORDS
Laser marking, injection moulding, master batch, printing, polypropylene
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PAPER INDEX
ABSTRACT
KEYWORDS
1. INTRODUCTION
1.1. INJECTION MOULDING MACHINE TYPE
1.2. LASER PRINTERS
1.3. PROBLEM IDENTIFICATION
1.4. DATA COLLECTION
2. EXPERIMENTAL TRIAL WITH MASTER BATCH MIXING
2.1. EXPERIMENTAL TRIALS ON EXISTING MATERIAL (340 MASTER BATCH)
2.2. COMPARISON STUDY OF EXISTING MASTER BATCH AND SUGGESTED
MASTER BATCH
2.2.1. GRADE 340 MASTER BATCH TRIALS
2.2.2. GRADE 394 MASTER BATCH TRIAL
3. EXPERIMENTAL TRIALS WITH SUGGESTED MATERIAL (394 MB)
3.1.1. CALCULATION OF NEW RPN
3.1.2. IMPROVED CALCULATION TRIAL
4. RESULT AND DISCUSSION
5. CONCLUSION
REFERENCES
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368
PAPER INDEX
ABSTRACT
KEYWORDS
1. INTRODUCTION
1.1. INJECTION MOULDING MACHINE TYPE
1.2. LASER PRINTERS
1.3. PROBLEM IDENTIFICATION
1.4. DATA COLLECTION
2. EXPERIMENTAL TRIAL WITH MASTER BATCH MIXING
2.1. EXPERIMENTAL TRIALS ON EXISTING MATERIAL (340 MASTER BATCH)
2.2. COMPARISON STUDY OF EXISTING MASTER BATCH AND SUGGESTED
MASTER BATCH
2.2.1. GRADE 340 MASTER BATCH TRIALS
2.2.2. GRADE 394 MASTER BATCH TRIAL
3. EXPERIMENTAL TRIALS WITH SUGGESTED MATERIAL (394 MB)
3.1.1. CALCULATION OF NEW RPN
3.1.2. IMPROVED CALCULATION TRIAL
4. RESULT AND DISCUSSION
5. CONCLUSION
REFERENCES
https://doi.org/10.17993/3ctecno.2023.v12n1e43.366-384
1. INTRODUCTION
Plastic injection moulding is the process of heating raw material to its melting point
(plastic resin in pellet form in our case), forcing the viscous material into a mould, and
allowing it to cool into a hardened shape. In almost every product you encounter,
injection moulded parts are used, from electronics to housewares to automotive to
food packaging. At its most basic, it's a very simple process, but there's a lot more to it
than that—from creating the mould to understanding the chemical and physical
properties of the material. Plastic injection moulding arose from metal pressure die
casting processes in the late 1800s. Plastics were introduced in the 1920s, but the
process was still very crude, with simple two-piece moulds manually clamped
together. Since then, the art and science of plastic injection moulding have advanced
significantly [1-5].
1.1. INJECTION MOULDING MACHINE TYPE
Injection moulding is a method of transforming thermoplastics or thermosetting
materials into a wide range of products. Plasticizing and injection units, clamping and
opening units, ejecting or knockout units, and an electric and hydraulic control system
comprise an injection machine or injector.
There are four basic types of injection moulding equipment according to the type of
screw or plunger. [6]
Four types of injection moulding machines.[6]
1. Conventional injection moulding machine.
2. Piston-type preplastifying machine.
3. Screw-type preplastifying machine.
4. Reciprocating-screw injection machine.
Figure 1. Plastic Injection Moulding machine. [4] (Courtesy: Polypastics Co., Ltd.)
