More and more woodworking shops are purchasing advanced computer controlled woodworking machines that they would not even have considered several years ago. One explanation is the increased demand for products that require patterns of a complexity that would be extremely time-consuming to produce by hand. Another reason is that computerized woodworking reduces the need for skilled labor which is becoming increasingly scarce and costly. Finally, the recent dramatic reduction in the cost of computerized woodworking equipment has put their price within the affordable range for all but the smallest shops.

PepperTree Kitchen and Bath, Inc., Salt Lake City, Utah, is a custom cabinet shop that specializes in producing European-style frameless cabinets. This type of cabinet dispenses with the frame by making the case of the cabinet thicker — typically 3/4 inch — to provide the necessary structural strength. One advantage is that the appearance is cleaner because the frame is gone and hinges are hidden —the walls and doors are all that is visible. Another plus is that the lack of a frame means that less labor is required to build them. The only drawback is that the rest of the structure must be built to considerably closer tolerances. This is because the frame of a frame-type cabinet can be scribed to compensate for inaccuracies while this option does not exist with a European-style cabinet.

A simultaneous trend in the cabinet industry is the increased popularity of painted surfaces with white and several pastels being the most popular colors at present. This creates problems with conventional 5-piece raised panel doors normally used with European-style cabinets because as the wood expands and contracts, cracks can appear in the paint which spoil its appearance. Another problem with these doors is that they require a lot of labor to build by hand; thus most smaller cabinet shops are forced to buy them at about $25 each from suppliers that use computer controlled equipment to produce them in high volumes. Cabinet shops that take this approach run the risk of late door deliveries causing them to miss their own deadlines.

Then he heard about the Techno Series III PC-Driven CNC Wood Router (Techno/Isel USA, New Hyde Park, New York) which is designed for production routing and drilling on a wide variety of materials including wood, plastic, MDF, solid surfacing materials and nonferrous metals. Sewell priced a model with two cutting heads, a 49-inch by 41 inch cutting area and Z-axis height of 2 inches at $19,000.

Table technical specifications include a rapid travel rate of 200 inches per minute, a Z-axis cutting force of 200-lbs. maximum, 0.0004-inch/foot resolution and repeatability and 0.003 inch absolute accuracy. This combination of capabilities and price proved irresistible so in early 1991

Sewell bought his first computer controlled machine. Sewell realized that the wide range of styles and sizes he needed would require a considerable amount of programming if conventional methods were used. So he hired a local programmer to write a simple basic program that automatically generates any size door in each of the five styles frequently produced by the company. Each style requires a 1-1/2" wide, 1/16" deep trough to be cut out in the shape of a square, arch, cathedral top or half circle pattern. Two different bits are required to produce these doors: a 1/4" round convex bit for the outside of the pattern and a convex bit for the inside.

1-1/2" wide flat area within the pattern. Finally, the convex bit is used to finish the inside edge of the pattern. An additional door style produced by the company is a mullion with four panes of glass. This style is produced by making a through cut for each pane while leaving a lip on the backside to secure the glass. In order to generate a program for any one of these styles, the user simply calls up the program corresponding to the style. The program prompts the user to enter the height and width of the door and then automatically generates an ASCII file which is read by the machine control program to produce the part. The new router has made it possible for PepperTree to produce one-piece doors with the patterns mentioned above in about two minutes.

Total cost of producing the doors has been reduced to $7 per door which is a 72% savings over the previous cost of purchasing them from an outside supplier.

The complicated process of cutting, fitting, sanding and assembling five-piece doors, which typically takes about an hour by hand per door, has been totally eliminated. The new one-piece doors expand and contract evenly thus avoiding paint cracking and improving appearance significantly over conventional 5-piece doors. Furthermore, PepperTree has complete control over when the doors are produced so they have eliminated installation delays caused by late deliveries from outside suppliers. Finally, Sewell is planning in the near future to begin programming custom-carved door patterns which can easily be produced by the Techno machine.