For optimal sanding of veneer products consistently, sanders should be configured with:

1. Conveyor with variable feed speed. The ability to adjust feed speed is critical to maintaining consistency when veneer sanding. Controlling the “dwell” time under the sanding platen directly affects the amount of material removed. Single and two-speed drive motors do not have enough adjustment to dial in the correct “dwell” time for each wood species or veneer type. speed of the conveyor should be between 9-12 mpm depending on the veneer type.

2. Electronic sensing of the workpiece. All veneer sanding machines must be able to automatically detect the size and shape of the workpiece. The machine must recognize this part shape and know the feed speed. In this way it can accurately control the sanding platen as to when and where it sands, reducing the chance of damaging the edges of the piece.

3. Anti-dubbing control of the sanding unit. In coordination with the sensing device, the sanding platen is controlled as to where it starts and stops sanding. This “lead in” “lead out” is critical to not sanding through the leading and trailing edges. This anti-dubbing control is adjusted through the controller and is automatically timed with the feed speed on the conveyor.

4. A segmented sanding platen (pad). The segmented platen is a key feature when sanding veneer products. The ability to copy the shape of a panel can only be achieved with the segmented platen. The more narrow the sectors, the greater copying capacity the machine will have. Standard widths range from 15-50mm; 22-32mm widths are most widely used. Other advantages include:
• Multi-part feeding: the ability for the operator to load multiple pieces across the conveyor confident that the machine will sand each with no burn-throughs on all edges of each part; and 
• Edge pressure control: the ability to add or reduce pressure on the edges automatically through the control. Raw veneer pieces may require less pressure on the edges than parts with solid wood rims or banding.

5. Electronic controller. While the machine can be configured without this feature, it does make the setup much easier for the operator. Programs can be saved to match each sanding operation being requested. The controller makes it no longer necessary to have operators who are highly trained for veneer sanding.

6. An abrasive belt with variable speed control. The ability to adjust the abrasive belt speed allows control of the aggressiveness of the sanding. The wide variety of wood species and different thicknesses of veneer products make this a key feature in maintaining a consistent finish quality. Abrasive speed for veneer typically ranges from 9-12 mps depending on the finish required. Combined with the conveyor speed adjustment, this gives the operator great flexibility in setting the machine properly for the application.

Source: Mike Johnson is the vice president of sales at Biesse America. For information on Biesse, call 704-357-3131 or visit Biesse.com.