In Conventional injection moulding machine, Plastic granules or pellets are poured
into a hopper and fed into the chamber of the heating cylinder in this process. A
plunger then compresses the material, forcing it through the heating cylinder's
increasingly hotter zones, where it is spread thin by a torpedo. The torpedo is placed
in the centre of the cylinder to accelerate the heating of the plastic mass's centre. The
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torpedo can also be heated from the inside as well as from the outside. The material
flows into the mould from the heating cylinder via a nozzle. The nozzle seals the
cylinder and the mould, preventing molten material from leaking. The clamp end of the
machine holds the mould closed. Two to three tonnes of pressure are typically applied
to polystyrene for each inch of projected area of the work-piece and runner system.[6]
To preplastify the plastic granules, Piston-type preplastifying machine uses a
torpedo ram heater. The fluid plastic is pushed into a holding chamber after the melt
stage until it is ready to be forced into the mould. Because the moulding chamber is
filled to shot capacity during the cooling time of the work-piece, this type of machine
produces work-pieces faster than a conventional machine. Because the injection
plunger is acting on fluid material, there is no pressure loss when compacting the
granules. This enables a larger work-piece with a larger projected area.[6]
Screw- Type preplastifying machine is an extruder that is used to plasticize plastic
material. The pellets are fed forward by the turning screw to the heated interior
surface of the extruder barrel. The molten, plasticized material exits the extruder and
enters a holding chamber before being forced into the mould or die by the injection
plunger. The use of a screw provides the following benefits: improved plastic melt
mixing and shear action, the ability to run a wider range of stiffer flow heat sensitive
materials, colour changes can be handled in less time, and fewer stresses are
obtained in the moulded part [6].
A horizontal extruder replaces the heating chamber in a reciprocating-screw
injection moulding machine. The rotation of a screw propels the plastic material
forward through the extruder barrel. The material changes from granular to plastic
molten as it moves through the heated barrel with the screw. As the material
advances, the screw returns to a limit switch, which determines the volume of material
in front of the extruder barrel. During the shot, the screw advances to displace the
material in the barrel. The screw acts as a ram or plunger in this machine.There are
several benefits to using reciprocating-screw injection moulding. Because of the
screw's mixing cation, it plasticizes heat-sensitive materials more efficiently and
blends colours more quickly [6].
The main component of injection moulding machine are clamping unit and injection
unit. Clamping unit consist of three main components such as mould, clamping motor
drive and Tier bars, the sender is clamped onto the edge of a workbench. Injection
Unit consist of three main components viz. Screw motor drive, reciprocating screw &
barrel and heaters, thermocouple, ring plunger.
1.2. LASER PRINTERS
Laser printers are another well-known laser-based consumer product, frequently
used in conjunction with personal computers. Their operating principle is based on
electro photography, also known as xerography, which is the same process used in
photocopiers. Figure 2 depicts the electro photographic process. Ions from a corona
discharge charge uniformly a photoreceptive surface with a layer of photoconductive
material. The surface is frequently that of a rotating drum. The surface is exposed
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torpedo can also be heated from the inside as well as from the outside. The material
flows into the mould from the heating cylinder via a nozzle. The nozzle seals the
cylinder and the mould, preventing molten material from leaking. The clamp end of the
machine holds the mould closed. Two to three tonnes of pressure are typically applied
to polystyrene for each inch of projected area of the work-piece and runner system.[6]
To preplastify the plastic granules, Piston-type preplastifying machine uses a
torpedo ram heater. The fluid plastic is pushed into a holding chamber after the melt
stage until it is ready to be forced into the mould. Because the moulding chamber is
filled to shot capacity during the cooling time of the work-piece, this type of machine
produces work-pieces faster than a conventional machine. Because the injection
plunger is acting on fluid material, there is no pressure loss when compacting the
granules. This enables a larger work-piece with a larger projected area.[6]
Screw- Type preplastifying machine is an extruder that is used to plasticize plastic
material. The pellets are fed forward by the turning screw to the heated interior
surface of the extruder barrel. The molten, plasticized material exits the extruder and
enters a holding chamber before being forced into the mould or die by the injection
plunger. The use of a screw provides the following benefits: improved plastic melt
mixing and shear action, the ability to run a wider range of stiffer flow heat sensitive
materials, colour changes can be handled in less time, and fewer stresses are
obtained in the moulded part [6].
