Managed to get some acetone and gave my head bed a clean but I’m still having issues with my prints coming off the heat bed mid print 
Weird thing is this was never a problem until yesterday.
ABS or PLA? ABS I use thin layer of ABS Glue (ABs + acetone) also use brim, keep an eye on anything that cause air movement.
I’m using PLA
I was able to print some small ABS parts Monday evening but since early morning Tuesday it seems most attempts fail.
Has the ambient temperature changed much? That’s been a problem for me, the thermistor measures the heat on the hot plate but I have 2mm of glass and the temperature on the top of the glass is dependent on what I have the AC set to in the summer.
I’ve done a little investigating and the new nozzle seems to be taking more power than the old one which is effecting thr temperature of both the nozzle and heat ed.
The ambient temperature may be part of the problem. It’s been a lot cooler in my place for the past couple of days. I’ll give that a try next.
With Pla its pretty normal to use blue tape or klapton as a printing surface. You need to ensure both are clean. Acetone or iso alcohol are both good for this, they need to be pure though ( no nail Polish remover).
Make sure the print head is close enough to the bed surface on the first layer so the extrusion is pressed outwards somewhat compared to subsequent layers. Also try pushing the first layer tempetature up 5-10 degrees.
Having a level bed etc goes without saying.
Yeah, I’ve noticed quite a few people use either but I’ve never needed it up now. I’ve used some acetone prior to that print but it doesn’t seem to help.
Also try printing with heated bed turned off. Pla doesn’t require a heat bed.
Hmm, yeah, I’ve not tried that yet 
Though my prints were sticking well when I had the heat bed on before.
I have done all glass printing, never used Kapton or painter’s tape. The main problem I had was when the heat bed was actually too hot, or the extrusion was too hot. You really want it to hit the glass and stick, which means putting the PLA through its glass-transition temperature as rapidly as possible without cooling too quickly to cause significant contraction. Try hotter, but definitely try cooler as well. Also, I used to try acetone/alcohol for bed cleaning, but the thing that has worked best was just a fresh razor scraper to get the surface dust/PLA residue free.
Its always annoying when things stop working for no apparent reason. New filament maybe? Make sure your hobbed bolt is clear and extruder idler is nice and tight, the fist layer should require the extruder to force extrudiate out against the bed surface to give a good bond. If its slipping, that won’t happen.
@Devin_Grady that makes a lot of sense now though initially quite counter intuitive.
I just tried another print with the bed off as @Tim_Rastall advised. It seemed to go well apart my MBP crashing mid print. I’ll run another print and see how that goes.
When I was printing with PLA on cold glass, I had very good results using hair spray.
Before each print, take the glass off (mine was held on with spring clips) and spray on a coat of hairspray. Let it dry then remount the glass.
@Tim_Rastall to be honest, it quite fun, rustrations a good teacher
The nozzles could be better fitted but it should be secured enough for the moment.
Turning the heat bed could be the answer, I’ve just got to run another print to know for sure.
I need to print some extruder parts for the nozzle but I want to get this resolved first.
@Yomi_Colledge Oh, no doubt - That last bit of advice about keeping the idler nice and tight was a hard earned bit of experience that had me replacing stepper drivers before I worked out my idler wasn’t staying tight as it should be (after a year of flawless operation).
cool
@Tim_Rastall yeah I’ve had moments similar. I not long ago replaced a stepper motor before realising it was actually the driver that was the problem.
Hairspray works wonders to keep PLA on the platform!!!
What is your bed material?