Nested based manufacturing, or NBM, is a production process that is generating a lot of interest in the wood industry. Many companies are questioning whether it is a viable alternative to their current production methods or feasible as an additional and separate system.
To provide insight into this complex issue, eight companies, representing a diverse group of operations, were interviewed about the implementation of NBM into their business. Besides using the manufacturing system for a number of different applications, these companies were also in varying stages of implementing and upgrading the system or software to fit their needs.
What exactly is NBM?
NBM is a production method in which a variety of parts are grouped, or nested, on a sheet of plywood, particleboard or MDF; those parts are then cut and machined using a CNC router. Visually, a nested sheet appears much like a puzzle with the parts of the project laid out in close proximity to minimize material waste and increase yield. Computer software determines the optimal layout and machining to get the desired finished product using the construction methods, tooling and parameters set into the system.
Although the primary objectives of nesting are the efficient use of material, quicker processing and less handling, many of the companies interviewed credit it with an improved product that is very repeatable. Because all the construction details are worked out in the office on a computer, companies also find that there are fewer errors and that NBM makes the whole construction process easier to control.
For most companies the process begins with drawing a project in a design software program. Once the drawing is finished with all final measurements and specifications checked, either the same software or another software program nests the parts of the project. This nesting information is then sent to another software program that gives directions to the router on which tools to use, the depth of cuts and the machining to be done on each part.
Software is an integral part of NBM.
Karl Frey, vice president of Routech, a division of SCM Group USA, says, "The software is driving the market - the simplicity of the software, the simplicity of the file management, the power of the software, the macros that are written behind the software makes everything happen automatically."
When nesting began in the woodworking industry, the geometry of the parts was not coming out of a third-party software package as it does today, says Todd Hammer, vice president of sales and marketing at Biesse Group America. Instead, he says, it was the result of an AutoCAD drawing done by an engineer.
Originally, one of the greatest challenges with NBM in the cabinet industry was creating CAD drawings faster than the machine could cut the parts, says Hammer. "Part of the solution to that challenge was integrating the front-end cabinet design software to have that provide the CAD drawing rather than having an engineer creating a CAD drawing at a workstation," he says. The efficiency was further improved by integrating the cabinet design software with the nesting process, says Hammer.
The routers have also changed with increased speeds, more flexible worktables and fixturing added and tooling improved. "Now the tables are becoming much more flexible, incorporating dual- zone machining centers to allow you to use the single-table machine very much like a twin-table router," says Hammer.
The vacuum requirements and getting volume to the machine have also been addressed.
Frey says, "Now, not only do we have big pumps, but we have big valves and big hoses."
According to the machine manufacturers, NBM will see continued improvements in the software, with the software becoming more powerful, and curved surface, radius work being integrated into the various cabinet design software packages.
Improved material handling in the form of automatic loading and unloading for the NBM cells is on the horizon. Some manufacturers see the smaller one- to five-man shops experiencing the most growth, while others see growth occurring in larger 50- to 100-man shops. If the profiles of the companies interviewed are any indication, the versatility of the process lends itself to companies of all sizes and to all types of products.
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