Developing or revamping a plant layout needs to
be be done with a microscope because it’s the details that maximize
performance, reduce manpower, improve product quality and comply with environmental
and safety regulations. At the same time, don’t forget to look through the
other end of the scope to make sure you
are not losing sight of the big picture.
Focus first on the big picture
Many years ago I built my first production line - for the machining and assembly of low-cost, vinyl wrapped, speaker boxes. It was a great success, doubling productivity ... until product demand died. From that I learned the hard way that the biggest mistake in plant layout only addressing short-term production needs. Hundreds of woodworking factory layouts later, I know not to assume anything, and, before getting into project details, I ask clients:
q To define your company's long-term goals and the project's mission statement.
q How much growth do you want, and how fast can you assimilate it?
q What is the potential of your product line? What is the total market? What are your competitors doing that could erode your market share?
q How much risk can you stand?
You must evaluate your products' evolution in the next few years, starting with the availability and relative cost of raw materials. As many traditional solid wood furniture makers found out when they switched to a veneered product, the rough mill remained important because of the increased cost of trim lumber. If your present product surface is plastic laminate and you go to natural wood veneers not only may you need a mechanized finishing line, but you will need to take into consideration all the secondary items to ensure that you have a cost effective finish in compliance with governmental regulations.
Your business is unique
You cannot just do a "me too" layout. Your cost factors and needs differ from those of your competitors. A good example is lumber yield. Investment in sophisticated equipment can improve yield but which way do you go, and how much should you invest? Fingerjointing is one way to increase yield; optimizing saws and edge gluing are others. Which equipment should you buy? (Don’t forget to check with marketing to determine what your customers will accept.) And, if you cannot afford to invest now, have you left room in your layout to install these processes in the future?
Should you tie rough mill operations together to maximize throughput and total productivity, thereby saving labor, but with some possible loss in yield? In many mills this may be a great idea: in others the yield loss is unacceptable. (What if you were in a country with very low labor costs and relatively high material costs?)
Pay attention to the smallest details
Product quality and output require more than equipment and motivated employees. The illustration of a finishing line in the accompanying article GORILLAS IN THE MIST shows how small details can define the shape of a line. Scissor lifts in the rough mill and panel machining departments are the first signs of a work environment that favors thinking humans over gorillas. They reduce physical labor, but alone only marginally increase throughput. Infeed package chains, singulators and automatic stackers will all increase production rates. (See MEAN MACHINES).
Control non-production time
Do not forget the effect of downtime on productivity. The clock does not stop during machine setup times, while the operators wait for a forklift or for instructions on how to run the next job. The flashing light to call the forklift when the last package is started and the computer terminal at the machine are all part of the layout.
Do not rush to judgment
Do not allow last minute panic to force "executive" edicts. Budget before bulldozing so you do not have to shrink buildings or leave out equipment. When you do budget -- avoid judgments based only on cash flow analyses. These tend to look for a much greater return on new investments than on current operations and favor existing rather than new technology. The result will be the continuation of the status quo, deferring the investment necessary for remaining a viable competitor.
Create a workable environment
In an ideal world, factory workers would work in as pleasant an environment as office employees. Okay, maybe it’s not possible, but there is no reason for them to be treated like animals in a stable. They are adding value to your product and if they freeze in winter, they cannot do their best work. Try to keep operations away from doors that are constantly opened in the winter and, conversely, away from noise and heat. Do not put workers either next to the dust collection system or finishing oven.
Are you politically correct? The most obvious example is to avoid raised supervisory offices which can be likened to prison watchtowers. Forgetting the image, the reality is that the steps to raised offices inhibit communication from the factory floor. Your worst nightmare should be a supervisor hollering down instructions on what to do next. (If this is your style, I cry for your company because you are substituting reaction for employee training and production planning. Don't you have systems that tell employees how, what, and when to do it?)
Visual cues and feedback is important. Today, employees tend to work in teams that interact with one another. They need to be close enough and visible to one another for this to take place. "U" shaped lines are great for quality feedback- operators can monitor both the input and output.
Employee safety must always be the top layout priority; start by analyzing the distance and path to each emergency exit. The nearest way out should never require that a worker climb over a conveyor or machine! Be careful of adjacent operations: Is a worker exposed to kickbacks from a saw or to piles of lumber tipping over?
Will you really be manufacturing today's product line 10 years from now? With the same raw materials and methods? Plan for both long-term change and flexibility in day-to-day operations! As a worst case scenario, consider alternate future uses of the building. Will a machining area that only needs a 12-foot high ceiling eventually be moved elsewhere and will you then be stuck with an inefficient building for warehousing? The cost of increasing the ceiling height and floor loadcapacity may be minor compared to the cost of being stuck with an unusable building.
Finally, flow
Manufacturing flexibility -- customized products in a mass-production environment-- and product quality are often higher priorities than improved flow and throughput. However, I cannot overstate the importance of flow in a production environment. The universal rule (that I keep repeating in this series of articles) is to pick up a board only once and never stack it again until the product is packed. Manual material handing is costly, increases process time, creates quality problems, and results in inventory costs (space and time). But be careful, it is too easy to draw conveyors connecting machines on a layout and very difficult to circumvent them when technology or product-mix changes production requirements. Your flow plan must include provisions for additional operations and new technologies as well as provide the flexibility to accommodate new products.
Remember, classical conveyorized assembly lines which led to the development of the automotive and appliance industries are not the only games in town. (Lucille Ball in the candy factory and Charlie Chaplin in Modern Times demonstrated their limitations.) Product size and run quantities often dictate better approaches to gain efficiency. The bottom line in flow is, simply, the bottom line! What is the pay-back and the risks of mechanization and physical consolidation of production? Be careful not to blindly duplicate your competitor’s layout (or clone successful European production lines). The equipment and manufacturing concepts may be great, but were the layouts planned with different investment parameters? Do they use different raw materials, and/or are they run by a workforce different from yours?
Good plant layout requires more than a sketch on the back of a placemat or application of the principles of Manufacturing Management 101. The realization of a successful project is much more. It requires team members with knowledge of your product line, production processes, budget limitations, management structure and workforce. To this add the objectivity and industry knowledge of a consulting engineer. Working together they will be an effective project team that comprehends all these aspects and is capable of success without disrupting current operations.
The above was adapted
from an article of the same title that first
appeared in Wood & Wood Products.
Effective, Not
Just Efficient Factories is an overview.
For detailed information please read these article in our P’s and
Q’s series:
q
Mean Machines: Combining operations - Lumber handling illustrations.
q
No Naked Machines: Fine tuning and accessories -
Panel saw example and illustrations.
q
Gorillas in the Mist:
Layout details for effective finishing
lines.