Inconsistent heat bed question

General LulzBot TAZ
1

My TAZ5 is only 5 months old, and I’ve been noticing inconsistencies in adhesion. I also had an issue with my capacative auto leveler. I was wondering if the leveling issue was due to heat, so I borrowed an infrared heat gun/thermemeter/whatever it’s called.

In the area where my capacative leveler would not get a good read (not sure if it’s coincidence), when the heat bed is set to 60 degrees for PLA, the bed is about 60 degrees. Everywhere else, it’s about 10 degrees higher.

*'s being 70 degrees and 0’s being 60 degrees, this is how the heat layout looks.

*****
*****
000**
*****
*****

Thats as you look at the bed. Looks like the hot areas are right at/over the main hookups for the bed.

Is this normal? Is my bed malfunctioning? I’m sure the capacative thing has to be a coincidence, a 10 degree difference shouldnt throw the reading off that much (at all?), but for sure I’m having adhesion issues when the center of my bed is 10 degrees cooler than the rest of it.

2

That is where all the wires for the heat bed connect to the wires coming off the head bed. So there is no heating elements in that area.

3

So the center of the heat bed is intentionally NOT heated? That makes no sense whatsoever.

4

the left hand edge of the heated bed where the wires enter it isn’t heated. The center itself should be heated, but thats also the smallest of the heat coils. It’s possible the coil that feeds the middle of the bed has damaged itself. You can see the coil pattern itself here:
http://www.sd3d.com/not-all-heated-beds-are-created-equal/ (Scroll down to the Taz section, please note that image is reversed. the wires are on the right there - That may also be a slightly earlier heated bed variant)