|
|
 |
|
Robotized Spraying of GRC Panels
The Need
|
The process of spraying GRC (Glass Reinforced
Cement) panels is still totally manual in most of the factories. The decrease in an
adequate supply of labor, the need to increase productivity, to reduce costs and to
achieve higher quality standards are the primary motives driving automation.
|
Example of application of GRC panels as wall units
|
The Technology
|
|
The manual manufacturing process of GRC panels
consists of two or four consecutive stages, depending on the panel type. Each phase
consists basically of spraying a layer of mortar and glass-fiber with a concentric
spraying gun. The mortar and the glass-fiber are mixed outside the gun while spraying. In
successive spraying cycles, several elements, such as insulation and anchoring, are placed
in the panels. Additionally, there are also series of operations prior to the spraying as
well as operations to be executed after the spraying. 
System structure scheme
|
|
The robotized spraying process is controlled
by three (3) main modules which are executed sequentially or in parallel, depending on the
task. The first module utilizes a common CAD environment with access to information
relating to the manufacturing tools and parameters and to the design rules for the
product. The off-line module is divided into three different submodules: kinematic
control, path planning and task planning. It uses the information generated by the CAD
environment. The last module controls the whole lay-out, including the robot and
peripheral equipment. The on-line control performs both the scheduling and monitoring of
the system.
|
Spraying cell
|
The
Benefits
|
|
The main advantages over traditional forms of
construction are lightness, good structure resistance and excellent superficial finishing
of GRC panels, which make them very useful. Key
aspects of this robotic manufacturing system are: a) a high level of integration among the
system modules, b) communications and management of data and information throughout the
system as a whole and c) automatic process, task and path planning of robots and
specialized machines.
The system has been designed to take into account the
flexible manufacturing concept. The robotized flexible manufacturing system has been
developed to be used on a group of different applications which are connected with 3D
surface treatment: spraying, painting, cleaning, sealing, etc.
The uniformity of the layers sprayed by the robot is
greater than in the manual application, because the robot describes rectilinear
trajectories in a specific direction over the mold surface, being transverse to the layers
projected before. Additionally if the cross-section is very irregular, as in manual
application, it is necessary to add excess material to cover the error in the zones which
have not achieved required thickness. The robotic surface application results in a
significant savings of material.
The robotized system replaces workmen in one of the hardest
tasks involved in the production of GRC panels, the application of the mortar. This
operation is done in a polluted environment due to the use of cement and glass-fiber.
The quantity of material to be applied by the gun is 28
kg/min. for the robot spraying versus 12 kg/min. for the manual application. The spraying
of the mortar with much higher pressure eliminates intermediate compaction. This is a
fundamental part of the manual application. The removal of compaction reduces handling and
therefore the robot non-productive time. This increases the overall productivity
significantly.
This system demonstrates the advantage that automation can
bring into quality and factory productivity in an off-site manufacturing process. |
Status
|
The most common applications of GRC panels are
for wall units, urban furniture, and ornamental decoration. A prototypical system has been
finished, and is now producing panels in a Dragados Construcciones factory near Madrid,
Spain. |
Barriers
|
Capital costs of initial investment.
Associated economies of scale or mass production must be realized to reduce costs, recover
the investment and achieve profitable operations. |
Points of Contact
Dragados y Construcciones, S.A., Avda. Tenerife 4-6. S.
Sebastian de los Reyes, 28700 Madrid, SPAIN. Phone: (34-1) 583-38 04
References
- C. Balaguer, J. M. Pastor, A. Garcia, L. F. Pe_in, F. J.
Rodriguez, A. Barrientos, R. Arancil, J. Florez, M. Esteban, J. A. Comas and E. Marquez.
Evaluation and Comparative Study of Robotics vs. Manual Spraying of GRC Panels,
Automatization and Robotics in Construction XII. E. Budny, A. McCrea, K. Szymanski
(Editors) 1995 pp. 489-497
- C. Balaguer, F. J. Rodriguez, J. M. Pastor, R. Arancil, A.
Barrientos, E. A. Puente, J. Florez, M. Esteban, J. A. Comas and E. Marquez. Robotized
System of GRC Panels for Construction Industry, Automatization and Robotics in
Construction X. G.H. Watson, R.L. Tucker and J.K. Walters (Editors) 1993 pp. 165-171
Disclaimer Statement
|
Neither the Construction
Industry Institute nor Purdue University in any way endorses this
technology or represents
that the information presented can be relied upon without further investigation. |
IRA08
|
