Glass Bed (Page 6 of 9)

I purchased 8" square 1/4" thick mirrors from Walmart, in the picture frame department for under 4.00 each.  These mirrors work perfectly, attached with binder clips.  I no longer use Kapton, juse lightly mist ABS glue on mirror.  Sticks great, have had no warping or curling, print removes easily.  Either turn the z-axes screw holder upside down, or print replacement so you can lower the bed to correct position for leveling.   In my opinion, this works better than Kapton.  Looks great too!  Seems to be no loss of heat-no problems.

Damn, not even so much as a mention...   I still think having the metal brackets are a better solution because they pull down on the glass keeping it in place with the natural spring tension of the metal.

I see, but what I've found is that I have the metal brackets angled down so that when the magnet makes contact the hanger strap has to flex up to meet it.  The memory in the metal bracket is trying to pull back down to it's original state so it's essentially applying downward pressure on the corners of the glass.  This method you've done with the air gap doesn't exert as much pressure downward since it relies just on magnetic field alone.  Looks better by leaps and bounds, but I'm gonna stay with what I have.  I don't mean to knock it hope it's not coming off wrong.  It's a vast improvement over clips maybe we'll get more adopters this way.  Can't believe more people haven't done it.

I went the mirror route as well.  PLA @ 50C, the prints stick well, and it's kind of neat to be able to see the underside of objects as they print.

< $2.50 @ Joann's after coupon

http://www.joann.com/darice-8-x8-square … xprd78605/

http://www.joann.com/coupon/

8x8 mirror @ Joann's is 1/4" thick with rounded edges.

Homing the Z does not mean that it's automatically perfect.  You need to level the bed to make sure.  Leveling procedure is to bring the bed to the glass and trying to slip a piece of paper underneath the hot end.  You'll want to do this at 3 points on the bed, right about where the leveling screwhead are.  If it doesn't go through at all, then your bed isn't level and will cause the symptoms you are seeing.  You'll want to do this with the extruder and bed on so that you take into account the heat expansion/contraction when printing.

If it slips under too easily, you're too high and you have to adjust the leveling screws for the bed.  Counterclockwise drops the bed and clockwise raises the bed.  These fine tuning adjustments should be checked before every print, but I usually do it about every time I turn the machine on and before I run a print.  It doesn't take long.  if you're using glass, you've probably printed the underbed screw caps so that tuning it can be done easier without having to remove the glass and punching through the Kapton on the bed.

EDIT:  Remember, the z-axis screw that hits the endstop is for gross aligning the head to the bed, the leveling screws fine tune this to make sure that you're close enough to extrude but far enough that you can lay down plastic on the bed.

was thinking of building a mount to move the Z-Axis switch to the print head, so that it levels off the glass bed itself. will have to experiment with that.

Also, cmetzel how well does your system deal with the occosional printhead dragging on the material?  every now and then I will get a shifted layer because the printhead caught and moved the glass bed.

yes meant z-axis. updated.

hmm, must have my flow rate a little high then. Will recalibrate.

For a SD3. do you have to change out the screw to do the glass bed install? If so is it M3 and what length do I need? I will be helping out a buddy who owns a SD3.

I tried 3/32 in. Thickness glass from homedepot. drilled three holes for screws.. turns out i don't have room to drill countersink(lost inch of print area). and after I heat up glass bed.. it starts to crack after 4 prints. Maybe it's the heat, or maybe it's spring's tension. but just want to report 3/32 from homedepot is too thin.
:-( what to do next... sigh... maybe I will try 6x6 tile next. or actually buy thicker shelf glass 5/16...

What are your successful glass thickness?