Frequently Asked Questions¶
How Does Beacon Work?¶
Beacon is an eddy current sensor. It uses a high frequency magnetic field to induce eddy currents in a conductive target and measures their strength. A sensor calibration curve is fitted to a model using the printer's z axis, allowing direct calculation of distance from raw measurements. Rapid and continuous measurement of distance makes high speed, high resolution meshing possible.
Industrial Use
Eddy current sensors are broadly used in industry for their high bandwidth, high temperature rating, high precision, and general immunity to contaminates.
What Bed Surfaces Work with Beacon?¶
Any high conductivity surface works with Beacon, but bare steel with glue, pei coated steel, or pei laminated steel are most commonly available.
Bare steel with glue and pei coated steel are the recommended surfaces. Beacon directly measures the surface, they are highly durable, and do not form bubbles or delaminate.
Plate Thickness
400um is the recommended minimum thickness for a steel plate, which provides enough skin depths at the measurement frequency to prevent overpenetration of the sensing magnetic field.
Stacked Surfaces
When working with laminated or metal substrate stack ups, Beacon senses the conductive subsurface -- thinner laminates and adhesives are recommended to reduce surface variations due to the stacked material thickness.
What Firmware does Beacon Support?¶
'Kalico' and 'Klipper' are the only supported firmwares at this time, to make use of the available processing power of a single board computer. Beacon produces a high volume of data during high speed meshes, and uses only precision models for calculating distance and temperature effects. No shortcuts are taken, in order to achieve the highest possible performance.
What Temperature can Beacon Operate At?¶
Beacon is rated for operation up to 120C at the sensor coil, and 110C at the amplifier. Barring actively heated build chambers, this allows operation in nearly any FDM environment.
All individual components used in Beacon are 125C and/or automotive rated, with any exceptions having alternative mitigations or appropriate derating in place. The PCBs are comprised of Low-CTE, High-Tg (185C+) name brand laminates. The epoxy protecting the temperature sensor is 250C rated.
As a safety precaution and to preserve working life, the LED is automatically powered down over 90C and the Accelerometer is automatically powered down over 102.5C.
My Bed has Large Fixed Magnets, Will it Affect Beacon?¶
Beacon is not recommended for use with beds featuring oversized fixed magnets. Ferromagnetic metals, which are present in all magnetic surface plates, exhibit Anisotropic Magnetoresistance (AMR). This means that very strong magnetic fields present in the upper surface of the plate can change the resistance enough to affect the eddy currents induced by Beacon.
If the magnets present in the bed are strong enough to reach magnetic saturation in the surface plate, very high magnetic field strengths will be present in the outer surface and Beacon will see sharp peaks. The Beacon software supports mesh exclusion zones, which may be sufficient for some bed designs, but if the magnets are really strong or cover a significant area it may not be worth the trouble.
In the future, we will provide quantitative guidance on maximum recommended magnet size for given plate thicknesses.
Magnetic Sheets
Magnetized rubber sheets have a high number of poles, and result in no detectable artifacts.