Defining as a peeling technology and process, an innovative cutting tool with larger shear angles and equipped with special cutting edge and tooth geometry will contribute to the enhancement of production efficiency and the improvement of the tool’s processing quality and service life. By Alvis Ren, manager of application technology, Leuco China.

Machining and processing of solid wood pieces is not a small challenge. On the one hand, it sets high requirement for the cutting finish; while on the other hand, it places stringent requirement on exotic woods or fine-lacquered woods. For example, whether the cutting tool could produce grooves? Whether the tool systems cutting across the grain or along the grain? Whether the tools should adopt the buckle design? These are all crucial factors need to be considered when designing a highly sophisticated cutting tool.

Currently, the wood processing standard considers the positioning of the cutting edge under a shear angle as a ‘drawing cut’. This results from the fact that in the direction of cut, the wedge angle of a cutting edge with shear angle is smaller than that of a cutting edge without shear angle. However, it is just an ‘inclinated’ cut.

The latest wood processing technology is the introduction of a cutting tool with shear angles ≥ 55 degree and equipped with special cutting edge and tooth geometry. Here, the cutting edge functions like a knife blade. With cutting procedures and methods differ from traditional cutting tools, the process is called ‘peeling’. Apart from the improvement with regard to tool precision, peeling with such cutting tools leads to enhanced cutting quality, longer tool life and better economic efficiency.

An Innovative Cutting Technique

This is a new type of wood processing technology differs from sawing, planing and milling. It has universal application in the most production areas such as corpus production, individual machining of linoleum, machining of flooring or high-gloss boards; it can also be used by joineries as well as by industrial woodworking companies.

Basically speaking, benefits provided by this peeling technique can be summarised as follows:
•Machining of solid wood by means of diamond tips with large wedge angle
•No chipping formed when cutting across the grain
•Finish-quality when peeling composite materials; no additional work steps needed
•Finish-quality when peeling fiber materials such as fabric, laminated panels, linoleum with jute fibers etc.
•Reducing of machine downtimes and no need for frequent tool changes

Thanks to the cutting tool with larger shear angle, the machining of solid wood across the grain is possible which means high chip caption and excellent cutting quality. Especially when machining solid wood, peeling creates finer and lighter chips which differ visibly from common chips and which can be extracted more easily.

In addition, when processing the workpiece placed on the machining center at very high processing speed, the conventional cutting tools will lead the machined boards detaching from the vacuum suction plate if high cutting resistance is formed. However, with the cutting tool featuring larger shear angle, the compound force caused by the cutting edge to the vertical direction of the board is conductive to form a tight fit between the workpiece and the vacuum suction plate.

Cutting to the ends of the boards with traditional cutting tools has often caused edge chipping, particularly in the case of jointing of overlapping veneer. The normal approach is to set aside part of the machining allowance to be milled off by the milling cutters.

In contrast, in the case of end-grain cutting, the new cutting system often allows to pass the edge against the feed without causing edge chipping. This also works with edged workpiece materials depending on edge thickness and board quality. Tool changes are no longer necessary, machine downtimes can be reduced.

In addition, the cutting tool can be used to process lightweight panels easily. Fabric coatings, leather, lightweight-wood core plywood made from Ceiba or poplar are very fibrous materials. It is a well-known fact that clean milling of fibre has been difficult or impossible. Thanks to the large shear angle of the cutting tool, the fibers are cleanly cut, even eliminating the need of post-processing.

Zero Joint With Laser & Plasma Technology

The most important advantages of laser edging by means of plasma- technology are the jointless edges with excellent humidity resistance. This becomes possible only when optimal cutting and jointing quality is achieved for the cutting section of the edges.

Thanks to the cutting edges with very large shear angle, the cutting tools cut the surface like ‘a pair of scissors’ with exceptional edge quality and surface finish quality. Meanwhile, the tools can process the edges and the machined surface without micro chippings.

Combination Of Technology & Efficiency

How to calculate the economic efficiency of a cutting tool? The economic efficiency is obtained by dividing the profit by the expenditure. In terms of cutting tool, profit means the service life of the tool, while expenditure means the price of the cutting tools. To make a cutting tool yielding more economic benefits, the ratio of the tool’s service life to the remaining price must be higher.

Then how to calculate the economic efficiency of a cutting tool with large shear angle? Here, the crucial point is to consider the relationship between the service life and the shear angle of the tool. Larger shear angle can significantly increase the service life of the tool.  This means less wear-and-tear and longer cutting cycles. For example, the service life of the cutting tool with a shear angle at 55 degree is twice as much as the tool with a shear angle at 35 degree.