Toasty Toes Reusable Heated Insole Proposal
Toasty Toes
City College of NY
ENGL 21007: Writing for Engineering
Ms. Crystal Rodwell
5.20.2024
Our product, Toasty Toes Reusable Heated Insole, addresses the inconvenience of wet socks on rainy days in NYC by offering a reusable, non-electronic warming shoe sole insert. Designed like chemical hand warmers, it dries socks and shoes from the inside, perfect for those spending extended time outdoors. Our manufacturing focus lies on the supersaturated solution concentration, cushioning material quality, and managing labor expenses. Our team of chemists is dedicated to creating an efficient solution for generating high temperatures cost-effectively. Quality assurance, backed by substantial funding, ensures reliable products with a lifetime warranty. Labor costs cover material sourcing, assembly, quality control, and shipping, all factored into our production process. Each set, priced at $29.99, comprises two warmers and cushion sleeves, costing $18.64 to manufacture.
Table of Contents
Summary [Tanzina]..…………………………………………………………………………… 1
Introduction [Jim]………………………………………….…………………………………… 3
Background & Purpose [Keeth]…………………………………………………………3
Proposed Program ………………………………………………………………………………. 5
Technical Description [Keeth, Jim] and Graphics [Meher]…………………………….. 5
Innovation Process…………………………………………………………………..……..……. 8
Cost and time…………..…………………………………………………………..……. 8
Material and Costs [Nicholas, Jim]……………………..……………………… 8
Labor Costs [Nicholas]….……………………………………………………… 11
Manufacturing Cost [Nicholas]….……………………………………………… 12
Factors affecting Costs [Meher, Jim]…………………………………………… 12
Appendices …………………………………………………………………………………….. 14
Timeline [Meher] …………………………………………………………………..…… 14
Product Creation Process [Sadman]……………………………………………… 15
Data Sheet [Tanzina]………………………………….…………………..…… 16
Evaluation Techniques [Tanzina]…………..……………………………………18
Supporting Letter [Sadman]…………………………………………………………….. 19
References………………………………………………………………………………………..21
Introduction
Toasty Toes Reusable Heated Insole is an innovative product designed to eliminate discomfort when faced with damp and cold conditions. Amidst a journey in which the fluctuating temperatures and the inclement weather become everyday obstacles, Toasty Toes Reusable Heated Insole is an unwavering and warm product for the journey. The heated soles inserted within the shoe are created on the principals of thoroughness and high-quality materials with a steadfast commitment to excellence. Through materials like PORON®, Toasty Toes Reusable Heated Insole is engineered to offer unprecedented comfort and durability to be able to allow users to explore any weather condition with self-confidence and ease.
As we are a young company, it is not financially responsible for us to sell our product directly and we would go through a wholesale retail process with Dick’s Sporting Goods and Walmart. Our wholesale price will be $29.99 for one product which includes both two warmers and two cushions. The global insole market reached 39.22 billion in 2023. The insole market has a compound annual growth rate of 7.1% every ten years. In the United States, the average forecasted annual revenue growth for a small company is about 480% in the first year, so we think we will have a very successful first year and sell 156,000 pairs of insoles. There are 4,615 Walmarts and 724 Dick’s Sporting Goods in the United States. If each store buys a case of 30 units, then in one year we would have made $4,291,585 after paying for our management costs.
Background & Purpose
The shoe sole was developed using the natural mechanics of the foot, to give the feet maximum movement without hindrance and risk of wandering off or getting injured. Finite element analysis (FEA) simulations, conducted by mechanical engineering experts, validate the structural integrity of a sole under various loading conditions, confirming its ability to flex and bend without compromising durability .
Without ignoring the possible risks associated with extensive use, all the safe measures are embedded into our design of the sole. Thermographic imaging studies, conducted in controlled laboratory settings, confirm that our sole maintains a safe surface temperature, preventing overheating and minimizing the risk of thermal injuries. Additionally, non-slip elements incorporated into the sole’s design enhance traction and stability, reducing the risk of slips, trips, and falls.
