Custom Woodworking with a Thermwood CNC Router

Custom woodworking consists of building products, either one at a time or in limited quantity. Traditionally this work has been done by hand and only recently has technology developed which makes a CNC router a practical and powerful tool for custom woodworkers. Thermwood is at the forefront in developing this new technology and is the only source for much of it.


Traditionally CNC routers have been used to produce a large quantity of identical parts. Thus, the often complex and expensive programming task could be spread over a large quantity of parts. The key to using a CNC router for custom woodworking is to simplify or eliminate programming so that it becomes practical to create a program for a single part.

The first development to address this was the development of cabinet design and kitchen layout software using the concept of parametric parts. Design software, such as CAD, is used to design individual parts. This is still not practical for designing and programming cabinets. A single cabinet can consist of dozens of parts, each of which must be individually designed including their interface with all the other parts. The programming task is just too great for any benefit that might be realized.

The new type of cabinet design software changes this by taking a different approach. Instead of designing each part, this software lets you design the cabinet itself. When the cabinet and all the joints and the size have been defined, the software then designs all the individual parts so they will fit together and make the cabinet you want. It is much easier to define the cabinet than it is to define each part of the cabinet.

This is where parametrics comes in. Parametric dimensions are dimensions that change in proportion when another dimension changes. If all you want to do is change the size of the cabinet, there is no reason to redefine all the parameters. You simply tell the software that you want the same cabinet in a new size and it changes all the part sizes as needed. Now it becomes practical to make custom size cabinets, since virtually all the programming work is done by the software. The practice of designing custom cabinets this way and then cutting them out on a CNC router has become known as Nested Based Manufacturing. Another area of this web site covers this in more detail.

Most CNC controls only accept programs carefully developed for them. The basic part design must be processed through CAM software which develops the path that the tool must take to produce the part. Then, the tool path must be processed through another piece of software called a Post Processor which develops the CNC code needed to make the machine travel the required path. This adds complexity to the process making it less suitable for short run and custom jobs.

Thermwood eliminates this complexity by including the CAM and Post Processor functions in the control itself, and they are automatic. All you need to do it copy the part design to the control and it does everything needed to run it, automatically.

We use the DXF format, which virtually every major software package exports, to transfer design detail to the control.

There is one area to watch for when looking at software. Some cabinet design software companies that offer separate, high cost CNC links, have removed the DXF output from their base package and placed it in their CNC link to force you to purchase this even though you will not be using their CAM and Post Processor software. Most design software, however, retains the DXF file export functions and work directly with Thermwood’s control.

In an effort to help custom shops find work for their machines, Thermwood, through the eCabinet Systems web site, maintains an area where Thermwood machine owners can post their name and contact information. Those looking for shops to custom make parts can then call and make arrangements directly. There is no cost for this service.

Another new area that can prove to be a huge benefit to custom shops concerns custom profiles for moldings or part edges. Traditionally, to machine a custom molding or a custom shape on a part, a custom shaped tool was needed. These custom tools have the same disadvantage as custom programming when only a few parts are required. The disadvantage is that the entire cost must be charged against one or two parts. Using eCabinet Systems software and the Thermwood control, an alternative approach is now available.

When a part with a custom shape is sent to the control, the control asks if you have a tool with the correct profile. If you say no, the control automatically creates a modeling program that uses standard tools to produce the shape. It does this by going back and forth with the tool, stepping over a little each time until the desired profile is developed.

This does take longer (about 15 minutes for an 8’ molding) but it is a highly efficient alternative to buying a new tool every time you need to make a new shape. Shapes can be put on straight or curved pieces including curved moldings and curved edges of parts. This capability gives the custom shop the ability to quickly produce virtually any shape without special tooling, opening new opportunities not available with other CNC routers.

Another approach available from Thermwood but not available from others is the ability to rent CNC programs for elaborate carvings which are used to produce custom designs. There is a small rental fee for each part produced using this program.

Thermwood offers a growing library of programs for carvings and carved parts. When you want to run the program, you purchase, through the control, a license. Cost per part is typically a few dollars.

You are normally charged for the license after program execution is a little over half over. If the program is stopped before this point because of defects uncovered in the material for example, it can be restarted without paying the license fee again. Once this point is passed, you need to pay the license fee again to restart the program. Note that you can stop the program at any time to replace a cutting tool, back up to the point where it broke and resume without purchasing another license fee.

This program offers the ability to add elaborate details without the time and expense normally required to develop custom programs. You can even scale the carving size up or down in each axis to better adapt it to your custom requirements. Thermwood will continue to add new programs and invites artists and wood carvers to submit designs of their own for the program. Should a design be submitted and accepted, Thermwood will split any design fees collected for use of that design with the person that submitted it.