Taffy Production Line
Project Overview
The Problem: Modern production lines have to be designed to be as fast as possible
with almost no error. When producing millions of products a day how does a company
keep track of it all? This project helps students to visualize how a product is produced.
The project describes how Salt Water Taffy is
made. The process starts with mixing raw
materials. The mixture is then baked in ovens
and subsequently cooled. The taffy ingredients
are pulled, folded and twisted (color can also be
added at this step). Finally, the mixture is put
into an extruding and cutting machine which
produces 7-gram pieces of wrapped taffy.
In this project students become design engineers.
They will need to set up the factory floor and to
decide how many of each machine the company
needs, how long it will take to make taffy, and
how much raw material is needed each day.
Background Information
In manufacturing taffy, the first step is mixing and heating the raw materials. The
mixture needs to be heated to 256ºF, and then poured onto cooling trays. After the
materials are cooled they are loaded on the taffy puller. This machine consists of
two rotating arms that stretch and pull the taffy. Color and flavoring are added at
this step if necessary. Finally, the taffy is loaded into an extruder machine that
rolls, cuts and wraps the taffy.
These finished taffies are now ready to be packaged and sent out to local
companies.
Specifications
There are some design and machine specifications that need to be taken into
consideration when designing the factory floor.
The taffy is produced by the following process:
 Three different ingredients, X, Y and Z, are first combined in a
large container in a ratio by weight of 10:3:1.
 Four separate types of machines are required: Mixers, Cooling
Trays, Pullers, and Extruders.
 The 20-kilogram batches of the raw materials are mixed and
heated for a period of 4 hours.
1



This 20-kilogram syrup is cooled for a period of 8 hours.
The Puller/Stretcher takes 30 kilogram batches and kneads
them for 4 hours.
The Extruder (which also cuts and wraps) takes 8 hours to
process 30 kg of taffy.
The chart below summarizes the four machine types, capacities, and required times.
Machine
Mixer
Cooling Tray
Puller
Extruder
Capacity (kg)
20
20
30
30
Time Required (hours)
4
8
4
8
Assumptions
As well as these specifications you may come across more assumptions that need
to be made. Assumptions are decisions you make along the way:
EXAMPLE:
Given Specification – Machine A has a 20-30 kg capacity
Discussion – You don’t want to use 20 kg because that is small capacity
but you also don’t want to use 30 because that is the maximum
Assumption – Machine A has a 25 kg capacity
OR:
Assumption – Wear-and-tear on machines is negligible. A machine can
run indefinitely without failing.
Assumptions often make solving the initial problem a little less overwhelming.
Once you have a basic grasp of the problem you can go back and alter your
assumptions so that the problem is more realistic or complete. To start, devise a
list of reasonable assumptions for this problem that makes it solvable, yet still
realistic. You MUST keep track of all your assumptions so you can easily go
back and change them.
2
Design Engineer Goal and Requirement Outline
Goal:
To make this process work in the most effective manner, the process engineer
must determine the amount of raw material, the number of Mixer/Oven machines,
the number of Cooling Tables, the number of Puller/Stretchers, and the number of
Extruder/Cut/Wrap Machines that are required to ensure a continuous 24 hour
operation.
Requirements:





The four different taffy-making machines (mixers/ovens, cooling tables,
pullers, and extruders) require different amounts of time to perform their
tasks, and they have different capacities. Therefore, the first step is to
determine a configuration of the four machines that would produce taffy in the
most efficient way. Decide what combination of these machines would allow
each machine to run continuously, and at full capacity.
Determine the total number of mixers/ovens, cooling tables, pullers, and
extruders that must be available to produce 2500 kg of taffy each day.
Determine the amount of each of the raw materials, X, Y, and Z that must be
available for a day to ensure the process can run continuously and efficiently.
Furthermore, what amounts of X, Y, and Z should be added to a single, 20-kg
capacity Mixer/Oven so that the ingredient ratios are correct?
List all assumptions you have made about the process, such as machine
breakdown and machine maintenance, and indicate how they have affected
your conclusions.
If time allows, a flow diagram of the process for the materials would be
interesting to develop.
Additional information that might be useful
Since all the taffy is manufactured using the same process, it can be assumed that
all the taffy is the same and can be divided up and/or mixed together at any step in
the process. This will not affect the results.
3
Design Engineer
Specification and Assumption Outline
Background Information
In manufacturing taffy, the first step is mixing and heating the raw materials. The
mixture needs to be heated to 256ºF, and then poured onto cooling trays. After the
materials are cooled they are loaded on the taffy puller. This machine consists of
two rotating arms that stretch and pull the taffy. Color and flavoring are added at
this step if necessary. Finally, the taffy is loaded into an extruder machine that
rolls, cuts and wraps the taffy.
These finished taffies are now ready to be packaged and sent out to local
companies.
Specifications
There are some design and machine specifications that need to be taken into
consideration when designing the factory floor.
The taffy is produced by the following process:
 Three different ingredients, X, Y and Z, are first combined in a
large container in a ratio by weight of 10:3:1.
 Four separate types of machines are required: Mixers, Cooling
Trays, Pullers, and Extruders.
 The 20-kilogram batches of the raw materials are mixed and
heated for a period of 4 hours.
 This 20-kilogram syrup is cooled for a period of 8 hours.
 The Puller/Stretcher takes 30 kilogram batches and kneads
them for 4 hours.
 The Extruder (which also cuts and wraps) takes 8 hours to
process 30 kg of taffy.
The chart below summarizes the four machine types, capacities, and required times.
Machine
Mixer
Cooling Tray
Puller
Extruder
Capacity (kg)
20
20
30
30
4
Time Required (hours)
4
8
4
8
Assumptions
As well as these specifications you may come across more assumptions that need
to be made. Assumptions are decisions you make along the way:
EXAMPLE:
Given Specification – Machine A has a 20-30 kg capacity
Discussion – You don’t want to use 20 kg because that is small capacity
but you also don’t want to use 30 because that is the maximum
Assumption – Machine A has a 25 kg capacity
OR:
Assumption – Wear-and-tear on machines is negligible. A machine can
run indefinitely without failing.
Assumptions often make solving the initial problem a little less overwhelming.
Once you have a basic grasp of the problem you can go back and alter your
assumptions so that the problem is more realistic or complete. To start, devise a
list of reasonable assumptions for this problem that makes it solvable, yet still
realistic. You MUST keep track of all your assumptions so you can easily go
back and change them.
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Rubric
5 points
4 point s
3 points
2 points
1 point
Excellent
Quality
Satisfactory
Needs Improvement
Unacceptable
Category
Value
1. Mathematical concepts are identified and correctly applied
5
2. Assumptions made during problem are clearly articulated
5
3. Work to support solution(s) is provided
5
4. Explanation, justification and point of view are clearly articulated
5
5. Investigation of possible solution(s) is thorough
5
6. Possible solution(s) is/are reasonable
5
7. Units of measure are correctly used
5
8. Project is typed and double-spaced (font no larger than 12 point)
5
9. Mechanics are correct (spelling, grammar, punctuation etc.)
5
Total Points
45
Extension 1:
Extension 2:
Extension 3:
6
Score
Extensions
Production Efficiency
Previously, it was assumed that every machine in the taffy production line was 100%
efficient – ingredients were turned completely into products with no losses. This is of
course never the case in real life; the efficiency of a machine must be less than 100%.
For the taffy production line, make the following assumptions about the efficiency of
each machine:
Machine
Efficiency
Mixer/Oven
93%
Cooling Tray
98%
Puller
95%
Extractor
98%
For example, an efficiency of 93% means that on average, 93% of the ingredients added
to a machine are converted to usable product and 7% of the material is wasted. Assume
that the wasted material cannot be recycled into the system.