A horizontal extruder replaces the heating chamber in a reciprocating-screw
injection moulding machine. The rotation of a screw propels the plastic material
forward through the extruder barrel. The material changes from granular to plastic
molten as it moves through the heated barrel with the screw. As the material
advances, the screw returns to a limit switch, which determines the volume of material
in front of the extruder barrel. During the shot, the screw advances to displace the
material in the barrel. The screw acts as a ram or plunger in this machine.There are
several benefits to using reciprocating-screw injection moulding. Because of the
screw's mixing cation, it plasticizes heat-sensitive materials more efficiently and
blends colours more quickly [6].
The main component of injection moulding machine are clamping unit and injection
unit. Clamping unit consist of three main components such as mould, clamping motor
drive and Tier bars, the sender is clamped onto the edge of a workbench. Injection
Unit consist of three main components viz. Screw motor drive, reciprocating screw &
barrel and heaters, thermocouple, ring plunger.
1.2. LASER PRINTERS
Laser printers are another well-known laser-based consumer product, frequently
used in conjunction with personal computers. Their operating principle is based on
electro photography, also known as xerography, which is the same process used in
photocopiers. Figure 2 depicts the electro photographic process. Ions from a corona
discharge charge uniformly a photoreceptive surface with a layer of photoconductive
material. The surface is frequently that of a rotating drum. The surface is exposed
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after charging by scanning the laser beam across it. The intensity of the beam is
varied to create a replica of the desired image. The pattern of light intensity replicates
the pattern of the to-be-printed text or graphics. In laser-illuminated regions, the
photoconductive layer conducts. This allows the electrostatic charge to move and
creates an electric charge pattern on the surface [7-12].
Figure 2. Basic working principle dia. [7]
This sequence is similar to that used in photocopiers, except that the pattern in the
exposure step is obtained from projection of an image of the text or graphics to be
copied in photocopiers. A computer generates the material and sends it to the laser
printer, which stores the data in its memory, composes one page of material at a time,
and controls the scanning of the laser beam to produce the desired image. Laser
printers produce high-quality prints with sharp images and consistent black levels. [7]
The various type of Lasers is green laser, UV laser, CO2 laser and MOPA laser.
1.3. PROBLEM IDENTIFICATION
As shown in the figure 3, the Engine Room RB Upper Cover has the good laser
marking as well as the defective information for the part. In the first stage, the parts
are kept in their respective jigs for further laser marking purposes. The part should be
properly held and jigged before beginning the laser marking. After that, the inspector
should check the part as per inspection and visually check for defects.
As shown in the defect information image below, some alphabetical letters, numeric
numbers, or any specific symbol are found cut or faintly printed; because of this, the
production team faced too many rejections. The faint marking refers to the cutting or
invisible letter found on a part after the laser marking process.
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Figure 3. Laser Printing Process on Upper Cover of the moulded part
1.4. DATA COLLECTION
Before experimentation, to investigate the process parameters of the printing
problem, it is necessary to have a thorough understanding of the process, which is
studied using a process flow chart. The first stage of the work was to collect the
rejection data due to faint laser marking. Performance information and performance
issues for the evaluation of three steps is done on a numerical scale. They are based
on the needs of the high-pressure moulding line of the company or the final product.
Priority is given to the cause with the highest rejection part number. After collecting
three months of production data from various parts in order to identify the part with the
highest rejection ratio. Table 1 displays rejection data for various moulding parts. PPM
stands for parts per million. According to the data presented, the highest rejection was
observed in the ENG ROOM R/B upper cover.
