Benes applies rapid prototyping principles for the development of a printer feeder table

In collaboration with the Mechatronica 4.0 project team, Benes managed to effectively apply rapid prototyping for the development of a highly accurate printer feeder table and the associated software. Techniques that come under the heading of rapid prototyping (RP), allow for a quick, cheap and efficient way of achieving a product prototype that already leans heavily on the individual requirements set. Consequently, the scale-up to a fully-fledged industrial product is only a small step. 

Sirris and Flanders Make made use of RP in order to develop a feeder table, compatible with an existing printer system. The development was done at the request of Benes, an SME in Haasrode that distributes printing systems and accessories.

The problem with the existing printer configuration was that it was only suitable for the printing of light materials on a roll, such as paper, textile and foil. An extension with a feeder table means creating opportunities for printing heavier materials such as flat panels (up to 40 kg).

RP allows concepts to be tested and optimized in a short period of time and with limited cost. Sirris and Flanders Make followed a systematic approach in order to generate and optimize concepts based on the design specifications. 3D printing (sintering of polyamide in this case) was used for the construction of the prototype, while the electronics for controlling the printer feeder were constructed on the basis of the open source dsPIC hardware platform and therefore allow automatic code generation from a Matlab/Simulink environment. The prototype realized resulted in a large expansion of functionalities with respect to the initial system in a budget-friendly manner.  

Brainstorming and selection of concepts

The system requirements were:

  • Compatibility with the current printer system.
  • Fast positioning up to accuracy within 20 microns, without overshoot.
  • A 1D rotational degree of freedom in the plane of the panel in order to prevent obstruction in the printer during the feeder process.
  • Treatment of panels with a mass up to 40 kg.

The initial printer system had an internal roller drive. To be able to meet the new system requirements, an external drive of the panel by means of a spindle was chosen for. A spindle may indeed be more expensive than a drive belt for example, but it is more reliable owing to the high rigidity. The spindle (see figure below) is driven by a stepping motor that is controlled accurately using a micro-stepping open-loop controller.

Schematic representation of the printer, the feeder table and the spindle drive by means of the electric motor (source: Flanders Make)

The rotational degree of freedom is achieved by providing a mechanical bearing case connection between the spindle and the panel (see figure below). Sirris made use of 3D printing technology to build this bearing case.

Representation of the printer feeder table with 1D degree of freedom introduced by means of a ball case between the panel and the spindle (source: Flanders Make)

Software design and implementation

The software includes, among other things, route planning and control of the motor, the processing of operator commands, control of the display and the communication with the printer.

Flanders Make designed the control algorithm in a Matlab Simulink environment. There is a direct conversion to the dsPIC hardware platform from this environment and accordingly, automatic code generation is possible. The dsPIC platform is an alternative to high-end platforms such as dSpace (see following figure).

The high-end platforms have the advantage of being flexible in use, accurate (16 bit A / D conversion) and have a high computational power and memory. Conversely, these platforms are expensive both to buy and in translation of software code, since the transfer to the final hardware is difficult. Because the hardware is in conformity with the final hardware used, this dsPIC platform also forms a good and representative evaluation environment.

Improved integration of the design cycle through automatic code generation by using the dsPIC platform that better connects to the final product wherein no significant computational power is required (source : Flanders Make, Sirris)

The dsPIC platform is built up around an inexpensive processor from Microchip (dsPIC33F), and includes a wide range of I/O capabilities. The processor can also be used in the finished product and therefore guarantees a correct assessment of the performance of the prototype.

Automatic code generation via the dsPIC platform thus provides a double benefit. On the one hand this results in a rapid evaluation of the algorithms, there being no manual code-integration required. On the other hand it allows the control algorithm to be evaluated before proceeding to the experimental validation. 

In the context of the Mechatronica 4.0 project, the project team will carry on with the development of the dsPIC platform as well as evaluating other rapid-prototyping hardware.

Proof of concept 

The design realized can be seen in the film clip below:

 

Contact Flanders Make: Maarten Witters, maarten.witters@flandersmake.be, +32 498 91 94 40