Ken Susnjara, president of CNC router manufacturer Thermwood, has worked hard to ensure that the woodworking industry keeps pace with the introduction of new technology and he is adamant that the way furniture manufacturers are working – with components made individually and brought together further down a production line – is not necessarily best practice.

Thermwood’s production concept is for all component parts to be produced on a single machine, one at a time. In simple terms, as the parts are machined, the machine operator sands and assembles the final product. When the cycle is complete, an entire piece of furniture has been built. The feasibility of this concept has, Mr Susnjara believes, been proven and he is now keen to promote his ideas to a wider audience.

With the advent in Europe of knock-down furniture, generally held together by dowels, and computer software which wrote programs for point-to-point machines, production went up while costs came down rapidly. However, this system requires that a number of machines are used and parts need to be moved around the production area between each process. Typically, a full sheet of material needs to be cut using a panel saw prior to being taken to a point-to-point machine for the dowel holes to be drilled. Each panel has to be set up individually on the vacuum table of the router and care has to be taken over the drilling of the edge dowel holes. Once processed, individual panels also need to be finished, usually by sanding, to ensure a consistent dimension.

Single machine

Thermwood’s ‘Furniture Fabrication’ approach stands tradition on its head and takes a single machine, one of the com-pany’s CNC routers, and works on a single sheet of material. If the piece of furniture is large, then several sheets may be required, but the principle remains the same. It also, fundamentally, replaces the dowel with a dado joint which inherently allows a modicum of adjustment.

Once the cabinet has been designed, or selected from an existing product menu, the data is transferred to the router where its own software takes over. Material is held in place using Thermwood’s universal vacuum table which pulls a high-flow vacuum through a particleboard or pegboard tabletop to hold the material in place. Location errors are avoided and the program contains a complete nest of parts with one program per sheet. In a few minutes a complete sheet can be cut into constituent parts and drilled as necessary. Each part is labelled by hand by the operator, using bar-coded labels automatically generated by the program, and these identify which parts need to be turned for additional processing.

This is, if anything, the downside of the concept, because a dado joint requires that some panels have to be machined twice. However, even with this additional task, considerable time and labour savings can still be identified. After removing the components from the table, the operator either loads a further panel to complete the job or assembles the item. Thermwood has developed a hot urethane, fast setting adhesive, which sets off in about two minutes, and a corner vacuum clamp which assembles one corner at a time and allows any size of cabinet to be constructed.

It has taken Thermwood several years to bring the idea to the point where it can be taken up on a commercial scale. In that time it has developed several unique production methods but, at the core of it all, lie two sophisticated computer programs. These, while completely separate, are symbiotic, giving Thermwood the edge over its competitors, Mr Susnjara believes.

Thermwood routers have always had a reputation for sophisticated software management and many of the company’s customers are happy to use the standard package for all their production needs. To make Furniture Fabrication work, however, something a bit more advanced was needed to ensure that the router could perform to a higher level and also to interface with the Cabinet Vision front-end software.

The software includes a machine code output utility created by Thermwood and integrated with the Cabinet Vision system. This utility converts the detailed part database into nested CNC programs that will execute on Thermwood’s 91000 SuperControl. Cabinet Vision’s package generates panel layouts in seconds, with matching bar-code labels and allows designers to create custom parts before attempting to build them in the shop.

Tool changing

A new concept such as this is also demanding on tooling and Thermwood has not ignored this aspect. Bulk tool changers are available which can hold up to 100 tools on each machine, while the automatic tool management system looks ahead to see what tools are required and locates them from the changer. Programs can be specified for different types of job ensuring that the most frequently used tools are always available.

Thermwood estimates that by switching to the Furniture Fabrication method of production, direct labour savings as high as 60% can be achieved.