Printer Friendly

FLEXIBLE manufacturing system solutions.

Flexible manufacturing system solutions

There are many ways to structure an FMS system, but the key is to keep the system flexible enough to be expanded or reshaped to meet future needs. This is particularly important when taking your first steps into flexible manufacturing.

The graphical solutions shown here were developed by the Burgmaster Div, Houdaille Industries Inc. Los Angeles, CA. Their basic FMS philosophy is "walk before you run.' They believe that newly automated production techniques must interface well with individual production engineering and manufacturing departments. To be effective, this transition to unmanned flexible manufacturing must be gradual so that plant productivity is not hampered or dismantled in the process.

This suggests a modular building-block approach where the unmanned production cell is set up to run parallel to regular production without interfering with it. This way you can learn as you go, practice with it, and find out what FMS can really do. Once you know the cell's true productivity, it can then be expanded to two or more cells, interfaced with a host computer, and integrated with a material-handling system.

The alternative is much more risky. Purchasing a full-scale FMS on a turnkey basis may mean that the system is outmoded by new technology before its typical five-year payback period has expired.

In Figure 1, the use of the gantry robot for part handling gives the system versatility. It provides simple three-axis access to the entire cell area. Potential rail expansion is inexpensive, limited only by machine-cycle times, and travels of 200 ft or more are practical. It also takes minimal floor space--one post every 20 ft. A second grantry robot can be added to boost cycle times.

Here, the machining time for the primary unit, the horizontal machining center, is 3 min or greater. The robot operates in a floor area of 300 sq ft with a transfer time of 90 sec or less. It transfers incoming random parts from the conveyor to the parts queue or to the mating fixtures in each of the six carousel positions (all six of which can be different for different parts). The parts queue compensates for different cycle times.

The carousel enables the system to handle long cycle times for the horizontal machine, complicated parts and fixturing, and avoids the need for a man to change fixtures. The second machine, a vertical turret lathe, supplements the machining center. It is used only intermittently for much shorter cycle operations and thus needs no storage.

The system relies on the 120-tool capacity of the machining center's chaindrive toolchanger and the 40-tool capacity of the turret-lathe's magazine to handle all tooling requirments without the need for automated tool-magazine changeovers. The robot and gantry are designed to handle parts only, not pallets. If pallet-handling is necessary, both robot and gantry would need to be beefed up, and the pallet queue would come into play.

A system of this type could handle up to 12 different sizes of parts on a batch or random basis, and could be expanded to four machines (with machining times ranging from 3 min to 8 min) without need for a second gantry robot.

The system of Figure 2 is based on wire-guided cart delivery of palleted parts. The strengths of the cart approach are its unlimited range (to extreme plant locations if necessary), and its ability to interface with a central automated pallet storage system, part load/unload storage, and tool storage. Although no tool-transfer method is shown, tools can be delivered by cart and installed in machines manually, or automated tool-transfer systems could be added later.

Carts are dual palleted so that they can deliver one pallet and pick up another from each carousel. The carousel's three or more vertical maching centers. pallet off the cart, rotates the pallet to orient it is necessary, and then spins a full 360 degrees to one of four storage positions or directly to the horizontal machining center's table.

The coordinate measuring machine and part-washing station are similarly automated to complete the manufacturing cycle. The CMM adds the potential for adaptive-control improvements in machining accuracy.

Depending on the cycle times, the cart-type handling system offers nearly unlimited system expansion, and is the easiest to modify through reprogramming the cart actions and simple rerouting of the wire guides.

In the system of Figure 3, a narrow gantry robot moves laterally, linking a simple parts-delivery/return conveyor to three or more vertical machining centers. A photo cell stops the conveyor if the robot is not available.

A 9-min machining-cycle time is about the limit for servicing three machines with a single robot. The use of a partturning robot was found less expensive (less complicated) than adding this function to the robot hand, but the two must be closely linked via controls by the robot supplier so that they operate as one entity.

Parts delivery is random, within the limits of the parts queue, and fixturing requirements are relatively simple, compared to the previous examples.

In the roller conveyor system of Figure 4, part loading/unloading of pallets is done manually, and the required parts conveyors and queueing stations are not shown.

The concept would work equally well for robot loading, and the number of men/robots required would depend on the system cycle time and part complexity/variety. For manual loading, a display would tell the operator which part to load next.

The roller conveyor, rather than a simple belt conveyor, is necessary to handle the combined weight of large offroad equipment transmission parts and pallets. The system was designed to start with only two machining stations, but to expand eventually to 12. The palleted part is sensed by bar codes on the fixturing. Cycle times per machine are 5 to 6 min, but this approach could be used with cycles as short as 1 min.

With the carousel storage capacity, two or three different parts can be handled randomly at each machine. With the final system capacity, this could mean 30 different parts on the conveyor at one time, but this would severely complicate part loading/unloading and increase the space requirements at that end.

For more information from Burgmaster on other modular solutions to FMS applications, circle E14.

Photo: Figure 1.

Photo: Figure 2.

Photo: Figure 3.

Photo: Figure 4.
COPYRIGHT 1984 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1984 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Houdaille-Burgmaster graphics
Publication:Tooling & Production
Date:Feb 1, 1984
Previous Article:How automatic guided vehicles link shop operation: applications in manufacturing.
Next Article:Selecting software for your micro.

Related Articles
DeVlieg-Bullard Sells Off Woodworking-Machines Division.

Terms of use | Copyright © 2017 Farlex, Inc. | Feedback | For webmasters