By the time your panels reach the edgebander, they have been sized and are starting to resemble a finished component.

Your edgebander is your last chance to make a positive impression on the edge. The smallest imperfections cannot be 'unseen.'

So, what are the issues we must deal with?

Sawing

A common problem is a little step on the bottom edge of a board created by the scoring blade when cutting. Even on a perfectly adjusted panel or beam saw, the scoring blade is set a tiny bit wider than the main blade to avoid chipping with the main blade. This small offset will create a wider glue line on one side of the panel. 

Nesting

The router bits used in the nesting process, because of their small diameter, pull instead of cutting some of the fibres in the panel core's loose centre. These fibres stand out and prevent a perfect edge application and/or contaminate the glue application unit.

Board swelling

Sometimes panels are cut and edged the next day or even the day after. If humidity is an issue, especially in the summer, the particle board edges soak it up like a sponge. It can lead to significant swelling of the outer board edges. 

What is the solution?

It is simple, just mill your imperfections away with the pre-milling station on your edgebander. It is normal practice to remove the thickness of the edge tape. Along with eliminating any imperfections, they also provide a reference line for the remainder of the edgebander's units.

What should be considered with pre-milling tooling?

Tool condition

Quite simple, keep the tools sharp! Too often the pre-milling tools are overrun and end up damaged. While not all machines allow it, most allow the tools to be adjusted. Any tool will wear on the hardest point, and the pre-milling tool is no exception. By adjusting tool height, you will spread the tool wear over more of the usable cutting height.

But the tools will still dull off. Inspect the tool and send them for regular service.

Tool design

Choose tooling that will increase tool life. More basic tool designs do not allow the chips to leave the tool and cause multiple cutting, excessive noise, and reduced tool life (figures 1-2, &2). Choose a tool which guides the chip away from the cutting edge and workpiece (figure 3). 

Figure 1: Tool with closed chip space

Figure 2: Chips cannot evacuate and therefore, will be cut multiple times.

Figure 3: AKE Pre miller with V-Line chip space