The purpose of our product is to create a removable sole that can be placed into shoes to provide heat for the feet. This product is to provide a source of heat for those who experience constant cold or wet feet. This product can be especially useful during the winter, when many people experience cold conditions and have to walk outside in conditions of ice and snow. In many cases, some water from the ice and snow can seep into people’s footwear. This leads people to have both wet and cold feet. This product was made to allow people to have a simple way to keep their feet warm in cold situations. It provides an easy process as the user just needs to apply this product to footwear by just slipping in the shoe.
Proposed Program
Technical Description and Graphics
Toasty Toes Reusable Heated Insole is a heated insole designed to be the perfect fusion of function and comfort leaving cold and damp feet situations as a thing of the past. The insoles are designed to be placed inside the shoes and it utilizes a unique chemical reaction to create heat. This provides a source for heat for consumers who face the discomfort of cold or wet feet, particularly during harsh winter conditions. The insole’s structure is composed of layers of meticulously selected materials and enables maximum movement, while also allowing the same level of support and safety as the original insole as its design underwent stringent testing procedures.
The beginning of the shoe sole’s design starts with shape and size to be more specifically targeted towards the average adult man’s foot. By using podiatric journals and anthropometric studies, the sole structure is required to be well fit on the human foot that minimizes discomfort and provides arch support when it is worn for long hours.
The Toasty Toes Reusable Heated Insole is described from the exterior to the interior, the exterior comprises the top cover and the cushion. The interior, in turn, consists of two main parts: the insulating case and the sodium acetate trihydrate solution. Within the insulating case, there is a subpart, a circular metal disc. The interior components will be described in the following order: insulating case, sodium acetate trihydrate solution, and circular metal disc.
Top Cover
The top cover is the part that comes in direct contact with the foot. It is 10.75 inches in length, 3.5 inches wide, and 0.38 mm thick. It has 1 mm holes spread throughout the cover. It is made of 100% Polyester Mesh. This cover is in the same shape as the sole. This part covers the top part of the sole which includes the insulating case with the solution and metal disc within it.
Polyester mesh fabric keeps moisture at a minimum and increases the breathability of shoes. Additionally, polyester is a low-priced material which reduces production cost and keeps the feet dry with an added benefit of reducing microbial growth.
Cushion
The cushion, made out of PORON®, is at the very bottom of the sole and below the insulating case with the solution. The cushion allows comfort for the person wearing the shoe, as well as support and impact protection. PORON® foam is designed to absorb shock and be as comfortable as possible. Comprehensive test data from material science research institutes certified PORON®’s exceptional suppression effect in cushioning applications which made the users feel extra comfort and reduced fatigue even if it was used for a prolonged time. The cushion is also in the shape of the sole. This part is 10.75 inches in length and 3.5 inches in width.
Insulating Case
The case is used as the insulation of the sole. This case is made of a plastic, Medium Density Polyethylene, or MDPE. This plastic is 10.5 inches long and 3.5 inches wide. This part contains the solution and the metal disc in the sole and prevents them from leaking. MDPE has high levels of insulation properties and maintains its structural quality. This helps to preserve its shape and disperse the impacts and pressures. This case is located under the top cover and is in the shape of the sole. The case can be removed or inserted as the user desires. The user activates the heat by snapping at the metal disc, then inserts the insulated case at the heel of the cushion to use in their shoe. To reuse the device, the user must take out the insulating case from the heel and allow it to melt in boiling water.
Sodium Acetate Trihydrate
The solution consists of Sodium Acetate Trihydrate (SAT) that is dissolved in water. The solution will use 846 grams of SAT for 8 fluid ounces of water. It is located in the insulated case and under the top cover. This solution is colorless and is an aqueous solution. It is used as a reactant for a chemical reaction to produce the heat in the heated sole. Whenever a foot is placed onto the heated insoles, the weight of the foot triggers a chemical reaction in the insole. The user can also manually activate it with their hand. This is due to the Sodium Acetate Trihydrate (SAT) solution stored in each unit, undergoing a phase change from liquid to solid when activated, generating heat that is retained to keep the user’s feet warm and comfortable.
