Henkel Harris creates tomorrow's antiques, says lead product engineer David Cooper. Since 1946, the company, located in Winchester, Va., has been manufacturing high-quality 18th century reproductions with carved details done by hand except it's not done by hand alone. In 1990 HH bought its first CNC router and has been steadily adding to its equipment to supplement the hand work.
"We used automation because of the volume we do," says Cooper. "We have to be as automated as possible. But I think the quality of the furniture demanded that hand work be involved in it."
The furniture HH builds has flat panels, contoured elements and carved parts, which require a number of specific machines to do the different processes. HH has three CMS routers, and an Axxiom, Biesse and Routech. There is also an Elox EDM machine for tooling at the plant.
"Unfortunately, the machines don't all use the same type of controller and that's been an issue with software," says Cooper. "We want to be able to have the one programming package that can program several different machines instead of software unique to each one."
One machine at a time
HH bought its CNC machines one at a time. "We started out trying to see what the CNC could do for us instead of having a surprise the day it was brought in," says Cooper. Over time, the machine showed a proven time savings and each new machine was purchased with a specific purpose in mind, he says.
"When you're running two shifts or a 24-hour day on a machine and you still have a backlog, you realize that you have to add some more equipment."
The company started out with a five-axis CMS MR64 CNC carving machine to handle the carving because HH wanted to keep the carving in house and cut back on the amount of hand carving that was required. The machine replaced master carving machines that required an operator tracing a model prepared by a master carver. The new carver provided more detail and less operator fatigue, says Cooper.
"We had quite a load of carving that we were doing. We were coming off the hand-operated machines into the automated CNC machines and trying to match the machinery to the workload as best we could."
The first CMS router is a five-axis machine that turns parts set in chucks, so the tooling and the part are moving. After the company realized the consistency and repeatability of the CNC equipment, it purchased an Axxiom MC-2615 twin-table, three-axis CNC machine to process end panel stock and flat parts. A second CMS PF102 four-axis CNC machine followed, which is similar to the first but uses clamps instead of chucks to hold parts. The company also has a second CNC carving machine, a CMS MR64.
When it came time to do edge boring, HH turned to a Biesse R346 twin-table point-to-point machine, which it purchased in 1999. Finally, a SCM Routech Record 130 CNC was purchased to provide CNC boring capabilities in the framing department to improve flow through the plant.
Centralized programming key
"We wanted to combine our programs at one point. You can do your programming in an engineering department and there are advantages to that for us," says Cooper. "You're able to keep control of the changes that you need to make, whether it's the sizes of the product or things you need to do to change the manufacturing of it."
HH bought the different CNC machines throughout a 15-year span and wanted the programming and tooling to be consistent from one machine to another. The fact that all the machinery and controller manufacturers were from different countries complicated integrating the systems and getting them all to work with one software program. Mastercam/CNC Software Inc. told the company that they could provide one software package to run all of the machines.
The new software has proven to be consistent and integrates everything from the engineering department. The engineers do drawings and engineering plans in AutoCAD and then transfer the information to Mastercam for CNC programming.
"Feed and speed rates are crucial and it's been a learning process for us," says Cooper. "Carving needs to be carefully oriented to wood grain direction. The feeds and speeds must be critically matched to the specific wood material to achieve the quality and look of hand carving. Mastercam shows us how different types of cuts will work under the delicate conditions associated with intricate wood craftsmanship."
Hand carving with fewer hands
Carvings are programmed into the CNC machine using a digitizer. A master model is created by a master carver who works with a 2-D drawing in a couple of views.
"The master carver will go through and actually carve that master model and we'll get with everyone involved with it to determine if it's the way we want it to look and do any fine-tuning," says Cooper. "They can digitize from there. We want our product to look hand-carved, because it is and we want to keep that on every piece."
The CNC machines produce a roughed-out part that individual carvers further refine. The goal is to find better ways to produce products and eliminate hand work, says Cooper. "The more technology advances, the more we'll be able to do with the wood itself in terms of carvings, details and things we can put on products."
An important part of getting automation to work is that the operator has to understand carving to be able to program a machine to run correctly.
"In order to get the finish detail you need, you have to have someone who knows what tooling to use and what steps to take to get that part cut without tearing out," says Cooper.
In terms of training CNC operators, Cooper says that it's easiest to train a person who already knows carving and woodworking to do the work. "We have operators here who look at a blank of wood and know what the problems are going to be," he says. If an operator can anticipate problems down the line, modifications can be made to the program before any wood is cut. "If you have someone who just operates the machine, he may run into problems and not catch things that at later stages of the part may be affected by it."
A lot of parts, particularly simpler turnings or parts that have uniform shapes, are run on automatic lathes to avoid overloading the CNC machines. Similarly, if a better cut can be accomplished by running parts through the tenon machine because a faster feed rate can be used and a saw blade might produce a cleaner cut, then a part will be done that way.
"When we can run it on a regular machine, we will run it on a regular machine," says Cooper. "If it's saving time to run it on a CNC machine or if there is some advantage to running it on CNC, we will."
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