1. Custom Rubber Omron Heater Control
Bingying Feng
Department of Aerospace and Mechanical Engineering
Case Western Reserve University
Cleveland, OH 44106-7079
Professor
Dr. Clare Rimnac
Supervisor
Alexis Abramson, Ph.D.
Case Western Reserve University, Cleveland, OH
and
John Bellett
Custom Rubber Corp., Cleveland, OH
26th February 2016
2. Table of Contents
Abstract........................................................................................................................................... 1
Introduction..................................................................................................................................... 2
Background ................................................................................................................................. 2
Project Objective......................................................................................................................... 3
Process Methodology...................................................................................................................... 4
Hypothesis................................................................................................................................... 4
Heat Analysis to the original machine ........................................................................................ 4
Stage One - Applying Insulation Boards to the Edge of the Machine ........................................ 6
Material Selection.................................................................................................................... 6
Process and Heat Analysis....................................................................................................... 6
Stage Two – Installing a Roof on the top.................................................................................... 6
Stage Three –Thermocouple Analysis ........................................................................................ 7
Experimental Samples Testing................................................................................................ 7
On-site Experiment.................................................................................................................. 8
Results and Discussion ................................................................................................................. 10
Stage One - Applying Insulation Boards to the Edge of the Machine ...................................... 10
Heat Analysis – 1st
Cycle....................................................................................................... 10
Heat Analysis – 2nd
Cycle...................................................................................................... 11
Bad Parts Number Analysis................................................................................................... 12
Stage One Discussion ............................................................................................................ 13
Stage Two - Installing a Roof on the top .................................................................................. 13
Stage Two Discussion ........................................................................................................... 13
Stage Three –Thermocouple Analysis ...................................................................................... 14
Experimental Samples Testing Results ................................................................................. 14
Sample Testing Discussion.................................................................................................... 14
On-site Experiment Results................................................................................................... 15
On-site Experiment Discussion ............................................................................................. 15
Magnetic Influence................................................................................................................ 15
Conclusion .................................................................................................................................... 17
Future Work .............................................................................................................................. 18
Acknowledgements....................................................................................................................... 19
3. References..................................................................................................................................... 20
Appendices.................................................................................................................................... 21
Appendix I: Overview of the Product and the Machine............................................................ 21
Appendix II: Properties of the Thermal Imaging Camera......................................................... 22
Appendix III: Heat Analysis of the Original Machine.............................................................. 23
Appendix IV: Sample of Pyropel MD-18 ................................................................................. 24
Appendix V: Machine with Insulation Board ........................................................................... 25
Appendix VI: Thermometer (Omega, RDXL4SD)................................................................... 26
Appendix VII: External Temperature Graph ............................................................................ 28
Appendix VIII: Internal Temperature Analysis ........................................................................ 29
Appendix IX: Bad Part Number Analysis................................................................................. 30
Appendix X: Experimental Sample Testing.............................................................................. 31
Type J - Room Temperature.................................................................................................. 31
Type J – Boiling Water Temperature .................................................................................... 32
Type K – Boiling Water Temperature................................................................................... 33
Appendix XI: On-site Experiment Results................................................................................ 34
Type K #1.............................................................................................................................. 34
Type K #2.............................................................................................................................. 35
Appendix XII: Budget............................................................................................................... 36
Appendix XIII: Gantt Chart ...................................................................................................... 37
4. 1
Abstract
Custom Rubber Company is currently producing rubber dog toys shaped as a
snowman using machine Press 131. The toy producing machine is fully functional now, but it
does not have a precise temperature control. Temperature in some area of its mold is always
exceeding the desired range for about 10 Fahrenheit. Higher temperature causes cracks on the
edges of toys, and lower temperature causes under cure. Uneven temperature distribution within
the heat chamber affects the quality of final products as well as the efficiency of productivity of
the manufacturing process.
There are three possible methods to solve the heat distribution problem. The major heat
loss is through the top and side edges of the heat chamber. Applying insulation boards to the
side edges of the machine to prevent heat loss could be the first method to improve the heat
distribution problem. This method has been proved to be effective. The productivity has been
improved and waste product during production has been reduced. Due to the difficulty of
applying insulation boards on the top edges, a roof is suggested to be installed on the top of the
machine to prevent direct contact between the molds with room temperature air. Reliability of
measurements from thermocouples could also be another cause of the uneven heat distribution.