Prin%
Prin%n
Prin%ng
OK PART
Engine
Laser
Printing
Process
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Figure 3. Laser Printing Process on Upper Cover of the moulded part
1.4. DATA COLLECTION
Before experimentation, to investigate the process parameters of the printing
problem, it is necessary to have a thorough understanding of the process, which is
studied using a process flow chart. The first stage of the work was to collect the
rejection data due to faint laser marking. Performance information and performance
issues for the evaluation of three steps is done on a numerical scale. They are based
on the needs of the high-pressure moulding line of the company or the final product.
Priority is given to the cause with the highest rejection part number. After collecting
three months of production data from various parts in order to identify the part with the
highest rejection ratio. Table 1 displays rejection data for various moulding parts. PPM
stands for parts per million. According to the data presented, the highest rejection was
observed in the ENG ROOM R/B upper cover.
DEFECTED PART
Prin%
Prin%n
Prin%ng
OK PART
Engine
Laser
Printing
Process
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Table 1. Theme Data (Part wise defect data)
By combining the three-month production rejection rate of various moulded parts in
a part-by-part pareto chart, it was discovered that the Engine Room RB Assembly
upper cover has the highest value as shown in pareto chart (figure 4), indicating the
highest total process rejection. Hence, the upper cover was chosen for further drill-
down analysis after studying the selected moulded part of the engine room RB
assembly.
Figure 4. Partwise rejection of the component (Pareto chart)
After selecting the moulded part with the highest rejection ratio for drill-down
analysis, it is necessary to investigate which type of rejection occurred as a result of
which part was rejected the most frequently. Printing cut issues, printing faint issues,
Part name Feb-22 Mar-22 Apr-22 Prod. Qty. Rej. Qty PPM
ENG ROOM R/B UPPER 5,762 8,752 74,58 21,972 1,456 66,266
ASSY R/B FRAME
FLOOR
12,432 14,235 9,663 36,330 498 13,708
COVER FUSE RB NO 2
R
3,456 2,564 2,657 8,677 250 28,812
UPPER RHD
PROTECTOR BASE 4,562
4,578
5,060 14,200 39 2,746
L TYPE 2P HOUSING
FEMALE Grey 6,532 12,452 4,591 23,575 15 636
PROTECTOR COVER
L74.4 W269.2 H34 PA66B 7,562 6,423 5,903 19,888 6 302
CONN COWL SIDE RH
C/B 2 PP N 6,452 5,423 5,855 17,730 5 282
TOTAL 46,758 54,427 41,187 1,42,372 2,269 15937
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and other process defects such as short mold, sink mark, flash, flow mark issue, and
so on are commonly found in laser-printed parts. Based on the detailed examination
of the collected rejection details, it was determined that the majority of the major
rejections occurred as a result of the Faint Laser Issue in Engine Room RB Upper
Cover, as shown in figure 5.
Figure 5. Rejection Detail Analysis (Pie Chart)
After studying part-wise defect data, a part-wise pareto chart, and pie chart data,
the part with the highest rejection ratio in three months is chosen for the part-wise
pareto chart. And, based on the large number of rejections, it has been determined
that the laser faint printing issue in Engine Room RB Upper Cover is a significant
factor. So, selecting the above parts and causes for project theme improvement and
experiment investigation of process parameters.
The 4M method analysis is a method for evaluating which of the 4M conditions is
responsible for a defect mode. The 4M is a method for identifying and grouping
causes that have an impact on a specific effect. The 4M categories of man, machine,
method, and material are often used in the cause-effect diagram, which is also called
a fishbone diagram. We discovered the following significant factors for the same issue
shown in Figure 6. In this method, raw material and master batch mixing are
considerable factors. In material, the master batch is not suitable for the laser printing
issue, and the raw material to master batch ratio is not optimized.
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and other process defects such as short mold, sink mark, flash, flow mark issue, and
so on are commonly found in laser-printed parts. Based on the detailed examination
of the collected rejection details, it was determined that the majority of the major
rejections occurred as a result of the Faint Laser Issue in Engine Room RB Upper
Cover, as shown in figure 5.
