Can custom furniture be built economically in North America? 

Thermwood, a supplier of technology and equipment, actually produced furniture in its own Dale, Ind., plant for six months last year. It was what Thermwood President Ken Susnjara calls an experiment, but it was a real-world exercise, too.

Thermwood completed the remaining open orders for a contemporary furniture manufacturer in Quebec that had ceased operations.

The primary focus of the experiment was to verify a highly variable product line could be efficiently machined and assembled using modern technology. I visited last fall and saw the furniture making cells in operation.

Susnjara says that furniture companies are oriented toward batch manufacturing, which works well for large quantities. Cell manufacturing is the alternative. Any cell can make any piece of furniture, and can make one piece of furniture at a time with a smaller parts count, with setups done by the machine. Using sheets on more than one job and grouping things together helps improve productivity.

"Cell manufacturing doesn't require human perfection. The machine takes care of it. It's less dependent on human performance," Susnjara says.

The Quebec company's product designs were electronically reproduced using Thermwood's eCabinet Systems design software, which is available free to any cabinet or furniture company, but only outputs to Thermwood's CNC control.

Strong integration

Thermwood's approach supports a strong integration between the design software and machine control. Actual nesting and CNC program generation are done automatically at the machine, not in the design software. This allows partial sheets to be reused and custom profile shapes to be handled more efficiently.

The veneered MDF product itself consists of a series of individual modules that are connected and combined in different ways. Add a wide selection of finishes, and there are 95 million unique products that can be produced. To specify and communicate the exact product the customer wants, Thermwood developed a web-based system to configure the product and then provide a three-dimensional model of that configuration. The software allows dealers to look at collections and keep track of production, and can communicate the order to the manufacturer.

"This online ordering is revolutionary in furniture, but is pretty standard elsewhere," Susnjara observes.

Component modules were combined into a complete piece of furniture using the same software. The resulting job file is placed on the server where it can be accessed by any of the CNC routers, which can then nest, program and post right at the machine.

Special connections

Special techniques and joints such as blind dadoes were developed to handle mass customizing furniture. In addition, the CNC router machines all of the parts for a piece of furniture which are labeled and stacked on a cart.

Labels are printed and small hole patterns called assembly marks were added to both parts of the joints to help assemblers put the pieces together. A color box on each part label indicates which item the part is for, allowing more than one piece of furniture to be matched in the same job.

Thermwood uses a "puzzle joint" to assemble frames that goes together easily and does not require fixtures, pocket drills or alignment jigs. Another special joint called a box miter produces what looks like a miter joint but works well in a case clamp.

Thermwood used its own CNC routers (two Thermwood Model 45s normally used in cabinet manufacturing) as the heart of the operation. Two edgebanders were used in the program, both made by Fravol, a line Thermwood distributes in the U.S.

A Fravol SX8 was used as an automatic straight line machine for quick changeover for different widths. Curved pieces were banded on a Fravol VSV manual edgebander. Both machines were modified by Thermwood for this operation.

Thermwood engineers also developed a real-time cost tracking system. All material, hardware and component data is contained in the job file that comes from eCabinet Systems software. When the machine runs the job, it keeps track of how much material was used and the time that was required.

Based on this production, Thermwood believes this approach could work for mass customized higher-end furniture, and is interested in supplying the technology and equipment needed to other furniture companies, and providing the capabilities of the sales and configuration software it developed.