Flexibility, versatility and new capabilities make CNC machining centers attractive to a wider audience.

 

CNC machining centers have grown in popularity due to their flexibility and the ability to process a variety of materials, including solid wood, composite wood panels, plastics, solid surface materials and other non-ferrous materials. Photo courtesy of Delmac.

Already a versatile piece of equipment, the CNC machining center keeps finding new applications. Wood & Wood Products queried machinery experts on the changes and benefits they see coming for these flexible workhorses.

Michael Cassell, North American CNC product manager for Holz-Her US, says that while the range of benefits provided by CNC technology are numerous, “the ability to perform a number of machining functions in a single setup is one of the most significant. The successful use of CNC technology eliminates the movement of parts to separate machines to perform individual, single functions.”

Kevin Walsh, sales manager for Richard T. Byrnes Co., agrees, adding that an advantage of multiple-function machines is the elimination of handling of the parts between operations. “The chance of damage to the part is minimized and the accuracy of the part is higher since it is located once and not several times.”

Larry Tolvert, technical support manager for Solid Wood Systems Inc., echoes Walsh’s statement. “In the past, the workpiece remained in place on the table and work was performed only on accessible surfaces. Now the workpiece can be turned and rotated, allowing access to machine practically all surfaces. This allows more operations to be performed without repositioning the workpiece,” he says.

“A single machine can do panel processing, solid wood, 3-D carvings, five piece doors, MDF doors and pretty much any other parts that might be needed,” says Ken Susnjara, founder and chairman of Thermwood Corp. “At times, a dedicated machine that performs a single task might be able to perform that task faster than a CNC machine, but in most cases if you consider the material handling and setup, it is likely that the new generation of CNC machines will be as productive or more productive.”

“With the CNC machining center we are exploring new niches,” says Cesare Magnani, North American product manager for Biesse Group America. “We are focusing on the versatility of the machining centers and in providing customers with standard solutions on the machine table that allows them to change the use of the machine quickly. For some customers, the flexibility and versatility of the CNC is a good solution.”

Flexibility is Key

“The power of the machining center is its flexible nature,” says David McFarland, senior CNC product manager for Stiles Machinery Inc. He noted that in addition to increased tooling, sawing and moulding capabilities are being viewed as standard options on many CNC machining centers.

“Sawing and moulding capabilities have been available on 3- and 4-axis machining centers for some time now,” says Bill Blackmon, Busellato product manager for Delmac. “These machines use an aggregate to change the spindle’s rotational axis from vertical to horizontal. But more recently, CNC machining centers are offering 5-axis capability. These machines allow the spindle’s rotational axis to vary from vertical, meaning a profile tool can be used at nearly any angle without the need for an aggregate.”

Cassell also notes that today’s CNC machines have the ability to “size, groove, saw, pocket, drill vertically and horizontally, machine anywhere within a full 360-degree circle [using the C axis] and machine/drill at any angle [using positional flex aggregates], while moulder aggregates can be used to perform this function — the incorporation of a full 5-axis head allows for many of these functions to be carried out simultaneously.”

Jeffrey Grant, vice president of Hendrick, says he sees customers requesting features such as 3-, 4- and 5-axis sawing capabilities; 0, 90-degree and full 4-axis moulding capability with up to 12-inch wide cutter capacity; as well as standard and 5-axis routing.

“Macros,” Walsh says, “are quite popular on our machines and other more developed CNCs. Standard operations are boring, mortising and tenoning that can be done parametrically."

“CNC technology enables the high production manufacturer to run an entire product portfolio with minimal setup and changeover time,” says Peter Riehle, president of Weinig USA. “Programs can be stored and run over and over again. If the programming system is suited for a job shop environment [shop programming at the control or offline], CNC machines are faster and produce consistent quality products. The key is that the shop programming is simple and fast, to have short programming times for short runs.”

Many of today’s CNC machining centers are designed with routing, boring and grooving capabilities. Photo courtesy of Stiles Machinery.

Growing List of Applications

CNC machines can process a wide range of materials, including: composite panels, solid wood, plastics, solid surface materials and non-ferrous metals.

