Build surface options

  • Okay, so I built my printer, and it uses a 24V heated bed with an aluminum surface. I put a sheet of glass over that, and have been quite happy with the surface for adhesion. The glass is basically as a replaceable surface since the aluminum is softer than the nozzle, and I don't want to deal with gouges in the surface.

    Currently, I'm using a Piezo sensor, which has a lot of advantages, but also has some challenges which I'd like to do something about. As such, I bought an IR sensor, and am considering ways to implement it. I have a mount solution that I'm reasonably happy with

    So as I understand it, putting a layer of matte black on the underside of the glass is one effective solution that allows a glass surface. I've considered using flat black BBQ paint on the aluminum, but I'm still concerned, because the back surface of the glass itself is also quite reflective, so I don't see this as a guarantee that the IR sensor won't get confused with reflections from both the top and bottom surfaces of the glass.

    I suppose that another solution is to use sheet metal, which I'm seeing on many printers. This ought to be a simple enough matter. I've heard that having printed patterns on the surface can have negative effects on reliability. If I go with this option should I just keep the steel clean? Would painting it white give better results? Other colours?

    My last issue is a bit picky, but is there a way to determine the actual sensing point for the sensor? I'd like to be as accurate as possible when setting the X/Y offsets from the sensor to the print head. I've been assuming that it would pick up from near the centre of the can between the IR diodes and the pickup. Hmmm. Thinking about it now, probably the midpoint between the pickup and the center point between the two emitters. I did my mount design assuming that it would be midpoint of the mounting screw holes. Regardless it's probably close enough, but if there's better information out there, I'd like to take it into account.

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