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EL-08 August 10, 1995

[Filename: EELUMBER.DOC]

Lumber Sorter

Contributor: Mary L. McAllister

Affiliation IET Dept. / Belk Building

Address: Western Carolina UniversityCullowhee, N.C. 28723

Phone: (704) 227-7272

Email: mmcallist@wcu.edu

Type: Design Problem

Student Time: Five to seven weeks

Location: Lab and research time

Summary

This is intended to be used with junior year electrical engineering students as a design

problem that could incorporate either a microcontroller or programmable logic controllers

in the solution. The student should have a basic understanding of one of the above.

Students should divide into groups of three and brainstorm a solution to the lumber

sorting problem in a furniture factory. The lumber for building the furniture frames is

delivered to the factory in 3ft., 4ft, 6ft, and 7ft lengths. The operations manager wants an

automated conveyor belt system installed so that the three and four foot lengths go to one

department and the six and seven foot lengths go to another department. At the moment

there is no automated system in place.

Report: Five to ten pages plus a sketch of the design and any associated software.

ABET Descriptors

Engr Sci Content: Electrical, microcontroller applications or programmable logic

controllers

Type: Component, systemElements: Synthesis, design evaluation

Features: Development of student creativity, open ended problem, alternative

solutions, feasibility considerations

Constraints: Time, economic factors, safety

Effort: Team

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Lumber Sorter

The Operations Manager of Realistic Furniture Manufacturing wants an automated

conveyor belt system installed in the factory. The lumber for making the furniture frames

is delivered to the factory in three, four, six, and seven foot lengths. The three and four

foot lengths are used in one area of the factory and the six and seven foot lengths are used

in another area. He wants a conveyor belt system designed . The system will have a

sensor that will sense the length of the lumber. The smaller pieces will automatically be

directed to the chair making area and the larger pieces to the sofa making area. The

system should also keep track of the total number of pieces of each length. Daily totals

will be accumulated. At the end of each day the number of pieces of each size that come

into the factory will be downloaded to the main computer. The main computer will keep

track of order sizes and inventory control.

In doing this project you are required to do the following:

Define the problem and the specifications that need to be met.

Brainstorm possible solutions

Explore computer simulation, graphics/visualization, microcontroller/PLC

programming tools that are relevant to and available at the university to help

you with this project.

Set up a simulation using the small conveyor belt , PLC workstation or

microcontrollers.

Conveyor belt Actuator pushes shorter lumber to other conveyor belt

sensor

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EL-08 August 10, 1995

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Lumber Sorter

Report your project results :

1. A minimum five page written report plus a graphical representation of the

design, and copies of any associated software.2. An oral presentation of the design with visual aids.

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EL-08 August 10, 1995

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Lumber Sorter

Engineering Notes:

This problem is perhaps best implemented with PLC controls although a microcontroller

would certainly work. As the professor you could make this just a simple project of

finding a sensor that would sense the length of the wood and then send a signal to an

actuator to push the shorter pieces off onto another conveyor belt going to another area of

the factory. Or you could tell the students to consider economic factors, safety factors,

simulations of alternate designs etc. Also, depending on the equipment you have available,

the students could simulate the design implementation with PLCs, small conveyor belts

etc.

Some issues that could be brought out in class by the professor when the assignment isgiven.

What happens if two pieces of equal or unequal length are laying on top of each

other? What kind of devices are necessary so that you make sure only one piece of

wood is measured at a time?

How fast a system is needed? (board ft./second)

Techniques that could be used to sense the length of the wood?

Safety issues using a conveyor belt.

What kind of conveyor belt is necessary? How wide, how long, what kind of

material?

Cost of conveyor belt system, cost savings over old system? Payback period.

What safety features are necessary? What happens if the wood gets jammed?

Emergency shutoff systems? Types of motors necessary to drive the conveyor belt

system?