“Traditionally best suited to panel processing applications, today’s CNC machining center has more CNC router functionality,” says McFarland. “Not every model of machining center is well suited for a dedicated solid wood application. However, some manufacturers have dedicated standard machine models for solid wood machining. Variations in machine base construction, router spindle horsepower specifications and various mechanical clamping devices combine to make the machining center more appropriate for solid wood.”

“Suitability [i.e., for solid wood or panel processing] is a function of application,” says Tim Rose, Hi Tech Panel Division at SCM GROUP USA. “Use the 80/20 rule and determine the most common operations and then look to the machine configuration to determine how well they fit. [The CNC machining centers] all have the power and structure for solid wood or panel processing, but [can be configured] to be better suited for one or the other, by selecting combinations of tables, drill heads and routers.”

“Many solid wood applications require 4- or 5-axis operations,” says Tolvert. “CNC machining centers have evolved to make these parts easy and efficient to produce. The newest generation of machining centers can be designed and equipped for either multi-purpose use — capable of producing almost anything imaginable — or part-specific applications, such as mortise and tenoning operations.”

According to Grant, “The recent trend in nested-based type cabinet manufacturing is morphing CNC machining centers and traditional CNC routers into a single-type, flat-bed panel processing machining center.

Blackmon also notes that for many customers, “Machining centers with a pod-and-rail work table vs. a flat table, are better suited to solid wood machining since the table can be more easily configured with various vacuum pods and clamps. Because the part is already elevated, no custom fixtures or clamps have to be built to facilitate edge machining.” A benefit of this type of configuration, he adds, is dust control. “With an open table, dust not picked up by the dust collector falls through the rails and into a trough or conveyor.”

Another option, mentioned by Rose, is a pod-and-rail system, which uses a tubeless vacuum and pneumatically enhanced clamps for positive hold.

Pneumatic systems have their supporters, who cite the ability to secure components that are narrow and may be difficult to hold with just a vacuum. “The key is that we can quickly replace regular vacuum ports with pneumatic clamps. At the same time, the multi-zone allows us to create as many vacuum areas or clamping areas on the machine as there are ports, offering total flexibility with increased productivity,” Magnani says.

In addition, Tolvert says, “Bar code readers can be incorporated into machining centers for faster program changes. The machines now also offer their own set-up capabilities, which enable the machines to position the clamps and workpiece holders automatically, without operator intervention.”

Benefits for Small Shops


For the small shop, McFarland says, “The machining center is the ‘all-in-one’ or ‘super’ machine. It is a flexible tool for the manufacture of a wide variety of components. With the on-board tooling ability to route, drill, groove, shape, saw, profile, sand, etc., the range of application capabilities is almost limitless. With the advent of conversion tables, the traditional machining center can even be configured for nesting applications.”

Jack Lim, vice president of sales for Omnitech Systems, echoes the benefits of CNC machining centers, particularly in regards to use by smaller shops. “Generally, a cell station with sliding table saw and a vertical drilling machine is more beneficial for larger companies doing a lot of repetitive parts,” says Lim. “But for the smaller shops that do mostly custom applications, nested-base manufacturing is more beneficial. They can change the design for each of their customers on the fly with a few clicks on the computer. After that, the machine can cut everything out. It doesn’t matter how much of the design has changed. If they don’t have this flexibility, each time they change the design, they go through many headaches.

“We have seen where a two-man shop with a multifunction machine doing nested-based manufacturing for custom work can produce more than the shop with a dedicated machine,” Lim adds. “The operational costs are much lower and they are able to produce much more.”

“The small shop benefits in the same way as a large shop,” says Rose. “The benefits are repeatability and accuracy, but also the ability to accurately schedule production because the machine will always operate at a reliable, repeatable pace.”

Cassell concurs. “The benefits of this technology are available to a one-man shop as to a production facility of hundreds of employees, offering reduction of manpower, shorter set-up and cycle times, improved quality and consistency, improved process and production flow. These are benefits any company can use and appreciate,” he says.

Walsh also agrees. “Whether a production shop or a one-man operation, if you want to take parts designed by a CAD program and produce them to a precise tolerance, superior quality — from one part to 1,000 pieces, there is no better way than a CNC. Customers need to be sure that the machine can do all the operations they want and also that the company supplying it offers support in parts, service, technical assistance and software.”

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