Toaster Redesign

Overview

Our team was given the Proctor Silex 2-Slice Toaster (seen below) to dissect and analyze with the goal to recommend changes to reduce part count and assembly time. We pieced together a step by step assembly guide for the toaster, and used techniques to identify potential parts that could be consolidated or removed. After iterating on design concepts, we reduced the 63 part (excluding heating and electronic components) Silex toaster to just 24 parts. The reduction in parts also led to a reduction in assembly steps from 28 to 11. Our new design maintains the simplicity of a toaster, while greatly reducing manufacturing and assembly costs.

Class
Design for Manufacturing and Sustainability
Role
Mechanical Engineer: DFMA Analysis, Material Selection, New Part Functional Design
Date
October 10, 2018

Process

Proctor Silex 2-Slice Toaster

This toaster retails for the price of 12.99 on Amazon. Due to the low price tag, we imagined there would be few parts to redesign. We were wrong.

Toaster Disassembly

While disassembling toaster, we recorded each part's function and gave it a name to help with future identification. We counted 63 total parts excluding the electronic and heating components that were out of the scope of the project.

Reassembly

Once fully disassembled, we embarked on the journey to put it all back together(ish) using the instructions we had just created. In doing so, we identified that 20 parts could be removed from the current design to reduce cost.

Identifying Functional Requirements

Through the process of disassembling and reassembling the toaster, we derived all of the actions that go into toasting bread. We added these requirements and more to a Quality Function Deployment, where we ranked the current toaster and two competitors relative to the importance to the customer.

Quantifying Functional Requirements

Through this we identified that the toaster needed temperature resistant surfaces, a simple control interface, cleaning feature, and compatible with multiple types of bread. We quantified this to the following

  1. A surface temperature no greater than 32°C under operation
  2. Less than 7 total buttons
  3. Less than 10 seconds of cleaning time
  4. Should support more than 5 types of bread for toasting

Solution Concept

Redesign Ideation

After much ideation and brainstorming, we landed on a tray design similar to a toaster oven. It consists of 4 main components. A stainless steel top casing, a L - shaped bottom and front face made of heat resistant phenolic, and a stainless steel slider to enclose on the bread. A single dial would control the duration of the bread toasting, and a led notification light and sound would notify the user that the bread has finished toasting. The brackets surrounding the bread tighten with the opening and closing of the drawer.

Concept Rendering

After sketching the concept, we creating a rendering and made a few minor changes. We changed the placement of the control interface to be on the side with the sliding drawer, as we felt it was more intuitive. (Electronic housing not shown)

Concept Rendering

Other final design choices include a thermochromic paint on the stainless steel top cover, which would help indicate its temperature similar the heated coils in the Silex toaster, and a safety an auto-circuit breaking function when the drawer is opened.