Overview
Choosing the right control points significantly impacts the accuracy of your layout. This article covers three key principles for selecting and recording control points to maximize stationing accuracy.
Scan control points that are far away. Errors only cover the area between recorded control points. When your control points are spaced far apart, you can print accurately over a larger area - even if the shown error is higher than with closer points. | |
More recorded points is always better.
It is better to have five control points with an 1/16" station error than only three with smaller errors. The more control points you have, the more accurate your print alignment will be. | |
Record control points around your print area.
To make sure your control points are spaced out properly, set them up around the area that you plan to print. |
1. Large Control Point Spacing Is Better
Distance between a control point and the laser tracker matters as much as the error value itself. A control point 10' away with a 1/32" error may actually perform worse than a control point 100' away with a 1/16" error — especially if your print area extends out to 100'.
Spread your control points as far apart as possible. They can be scanned in any shape or random arrangement — the key is that they cannot all fall on a single straight line.
⚠️ Do not record all control points in a straight line. This will degrade stationing accuracy.
2. More Recorded Points Is Always Better
The minimum is 3 control points, but recording more improves accuracy. For example, 4 control points with 1/16" error is better than 3 control points with the same 1/16" error.
More points give the system a larger dataset for a better "best fit" calculation when matching your scanned points to the digital files.
3. Record Control Points Around Your Print Area
Position control points around the perimeter of your intended print area, not clustered inside it. This ensures adequate spacing relative to where the robot will be printing from that station.