Assembly in Action: Servomotors Increase Coating Machine Accuracy, Throughput
In December 2010, the company introduced its first conformal coating machine, the MACCS 400. This machine quickly applies protective conformal coatings to PCB-mounted components, and can accommodate both inline and batch processing operations. It can coat PCBs as large as 500 by 480 millimeters and on-board components as high as 90 millimeters.
The heart of the MACCS 400 is its five-axis motion control system, which enables the machine to spray three-dimensional coatings at an accuracy of 25 microns with very high throughput.
The motion control system features several Baldor Electric products, including three BSM servomotors linked to MicroFlex e100 drives, two stepper motors, a NextMove e100 controller and Mint language software.
ACR selected these system components for several reasons. The BSM servomotors are used because they meet the Ethernet PowerLink standard. The NextMove controller interfaces seamlessly with ACR’s proprietary coating software and uses real-time interpolation to allow smooth tangential movement of the spray head. Finally, the components allow for simple plug-together system building.
The X and Y axes of the motion control system are based on a novel H-belt actuator, driven by two BSM servomotors linked to MicroFlex e100 drives. Because the two servomotors occupy fixed positions at the bottom of the actuator and jointly act on a single belt, they do not contribute to the load inertia.
This design permits very fast and accurate movement. The MACCS 400 can accommodate X-Y velocities as high as 800 millimeters per second.
The Z axis controls the above-board height of the spray head and is driven by a third BSM servomotor linked to a MicroFlex e100 drive. All three drives are synchronized to facilitate high-speed Cartesian movement of the spray head. Its angle and orientation are controlled by two rotary axes, which are driven by stepper motors.
All five axes are controlled by a NextMove e100 controller, while overall control of the machine is handled by ACR’s coating software. This software is written in the VB.NET object-oriented programming language and provides a very intuitive graphical user interface. It runs under Windows XP on a built-in host PC.
A self-contained, free-standing machine, MACCS 400 can apply a wide range of conformal coatings, including Parylene and many HumiSeal products. The machine is capable of completely autonomous operation, or it can be equipped with chain conveyors and form part of an integrated PCB production line. It also allows for cartridge or pressure vessel feed, multiple spray heads, fluid viscosity control, a bar code reader and a laser pointer.
The MACCS 400 features a built-in purge and solvent cups for flushing and has a small 1.4-square-meter footprint. It complies with the Surface Mount Equipment Manufacturers Association mechanical and electrical interface standards.
For more information about servomotors, call 479-646-4711 or visit www.baldor.com.
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