Innovative Scanner Control

SCANahead is an innovative scanner control technology of laser scan systems to improve dynamics and precision.

Advantages

• Increase in productivity due to significantly shorter acceleration phases without tracking error
• Fast marking of circles without necking effects
• Auto delay function of the RTC6: Laser and scanner delays are set automatically

Principle

Scan systems with SCANahead control always accelerate to the maximum (i.e. in the minimum acceleration time t_a). In contrast to the conventional control with tracking error t_s which have a constant acceleration time regardless of the target speed, scan systems with SCANahead control require suitably generated control values, for example with an RTC6 control board.

RTC control boards with SCANahead function generates suitable control values with automatically determined delays for each scan system. Limiting the acceleration of the target path to the maximum acceleration of the scanner axes in the scan head (blue line) ensures that the dynamic potential of the galvos is fully utilized.

The calculation is performed in real time – the execution of the movement is accordingly offset by the preview time t_p.

SCANahead Control Compared to Conventional Control

	Conventional Control	SCANahead Control
Dynamics	Acceleration time ta is constant Dynamic potential of the galvanometer scanner not used efficiently at all times	Scanner axis acceleration always at maximum Fully utilized galvo dynamics
Tracking error [ts]	Finite, constant tracking error Limits precision of image field correction at high speeds Typically optimized for a single application Several different tunings necessary, only possible in digital scan systems	No tracking error ts = 0 Precise image field correction even at high speeds Only one tuning needed – optimum performance across all applications A constant preview time tp is used to determine the navigable trajectory
Use of delays	Delays must be determined and set manually Optimization of the delay settings by the user necessary	Set by the auto-delay function of the RTC6
Example application: Circles and arcs  (Circle: v = 2.8 m/s)	Necking effects (caused by the tracking error) Adjustment of the circle diameter necessary	No necking effects
Example application: 90° corners (Corner: v = 1 m/s)	Tracking error can result in a significant corner rounding	Significantly smaller deviations during traversal of 90° corners at a wide range of speeds

Example 3D Printing

In additive manufacturing, two-dimensional structures are typically realized by bidirectional hatching. A large part of the process time in scan systems with conventional control is required for the turnaround times for acceleration and deceleration processes.
Scan systems with SCANahead control significantly reduce these turnaround times and therefore contribute to a significant increase in productivity.

Products with SCANahead

The following scan systems support SCANahead:

excelliSCAN

intelliSCAN IV

fiberSYS