All new incoming thermocouples and old ones must be tested and calibrated periodically to make
sure they all provide measurements with small errors. Furthermore, in order to prevent magnetic
influence to measurements of thermocouples, Custom Rubber is better to apply a layer of
insulation materials to the head of all thermocouples.
5. 2
Introduction
Background
Custom Rubber Corp. is a leader company in molding rubber parts and products that
meet the specifics of their customers’ needs. Custom Rubber Corp. is dedicated to making
investments in new equipment so that they can provide their customers the most customized and
efficient manufacturing for molding rubber products [1]. They are always pursuing the
committed to quality on all their products. As any imperfect process or problem occurs, they will
immediately diagnose the solve the problem.
Custom Rubber Company is currently producing rubber dog toys shaped as a snowman
using machine Press 131 (See Appendix I). There are two colors of the rubber used to produce
dog toys: pink and blue. Products produced with different color’s rubber will require different
temperature settings. These toys are intended to be bitten by dogs, and the customers of this
“snowman” toy are pet owners. Thus the appearance of the toy is very essential factor.
The toy producing machine is fully functional now, but it does not have a precise
temperature control. Temperature in some area of its mold is always exceeding the desired range
for about 10 Fahrenheit. Higher temperature causes cracks on the edges of toys, and lower
temperature causes under cure.
The heat chamber of the machine includes two plates: The Fixed Platen (Figure 1) and
the Movable Platen (Figure 2). The Fixed Platen contains 4 straight heaters, located vertically,
which have equal gaps between each other. Between one pair of the heaters, there is a
thermocouple used to detect the temperature of surrounding areas. All four heaters and two
sensors are all controlled by a CPU. One thermocouple is responsible of two adjacent heaters. If
one thermal couple detects the temperature of its surrounding areas is exceeding the acceptable
temperature range, it will send feedback to CPU to inform the CPU to take action either to heat
its related heaters up or turn them down.
One possible reason for the exceeding temperature could be that the temperature is not
distributed evenly in the heating chamber. Thus some areas might have higher temperature than
other areas. Product exposed to these higher or lower temperature areas is highly likely to have
quality issues.
6. 3
Figure 1. Fixed Platen Figure 2. Movable Platen
Project Objective
Uneven temperature distribution within the mold affects the quality of final products as
well as the efficiency of productivity of the manufacturing process. The objective of this project
is to diagnose the actual cause of the exceeding temperatures and to provide some solutions for
improvement of the heat distribution problem. Successful solutions could improve the
productivity and decrease waste product during production. It could also potentially save energy
for the company as well.
7. 4
Process Methodology
Hypothesis
Before giving any specific analysis or improvement method, I made a hypothesis based
on the current structure and set up of this machine. The machine has insulation boards at both
ends of the platens (Figure 3). The heaters and molds are clamped within the insulation boards in
order to keep all heat energy be inside of the heat chamber. However, there are not any covers
around its edges. My hypothesis is that the heat loss around the edge of the heat chamber is the
reason to cause the uneven heat distribution inside the heat chamber.
Figure 3. Heat chamber assembly view
Heat Analysis to the original machine
After making my hypotheses, I did heat analysis to the original machine to testify my
hypotheses using thermal imaging camera. The thermal imaging camera I am using is FLIR E4
(Appendix II), which is provided by CRC. The software I used to analysis the thermal imaging is
FLIR Tods.
I took thermal images for the heat chamber during operation both from the top view and
the side view. The set temperature for this machine at that moment is 160°C, 165.56 °C (320 ºF,
330 ºF) for the Fixed Platen and the Movable Platen.
From the top view image, the highest temperature is 161.39 °C (322.5 ºF), which is
located at where the heaters are. However, the lowest temperature on the heat chamber’s edge is
8. 5
57.72 °C (123.30 ºF). The temperature difference is 103.67 °C, which is huge in our case
(Appendix III).
From the side view, highest temperature is 151.11°C (304.0 ºF). The highest temperature
here is lower than the top view’s because the location of the heater is covered by thick metal
plates. Thus the temperature difference of highest temperature is totally reasonable to occur.
