Tech Talk
What is "Production Machining of Laminates"?
As any company that survived the financial pressures of the early 90's knows, it isn't good enough just to produce a good product or service; efficiency is every bit as important. Inventories, labour content, choice of material, materials handling, processing, waste content & waste disposal, assembly, and machining costs all have to be scrutinized and analyzed constantly for methods to maintain or reduce manufacturing costs, without sacrificing quality. The world market requirements of better products, at lower costs and faster deliveries, complicated by demands for shorter runs, have triggered an unprecedented capital equipment investment in the last two or three years. Modern woodworking machinery must reduce unit cost by reducing labour and producing more. The payback for this efficiency is already being seen in some segments of manufacturing, in that their capacity to produce is beyond their market requirements, even without a down turn. But, I'll leave that problem to the economists.
In the tooling industry, our problem is to keep up with the demands of modern machinery. The customer is putting a lot more thought into things like: feed rates, tool changing, order of processing, eliminating handling between machining steps, and reducing machining steps, than ever before. The old concept, that a machine is only as good as the tool it is driving, has never been more evident than now. The life span of current high production woodworking tools, such as Diamond tools and Insert tools, makes them more of a capitol investment than an operating expense. As a result, we're finding the cost of the tool is less a factor than it's efficiency, and the more reliable tools justify their initial cost for longer than any depreciation period.High production machining of laminates is done on the Panel saw, the Router, the Tenoner, the Edge Bander, and the Through Feed Boring machine. The first step in machining anything is usually the sizing on a Panel Saw. The methods for sawing depend on the material, the laminate, and the required finish.If the material is going directly to the edge bander, from the saw, the quality of cut is critical. A chipped, or wavy, or uneven edge is not acceptable. Scoring is required, and it must be accurate. Only the laminate itself, should be cut. There is no advantage in cutting into the substrate with the scoring blade, and deep scoring will result in poor edge banding. I believe very strongly in Diamond Scoring. Long term, it reduces tooling costs, sharpening costs, and, contrary to old thinking, it is not difficult to set up. A good, experienced operator can adjust for main blade wear in minutes, and will run his blades in order of kerf size to minimize adjustment. Feed rates on the panel saw depend on stack height, machine condition, and blade specifications and quality. Determine, through trial and error, record keeping, and a good ammeter, what the most efficient conditions are for your environment. Know, at what ammeter reading, it is time for the blades to come off, and stick to it. Running them too long will result in either an uneven (wavy) cut, or some degree of chipping, or both.If the material goes from the Panel saw to the Router or Tenoner for finish machining, obviously the finish cut at the saw isn't as critical. Often in these situations scoring is not used, (but not always) and the saw blades can be left on the machine a little longer. But, be cautious, I've seen the results of running blades too long. It can cause permanent damage to the blade as well as excessive wear on machine components. As a blade gets dull, obviously, there is more resistance to cutting, causing everything; motors, bearings, and belts to carry a heavier load. Plus, the duller the saw, the more heat is generated at the tip. This accelerates wear on the tooth and causes blade run-out.Sizing material on an automatic Router, at high rates, to a finished surface, is usually best done with Spiral Tools. We previously did a whole article on spiral router applications, but basically if you need to route fast, Spirals are the answer, but they are not particularly efficient or cost effective in slow feed rate applications. Single sided laminates (or veneers), with the finish side up, are routed with Downcut Spirals, and Upcut Spirals, if the finish is down. If the material is double sided we recommend Compression Spirals. Quality maintenance of Compression Spirals, however, is very important. If, during the re-sharpening process, the diameters of the two components of a Compression Tool are not kept identical, a line or step, that may be hardly detectable on some materials, could result on the edge.Applications where high feed rates aren't possible should be routed with Insert Tools, or Diamond Tools. Your tool supplier should be able to determine the best design for any specific application. When routing any laminated material, the laminated edge is the most abrasive to the tool, therefore it is important to adjust the tool regularly so it wears evenly through its length and not just at the laminate surface. The steel door industry does this by oscillating the tool constantly, during the cutting action, and it is very effective. I don't believe this is currently available on Routers, but I've heard it is being worked on.There are many ways to size and finish on a Tenoning Line. How it is done depends the material, feed rate desired, accuracy of the finish size, and, if there is any profiling involved. A Tenoner can be set up to: Score and Hog, / Double Hog, / Hog and Joint, / Hog, Rough and Finish Joint. Profiling can also be done by single stage, or two stage - Roughing and Finishing. The fundamental principle behind all the various methods is: the more machining stations you have, and the less material each one removes, the higher the productivity, and finish quality you will get. Hogging has replaced Sawing on the Tenoner for primarily waste management purposes - all waste goes up the dust collector.One of the things not addressed here, is the effect the different methods of machining laminates has on Tool Life. The principle mentioned previously, basically, still applies - the less material a tool has to remove, the longer it will last, however, this obviously doesn't work to infinity. Production and quality requirements are the real deciding factors in the choice of machining methods. by: Doug Reid, President, B.C. Saw
