Rexroth’s camoLINE is a Cartesian Motion building system that allows rapid combination of pneumatic and electromechanical components.
Special machine construction and standardization: — this used to be a contradiction. Here is how one manufacturer developed a modular system to assemble handling systems with standard and custom components.
Schiller automation systems are used in the production of semiconductors in all clean room classes, in microelectronics processes, and in the production of solar cells and Smart Cards. Schiller recently chose camoLINE from Rexroth for its custom equipment. The camoLINE modular system covers commonly used handling tasks with flexible components from linear motion and assembly systems, pneumatics, drives, and controls.
The camoLINE systems offer features required for individual handling systems, such as electric and pneumatic axes, connecting elements and profile struts, ball-screw assemblies, and toothed-belt drives for high travel speeds. Depending on customer requirements, either servo or stepping motors can be used with an integrated belt drive or a planetary gear.
Schiller’s automation equipment moves pieces and parts precisely. “Through positive locking connectors the modular system achieves a level of accuracy in the supporting structure previously obtained only with specially milled parts, says Karl Letzgus, chief designer at Schiller.
The finely-scaled pneumatic parallel, angle and radial grippers cover a broad spectrum of requirements.
Letzgus first used the camoLINE system to automate a production line for solar cells. Production involved multiple procedures, including interlinking 18 process modules, un-stacking and transporting blanks, loading and unloading process stations, precisely aligning cells, checking quality inline, and sorting according to power ratings, and finally arranging the finished solar cells into magazine style racks.
“With this system, explained Letzgus, “we can guarantee repetitive accuracies of 0.02 mm and stress-free handling of sensitive cells.” “Stress-free” movement is critical here, as even the slightest stress on the edges could shatter the solar cells. In such a case the loss of a single solar cell would be the least of the problems. Considerably more dangerous would be the splinters that would contaminate and damage the whole system. But the engineers allowed for this: Special motion profiles guarantee safe, self cleaning of the system.
From A to Z
Rexroth was involved as a consulting partner from the start in the design of the system: Ralf Schirmer combined 19 different handling modules, including aluminum profiles, linear motion systems from the Compact Module Family, and electric and pneumatic drives. Thisarrangement simplified construction and assembly. “We achieved a high-precision and stable support structure by using intelligent connection technology,” said Letzgus. The aluminum profile struts have two rows of centering holes with standard spacing. Centering rings let the customer connect the individual components of the building system to each other, either directly or through matching connection elements, to create positive locking joints that need no further adjustment. Angle brackets ensure precise and stable fixing to the mounting base.
With positive-locking connectors, camoLINE supports structures in a way that could previously only be attained with additional and expensive custom-fabricated parts.
“The design saves up to 75% on part fabrication,” continued Letzgus. The profile constructions are easy to erect. The Rexroth linear motion axes can then be mounted to them either directly or through standard connection elements using positive-locking centering rings. All the connection dimensions are identical, so the engineers were free to choose the most appropriate pneumatic or electric drive units.
The electromechanical Compact Modules in the linear motion range are available with ball screw drives for positioning accuracy or with toothed belt drives for high-speed travel. With two ball-rail systems integrated in their aluminum extrusion frame, the Compact Modules are rigid and have high load capacity. The engineers attached motors to the drive end of the compact linear modules through a locating feature and a fastening thread. The engineers use standard interfaces for directly attaching the motor attachment and timing belt side drives or planetary gears. Pneumatic actuators, likewise ready to assemble, round off the system.
Mini Slides with an intelligent stroke-setting facility, Rotary Compact Modules and three types of pneumatic grippers fulfill a range of requirements. Standard interfaces let the engineers combine the pneumatic and electric axes in most configurations. In this way camoLINE eliminated a large part of the design and installation effort for pick-and place applications and linear and X-Y gantries.
This picture shows the electromechanical linear systems of the camoLINE Compact Module Family.
The linear modules are available with ball screw assembly or toothed belt drive versions.
Design and Assembly
The manufacture of solar cells involves complex special machine construction and custom handling; individual modules seldom fulfill the exact processing requirements. The coordinated components and axes of camoLINE, on the other hand, open the possibility for standardization, even for such applications as these. Says Letzgus, “On completion of the concept phase we are operating up to 30% faster with such components in the subsequent project design phase by using this modular building system.”
Shorter response times forchanges in outline conditions made it considerably easier to meet the deadline for commissioning the solar cells: “In a simultaneous engineering process we produced the various handling modules in parallel with the process development being carried out by the customer,” recalls Letzgus. The camoLINE system passed the “baptism of fire” with Schiller and is now being used in a number of other installations, which lets Schiller develop and deliver custom systems even faster.
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Bosch Rexroth Corp. http://www.boschrexroth-us.com