However, from the side view, the lowest temperature on the edge is 87.72°C (189.9ºF)
(Appendix III). The temperature difference from highest and lowest temperature is still big
(63.39 °C), but the side edge is still better than the top edge. The reason could be the movable
door on the side of the machine (Figure 4). There is a plastic movable door on the side of the
machine, and it will be closed when the machine is running. However, there is not such a cover
on the top side. This plastic door can prevent the edge of the machine contact with the ambient
air directly, which prevent the heat loss on the side.
Figure 4. Side view of the Machine with door closed
From this heat analysis, I could conclude that the heat is losing from the edge, especially
the top edge, of the heat chamber, and the heat loss is one cause of the uneven heat distribution.
In order to reduce the heat loss, I planned to apply insulation material around the edges of the
heat chamber.
9. 6
Stage One - Applying Insulation Boards to the Edge of the Machine
Since the heat loss is around the edge of the machine, we planned to apply a layer of
insulation material to the edges. The side edges can be installed insulation board very easy, but
we had troubles to install insulation boards to the top edges. There are many air tubes connected
the heat chamber from the top edges, so it is very difficult to stick any insulation boards on such
an irregular surface. Thus, at our first stage, we planned to just apply insulation material to the
side edge to see if this gives any improvement.
Material Selection
The insulation material we chose to apply to the edge is Pyropel MD-18 (Appendix IV).
MD means medium density, so our material is a lightweight board with superior insulation
properties [2]. The lightweight property of this material can provide the machine a relatively
small additional load, which will not affect the machine’s operation. It is formed of semi-rigid
fiberboard, and has a color of gold. The thickness of the insulation board is ¼ in. It has a thermal
conductivity of 0.31 at 93.33 °C (200 ºF) and 0.36 at 204.44°C (400 ºF) [3]. Such a low thermal
conductivity can provide an excellent thermal barrier effect. It can also be continuous used under
315.56 °C (600 ºF), which is suitable for our machine because the maximum temperature of the
heat chamber will not exceed 500 ºF.
Process and Heat Analysis
Under help of operators, the insulation board was finally installed onto the edge of the
heat chamber (Appendix V). Then I used thermal imaging camera to took several sets of picture
both from the top view and the side view. I intended to compare these data sets to those sets I got
from the original machine, and would like to see if we have gained any improvement on heat
distribution.
Stage Two – Installing a Roof on the top
Since the major heat loss is through the top edges of the heat chamber, and we are not
able to install insulation board on them, I planned to install a roof, similar one as the movable
door on the side of the machine, on the top. The top cover and the movable doors on both sides
10. 7
could form a big box that could contain the entire machine inside. The heat could be contained
inside the outer box of the machine, and the outer box could reduce the direct contact between
the heat chamber and the surrounding cold air.
Stage Three –Thermocouple Analysis
Custom Rubber Corp. is using different types of thermocouples on different machines.
On the tested machine, they are using type J spring adjustable Thermocouples (TEMPCO, part
number TCP10220) [3]. However, some other machines are using type K thermocouples.
Type J thermocouples are made of Iron and Constantan, and Type K is made of Chromel
and Alumel. They have different testing range: J has a range of 0 to 2926 °C (32 to 5300 ºF); K
has a range of -184.44 to 1260°C (-300 to 2300 ºF) [5].
Different types of thermocouples could provide different temperature feedback. The
errors between two thermocouples may not be big. However, Custom Rubber Corp. need a very
precise temperature control, small temperature difference could cause waste products. In this
stage, I am going to test if different types of thermocouples gives standard temperature
feedbacks. Are all feedbacks gain from thermocouples reliable?
Experimental Samples Testing
In order to test if type K and Type J thermocouples will give standard feedbacks, I bought
two sample thermocouples from Omega (Figure 5 & 6). The Thermocouple shown in Figure 5 is
a type K rod type thermocouple, and the one shown in Figure 6 is a type J wire type
thermocouple (Omega, CHAL 005). The difference between rod type and wire type is that only
rod type will give the actual testing temperature. The wire type thermocouple is testing the
temperature difference between the end of the wire and the tip of the wire. In the other words, I
will have to add the room temperature to the tested result in order to get the actual temperature.