Using these values for machine efficiency, compute the efficiency of the entire
production line: what percentage of raw material (by weight) eventually becomes taffy?
For 100% efficient machines, it was previously determined that 3 Mixers/Ovens, 6
Cooling Trays, 2 Pullers, and 4 Extruders constituted the most efficient production line.
However, the situation changes when the production efficiency is less than 100%.
Consider the following flow chart that shows the flow of ingredients through a
production line whose efficiency values come from the table above:
3 Mixers/Ovens
60 kg
93%
4.2 kg
3 Cooling Trays
55.8 kg
98%
2 Pullers
54.68 kg
1.12 kg
2 Extractors
95%
2.73 kg
51.95 kg
98%
TAFFY
50.91 kg
1.04 kg
Red arrows represent losses due to inefficiency. Due to these losses, as the material proceeds
along the production line, each machine operates further below capacity. For example, the 2
Extractors together have a capacity of 60 kg, yet only 51.95 kg can be put into those
machines because previous losses have occurred.

Your task is to reconfigure the production line with the efficiency of each machine in
mind. Ideally, each machine in the series should be operating continuously and as close
to full capacity as possible. Justify your configuration mathematically and provide a
verbal explanation.
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Extensions
Breakdowns & Maintenance
Single Breakdowns
Originally, the assumption was made that all of the machines involved in the taffy
production line could run indefinitely without problems. In the real world, machine
breakdowns do occur, and companies must be prepared to handle this problem. To begin
studying breakdowns in the taffy production line, consider the effect of a single machine
failure on the system.
Work with the original optimal “unit” of machines: 3 Mixers/Ovens, 6 Cooling,
Trays, 2 Pullers, and 4 Extruders. Suppose that one machine on this taffy production line
has broken down. Since each machine has a different capacity and operating time, the
effect of a machine failure depends on the type of machine that failed. Examine four
cases: the failure of a single Mixer/Oven, Cooling Tray, Puller, and Extruder. For all
four machines, assume that a failure can be repaired in one operating period (four hours
for the Mixer/Oven and Puller, eight hours for the Cooling Tray and Extruder).
For each of the four machine breakdown cases:
 Determine the effect on the system: How much product is lost?
 How much time elapses until the line has resumed full capacity?
Maintenance Plan
It is decided that each machine in the production unit will be shut down for
maintenance once each week. The company believes that this will greatly lower the
incidence of unpredictable and costly breakdowns. Even so, shutting down machines for
maintenance results in lost machine time, which means less taffy produced, which means less
money. With that in mind, devise a 7-day maintenance schedule such that production losses
are minimized but each machine receives one period of maintenance each week. Assume
that this procedure can be completed in one operating period (four hours for the Mixer/Oven
and Puller, eight hours for the Cooling Tray and Extruder). With your schedule, by how
much does production decrease due to machine shutdowns?
Note: You may assume that no spontaneous machine breakdowns occur; the only machine
downtime is for maintenance.
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Extensions
Adding Dye
One Dye
Taffy is commonly dyed to be any number of colors. Due to the nature of taffymaking, dye must be added during the pulling process. To investigate the addition of
dye, add the following Specification to the problem:

A fourth material, red dye, is added to the mixture during the pulling process in a
ratio of 1:8 by weight.
This addition of new material during the production process will change the optimal
configuration of machines. For example, the Pullers can no longer be filled to full
capacity initially, because additional material (the dye) must be added during pulling.


Determine a new configuration of machines so that the process can still operate
continuously and as efficiently as possible.
Determine the total number of mixers/ovens, cooling tables, pullers, and extruders
that must be available to produce at least 2500 kg of taffy each day.
Two Different Dyes
A factory would typically make taffy of many different colors, rather than only
one. To make this investigation of dyeing more complex, now consider two different
dyeing processes. Replace the Specification about red dye from above with the following
guidelines:


A factory makes red- and blue-colored taffy. To make red taffy, red dye is added to
the mixture during the pulling process in a ratio of 1:8 by weight. For blue taffy, a
different dye is added during pulling in a ratio of 1:9 by weight.
The factory needs to produce at least 3600 kg of each color of taffy per day.
As in the one-dye scenario, Puller machines cannot be filled to capacity initially; space
must be left for the dye. In addition, once the taffy has been dyed, different-colored taffy
obviously cannot be recombined. Answer the following questions regarding this new
scenario.


Determine a new configuration of machines so that the process can still operate
continuously and as efficiently as possible.
Determine the total number of mixers/ovens, cooling tables, pullers, and extruders
that must be available to produce at least 3600 kg of each color of taffy each day.
9