Metal disc
This metal disc is made of stainless steel. This part is 0.5 mm thick and 1 inch in diameter. The disc appears to be silver in color. This subpart is located inside the insulating case and is surrounded by the solution. The stainless-steel disc found in the structure of the insole is the nucleation point to effectively “turn on” the heat. It reacts with the unstable solution to crystalize the supersaturated solution.
Innovation Process
Cost and Time
Materials and Cost
| Materials | Cost | Description |
|---|---|---|
| Sodium Acetate Trihydrate | $8.37 | This component serves as the heating agent within the sole. It undergoes a phase change from liquid to solid when heated, providing prolonged warmth to the wearer. |
| Metal Disc | $0.08 | These discs act as conductors, distributing heat evenly across the sole’s surface. They are crucial for optimizing heat transfer and ensuring consistent warmth. |
| Insulation Case Material | $0.17 | This material surrounds the heating elements, providing thermal insulation to contain heat within the sole while protecting the wearer from excessive warmth. It is chosen for its lightweight and insulating properties. |
| Cushioning Material | $0.68 | Designed for comfort, this material lines the bottom of the sole, providing support and shock absorption for the wearer’s foot. It enhances the overall comfort and wearability of the heated soles. |
| Top Cover | $0.02 | This layer serves as the interface between the foot and the rest of the sole. It is typically made from a durable polyester knit mesh. |
| Total Material Cost per Pair | $18.64 | The sum of these individual material costs represents the total expense incurred for producing one pair of heated soles. |
The Toasty Toes insole comprises five components: the SAT warming solution, insulation case, cushion sleeve, metal disc, and top cover. Each insole requires approximately 846 grams of SAT solution, sourced in bulk from Lab Alley at $335 per 25-kilogram bucket. Consequently, the material cost per unit is $11.17. However, due to our exclusive contract with Lab Alley, we receive a 25% discount on each 25 kg bucket of SAT, reducing our cost to $8.37 per insole.
The eBay-sourced 304 stainless steel roll sheet plates, each with a thickness of 0.5 mm, are priced at $52.45, equivalent to 588 1-inch level circles in total, resulting in a cost of approximately $0.089 per metal disc. The metal sheet measures 39.37 inches long by 11.81 inches wide, providing an area of about 465 in². With each metal disc having a 1-inch diameter and an area of 0.79 in², approximately 588 discs can fit on one sheet of stainless steel. Consequently, we can manufacture 588 discs for about eight cents each.
MDPE insulation material is one of the steps that enable the Toasty Toes Heated Insole to be a successful product. MDPE costs $1.75 per square foot when purchased wholesale. If we purchase the polyethylene sheets from Lundell Plastics Corporation, we can buy a 4′ x 8′ sheet of plastic for $1.75. From one plastic sheet, we can cut 10 soles for $0.175 each, resulting in a manufacturing cost of $0.17 per sole.
We will purchase our foam from iTapeStore, where PORON® by Rogers Corporation is sold at discounted rates. We will buy the 300′ x 45″ sheet of PORON®, costing $3605. Since the average male foot area is about 36.75 inches and the PORON® sheet area is 194,400 square inches, we can create approximately 5289.79 insoles. With this, we can manufacture soles for $0.68 each.
The heated insole in our Toasty Toes line features a moisture-wicking polyester mesh cover from Fabric Wholesale Direct. 200 yards of polyester mesh fabric can be purchased at $1.50 per yard, resulting in lower manufacturing costs. If we purchase a sheet of fabric that is 200 yards by 63 inches for $298, we will have 453,600 square inches of mesh. Since the average male foot area is about 36.75 inches in width, one purchase of 200 yards will yield approximately 12,342.85 soles, allowing us to manufacture each sole for $0.68.
