# Group 5 - Two Power Sanders

Ryobi Corner Sander
Battery Powered Ryobi Corner Sander

## Introduction

For the MAE 277 reverse engineering project, our group was given two electric powered RYOBI corner sanders (Model #’s P400 & CFS1502). One of the sanders is powered by an electric cord and the other is battery-powered. Throughout the semester, we will be dissecting and analyzing the components that make these two products work. We will then compare the different results for the two sanders to figure out which one is more efficient than the other.

## Gate 3

### Engineering Analysis

Problem Statement: If you use a 400 ft extension cord for the power sander, will that 400 foot extension cord be enough to power the Ryobi power sander.

Diagram: [1]

Assumptions:

• For the sander to run it needs 120 volts
• The sander will not be able to run with 60 volts supplied from the cord
• The current for the sander to run is 1.2 A
• The radius of the extension cord is 1.5 mm
• The extension cord is made out of copper
• The temperature is 20 degrees Celsius
• The resistivity is 1.62 x 10-8
• The cord is made out of copper

Governing Equations:

• R = V/i
• R = (resistivity) * (L/A)
• A = π*r^2

Solution:

R = V/i R = 60/1.2 = 50 ohms R = (resistivity) * (L/A) A = 3.14 * .00152 50 = (1.62 x 10-8) *(L/7.07x10-6) L = 71,590 ft

400ft < 71,590ft So the 400 ft extension cord would be enough to power the Ryobi power sander.

Discussion:

The 400 foot extension cord would be able to deliver enough power to the power sander. The 400 foot extension cord won’t be enough because it would take 71,590 feet of extension cord until the power sander wouldn’t be able to have enough power to run. This is true only under the assumption that the power sander would not work at 60 volts. However any higher voltage that the sander would not work at would mean the length of the cord would be less than 71,590 ft.

## Gate 4

### Assembly

#### RYOBI Battery-Powered Corner Sander

 Step Description Easiness Tools Used Pictures 1 Place the electric motor and switch assembly into the housing so that the spindle is placed into the lube. This part is fitted into the casing. The wires should be tucked into the outer parts of the housing so they will not be pinched when it is put together. 1 Hands Casing and Motor 2 Place the black switch in it\'s fitted housing next to the motor. Then place the yellow on/off switch over the black one. 1 Hands Casing and Motor 3 Place the small metal clip against the yellow switch to stabalize the switch. 3 Hands Metal Clip 4 Place the gears and bearing with counterweight into its fitted spot in the housing. The gears should be able to now spin the spindle. 1 Hands Casing and Motor 5 Place the two white connectors into the housing. The smaller one fits in below the switch assembly. If looking at the sander with the motor to the top right, the larger connector will be placed about an inch to the left of the gears in it\'s fitted spot. 1 Hands Casing and Motor 6 Slide the other casing onto the casing with the motor, gears, and switch assembly. It should match up so that connectors go into their fitted spots. The connectors should now be seen on the botton of the sander. 2 Hands Casing and Motor 7 There are eleven Phillips head #2 screws that need to be screwed onto the outer casing. There are designated holes for the screws, and they are the only holes on the sander. 2 Phillips head #2 screw-driver Casing and Motor 8 This is the orange piece that can be taken out by hand. It is located along the handle next to the rubber grip 1 Hands Casing and Motor 9 Snap the velcro pad housing onto the bottom of the sander. It snaps on using the connectors. 1 Hands Casing and Motor 10 There are five phillips head #2 screws that need to screw the sand-paper velcro pad onto the sander. 2 Phillips head #2 screw-driver Casing and Motor