This document summarizes an FMEA analysis performed on a toaster oven that exploded. The analysis identified potential failure modes of components like the sensor, fuse, wires, switch, and heating rods. An FMEA chart was created listing these failure modes along with their possible causes, effects, and ratings for occurrence, severity, and detection. The analysis found that a defective sensor, fuse, wires, switch, or cracked heating rods could have led to overheating and the oven explosion.

1. Department of Mechanical Engineering
Gannon University
Reliability Engineering (GENG 621)
FMEA analysis for the Toaster Oven that exploded
Dinesh Raj Goud
Introduction:
Failure Mode and Effect Analysis (FMEA) is a proactive tool for
discovering and correcting design deficiencies through the analysis of potential
failure modes, effects, and mechanism, followed by recommendation of corrective
action. It may be described as systemized group of activities intended to recognize
and evaluate the potential failure of a product or process and its effects, identify

2. actions that eliminate or reduce the likelihood of the potential failure occurrence,
and document the process.
Overview of Project:
The purpose of our project is to perform a Failure Mode and Effect
Analysis (FMEA) for Toast-R-Oven. Taking into the consideration of various parts
with their failure modes and failure mechanism, a chart is prepared in which these
failure modes and mechanism are rated under three criteria Severity , Occurrence
and Detection Ranking, followed by the recommended actions.
First have a look at the product with which we are dealing that is
Toast-R-Oven. It is a kitchen appliance used to facilitate Toasting, Baking or
Broiling of food to make food preparation easier. Now a day, customer likes using
oven instead of using Microwave for warm up or baking.
This equipment contains many parts in order to reach its goals. The main parts
are Temperature selector for Toasting & Broil mode; TOAST/Off-On selector;
Toasting Levels Switch(light, Medium & dark); Heating elements; Casing; Glass
Door.
Toast-R-Oven is equipped with a tamper-resistant screw to adjust each function
with its specific time. Those functions are:
1. Baking.
2. Broiling.
3. Toasting.
4. Keeping warm.
Failure Mode and Effects Analysis (FMEA):
FMEA of this Bridge is consists of

3.  Failure Mode :It gives information about “How could
toasting, baking/broiling of food fails”
 Failure Mechanism : The Reason for the failure.
 Failure Effects : Consequences of failure.
 Frequency Ranking(O) : Its gives rate of occurrence, scaled between (1-
10)
 Severity Ranking (S) : It shows seriousness of the failure, scaled
between (1-10)
 Detection Ranking (D) : The ability to detect failure , scaled between
(1-10)
 Risk Product Number(RPN) : Relative importance of the failure (RPN =
S*O*D)
FMEA Table

4. Project Report:
While performing this FMEA analysis of Toast-R-Oven, we Observed that
the inside heating rod (on the upper side) was exploded could be the ceramic
fixtures (explosion caused the ceramic powder to scatter all over) that connect the
heating rods, part of the heating rod assembly. Based upon all the factors that had
led to the toaster oven failure we had calculated related RPN values, by rating
these parts under according to the severity, occurrence and detection ranking.
Observation of Failure of the Toaster Oven
The toaster oven on which we made FMEA is categorized based on the
following parts that had led to the explosion:

5.  Sensor: The sensor when it is unable to sense the temp (Probably a
Defective Sensor). That might had cause overheating in the panel therefore
the heating rods temp went up and caused explosion.
 Fuse: A Defective Fuse can cause an electric overload which probably
would charge high voltage into the heating rod coil causing explosion.
 Wires: The connecting wires also add a factor to the explosion due to poor
wire material and insulation.
 Switch: A defective Switch or loose contact between the Switch and the
circuit could cause overheating and might have caused explosion.
 Heating Rods: Cracked, Bended, defective material of the Heating rods or
the coil inside the heating rods and deformation in the heating rods due to
fatigue might have caused the heat stress concentrated over an area that led
to overheating and explosion.
Based on all these assumption that we made on our observations we had
drawn an FMEA chart and calculated the relative RPN with the Occurrence,
Severity and detection factors.
References:
Text Book: LIFE CYCLE RELIABILITY ENGINEERING by Guangbin Yang
http://www.amazon.com/gp/product/B00006IUW1