Figure 5. Rejection Detail Analysis (Pie Chart)
After studying part-wise defect data, a part-wise pareto chart, and pie chart data,
the part with the highest rejection ratio in three months is chosen for the part-wise
pareto chart. And, based on the large number of rejections, it has been determined
that the laser faint printing issue in Engine Room RB Upper Cover is a significant
factor. So, selecting the above parts and causes for project theme improvement and
experiment investigation of process parameters.
The 4M method analysis is a method for evaluating which of the 4M conditions is
responsible for a defect mode. The 4M is a method for identifying and grouping
causes that have an impact on a specific effect. The 4M categories of man, machine,
method, and material are often used in the cause-effect diagram, which is also called
a fishbone diagram. We discovered the following significant factors for the same issue
shown in Figure 6. In this method, raw material and master batch mixing are
considerable factors. In material, the master batch is not suitable for the laser printing
issue, and the raw material to master batch ratio is not optimized.
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Figure 6. Fish bone dia.
The major problem of printing on the company's moulded part is discussed and
resolved with many trials and experiments by changing the different process
parameters in this project. The main objective of the work is to find the cause of faint
printing. Also, to investigate the problem, an experiment with the existing material
using a different batch mixing percentage and time is needed. It is necessary to
finalise the percentage of the master batch and the time for mixing MB. The
experiments have to be carried out with different batch mixing percentages and times
for the suggested material. The final objective of the work is to reduce or eliminate the
rejection rate of the laser printing process in Part Engine Room RB Assembly Upper
by 100%.
A process flow chart is a diagram that represents the decision-making procedures
and the sequential steps of a process. Every step in the chart or visual representation
is denoted by a shape. To depict the movement and direction of the process, these
forms are joined by an arrow or line. From the initial receipt of raw materials to the
final dispatch stage, the following process flow chart is included. Here, the raw
material mixing and raw material loading on the hopper are very important stages.
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Figure 7. Process Flow chart
2. EXPERIMENTAL TRIAL WITH MASTER BATCH
MIXING
2.1. EXPERIMENTAL TRIALS ON EXISTING MATERIAL (340
MASTER BATCH)
To find the exact cause of printing failure on the part, various trials need to be taken
with reference to the rejection rate as discussed above. To determine the precise
cause of printing on the top cover, various trials for master batch mixing, ranging from
8% to 3%, are considered, and the rejection ratio is calculated. A sample image of raw
material with the master batch is given in Figure 8. The existing master batch 340 has
a melting point of 1240 °C and a heat stability of 2800C. The upper cover is subjected
to five trials with existing material, namely master batch 340, with a MB mixing time of
10 minutes. The total lot for each trial is taken as 50, and it has been observed that
the percentage of rejection is reduced with a reduction in the percentage of master
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Figure 7. Process Flow chart
2. EXPERIMENTAL TRIAL WITH MASTER BATCH
MIXING
2.1. EXPERIMENTAL TRIALS ON EXISTING MATERIAL (340
MASTER BATCH)
To find the exact cause of printing failure on the part, various trials need to be taken
with reference to the rejection rate as discussed above. To determine the precise
cause of printing on the top cover, various trials for master batch mixing, ranging from
8% to 3%, are considered, and the rejection ratio is calculated. A sample image of raw
material with the master batch is given in Figure 8. The existing master batch 340 has
a melting point of 1240 °C and a heat stability of 2800C. The upper cover is subjected
to five trials with existing material, namely master batch 340, with a MB mixing time of
10 minutes. The total lot for each trial is taken as 50, and it has been observed that
the percentage of rejection is reduced with a reduction in the percentage of master
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batch mixing. The results obtained on the injection moulding machine for five different
trials are given in table 2.
