Press Release
<< return to list

Multi-tasking motion control system accelerates fluid filling

March 29, 2004 -- An advanced motion control system from Baldor is at the heart of an innovative continuous fluid packaging machine. The new inline filling machine utilises detachable pump carts and programmable motion to achieve batch changeovers of just a few minutes.

Developed by Fluid Packaging Solutions (Alpharetta GA, USA) to eliminate any production delay caused by clean- or wash-in-place procedures, the new Universal Flow Positive Displacement Filler is based on a precision servo motor system engineered with the help of Baldor and its distributor Control Corporation of America.

Four servo motor axes are employed to drive a flighted conveyor, to load bottle/container pucks onto it using a phasing conveyor driven by a feedscrew, and to control the X and Y motion of the filling head. The filling head synchronises with the containers, and then inserts and withdraws nozzles that fill from the bottom up, before returning to the starting position.

Fluid containers are filled four at a time, from pump carts that attach onto the conveyor. Each of the cart's four nozzles is controlled by a further servo axis for precise fluid dispensing. The pump carts contain all the wetted parts of the system, and a typical machine is supplied with two carts, so that one may be wheeled away for pressure-cleaning and priming for the next application without disrupting the filling process. This provides a major gain in productivity compared with typical fluid packaging lines of today. Using this technique, Fluid Packaging Solutions' machine achieves typical filling speeds of ~100 containers per minute, with changeovers taking a new standard-setting time of under five minutes. This rapid changeover allows users to process much smaller batches, reducing inventory levels and business costs.

Baldor provided all motion, I/O and human-machine interface system components required for the machine, and wrote the application software using the MintMT motion language. Development time was greatly reduced, and machine functionality and flexibility was greatly enhanced, by means of MintMT's built-in multi-tasking operating system. Baldor used this facility to divide the major control functions of the machine into small discrete tasks - controlling the materials handling axes, the X-Y indexing and filling motion, human-machine interfaces etc.

The availability of application-level software in the form of 'keywords' within the Mint language also contributed to rapid software creation. Examples include the use of the FLY command which synchronizes the movement of two axes while controlling the position of one - providing an elegant solution for matching the filling head movement with the containers. The control program also uses the OFFSET command, which allows a positional move to be added onto a base velocity, providing a solution for the 'phasing conveyor' feeding mechanism.

"Once the basic hardware architecture and functionality was defined, the high-level commands of the Mint language allowed us to create a working control program rapidly", notes Baldor Application Specialist Mike Mitchell. "As this machine requires a large number of motion profiles - from simple velocity control, through point to point positioning, to reciprocating indexed movement - the language's keywords saved many days of programming effort and allowed us to focus effort on adding features".

All major axes on the main conveyor and pump carts are controlled by Baldor intelligent drives from its MintDrive or Flex+Drive families, which combine a single-axis drive with built-in positioning capability. They are linked by a CAN network running the CANopen protocol. The main conveyor is the master node on the network; all the other drives are slaved to this axis. Because of this master-slave configuration, network traffic is minimal and the CAN network offers the speed necessary to coordinate system operation in real-time, with the master axis controlling the speed of dispensing.

The distributed and multi-tasking hardware/software architecture allowed Baldor to design flexibility into the system, including the ability to take one or more pump nozzles offline if required for maintenance or repair. The system will automatically recalculate filling speeds and adjust all the axes to a new speed.

Another example of the flexibility supported by Mint is found on the pump carts. Each cart includes its own HMI panel. When it is disconnected from the conveyor, and wheeled away for cleaning, one of the intelligent drives switches to a secondary control program, becoming the master of a subsidiary control network that automatically rinses, cleans and runs specific cleaning agents through the tank and pumps.