11. 8
Figure 5. Type K, Rod Type Thermocouple Figure 6. Type J, Wire Type Thermocouples
I tested both thermocouples in boiling water in order to find if they give results close to
100°C, and how close are their results. I heated up water in a boiler, and made sure it is boiling
for a while. Then I tested type K thermocouple in the water first for a few seconds, and used
thermometer data logger (Omega, RDXL4SD, Appendix VI) [6] to record the results. Before I
record data for type J, I first record the room temperature. Then, do the same procedure as I did
for type K.
On-site Experiment
After finishing my sample testing, I planned to do an experiment on the actual machine to
test the reliability of their current thermocouples. Each thermocouple in the machine has a
temperature setting. If the measured temperature is higher than the setting, CPU will shut down
the thermocouple for a while till the temperature is back to desired range. If the measured
temperature is lower, CPU will heat up the thermocouples. Temperature setting for one plate is
always the same in order to make sure the rubber is cooked under the same temperature.
However, if the thermocouples on the same plate have errors on their detect results, the CPU will
give inaccurate directions based on the inaccurate feedback from thermocouples.
This “snowman” machine has 6 thermocouples mounted at different location. The
thermocouples that I cared about were the two located right behind the mold. As showed in
Figure 3. Heat chamber assembly view, the machine has two parts: the fixed platen (on the left)
and the movable platen (on the right). The two thermocouples are located on the fixed platen,
right behind the mold and above the heaters. The two heater is inserted into the thermocouple
12. 9
holes of the machine as showed in Figure7. I planned to replace the original thermocouples with
my type K thermocouples to see if mine gives the same results. The original thermocouples are
connected to the CPU even when I pulled them out. In order to prevent the CPU to keep heating
up the heater when the original thermocouples are exposed to room temperature, I immediately
set the setting to room temperature after I pulled the thermocouples out. Then I insert my type K
thermocouples into the thermocouple holes, and used thermometer to record the results.
Figure 7. Location of Thermocouple Holes
13. 10
Results and Discussion
Stage One - Applying Insulation Boards to the Edge of the Machine
Heat Analysis – 1st Cycle
By using thermal imaging camera, I took another sets of thermal image for the heat
chamber with insulation board during operation both from the top viwe and the side view. The
temperature for this machine is set to be 171°C, 171 °C (340 ºF, 340 ºF) for the Fixed Platen and
the Movable Platen. Due to the schedule of production, they are using different material to
produce which need different temperature. However, this will not affect my heat analysis
In the top view image, the lowest temperature is 172.22 °C (342 ºF), which is located at
where the heaters are. The lowest temperature on the top edge of the heat chamber is 80.33 °C
(176.6 ºF) (Appendix VII). The temperature difference is reduced to 91.89 °C. Compared to the
previous temperature difference (103.67°C), we have gained a little improvement. (Table 1)
In the side view image, highest temperature is 153.94 °C (309.1 ºF). The highest
temperature here is lower than the top view’s because the location of the heater is covered by
thick metal plates. Thus the temperature difference of highest temperature is totally reasonable to
occur. The lowest temperature on the side edge is 88.67 °C (191.6 ºF) (Appendix VII).
Compared to previous temperature difference of 63.39 °C, we still have 65.27 °C (Table 1).
Without Insulation Boards With Insulation Boards
Temp Diff of Top Edges
103.63°C 91.67°C
64.24% 53.23%
Temp Diff of Side Edge
63.39°C 65.27°C
41.95% 42.40%
Table 1. External Temperature Comparison
From the temperature results of top edge, an improvement is shown from the decreased
temperature difference, but temperature difference did not decrease a little. However, this does
not mean there isn’t any improvement of the side edge. Notice that we have applied a layer of
insulation board with a very low thermal conductivity to the side edge. The temperature on the
surface of the insulation board does not represent the actual temperature of the heat chamber
surface. Due to the low thermal conductivity, the temperature underneath the insulation board
14. 11
should be much higher than that on the external surface. Thus, the actual temperature of the heat
chamber surface should be higher than measured temperature, and the temperature difference
should be smaller than 42.40%. As a result, I can say that the insulation board has provided some
improvements to the heat distribution issue.