Figure 8. Raw material and master batch mixing
From the above-mentioned analysis, it is evident that master batch percentage and
master batch Mixing time is a considerable factor for printing faint lines. Hence, there
is a need to improve the master batch mixing as well as change the master batch and
check the issue of mixing at the same percentage level. For this purpose, Master
Batch 394 is suggested for mixing with a mixing ratio of 2% and a MB mixing time of
10 minutes. The comparison study of the existing master batch and the suggested
master batch is given in table 2.
Table 2. Trail on Upper Cover with Existing Material (Master Batch Grade & MB Mixing ratio
2.2. COMPARISON STUDY OF EXISTING MASTER BATCH AND
SUGGESTED MASTER BATCH
Based on the number of trials taken, the 2% master batch mixing has been
finalized for further trials for existing as well as suggested materials for Batch 394. By
operating the injection moulding machine for different operating variables and process
parameters of the raw material mixing method, we took the rejection of no. part
reading from the mixing of RM with master batch.
Master Batch
Raw Material
+
Trial Raw Material
PP
% of
Master
Batch 340
MB Mixing
time. In
min.
Trial
Lot NG Rejection
%
T1 100% 8% 10 50 7 14%
T2 100% 7% 10 50 7 14%
T3 100% 6% 10 50 6 12%
T4 100% 5% 10 50 5 10%
T5 100% 4% 10 50 5 10%
T6 100% 3% 10 50 2 10%
T7 100% 2% 10 50 1 8%
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Following an examination of both the 340 master bath and the 394 master batch, it
was determined that the value of the multi-flow index for the 340 master bath is less
than required, while the value for the 394 master batch is in the middle of the
specifications. As shown in the comparative study above, the carbon used in both
master batches is different. It has been concluded that the 394 master batch is a
suitable factor; further, there is a need to conduct a trial in an optimized percentage of
the master batch with new laser carbon with proper mixing time. Furthermore, a trial in
an optimized percentage of the master batch with new laser carbon and proper mixing
time is required.
2.2.1. GRADE 340 MASTER BATCH TRIALS
The carbon used in both master batches is different, as shown in the comparative
study above.It has been concluded that the 394 master batch is a suitable factor;
further, there is a need to conduct a trial in an optimized percentage of the master
batch with new laser carbon with proper mixing time. Furthermore, a trial in an
optimized percentage of the master batch with the new laser carbon with proper
mixing time is required. So, for the next trial, the master batch mixing ratio is set to 2%
and the mixing time is set to 10 minutes.
Table 3. Grade 340 Master batch trial Table
Existing Master Batch
MFI :- 0.29
Gram per 10 min) by ASTM D1238
Melting point (°c) :-124
Heat Stability (°c) :280
Carbon used:- Black (WN-96)
Master Batch 340 /TP/P
Existing Use
:Master Batch 340 Grade
Suggested Master Batch
MFI :- 25.1
Gram per 10 min) by ASTM D1238
Melting point (°c) :-126
Heat Stability (°c) :280
Carbon used :- Laser Black
Suggested
:Master Batch 394 Grade
Master Batch 394 /TP/P
Sr/no Trial Raw Material
PP
% of
Master
Batch 340
Trial Lot NG Rejection
%
1 T1 100% 2% 50 3 6%
2 T2 100% 2% 50 4 8%
3 T3 100% 2% 50 3 6%
4 T4 100% 2% 50 3 6%
5 T5 100% 2% 50 4 8%
6 T6 100% 2% 50 4 8%
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Following an examination of both the 340 master bath and the 394 master batch, it
was determined that the value of the multi-flow index for the 340 master bath is less
than required, while the value for the 394 master batch is in the middle of the
specifications. As shown in the comparative study above, the carbon used in both
master batches is different. It has been concluded that the 394 master batch is a
suitable factor; further, there is a need to conduct a trial in an optimized percentage of
the master batch with new laser carbon with proper mixing time. Furthermore, a trial in
an optimized percentage of the master batch with new laser carbon and proper mixing
time is required.
