TRIZ MOTIVATED DESIGN OF A TWO-ARMED MANIPULATOR FOR THE STAMPING INDUSTRY

摘要

Abstract We present a model of a two-armed robot developed using a TRIZ-inspired methodology. The methodology has been applied to solve a problem with the local stamping industry which currently utilizes manual labor for the job. The quality and quantity of products produced even by trained machine operators is much lower than expected of a competitive industry. We have developed a new type of robotic manipulator that, with the help of additional parts, replaces two human operators. The new manipulator model is economical and efficient in terms of design, manufacture and control. Keywords: TRIZ, ARIZ, Automation, Robotic manipulator, Stamping 1. Introduction A large number of repetitive processes in the Mexican industrial sector are currently being performed using human labor. This makes it difficult to maintain standards, optimize the use of machines and boost Mexico’s competitive standings with the rest of the world. Rapid advances in this sector, together with an increasing international pressure to enhance product quality and reduce manufacturing time and costs, require automation of these processes. Stamping (or printing) machines are very common in the plastic injection market. Every little plastic piece in the need of a stamp (markings) must go through a stamping machine. Given the low manufacturing costs in Mexico and other developing countries it is not always convenient to change to new, more efficient, mechanical machines. Automated machines with external (low cost) robots may be one of the best solutions due to low costs and simple external installation. In this paper we attempt to solve a similar problem with a local industry making control knobs for kitchen stoves. The industry currently utilizes manual techniques for the stamping of these knobs (the stamping machine itself is automatic). The manual labor is needed to feed the machine with unprinted knobs. When the problem was brought to us we started evaluating various “ready made” solutions, specifically robotic arms to perform the job. However, we faced two problems: the high cost of commercial systems and unavailability of a robot that “optimally” solves this problem. Most robots are overkill for this type of problem and the user must pay for extra useless features. We thus developed a new and unique robotic solution after a long process of evaluating alternatives and were directed by the TRIZ methodology. One of the main ideas of this new robotic system is the utilization of two arms fixed at 90°. This separation helps the robot work twice as fast to improve the printing and stamping of the plastic pieces while reducing the robot control and error detection work. To achieve an equilibrium state we use the concept of counter weight to cancel the effect of two robotic arms. It is important to point out that the project was strongly influenced by TRIZ methodology but not a full application of ARIZ or any other related algorithm.