Labor Costs
| Stages | Job Position | Hourly Wage | Labor Hours | Total Cost per week | Annual Salary |
| Material Preparation | Stockers | $12.70 | 40 hours | $508 | $26,416 |
| Industrial Machinery and Maintenance Workers | $25.50 | 40 hours | $1,020 | $53,040 | |
| Component Assembly | Sewing Machine Operators | $10.57 | 40 hours | $422.80 | $22,005.60 |
| Shoe Machine Operators and Tenders | $15 | 40 hours | $600 | $31,200 | |
| Assemblers and Fabricators | $15.47 | 40 hours | $618.80 | $32,177.60 | |
| Manufacturing Chemist | $30 | 40 hours | $1,200 | $62,400 | |
| Quality Control and Testing | Quality Control Inspectors | $18.55 | 40 hours | $742 | $38,584 |
| Testing Technicians | $20 | 40 hours | $800 | $41,600 | |
| Packaging and Shipping | Warehouse Associates | $15.57 | 40 hours | $622.80 | $32,345.60 |
| Shipping Clerks | $15.32 | 40 hours | $612.80 | $31,801.60 | |
| Total Labor Cost for a year | |||||
| Total Labor Cost | $351,571.40 | ||||
Manufacturing Cost:
| Labor Cost per Pair | $2.25 |
| Material Cost per Pair | $18.64 |
| Factory Cost per Pair | $0.096 |
| Total Cost per Pair = Labor Cost per Pair + Material Cost per Pair + Factory Cost per Pair | |
| $20.98 | |
So, the total cost per pair of heated soles, including labor cost, material cost, and factory expenses, is $20.98.
| Total Factory space: | 10,000 square feet |
The factory that we rent out costs $15,000 a year and it includes all the machinery needed, a dedicated storage area, water, and electricity provided. Storage space for raw materials, finished goods, and inventory management, we’ve allocated 2,000 square feet. The rest of the factory space is divided into manufacturing and assembly areas occupying 4,000 square feet, quality control and testing areas utilizing 1,500 square feet, packaging and shipping areas utilizing another 1,500 square feet, and administrative such as an office, a break room and a utility room that uses up the remaining 1,000 square feet of the total 10,000 square feet. With this amount of space, we are able to make 156,000 pairs of soles per year and sell them in bulk to retail stores for $29.99
Factors Affecting Costs
Amongst others, variables that may affect cost are employment benefits, number of hours the factory remains open, and the state of machinery. As Toasty Toes INC. grows in size, employee benefits will increase. For now, the workers are provided with workers’ compensation, disability benefits, and paid time off. When the monthly production quota is not met due to unforeseen circumstances such as staff shortage, material shortage, or machine replacement, employees will have to work overtime. Though the factory will be kept on a strict schedule with maintenance and inspections done on the third Sunday of every month, the company must be able to provide for employees working overtime. If an employee works more than 40 hours per week, they will be paid overtime at a rate of 1.5 times their original salary.
The monthly machine maintenance fees will equate to about 2 – 5% of Replacement Asset Value (RAV). Any unforeseen damages to equipment will require more expenditure to be allocated for its maintenance. When a machine is damaged, it may potentially damage the products it is creating, rendering the created batch useless. The material used to create the defective products will be wasted, resulting in a profit loss.
Alongside manufacturing and labor costs, Toasty Toes has shipping and marketing costs to take the product to market. To bulk ship the toasty toes insole, the costs come to $3 an insole. As each crate can hold approximately 3,000 insoles, after fees and taxes, it would cost $10,283.80 to ship Toasty Toes through the Old Dominion Freight Line Company. This cost illustrates the challenges of providing a stable and quick transport service at a reasonable cost to make sure that the shipment will reach all retailers in a timely fashion.
Along with this, marketing cost is also a fundamental factor in shaping product awareness in consumers and enhancing engagement among consumers. Regarding the specific figures that depend on the launch campaign scope and the expected outcomes, a budget for product launching marketing can run from $10,000 to $100,000 or even more. Such costs cover all of the engaging events to attract not only the consumers but as well the sympathy of the target audiences.
After adding up every cost such as labor, factory, marketing, and shipping the soles, the total annual cost is $386,855. Assuming we sell every pair at $29.99, the total revenue generated from selling all the shoes would be $4,678,440. After subtracting the total annual cost from the total revenue and taxes, our profit would amount to $4,291,585.