Heat Analysis – 2nd Cycle
Although the external temperature had provided evidences to show the improvement, but
I still plan to used internal temperature as a reference for further heat analysis. The internal
temperature is shown on the display panel of the machine. It can show temperature for 4 area of
the heat chamber: TC3-Ext.Fixed Platen, TC4-Int. Fixed Platen, TC1-Ext. Movable Platen, TC2-
Ext. Movable Platen (Figure 5). Ext means the outer layer of a platen, and Int means internal
layer of a platen. The temperature for this cycle is set to be 176.67°C (350 ºF) for TC3, 176.67°C
(350 ºF) for TC4, 182.22 °C (360 ºF) for TC1, 182.22 °C (360 ºF) for TC2. The temperature is
allowed to have ±-15°C (5 ºF) tolerance. Thus, the Min and Max Temperature is equal to set
temperature ±-15°C (5 ºF). The fourth column, Read Temperature, is the parameter that I care
the most. This column tells me what is the exact temperature of the platen.
Figure 5. Sample of one internal temperature data set
In order to eliminate the bias of my heat analysis. I randomly chose three cycles in 1 shift
as my sample to do test. I record all read temperatures every 1 minute and 10 second. In a 10
minutes’ cycle, I record 8 groups of read temperature per cycles. All recorded numbers could be
find in Appendix VIII. I found means, standard deviation and percentage of difference (Read
15. 12
numbers compare to set temperatures) for every group. Then found the final mean, std dev and %
of difference for all three sample cycles (Table 2). Unfortunately, I was unable to have a
systematic data record for the original machine. I only have one set of data of the original
machine to conduct my heat analysis (Table 3). By comparing temperature existing temperature
sets, only a little improvement is obtained. However, I am not going to rely heavily on this heat
analysis due to lack of enough comparison data.
Table 2. Heat Analysis for Internal Temp
Table 3. Heat Analysis for Internal Temp
Bad Parts Number Analysis
The last analysis needed to be done is the bad part number analysis. I intend to check if
the bad part number is reduced by applying insulation boards to the machine. There are various
causes of bad parts, but the bad parts caused by heat problems are splits and under cure. I
randomly chose several days of a week, both before and after installed insulation boards, and
randomly picked 1 or 2 shift(s) from that day (Appendix IX). As shown in Table 4, bad parts
number due to the heat distribution issue is decreased so far. Before adding insulation boards to
the edges of the heat chamber, there were about 37.5 splits and 1.25 under cure per shift. After
16. 13
installing insulation boards, the bad part number has reduced to 3.55 splits and 0.33 under cure
per shift. From bad part number analysis, this method has given a huge improvement that
heavily enhanced the productivity and reduce waste products during production.
Without insulation boards With Insulation Board
Splits 37.5 1.25
Under Cure 3.55 0.33
Table 4: Bad Part Number Analysis
Stage One Discussion
From the outer temperature testing, I found that the temperature difference between
maximum and minimum temperature is reduced both from top edges and side edges. Although I
cannot provide sufficient evidence to show any improvement with internal temperature, our final
goal is achieved. The objective of this project is to reduce waste products during production, and
this goal is proved to be achieved with bad part number analysis. By applying several pieces of
insulation boards to the edges of heat chamber, the waste parts rate is significantly reduced.
Stage Two - Installing a Roof on the top
Stage Two Discussion
From the heat analysis for the original machine, I found that the minimum temperature on
the top edge is always lower that on the side edges. Thus, major heat loss occurs at the top edge
of the heat chamber. On both side of the machine, there are safety doors that must be closed
during operation in order to keep operator’s safety. The safety doors do not just provide
protections for operators, they also act as a protection for heat energy. The safety door reduced
the direct contact between the heat chamber and the ambient cold air.
However, there is not such a safety door on the top, and it is very difficult to install any
insulation boards to the top edges because of all the air tubes connected to the heat chamber
through its top edges (Figure 6). As a result, it is very necessary to install a roof to the machine
in order to reduce heat loss from the top edges. As I proved that applying insulation boards to the
edges of heat chamber is actually improved the heat distribution problem, this method will also
work as well.
