ARTIGO PRENSA DIDÁTICA

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Educational Compression Testing Machine for

Teleoperated Teaching of the metals flow curvesLucas Boeira Michels

Instituto Federal de Santa Catarina

Yuri Crotti

Luan Carlos CasagrandeVilson Gruber

Roderval Marcelino

Universidade Federal de Santa Catarina

Lirio Schaeffer

Universidade Federal do Rio Grande do Sul

Abstract — Today in the world, there are numerous

educational experiments teleoperetad to support the teaching of

engineering, but the number of this remote experiments in the

area of metal forming is not enough. This article will show a new

remote experiment called Educational Compression TestingMachine teleoperated via Internet. This experiment will create

the possibility for the students to do a real compression test and

to collect force applied in the specimen and size data during the

experimentation process. These data will be useful for the

construction of flow curve of metals aiming the calculation for

projects of formed parts. The remote experiment is divided in

two basic parts: the website and the Educational Compression

Testing Machine. For data acquisition, control and data

processing, as well as the interface between the user and the

machine was used the Raspberry Pi that is a small size and low

cost microcomputer. The reduced structure for the experiment

and the low cost were defined as priority for this work, aiming tofit the necessity of undeveloped countries.

Keywords — Teleopered Experiment; Remote experiment, fl ow

curve; Raspberr y Pi; Compression testing machine;

I.

I NTRODUCTION

Remote experiments are not a novelty in engineeringeducation [1]. However, just few topics were contemplatedwith teleoperated experiments. Recently we had initiatives tocreate experiments in the field of production engineering as[1,2]. Nowadays the interest in this type of development isgrowing because the number of experiments is not enough. Inthe work of [2,3] was developed a teleoperated lab from acommercial testing machine traction with support of robots forreplacement of the specimen. However, the final cost to

develop this project was high, and consequently, undeveloped

countries would not be able to afford this project.

II.

FLOW CURVES AND CONFORMATION

Flow curves are essential in metallurgical engineering,mainly for mechanical forming area, because this is the best

way to get the parameters from a metal and consequently it is possible to predict its behavior during the forming process.These curves are obtained from tension and compressiontesting. However, the best mechanism to achieve the flow

curves in a forming process is the compression approach [4] because disruption in brittle materials occurs after the elasticzone and therefore the data are not very significant.

Flow curves are made with the force data, displacement(size range), height and initial and final diameter of mechanicaltest specimens.

It is possible to get all the parameters and necessary

information useful for the mechanical design manufacturingusing equations and mathematical graph software.

III. ARTICLE OBJETIVE

This work will present an Educational Compression TestingMachine teleoperated via Internet that has the objective to provide the necessary data for the construction of flow curves.This experiment is different from others because it wasdeveloped in order to facilitate the data acquisition and itsdevelopment. In addition, this is an educational machine, andconsequently, the mechanical components have a smaller scale.The electronic components have reduced complexity ofconfiguration and they have a lower cost too.

IV.

R EMOTE EXPERIMENT COMPONENTS

The experiment consist of the following components(Figure 1):

A.

Compression Testing Machine

This component is a mechanical structure that isresponsible for the processes of compression of the specimenthrough the force of a hydraulic cylinder (Figure 2). This is themain component of the experiment because this is the placewhere occurs the phenomenon under study. The machine hastwo different sensors that are responsible to measure force and

Fig. 1 – Overview of the Experiment



displacement. These sensors are fundamental for theexperiment because they will register the behavior of themechanical test specimen during the experimentation process.In addition, they will provide the necessary data that isessential for the construction of the flow curve of the metal.

The microcomputer will control the streaming of videothrough a webcam. The replacement of specimen will berealized by a low cost system with a step motor that will createa linear movement of advancement and return.

Fig. 2 - Educational Compression Testing Machine Tele Operated

B.

Hydraulic Unit;

The Hydraulic unit and the pumping oil system areresponsible to generate the necessary flow of oil to thehydraulic cylinder.

C. Motor Drive Panel;

The motor drive panel is a fundamental part to start the pump of the hydraulic unit. This panel has a frequencyinverter to control the motor start and the voltage conversionfrom 220V to 380V.

D.

Data Processing Panel;

The data processing panel has a component calledRaspberry Pi (Figure 3).

Fig. 3 - Raspberry Pi

This equipment is responsible for the data acquisition fromthe sensors, to stream the video from the webcam, to controlthe relays, motor and the lamps, and to control thecommunication between the user and the machine through the

network. Raspberry Pi is a modern, small and low costmicrocomputer that additionally to all the computer functionscan do the data acquisition, control and signal processing [3].

E.

Electrical Power;

Electrical power must be 220 volts to charge all thecircuits in the control panel and others circuits.

F.

Devices with Internet Access;

All the devices with network access will have access to theexperiment. Consequently, the user will be able to access theexperiment from everywhere with network access at anytime.

G. Internet Access;

Internet is responsible to allow the interface between themicrocomputer and the users.

H. Remote Experiment Website

The website will provide the control and monitoring of theexperiment in real time. The web page was developed usingthe learning management system MOODLE. This important

tool created the possibility to export the data from theexperimentation process and to explain material about thisexperiment and the flow curves.

V.

EXPERIMENTATION PROCESS

In the beginning of the process, the user will need to accessthe Web Site www.labtel.com.br and chose the optionEducational Compression Testing Machine. In this new

environment, the student will be able to start theexperimentation and to watch the execution process. Duringthis performance, the webcam will show the low cost system

positioning the specimen and after that, the compression anddiscard of the specimen. Finally, the user will be able to get allthe output data and to use spreadsheets in the Web page tocalculate and to create the flow curve. The dimensions of the

specimen are given in the beginning of the experiment. Beforecreating the flow curve, the learner can watch instructional

videos and read texts about the subject.

R EFERENCES

[1] C. Terkowsky, I. Jahnke, C. Pleul né: Burkhardt, R. Licari, P.

Johannssen, G. Buffa et al. Developing Tele-Operated

Laboratories for Manufacturing Engineering Education.

Platform for E-Learning and Telemetric Experimentation

(PeTEX). Internacional Journal of Online Engineering i-JOE,

2010. 60-70.

[2] L. B. Michels, V. Gruber, R. Marcelino, J. B Silva, L.

Schaeffer. Using remote experimentation for study on

engineering concepts through a didatic press. 2nd

Experiment@ Internacional Conference - Exp'at. Coimbra:

[s.n.]. 2013. p. 191-193.

[3] C. Pleul, C. Terkowsky, I. Jahnke, A. E. Tekkaya. Hoslistical

integrated laboratory experiments for engineering education in

manufacturing technology. WEE2011. Lisboa-Portugal: [s.n.].

2011.

[4] C. Terkowsky, C. Pleul, I. Jahnke, A. E. Tekkaya. Platform for

E-learning and Telemetric experimentation (PeTEX): Tele-

operated Laboratories for Production Engineering Education.

Global Engineering Education Conference (EDUCON). [S.l.]:

[s.n.]. 2011.

[5] L. Schaeffer. Conformação Mecânica. 3ª Edicação. ed. Porto

Alegre: Livre Editora, 2009.

[6] S. Goodwin. Smart Home automation with Linux and

Raspberry. 2. ed. [S.l.]: [s.n.], 2013.



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ARTIGO PRENSA DIDÁTICA