Appendices
Timeline
Weeks 1 – 3: The Stockers are in charge of keeping track of inventory. They will order materials at a minimum of two months in advance. This grace period allows plenty of time to resolve late/problematic deliveries and damaged cargo that may otherwise halt the production process. Shipping clerks oversee the receival of products and will check all materials for damage before storing them for production use.
Week 4: The materials are then prepared for the production process and scheduled machine maintenance/inspection is done by Industrial Machinery and Maintenance Workers.
Week 5: Sewing Machine Operators prepare the polyester mesh top cover and case while the Shoe Machine Operators and Tenders prep the cushion and insulated case.
Week 6: Manufacturing Chemists oversee and prepare the SAT solution. The solution is then placed inside of the insulated case along with the ready made metal disc.
Week 7: Assemblers and fabricators assemble all parts of the sole. During this stage, a random population of 1% is selected to be tested for customer safety and satisfaction. The products will be tested by the Quality Control Inspector and Testing Technicians. If products do not meet quality standards they will be discarded.
Week 9: Shipping clerks oversee shipping schedules and prepare finished soles for shipping.
Weeks 10 – 13: Warehouse associates inspect the packaging one last time before shipping the products to their destinations for market availability.
Product Creation Process:
- Material Selection and Preparing Polyethylene Plastics:
- Begin by selecting high-quality polyethylene plastics suitable for durability and flexibility.
- Utilize a precision cutting machine to cut the plastics into pairs, ensuring accuracy for various shoe sizes.
- Packet Formation and Solution Filling:
- Employ a specialized sewing machine to craft a sealed packet for each pair of cut plastics.
- Fill each packet with a precise amount of Sodium Acetate Trihydrate solution, optimized for consistent heating performance.
- Integration of Stainless-Steel Disc:
- Insert a meticulously engineered stainless-steel disc into the solution within each packet.
- The stainless-steel disc should be placed near the top part of the packet for easy activation.
- Seal each packet securely to prevent leakage and ensure long-lasting functionality.
- Creation of outer insole:
- Cut the polyester mesh and PORON foam to precise sizes using the cutting machine.
- Assemble the outer insole by layering the Polyester Mesh over the PORON foam and sewing them together, leaving a section unsewn that matches the width of the insulated case for easy insertion.
- Quality Assurance and Final Inspection:
- Conduct quality assurance tests to validate heating performance, durability, and comfort.
- Perform a final inspection to ensure each Heat Sole meets quality standards before packaging.
- Packaging for Distribution:
- Carefully package each pair of Heat Soles for distribution, ensuring they are well-presented and protected for immediate use.
Data sheet
| Product Name | Toasty Toes Reusable Heated Insole Men’s Shoe Insert Sole Size 10.5 |
| Model Number | TT7369263M10.5 |
| Description | The Toasty Toes Reusable Heated Insole is a sole insert that can be used to warm up the user’s feet. The user will simply flex the metal disc and the warming solution will crystalize and generate heat. This product is best used after the rain when the user’s socks are wet. The foot warmer is reusable and just needs to be boiled to be used again. |
| Dimensions | Combined: 10.75 x 4.5 x 0.7 inches (LxWxH), 9 ouncesWarmer: 10.60 x 4.2 x 0.5 inches, 8 ouncesCushion: 10.75 x 4.5 x 0.2 inches, 1 ounces |
| Technical Specifications | The product is two separate parts: the warmer and the cushion. The warmer is the part that has the chemical reaction and can be inserted/removed during use. The cushion is effectively a sleeve to hold the warmer, that adds comfort and protection to the user’s foot. |
| Functional Features | The solution in the warmer can be used indefinitely as it has unlimited uses. The warmer can reach temperatures up to 140° F internally, but the heat will be reduced by the insulation provided by the cushion. The cushion has padding to absorb the pressure from the user walking to insure the warmer doesn’t break. The foot warmer expends heat for 70 – 80 minutes before it needs to be boiled to reset. |
| Installation | For first use, snap the metal disc to activate the chemical reaction to harden the solution. Then simply insert the warmer into the cushion and insert the insert sole into the shoe. Once the heat has dissipated, remove the warmer from the shoe and cushion and let it boil in hot water for 15 minutes. The crystals will liquify and once cooled the product can be used again. |
