3.Machining and processing HPL
File, sand paper, scraper
Files are suitable for edge finishing. Always file from the decorative side towards the substrate. Fine files or sand paper (100 – 150 grit) or scraper can be used for breaking edges.
Hand Planes
Hand planes can also be used for edge finishing. It is recommended to use metal planes with HSS blades, where the contact surface does not wear out when sliding along the sheet edge. The cutting angle of the blade should be approximately 15 °.
Edge finishing with hand-held routers
Hand-held routers are mainly used for trimming protruding sheet edges. The handheld router has to be covered with a non-abrasive material to protect the surface during sliding. Dirt particles and routing shavings always have to be removed carefully.
Routing cutters with single or double flute TCT cutters are recommended, for larger diameters those are also available with reversible plates. Height- adjustable routing cutters with axially parallel blades are preferable because they allow more efficient use of the tool. The edges are broken afterwards. The sheet should only protrude as much as necessary (2 – 3 mm) to avoid unnecessary strain on the tool.
Edge finishing with stationary machines
Router and cutting heads with interchangeable tungsten carbide tipped blades have proven to be effective on table routers:
A speed of 12000 rpm is preferable when routing HPL up to approx. 5 mm thickness and a tooldiameterofe.g. 100 mm(Note: the maximum speed of the tool used!). This is equivalent to a cutting speed of 60 m/s. Lower tool speeds are recommended for HPL composite elements (approx. 3000 – 6000 rpm, equivalent to 15 – 30 m/s). The tool life depends on the height setting of the tool location and shape, required cutting quality and substrate. For large quantities it is advantageous to use tools with polycrystalline diamond cutters.
Bench routers can be used with single or double flute TCT cutters, also with interchangeable blades, at an ideal cutting speed of 10 – 15 m/s. This tool is also used for cutouts. HPL-Compact and HPL composite elements can only be routed properly if clamping devices are used. 2 mm allowance per edge is sufficient in most cases. For curved edges, it is often advisable to pre-cut the approximate shape to avoid excessive routing.
A surface planer (with a feed rate of 5 – 15 rpm, a cutting speed of 12 – 15 m/s and a speed of 3000 rpm) is only of limited suitability due to the short service lives of the usual blades. TCT blades should be used for larger quantities.
Edge-banding machines play an important role. With feed speeds of 10 – 32 m/ min they are recommended particularly for order-specific manufac-turing and for short runs. These machines are designed for one-sided machining and typically have an optional panel sizing section with jointing cutters and a edge banding section. Edge finishing consists of a cutting unit, a pre-routing unit, a profiling or alternatively an external routing unit as well as scraper, sanding or polishing units for producing the edge finish. Jointing cutters with polycrystalline diamond cutters (PCD) are recommended for joining the workpiece edges.
Double-end profilers in the classic sense consist of two parallel routing units which can be independently moved using an adjusting system. After the routing units, a laminating system can be directly linked to the system. The maximum feed speeds mainly depend on the type of edging tape and range from approx. 20 m/min for solid wood banding and sophisticated soft forming edges and approx. 40 – 60 m/ min for plastic edges (1 – 3 mm thickness) to 120 m/minfor thin edges (melamine paper edges with 0.3 – 0.4 mm thickness). Panel sizing is generally carried out with cutting machines. Standard tool diameter is 250 mm at a speed of 6000 rpm, equipped with PCD.
