When faced with a new mechanical engineering project, the professional in charge of the movement system has the question of carrying out a redesign of the mechanical transmissions or existing reducers, or develop a completely new system. In this article, we will try to respond to this recurring problem in the sector. Let's go there! The decision is not an easy one to make. Many industry leaders, as CLR, they have a wide portfolio of standard drive solutions (SAS) that allow you to quickly execute a redesign of gear transmissions. However, there are specific situations in which, due to the requirements or characteristics of the application, the transmission must be designed from scratch.

Design or redesign of mechanical transmissions?

In evaluating this decision, it should be borne in mind that system specifications must be derived from calculations, real measurements in existing machinery and simulations in specialized software, which allow us to deduce the speeds, loads and torques necessary for each application. Although it is common to think that the design of a gear transmission system It's more complicated than redesigning an existing one, that's not always the case. Some considerations must be taken into account.

New systems, such as replacement systems, follow the same physical laws, but operate with different laws of control.

Loads, speeds and torques behave differently depending on the controller they operate with: digital or analog. If the designer is not aware of this, the final product may not live up to the expectations expressed in the design. A key factor to consider in the new system is time. A digital system works in three quantifiable steps:

• • Measure.

• • Calculate.
  • Produce.

The digital controller requires specific fractions of time to execute each of these functions. On the other hand, an analog system does not have this drawback, since it measures and produces almost simultaneously and continuously.

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• Design approach and hardware shopping list

In a new system, the design can be defined in two ways: The first is the simplest: the control engineer completely defines the system and orders the components needed to do the job. He is solely responsible for the final result. In the other way, the new system involves a customer who has a resident engineer, who will help define the mechanical transmission design and other components. In this case, the expert assumes that the components selected by the resident engineer are perfectly adapted to the needs of the project. However, most of the time this is not the case. The resident could have determined loads, speeds and torques based on calculations and limited measurements, which did not take into account all the variables affecting this type of project. [caption id="attachment_1711" align="aligncenter” width="423"]

CLR reducer design with helical gears-endless [/caption].

• Strategy

Flaws in the calculation are especially problematic when the control system contains multiple axes. For example, in a pick-and-place system, the X, Y and Z axes must converge at a specific point in time. If there is a delay in any of these, components can be installed in the wrong place or affect the overall performance of the machine. Therefore, when thinking about design or redesign, especially when it comes to mechanical transmissions, it is necessary to determine the relevant parameters to optimize performance.

• Validation

When the system doesn't meet expectations, the main reason is a miscalculation. For this not to happen, it is necessary to carry out the respective validations and check that both hardware and finished model are compatible. In that case, it may be necessary to build a Bode diagram or execute a fast Fourier transformation (FFT) algorithm, which makes it possible to find the reason why the system is vibrating, resonating or not rejecting the disturbance. During the implementation of the above considerations, the engineer may conclude that the only way to obtain the desired control and operation is to make major modifications to the design of the electromechanical transmissions, gears and other components of the system. This redesign may force him to change his entire theory about the method needed to tune the system. In this regard, you can think of a simple control method -PID (Proportional, Integral, Derivative) or PIV (Proportional, Integral, Speed) -, typical of a large number of systems. You can also use mechatronics software -such as MechAware-, which allow you to redesign by including in the system customized algorithms and filters adaptable to the most stringent applications and specific needs, in order to minimize the challenges of redesign. Thus, the key between choosing design and redesign lies in the collation of the results of the analyses and measurements with the technical specifications required in the final product. This will allow us to define if, using specialized software and a drive solution, an efficient redesign can be executed that meets expectations. Or, if - on the contrary - you have to start modeling from scratch. Whatever your approach, in CLR you will find a committed engineering team in offering you the most competitive solutions to approach your project. We will study your case or idea, and we will propose a strategic line of action adapted to the particularities and needs of your company. Would you like to speak to one of our Project Managers? Contact us without commitment.