Here's 2 prints of the top plate of the companion cube gift box in

Here’s 2 prints of the top plate of the companion cube gift box in PLA. This is a fairly large flat print that has been giving me trouble. Both prints were done with from the same gcode file. The one on the left suffers from really bad warping which has been a problem I’ve been having for quite some time. The one on the right came out absolutely flat, no warping. What changed? I turned on my hot bed! I don’t have any control over it, the hot plate is either on or off so I thought it would be too hot for PLA at around 160 deg. But what a difference, I can finally print some large jobs. I should have tried this sooner.

I have read that ambient air temp is hugely important. If you want the print to remain flat, you need to keep the air temp around the object constant. (+ or - 2 degrees or a untimely draft can destroy the print, or so I have heard)

I figured out the ambient temp issue too the hard way. So I built a case for the printer works great now. The case heats up from the heated bed and you have your ambient temp just about right. I talk about it a little in my blog.

I print ABS in a fairly cold basement (you need a hoodie or sweater). Obviously I have to use the bed no matter what, but I have always had cracking during the print due to the ambient air temp. I stapled a $1 plastic drop cloth around my machine as a little heat tent. No more cracks, period. --And Camerin is spot-on (nice to meet you, Camerin) The little tent I made only raises the ambient temp by maybe 10 degrees F which is what? -Maybe 3 or 4 degrees C? --Made all the difference in the world.

You can hook up your hot plate to a SSR and control it from one of the mosfets.

@Chris_Thompson1 That was going to be my next question, but I think I’ll start a new thread for that.