In a not so distant past, making a metal part depended on the knowledge and the precision of the operator. Today, machines like lathes and milling machines, which shape anything from a screw to an aluminum alloy wheel, have coupled to them electronic equipment called CNC, which stands for computerized numerical control. The CNC receives information on how the machine is going to carry out an operation, and passes it on to the system using electronic signals, responsible for setting the motors in motion. The machine accordingly carries out all the movements for the production of the desired part, in the sequenced programmed and without the intervention of the operator. A process that needs to be understood by every student of professional training courses in the area of mechanics and by future engineers.
With the objective of facilitating this learning, a student and a professor from the Mechatronics and Mechanical Systems Department of the Polytechnic School of the University of São Paulo (Poli-USP) developed a software dubbed as CNC Programmer, which simulates an industrial environment and acts as if it were, in effect, a planner, analyzing all the parameters involved in the task proposed.
“The software helps one to understand how the process is carried out, because it programs the manufacturing time of the part and simulates all the steps need to carry out the production of a part”, says Professor Marco Stipkovic Filho, the coordinator of the project at Adiante Informática, a company formed by him and former pupil Sérgio Luís Rabelo de Almeida, who today gives lessons at Mackenzie University and the Mauá Technology Institute. With funding from FAPESP’s Small Business Innovation Research Program (PIPE), the software is ready and has already been sold to National Service for Industrial Training (Senai in the Portuguese acronym), which has installed it at 14 units scattered over Brazil. The Federal University of Pernambuco (UFPE) has also required the program for the mechanical engineering course.
CNC language is based on alphanumeric sentences that can be programmed by the pupil or imported from already existing programs. All in Portuguese, to facilitate the learning process. If a parameter is keyed in incorrectly, the mistake is pointed out with a warning message. “The resources were implemented for the pupil to be able to learn effectively”, says Almeida.
Protection and quote
The CNC Programmer was developed with open architecture, which allows modifications in its use, under the supervision of the company, according to the machine and the needs of the customer. To protect the program from pirate copies, a small component was developed by the researchers to be put at the back of the computer. The system only works if it has this part, which is part of the software package.
Amongst the functions of the program are how to select suitable tools and to establish the conditions for machining, besides calculating how much electricity the machine consumes to manufacture the parts. The tools and the machines are chosen in accordance with the geometry of the parts. The cylindrical ones are machined on lathes, whereas the prismatic ones – with the format of rectangular prisms – are made on milling machines. Furthermore, the software chooses the machine that has adequate power for carrying out the programmed task, simulates the manufacture time and generates the quote with precision, without the need to make a pilot part. “The software makes it possible to see the parts in three-dimensional format, allowing the pupil to look at it from various angles before it is made”, Stipkovic says.
The other software that exists in the market is intended only for professionals that are already working in industrial production. “The majority is in English and have prices that are prohibitive for schools”, says Almeida. Sold at R$ 2,000.00, the CNC Programmer is compatible with the main machines in the market.
Development of computing tools for teaching and apprenticeship in CNC machining processes (nº 01/08335-4); Modality The Small Business Innovation Research Program (PIPE); Coordinator Marco Stipkovic Filho – USP/Adiante Informática; Investment R$ 26,520.00 and US$ 15,039.00 (FAPESP)