In the summer of 2008, David Brigham of Four Corners, LLC went to the big woodworking show in Atlanta with the intention of evaluating the latest in 5-axis CNC router technology. He liked what he saw and stepped up to sign a contract for a big Multiax T115 5-Axis Precision CNC router with a 6’ x 12’ table and 4’ of Z. It was a gutsy move, but business was good, and he thought he could afford it.

Three months later the economy went into a tailspin, and soon a number of Brigham’s competitors were contemplating the prospect of going out of business. In the early months of the following year, he experienced feelings of trepidation every time he made a payment on his new equipment. These subsided by midyear when he took a look at the work flowing through his shop and came to the realization that his new 5-axis capabilities were actually carrying Four Corners through hard times.

In 2010, the economy had not recovered, but Four Corners was having its best year ever. Today, its sales volume is roughly twice what it was before getting heavily into 5-axis work, while the staffing level has not changed. He continues to operate with nine people, five in the shop and four in the office.

The company has eight CNC machines: six 3-axis routers; a 5-axis mill used for small, narrow items such as guitar necks and chair legs; and the big 5-axis router. All of these systems are programmed using Mastercam X6 Router, 2.5D and 5-axis (from CNC Software, Inc., Tolland, CT). This software was chosen because it allows him to manufacture any shape his customers can conceive, and it gave him responsive Reseller support delivered by (Services Four Automation now Cimquest) via interactive video conferencing.

Machine vs. Labor Content

When Four Corners opened it doors 16 years ago, it specialized in production work—chair seats and furniture panels, for example. Rapidly making these items one after another meant that an operator had to be pretty much dedicated to loading and unloading the machine. The profit margin on this type of work was low and the labor content high. The company still does a lot of this type of work. In fact, it has enough equipment and staff to offload spikes in production work that would bury smaller shops.

However, when Brigham acquired the big 5-axis system, he began accepting unique projects that frequently required the cutting of amorphous shapes, not only in wood but also in materials like aluminum and plastic. He found that a great deal of this was coming to him because the word "no" was not in his vocabulary. He was willing to attempt anything.

Brigham uses Mastercam to create the complex surface the customer wants. He does this by importing a model, replicating a drawing, or digitizing an artifact supplied by the customer using an arm-type measurement system or a laser scanner.

Once he has the surface, Mastercam will automatically lay down toolpaths that allow his 5-axis system to cut it. Before it is posted, the programmer watches a simulation of the program to make sure that part will be dimensionally correct and that there will be no tool or spindle crashes. After this step, the 5-axis router can be trusted to cut for hours at a time with no operator intervention.

Diverse Applications

Today, Brigham’s staff frequently loads one, two, or several complex shapes onto the router and runs them overnight. On the other hand, the growing recognition of the company's 5-axis expertise has also given it access to smaller, amorphous fast-turn jobs that it produces on the 5-axis mill. Here are some typical examples of this atypical work:

Sculptured Stair Rail Fitting: A carved staircase fitting served as the transition for a 60° turn on a balcony. The part was modeled in 3D, based on 2D drawings provided by the architect. Several versions of the model and architect’s drawings were exchanged until agreement on the final shape was reached. After that, programming in Mastercam and manufacturing the piece went quickly.

Decorative Carving: Decorative carving on a mansion bracket had badly deteriorated. The owner wanted a new hand-carved replacement. To reduce the labor content of this project, Four Corners digitized the original and used the 5-axis lathe to remove about 90% of the material with a ball mill. The piece was finished by a woodcarver in about three hours compared to the 2-3 days it would have taken to carve the piece entirely with hand tools since several of these pieces were milled without compromising the hand-carved aesthetics of the pieces. This is a type of project Four Corners is getting with increasing frequency. “I tell customers to let the CNC do the bullwork and let the artist spend his time doing what he does best,” Brigham said.

3D Staircase Panels: This project called for the production of 90 elaborate interconnecting 3D decorative panels for a curved residential staircase. There were four sets of six panels that had repeating patterns. All of the other panels were unique. Four Corners used Rhino design software to develop models for each of the panels based on drawings provided by the customer in plan and elevation views. Once the models were approved, they were imported into Mastercam where parallel surface toolpaths were created for single-setup cutting on the big 5-axis router.

Yacht Spiral Staircase Rail: One of the most interesting projects Four Corners has done recently was handrails for an elliptical staircase spanning three decks of a 150 ft. yacht. The close-fitting rails have smooth compound curves that mate precisely with the wall and match the decline of the staircase. The inner lip of the rail is undercut using a ball mill so that users can grip it firmly. The rails attach via machined back surfaces that fit into slots in the wall. Four Corners received models for the rail pieces from the customer. Once the surfaces were established, Mastercam quickly layed down parallel surface toolpaths for cutting the rails from solid cherry with just a single set-up on the big 5-axis router.

Non-Woodworking Projects: A mold for making polyurethane airliner head rests was roughed on the 3-axis mill, then shifted to the 5-axis router because of its ability to reach undercuts along the top edges without having to reposition the piece.

The shop was asked to manufacture tooling used for bending and shaping aluminum fairings for a 1943 Howard airplane. The customer provided the shape it wanted in the form of a clay model, which Four Corners captured using a Microscribe digitizer. The data was imported into Mastercam, where the surfaces were created and parallel surface toolpaths were automatically created for manufacturing left-hand and right-hand versions of the part from white oak. Brigham said it only took about a half-hour to generate the CNC program once the model had been created.

Anything You Need

These days when new acquaintances ask what he does, Brigham says, “I’m a woodworker.”

“Of course they are thinking planes and chisels and things like that,” he continued. They might respond by saying something like “isn't that quaint.” Then he explains what he does in a little more detail. When they invariably ask “What exactly do you make,” he says, “Anything you need.”

That attitude along with the right equipment and the right software is allowing Four Corners to continually expand and prosper.

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