2.2.1. GRADE 340 MASTER BATCH TRIALS
The carbon used in both master batches is different, as shown in the comparative
study above.It has been concluded that the 394 master batch is a suitable factor;
further, there is a need to conduct a trial in an optimized percentage of the master
batch with new laser carbon with proper mixing time. Furthermore, a trial in an
optimized percentage of the master batch with the new laser carbon with proper
mixing time is required. So, for the next trial, the master batch mixing ratio is set to 2%
and the mixing time is set to 10 minutes.
Table 3. Grade 340 Master batch trial Table
Existing Master Batch
MFI :- 0.29
Gram per 10 min) by ASTM D1238
Melting point (°c) :-124
Heat Stability (°c) :280
Carbon used:- Black (WN-96)
Master Batch 340 /TP/P
Existing Use
:Master Batch 340 Grade
Suggested Master Batch
MFI :- 25.1
Gram per 10 min) by ASTM D1238
Melting point (°c) :-126
Heat Stability (°c) :280
Carbon used :- Laser Black
Suggested
:Master Batch 394 Grade
Master Batch 394 /TP/P
Sr/no
Trial
Raw Material
PP
% of
Master
Batch 340
Trial Lot
NG
Rejection
%
1
T1
100%
2%
50
3
6%
2
T2
100%
2%
50
4
8%
3
T3
100%
2%
50
3
6%
4
T4
100%
2%
50
3
6%
5
T5
100%
2%
50
4
8%
6
T6
100%
2%
50
4
8%
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Figure 9. Grade 340 Master batch trial Graph
2.2.2. GRADE 394 MASTER BATCH TRIAL
As per the comparative study, the carbon used in both master batches is different,
as shown in the comparative study. It has been concluded that the 394 master batch
is a suitable factor; further, there is a need to conduct a trial in an optimized
percentage of the master batch with new laser carbon with proper mixing time.
Furthermore, a trial in an optimized percentage of the master batch with the new laser
carbon with proper mixing time is required. So, for the next trial, the two percentages
of the master batch mixing ratio and the mixing time of 10 minutes are fixed.
Table 4. Grade 394 Master batch trial Table
% MB vs Rej.
0 %
2 %
4 %
6 %
8 %
Trial
T1
T2
T3
T4
T5
8 %
6 %
6 %
8 %
6 %
% Rej.
Sr/no Trial Raw Material
PP
% of Master
Batch 394 Trial Lot NG % Rej
1 T1 100% 2% 50 2 4%
2 T2 100% 2% 50 2 4%
3 T3 100% 2% 50 1 2%
4 T4 100% 2% 50 2 4%
5 T5 100% 2% 50 1 2%
6 T6 100% 2% 50 1 2%
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Figure 10. Grade 394 Master batch trial Graph
After taking a constant value of the percentage of master batch mixing and the
master batch mixing time mentioned above, it was discovered that the laser printing
rejection is lower in the 394 master batch than in the 340 master batch, though the
difference is not significant. It has been concluded that the master batch grade
change has a positive impact on reducing laser printing rejection.
3. EXPERIMENTAL TRIALS WITH SUGGESTED
MATERIAL (394 MB)
3.1.1. CALCULATION OF NEW RPN
After finding the solution for cause, it has been concluded that the main causes, like
the first percentage of master batch mixing, the second master batch mixing time, and
the third master batch change (394), are now finalized for the further trial calculation
as shown in table 5. solution for the causes, let's head towards calculating a new RPN
after taking action and a percentage decrease in rejection data.
Table 5. Trial with 394 MB with 2% RM mixing
Sr/no Trial Raw
Material PP
% of Master
Batch 394 Trial Lot NG Rejection
%
1 T1 100% 2% 50 2 4%
2 T2 100% 2% 50 2 4%
3 T3 100% 2% 50 1 2%
4 T4 100% 2% 50 2 4%
5 T5 100% 2% 50 1 2%
6 T6 100% 2% 50 1 1%
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Figure 10. Grade 394 Master batch trial Graph
After taking a constant value of the percentage of master batch mixing and the
master batch mixing time mentioned above, it was discovered that the laser printing
rejection is lower in the 394 master batch than in the 340 master batch, though the
difference is not significant. It has been concluded that the master batch grade
change has a positive impact on reducing laser printing rejection.
