Virtual Lathe - Sacred Heart College
Sacred Heart College, Auckland, is a Catholic Marist boys' school with 1015 Year 7-13 students. At junior level (Years 7-9) four technology areas – Electronics and Control, Resistant Materials, Food and ICT – are compulsory, with classes rotating each term. From Year 10 onwards students have the opportunity to select one of these technology areas to work in as an option subject. A computer room is available for exclusive use by the technology department.
Francois du Plessis teaches Electronics and Control Technology; the main focus of this area being robotics. Students work with electronic circuits but also use Materials Technology in the design and making of robots. Production processes include vacuum forming, welding, lathe work and circuit making.
In 2006 Francois had a combined Year 12/13 class which had 15 boys working at Level 2 and six at Level 3. After agreeing, with the support of his Head of Department, to take on the Virtual Lathe trial with his Year 13 students, Francois wanted a project that involved both Materials Technology and Electronics and Controls. He decided on a keypad operated safe since this involves complex microcontroller technology, lathe work, welding as well as spray painting. Students would also have the opportunity to use a wide range of timbers and plastic manufacturing processes.
Brief
Students were given the task of designing and making a keypad operated safe for a client. They would make the hinges and a knob or handle for the door. Francois expected them to learn the skills of using a centre, parting, drilling, turning and knurling on the lathe. They had to negotiate their own client from the Sacred Heart College staff.
Students were given instruction sheets which guided them step by step through the different stages in the technological process. Their first task was to identify and interview their clients. After obtaining the client's needs and preferences through an interview, they had to write a design brief with specifications. Students were able to use this to work towards Achievement Standard (AS) 90620.
Francois imposed some constraints on the projects, such as the budget - $60 for electronic parts. Materials used had to be those available in the school workshop - mild steel, sheet metal and a range of timbers and plastics. The use of a centre lathe during the manufacturing process was compulsory as was evidence they had used the Virtual Lathe.
Students did most of the research through accessing the internet as well as looking at safes commercially available. Most of the class used Google SketchUp
to draw a number of concept ideas and working drawings of their final design. This software proved to be very popular amongst the students due to its ease of use.
Development
Most students already had a sound knowledge of microcontrollers as this had been taught since Level 1. Their challenge was to connect a PICAXE -28 microcontroller to a numeric keypad, and then to programme it to utilise a four digit pin number to trigger the locking device. Another design challenge was what to do in the event of a circuit malfunction. This section of the unit was used to work towards AS 90681 and Unit Standard 19747.
The students were next introduced to the metal lathe, with a brief look at the history and different parts of a lathe. They were also shown a number of video clips and PowerPoint presentations that Francois had downloaded from the internet through Yahoo Videos. These focussed mainly on the four processes: turning, facing, parting and drilling.
The Virtual Lathe software was one of the main attractions of this unit. Students were given the task of turning a set of "bullet hinges” on the simulation software, this exercise covering the four processes. The class then covered taper turning which they used in their design of a knob for the safe door.
The skills attained through this software were then put into practice on a real metal lathe, with the students fabricating what they had designed on the software.
As most of the students had no prior welding experience Francois decided to use 5mm steel plate and channel iron, as this is much easier for inexperienced welders to use. The students had to use the power saw to cut the materials into the required size, as specified by their clients.
Working on these advanced skills in Materials Technology enabled students to work on AS 90687.
Results
The finishing stage involved the students grinding and cleaning their safes followed by painting with primer and a final coat of paint. Lastly they fitted their electronic circuit and solenoid switch.
Francois reports that students were very excited about this project from the start. Not only did they have the opportunity to create a quality project with 'take home' value, but they were also challenged with a real life situation involving stakeholders. Students had the opportunity to apply their knowledge of microcontrollers but were also faced with a number of problems, especially with regard to power supplies.
According to Francois the Virtual Lathe software is an amazing teaching tool and resource for students and teachers. In addition to boosting student confidence when working on a real lathe, it teaches the core skills of lathe work. The combination of the software and the actual lathe was one of the highlights of this project.
Francois notes that the software feature in which student activities could be viewed in the form of a screen recording, is not a very effective method, since teachers do not have time to monitor every student's work in this way. He feels it would be more effective from a teacher's perspective to have the software automatically record data of student progress on a central database, one which would show individual progression as well as the different progression levels.
He also noted that the software allows too much for student error. Students are allowed to make serious errors on the software without any consequences. He thinks that the programme should not allow, for example, someone to make a 10mm cut at a time.