| Compliance & Licenses | This product is not TSA liquid compliant as it contains more than 3.4 ounces of liquid. These are the license we have: Sales Tax License and Business Corporation (Domestic) Certificate of Incorporation (DOS-1239-f) |
| Warranty | Toasty Toes Reusable Heated Insole has a 30 day full warranty for the entire product and a lifetime warranty for the warmer. If the warmer is damaged in any way, simply mail back the product and we will replace it. |
| Packaging | The product comes in a cardboard box 12 x 5.5 x 1 inches and enclosed in an airtight plastic bag. |
Evaluation Techniques
The product will undergo evaluation at multiple stages of production. The SAT solution will be chemically analyzed to determine the optimal blend capable of achieving a perfect balance between cost-effectiveness and maximum heat output. We will conduct trials using various concentrations of the supersaturated SAT solution, with chemists selecting the most suitable solution based on criteria such as maximum heat output, user safety, duration of heat retention, and cost-effectiveness. Once the solution is chosen, we will simulate the customer experience by subjecting it to multiple heating and cooling cycles, replicating real-world usage conditions. This process will identify solutions that meet our lifetime usage guarantee, allowing for over 100 uses. Additionally, we will assess the reliability of the insert materials, including the warmer’s plastic case and cushion. Tensile strength tests will be conducted on the plastic to ensure it remains leak-proof under pressure. The cushion material will undergo real-life wear and tear testing to ensure comfort for the user during prolonged use of the foot warmer.
To ensure the safety of our product both during production and post-production, all chemicals will adhere to the regulations set by the Environmental Protection Agency (EPA), which outline safety standards, labeling requirements, and permissible ingredients. During production, we will identify potential hazards associated with the chemical product and implement mitigation techniques to avoid them. Strict quality control policies will be in place to ensure the purity of the product for post-production. We will clearly label chemical products with appropriate warnings, symbols, and safety instructions for the user. For the safety of the consumer, we will use high-purity sodium acetate trihydrate (SAT) free from impurities or contaminants. In its pure form, SAT is considered safe for skin contact, and dissolving it in water will not cause any adverse effects to the user. However, if the user were to get the SAT solution on their skin, we would advise them to immediately wash it off and seek assistance from a healthcare provider for immediate assistance.
Supporting letter
April 4, 2024
Professor Crystal Rodwell
Sadman Rahin
160 Convent Ave
Harlem, NY, 10031
Dear Professor Rodwell,
It has been a fascinating and productive few months working alongside the members of the Toasty Toes group on our outstanding innovation, the Heated Insoles for Shoes. We would love to partner up with you to launch this revolutionary product that would aid millions of people in fighting the harsh cold of the winter.
We have taken the idea of hand warmers, a household item used to warm the hands, and applied it to reusable insoles for the shoes. We are very excited to work alongside you to put our plan in motion and make our product available to people in need. Our group consists of hardworking and dedicated people from different backgrounds. Namely, Sadman Rahin, Keeth Perera, Nicholas Deng, Meher Kapoor, Tanzina Sumona, and Jim Ferdous. We have combined our expertise and ideas together to make this amazing innovation happen.
We have shaped our imagination from the first draft of ideas to identifying all the materials, production process, labor, and maintenance costs. Our product has passed multiple audits and technical checkups and has worked flawlessly in every lab test. We have also provided free samples and the consumers have loved our product in the aspects of both functionality and comfortability.
I have provided a proposal including schedules and all the technical descriptions that will help answer any inquiries you have. If you need more information or have any questions, please feel free to ask.
We hope you will love our product idea and join us in our future ventures. We would love to make you a partner of Toasty Toes and together we can help distribute this product to help people fight the cold in the upcoming winter. We look forward to your response.
Thank you for your time and consideration,
Sadman Rahin, Partner of The Toasty Toes Group
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