Here comes the virtual factory

ControlDesign.com

Industry expert and frequent Control Design contributor Loren Shaum reports on new, evolving 3-D technology that could lead to complete process simulation and commissioning before installation.

By Loren Shaum

VARIOUS FORMS of machine simulation have been around our industry for sometime now. Many of them started on early Unix platforms in academia, and were aimed more towards simulating early robot designs. In the past 10 years, machine simulation used to predict sequences and events during production has made dramatic advances. As more successes in time-reduced machine commissioning come from early simulation activities, more in-depth 3-D packages are evolving that could lead to complete process simulation and commissioning before installation.

New Machine Development
Assembleon Netherlands B.V., a 100% subsidiary of Royal Philips Electronics, recently implemented simulation tools as part of its new machine development strategy. The project had to meet stringent objectives to be successful These objectives included low-cost hardware, robot-to-robot calibration, robot deformation, printed circuit board (PCB) calibration, diagnostics, short development cycle, urgent deadlines, and exceptional cycle time (see "Design Requirements" sidebar below).

Rik van der Burg, Assembleon’s motion architect/team leader for motion control and machine dynamics in its mechatronics engineering division, provides some insight into its A-Series SMT machine development, which is made up of three models: AX-30, AX-501 and AX-201 (See Figure 1 below). “Parallel placement technology allows production volume flexibility and throughput via robot expansion,” says van der Burg. “This assures an attractive investment pattern in comparison with all other multifunctional machines, which only can be expanded on a per machine basis. Simple scalability is based on a minimum configuration offering an IPC 9850 output of 30,000 chips per hour (cph) and expandable to 110,000 cph in cost-effective 5.5K cph increments on the same machine footprint.”

	FIGURE 1: SERIOUS SMT
	In parallel to software development for its AX-301 Pick-and-Place machines, Assembelon used simulation software and associated tools to focus on building machines instead of debugging complex mathematics and correction software.

Van der Burg adds, in the development phase of the AX control system, Assembleon extensively used Cimulation software from Cimetrix loaded with the AX machine model. “In parallel to our software development, we developed and tested the robots,” says van der Burg. “The Cimulation package and its Cimetrix Open Development Environment, Version 6 (CODE 6) software helped us do parallel (hardware and software) developments. The machine and target correction features of Code helped us concentrate on building machines instead of debugging complex mathematics and machine correction software. It certainly helped speed up our development process, providing a stable foundation for our own software developments.”

Brian Rubow, Cimetrix’ product manager, adds that, “During initial development, Cimulation played a key role in increasing software development productivity, and in preparing the equipment software for the hardware when it became available, which significantly improved hardware and software development cycles.”

More than one technology supplier to machine builders started with a simulation package as its initial product offering. Cimetrix was created based on research in robotic arm simulation in the 1980s at Brigham Young University. Now the Cimulation package embedded in Code 6 offers significant possibilities to machine builders that want to ensure automation success before starting machine construction. Over the past several years, says Rubow, Code 6 has evolved into a machine control developmental platform that implements Cimulation to predict very sophisticated and precise motion capabilities prior to machine assembly (See Figure 2 below).

FIGURE 2: PREDICT PERFORMANCE, THEN ASSEMBLE

Over the past several years, simulation packages have emerged into a machine control developmental platform that can predict very sophisticated and precise motion capabilities prior to machine assembly.

The final AX machines incorporate robots that have their own PC-based control system running autonomously, and include a Code server. Each has on-board calibration maps, which stay with the robot when moving or adding a robot to the machine. The calibration maps are loaded at power-up into the Code package. This allows calibration-free reconfiguration.

All placement heads also have onboard calibration data. Exchanging the placement heads can be done without an accuracy penalty, just as with the robots. Each placement head contains a downward-looking camera for fiducial identification and a laser alignment camera for component alignment. The module is calibrated offline. The short geometrical chain—measured fiducial information is coupled to the measured component position—results in the highest accuracy (50 µm accuracy or better at 4σ) achievable, according to van der Burg.