Due to limitation of time, Customer Rubber Corp. has not install a roof to the machine
yet. I cannot conduct any actual heat analysis for this method so far. However, this reasonable
17. 14
suggestion has been provided to the company. It will not be expensive or difficult for them to
install a roof to the machine. If they find it is necessary, they can always take my advice.
Figure 6. Top edges of the heat chamber Figure 7. Safety door on the side
Stage Three –Thermocouple Analysis
Experimental Samples Testing Results
In this stage, I tested both types of thermocouples in boiling water to see if both of them
gives feedbacks around 100°C. All the recorded data are shown in Appendix X. I recorded one
set of data for room temperature in order to calculate the actual temperature measured by type J.
Then I recorded two sets of data for both type K and type J in boiling water. By taking the means
of those two sets of recorded data:
Type K: 98.79°C
Type J: 104.07°C (include room temperature)
Both results are close to 100°C, but temperature between this two values is about 5.28°C
(41.5 ºF).
Sample Testing Discussion
By doing the sample test, I found that both thermocouples are very close to 100°C.
However, both of them have measurement errors. If I only focus on either one of the two
thermocouples, I found that the error for either one is small: 0.01 for type K and 0.04 for type J.
Both thermocouples’ error is within its allowable error range. However, if I analyze both of them
together, I found that there are 5.28°C temperature difference. 5.28°C (41.5ºF) could be an
essential error for Custom Rubber Company which requires precise temperature control.
18. 15
Due to the big temperature difference of measured results from different types of
thermocouples, temperature settings for machines with type K thermocouples may not suitable
for those with type J thermocouples. Nowadays, Custom Rubber Corp. is using different types of
thermocouples for different machines. Rather than having a standard temperature setting system
for all machines, their process engineer should come up with unique temperature settings for
different machines if the machines have different types of thermocouples. My suggestion is that
test and calibrate their current thermocouples, update their current temperature settings to more
suitable ones. All new purchased thermocouples should also be tested and calibrated before using
in order to make sure that they all have a standard measured results with an acceptable error.
Currently, I haven’t found any efficient ways to calibrate the thermocouples. My suggestion is
that to test all the thermocouples in boiling or ice waters, and choose those which gives close
measured results.
On-site Experiment Results
By replacing the original thermocouples in the machine with my type K thermocouples, I
have my results showing in Appendix XI. By taking means of all data, I have one type K gave a
result of 134.43°C, and the other one gave 130.04°C. There is a 4.39°C (39.90 ºF) temperature
difference between the measured temperatures.
On-site Experiment Discussion
The original thermocouples gave the same measured results when testing in the
thermocouple holes of the fixed platen, but mines showed that the temperatures on the same
holes have a 4.39 °C’s temperature difference. My guessing is that since the original
thermocouples have been used for years, it is possible that those two thermocouples have errors
when measuring. As a result, the CPU was always having a wrong feedback from
thermocouples, and cause it to give wrong directions to the heaters. As a result, I believe all of
their thermocouples in using should be test and calibrate periodically. Replace thermocouples
that have relatively big errors with new ones to make sure thermocouples will always provide
correct and accurate feedback to the CPU.
Magnetic Influence
19. 16
When I was testing the temperature on the surface of the machine mold, I tried to use a
magnet to hold the thermocouple in place. However, the temperature suddenly decreased around
4°C (40 ºF) immediately after I put the magnet onto the thermocouples. After I removed the
magnet, the measured result returned to its actual temperature. As a result, I believe the
measurement of a thermocouple can be influenced by the magnetic force.
Thermocouple is a heat sensor that consists of two different conductors forming electrical
junctions at different temperatures. As a result of thermoelectric effect, thermocouples produce a
temperature dependent voltage, and this voltage can be used to measure the temperature [7]. If a
magnetic force is applied to thermocouples, the voltage used to determine temperatures will be
affected.
Type J is made with Iron and Constantan, and type K is made of Chromel and Alumel.
Both of their measured results can be affected by magnetic force. In the other words, when
people are using thermocouples to do measurements, especially on metals, they should make
sure there is no magnetic force affected on the thermocouples. In our case, molds of the
machines in Custom Rubber Corp are mostly made of metals, they should apply a layer of
insulation material on the surface of the thermocouples to make sure it will not be affected by
magnetic force.
