Group 5 - Two Power Sanders

Revision as of 15:42, 6 December 2009

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 1

Work proposal

Management proposal

Product assessment

Gate 2

Causes of Corrective Action

Product Dissection Plan

Analysis

Gate 3

Component Summary

Design Revisions

Recommend at least 3 design changes for the product at the component level, including features you would change or eliminate and components you would combine or eliminate. These changes should improve the product by reducing its cost/weight/maintenance or enhancing its functionality/ergonomics/reliability. Keep in mind the products target audience and price point when making changes. Publish these results to your group’s wiki.

1. Change the design of the outer shell - Since the sander will be pushed in a horizontal direction to the surface, the outer shell should be at an angle instead of going straight down on the plane. It would make it easier to maneuver and it would be more comfortable for long term use. It is the same reason that when a person is using a saw they hold it at a 45 degree angle when the direction of the cut is going straight down. It makes it easier and more comfortable to cut.
2. Change the location of the on/off switch on battery powered sander - When holding the battery powered sander the user’s thumb sometimes rubs up against on/off switch causing the sander to turn off during use. The switch can be placed an inch lower than where it is right now so it is still easy to access, but out of the way enough so it won’t accidentally get hit.
3. A longer cord for the AC sander - The cord that comes with the sander is about 9 feet long. If using this sander for large projects often times there are large pieces of wood. This can become a problem and extension cords would be needed. A 15 foot cord would be long enough because there are not many pieces of wood that are longer than that, and it would leave room for an outlet that is far away.

Solid Modeled Assembly

Assembly video

The CAD package I choose to use is Professional Engineer (Pro/E) by PTC. I choose this CAD package because it has simple modeling features and available tutorials.

[1]

When redesigning components for the solid modeling portion of the project we decided to create a hybrid of both sanders. Both sanders had features that we wanted to have in variant design. We liked the simplicity of the inner components (motor/switch/leads) of the P400 sander because they we neatly put together and more user friendly. The P400 also had a nice battery operated power system that we wanted include in our design which allows the sander to be more portable. We also liked the vacuum system in the CFS1502 which gives our sander a dust management capability. The CFS1502 also has better ergonomics with its “mouse” type control. When we put all these functions into one design we may have came up with a totally new product but in reality we only change a couple components:

Components #1 & #2:

[2] [3]

The right and left outer casings were redesigned to allow the addition of features such as the vacuum system.

Component #3

[4]

While dissecting the sanders we noticed that the sand paper Velcro pad and housing were separate components. We decided to combine these components into one which eliminates extra fasteners, and one manufacturing process. This will lower the cost of manufacturing the sander and keep it competitive in the market.

Assembly:

[5]

Aside from those components the rest of the sander is basically borrowed parts from the other two sanders. The battery/motor/switch system is borrowed from the P400, and the vacuum/ bearing spindle assembly is borrowed from the CFS1502. Altogether the consumer is getting the best of both worlds with our variant design.

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: [6]

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

RYOBI Corner Sander

References

Ryobi Corner Cat Power Sander Parts (model #CFS1502)