3. EXPERIMENTAL TRIALS WITH SUGGESTED
MATERIAL (394 MB)
3.1.1. CALCULATION OF NEW RPN
After finding the solution for cause, it has been concluded that the main causes, like
the first percentage of master batch mixing, the second master batch mixing time, and
the third master batch change (394), are now finalized for the further trial calculation
as shown in table 5. solution for the causes, let's head towards calculating a new RPN
after taking action and a percentage decrease in rejection data.
Table 5. Trial with 394 MB with 2% RM mixing
Sr/no
Trial
Raw
Material PP
% of Master
Batch 394
Trial Lot
NG
Rejection
%
1
T1
100%
2%
50
2
4%
2
T2
100%
2%
50
2
4%
3
T3
100%
2%
50
1
2%
4
T4
100%
2%
50
2
4%
5
T5
100%
2%
50
1
2%
6
T6
100%
2%
50
1
1%
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3.1.2. IMPROVED CALCULATION TRIAL
After taking actions, there is a change in the rejection number of the part value that
is reduced by almost 50%. It is time to collect data after implementing the RM mixing
process parameter and the percentage of RM mixing as shown in the table 6.
Table 6. Trial with 394 MB with 1% RM mixing
Table 6 shows how lowering the percentage of master batch mixing affects the
rejection part number ratio in the laser printing issue. Based on the above-mentioned
trials, it has been determined that tumbler mixing for 30 minutes of a new master
batch in a 1 percent ratio produces the best laser printing results with the least
rejection.
4. RESULT AND DISCUSSION
As per the experimentation carried out to resolve the issue of faint printing on upper
cover of the moulded part in the industry, it has been observed that there are no any
problems in the process parameters set for moulding and the moulded part in injection
moulding is perfect. It means, the faint printing on the moulded upper cover is not an
issue of injection moulding and it was the problem due to master batch mixing in the
raw material. Based on the several trials by reducing percentage of master batch 394,
it has been observed that the 1% mixing of master batch 394 is improved the printing
quality and the reduces rejection rate. Based on the analysis carried out the net cost
saving of the printing on the moulded part is INR 2,70,812 as shown in table 7 and the
reduction in rejection quantity is shown in figure 11.
Trial Raw Material PP % Of Master
Batch 394 Trial Lot NG % Rejection
T1 100% 3% 50 3 6%
T2 100% 2.5% 50 2 3%
T3 100% 1% 50 1 1%
T4 100% 1% 50 0 0%
T5 100% 1% 50 0 0%
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Table 7. Net cost saving due to reducing rejection quantity
Figure 11. statistics of rejection and reduction in rejection
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Table 7. Net cost saving due to reducing rejection quantity
Figure 11. statistics of rejection and reduction in rejection
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To reduce the further rejection of printing on any moulded part the standardization
in process is very important. The process can be standardized with five quality steps
as shown in figure 12. This is the future scope of this research work.
Figure 12. Standardization in process
5. CONCLUSION
•
The analysis, investigation methodology is allowed to study and analyze every
step of perform making process and to achieve the improvement in product and
process quality. The improvements obtained by the implementation of the
recommended actions thus reduce the individual rejection of part and risk level
associated with each defect is reduced.
•
By using 4M methodology it is help to easy recognize the main root cause and
improvement.
•After implementation of action the rejection value of faint laser marking is reduced
for each of the part, and the total cost saving Detail is as follow.
•By this way laser faint issue, Development time, and cost has been reduced and
also there is less chance of occurring same kind of failure in future.
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