20. 17
Conclusion
According to the actions I have taken so far, I found the heat distribution problem of the
“snowman” machine in Custom Rubber Corp can be improved by three possible method.
1. Applying insulation boards to the edges of the machine
2. Installing a roof on the top of the machine
3. Testing and Calibrating all (new purchased & old) thermocouples periodically
The first solution, applying insulation boards to the edges of the machine, is proved to be
effective. From external temperature analysis, the heat distribution is improved on both top and
side edges. Although I did not collect enough evidence to prove any improvements through
internal temperature analysis, bad part number analysis can demonstrate the productivity is
improved. Before applying insulation boards to the machine, there were about 37.5 splits and
1.25 under cure per shift. However, the waste parts have been reduced to 3.55 splits and 0.33
under cure per shift with this method. The objective of this project is proved to be achieved. The
productivity has been improved and waste product during production has been reduced.
If the applying insulation boards to the edges of the machine can improve the heat
distribution problem well, then installing a roof on the top of the machine should also be
effective theoretically. There ae two safety door on both sides of the machine, but there is not
any covers on the top. Furthermore, it is very difficult to apply insulation boards to the top edges
because of its mess air tube connected to the mold through the top edges. The top edges of the
machine is currently contacting with the room temperature’s air directly. In order to prevent the
heat energy to lose from the top edges, a roof should be installed on the top of the machine.
Reliability of measurements from thermocouples could also be another cause of the
uneven heat distribution. By carrying out sample test, different types of thermocouples is shown
to have relatively big difference between each other. There were about 5.28 (41.5 F) temperature
difference between type K and type J thermocouples. Since Custom Rubber Corp is using type K
for some of their machines and type J for the others, temperature setting for one machine with
type K may not suitable for one with type J. By taking on-site experiment, I found that their
original thermocouples are having inaccurate measured results. There is about 4.09°C between
two of their original thermocouples currently installed in the machine. My suggestion for this
problem is that to test and calibrate all new incoming thermocouples and old ones to make sure
21. 18
they all provide results with small errors. Furthermore, in order to prevent magnetic influence to
measurements of thermocouples, Custom Rubber is better to apply a layer of insulation materials
to the head of all thermocouples.
Future Work
Except method one, applying insulation boards to the edges of the machine, the other two
methods need future diagnose and analysis. My second suggestion for Custom Rubber Corp. is to
installing a roof on the top of the machine. However, due to limitation of time, they are not able
to finish installing the roof by now. I do not have a chance to do any analysis to this method and
prove its effectiveness. In the future, if the roof is installed, further thermal analysis and bad part
number analysis should be applied.
By the end of my thermocouple analysis, I still haven’t found a very efficient way to
calibrate all the thermocouples. My current suggestion is to test all the thermocouples in boiling
water and choose those with close measurements. For future work, a more effective method to
calibrate every one of thermocouples should be carried out.
22. 19
Acknowledgements
The team would like to thank the following people for contributing to the success of this project:
1. Dr. Clare Rimnac – for her advice, help and support.
2. Dr. Alexis Abramson – for her technical advice, thermometer and thermal couples.
3. John Bellett – for giving me relevant documents, information and suggestions.
4. Charlie Braun – for giving me a chance to have this project in Custom Rubber Co.
5. Maintenances – for installing insulation boards and helping me to do the thermocouple
experiments.
23. 20
References
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[2] “Physical Properties,” Albany International, accessed February 20, 2016,
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[3] “Item # MD-18, Pyropel (Rigid and Flexible 600ºF Polyimide Fiber Insulating Boards &
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25. 22
Appendix II: Properties of the Thermal Imaging Camera
http://store.flir.com/product/e4-infrared-camera-engineering-special/ex-series-infrared-cameras
26. 23
Appendix III: Heat Analysis of the Original Machine
Top view of the heat chamber when running
Side View of the heat chamber when running
31. 28
Appendix VII: External Temperature Graph
Top view of the heat chamber when running
Side View of the heat chamber when running
32. 29
Appendix VIII: Internal Temperature Analysis
All Recorded Read Temperature for the Machine without Insulation Board.
All Recorded Read Temperature for the Machine with Insulation Board.
