Excessive heat near wipe tower  

Excessive heat near wipe tower

I'm attempting to print something that takes up dang near 100% of the available bed space. The print grows laterally at a 45° to the point that it overhangs part of the wipe tower. In reality, I got it a bit too close and it accidentally touched. I'll need to work on that a bit more. In the first picture below, you can see that there's basically a triangular shaped cavity that is being formed. As the layers go up, the object is getting closer to the wipe tower.

This next picture shows how close the box lid gets to the wipe tower. Perhaps this traps a lot of heat down low?

Here's a picture of the second or third layer. On the left is a black rectangle that I'm using as a make-shift wipe tower. It is a simple object that I've enabled the "wipe into this object." On the right, is the actual wipe tower. At the 2.4mm height, the design goes from a 4 color to a 2 color design, making the upper part of the wipe tower much smaller. I was able to fit it between some of the ribs on the box lid.

And here you can see the problem. All along this edge, there's a lot of what appears to be overheating that has occurred. This is near the wipe tower, but should that really matter? Any thoughts on how to improve it? This was printed in PLA, would PETG be a better choice? I may be able to shrink the design by 5cm. That'd give a whole lot of room to get much further away from the wipe tower, perhaps that would help.