Aluminum bed upgrade?

[pichuete]

has anyone noticed significant Print Quality improvement with the aluminum Y plate? im having serious problem with "Z banding" i have replaced rods align and tight things but i have notice that my Bed expands and contracts quite a lot during ABS prints . it moves almost .2 mm up and down every time the HB turns on and off .

wonder if the aluminum plate is the solution or is actually the Heated bed that is only expanding..

[BLKKROW]

has anyone noticed significant Print Quality improvement with the aluminum Y plate? im having serious problem with "Z banding" i have replaced rods align and tight things but i have notice that my Bed expands and contracts quite a lot during ABS prints . it moves almost .2 mm up and down every time the HB turns on and off .

wonder if the aluminum plate is the solution or is actually the Heated bed that is only expanding..

I print in PLA and was having terrible Z banding issues, once I turned my heated bed off I finally was printing decently. So I purchased the aluminum Y bed and will try that soon.

[printbus]

Some miscellaneous points in case they are of interest to someone...

I remember reading threads or blogs in the reprap world bemoaining warping and temperature gradient issues in the Prusa style heat beds. I remember hearing how guru nophead had relocated the bed sensing thermistor away from the center of the bed in order to obtain a more realistic average of the bed temperature. Someone had reported they had good luck with "filling in the gap" between the heater and the y-bed at the edges of the heater, leaving some air gap between the rest of the heater area and the y-bed insulator. (I don't remember how this was done - more insulation just along the edge or kapton tape on the sides maybe?) Keeping the print bed covered with another insulator during preheat was found to help bring the entire bed up to the same temperature.

Multiple people had also praised the Panucatt Helios heater as a significant improvement over the basic MK boards.

• 1/8-inch thick specifically intended to minimize warping (MK heaters are 1/16-inch)
• Heat traces are on the print-bed side of the heater, not underneath like on the MK heaters (heat applied to the glass, not air or the insulator)
• Hole through the heat bed to allow the thermistor to be installed touching the glass (or aluminum if that is the print surface) for a more accurate reading
• Self-adhesive fiberglass insulation strips for application on the bottom side of the heater
• Corner mounting holes intended for use with flat-head hardware, eliminating the need for the print glass corners to be cut diagonal or for the glass to sized so it fits inside the corner screw heads. I personally think that the closer the print bed clips are to the corner hardware, the more rigid the print bed will be. Here, corner clips could be installed right up against the hardware.

Unfortunately, Panucatt only shows a 200mm size heater, and for the six months I've been waiting to buy one, they've never been in stock. But the heater might provide some ideas on what others have done. I emailed Panucatt a few months ago about product status, but never heard back. Maybe if they get a bunch of interest in larger ones, etc., they'll have some made up.

FWIW, when I migrated to Smoothieboard, I also noticed smoothieware is considerably different in how temperatures are maintained. Once the print bed is at temperature, Marlin will toggle power on and off every few seconds, leading to the possibility of z-banding if the heater does warp as it heats/cools. Smoothieware uses a PWM to maintain temperature that is usually fast enough that you can't see the status light toggling on and off. So it must be turned on and off at something like 15 times a second (or faster). I'm not suggesting that migrating to Smoothieboard would solve the z-banding issues people have, but maybe someone knows enough about Marlin firmware to see if the update rate could be sped up, reducing the heater cycle times... I know that Marlin has a setting that allows the optional print cooling fan to be driven with a "fast" PWM to eliminate fan whine. Maybe something similar could be done for the print bed heater. Of course, you'd have to have a solid state relay or MOSFET switch for this - a mechanical relay won't cut it. EDIT: Ah, I see Chadd is already headed down this path of a faster heater control loop...

[BLKKROW]

I finally had time to swap out the Y bed's.

Aluminum weighs in at 780g
Wood weights in at 548g.

Both of these are without hardware (wheels, screws, etc).