Printing the first part (updating as we go)

So the last week I have been busy, trying to adjust the settings for  the PrimaSelect PETG. The filament I am going to use for printing the prototype. So this morning I started a print for the first part for Valify, I was printing on a raft because of the support structures. Some hours later I saw that one corner of the part has once again lifted from the raft. Making this a failed print. But on the other hand, I had the chance to feel and squeeze on a partly printed part made from the PrimaSelect PETG filament. And I have to say I like it. it feels rock solid. But still there is some flexibility that can absorb shocks and thats great.

 

So this time I got tired of using rafts, so I redesign the part trying to minimize 90 degrees overhangs and making the need of support less.

Old part: Estimated time from Ideamaker was around 55H and consumption 750g filament. 3Layers  and 30% infill
New part: Estimated time from Ideamaker was around 45H and consumption 550g filament. 3layers and 25% infill

For the redesigned part I do not actually need to use any support structure. Which are great, because they can be frustrated to work with and happily leaves marks on the surfaces. I also save money and time on the new part. So this was actually a real success!

So late tonight I started the print again. This time printing without raft and a heat bed temperature at 100C (actual temp is around 72C) The build Surface I went with at the end is the PEI Ultem sheet, because I got it working well on this and did not bother to change anymore.

 

 

Update: After 5h the part started lifting from one corner. Making me cancel the print. Lets try to add a brim and start it again.

 

This morning I restarted the print with a brim. Flow rate changed to 115% on first 2 layers then go down to 105% to minimize stringing and nozzle oozing. I also changed the heat bed to 95C. I also redesign the sharp corners on the model to use a radius of 10mm. I read this could release tensions from sharp edges. I am 4.5 hours into the job and so far everything looks good.

 

Printing for 12Hours now and it still looks good (crossing my fingers).

Damn. I found this when I woke up this morning. Layers had shifted quite a lot. This print seems not willing to coporatate. Every time I try to print it a new problem Ariases. Quite frustrated. print is again aborted.

So attempt to print with only 7h left on the 44h print I spotted two small cracks on the body (only on the outer shell).

As I stated before, when I solve one problem, another problem arises.
Reading around the internet I found a lot of different answers on warping and cracking.
So to sum up the things I found:

Lifting/warping:
-Reduce infill to 10-15%? Prevent internal stresses within the model.
-Shells, No more then 2-3 shells. More material that attempting to shrink inward.
-High temperature for heat bed, causing the lower levels to not be able to cool.

Cracking:
-Airflow, print shielded from breezes (I print without the top cover?)
-Filament temperature, lower temperatures results in weaker layer bond. I am printing 225C, Filamented is rated at at 190-230C.

So what do you guys recommend to test for the next big print? I have no problems running small things like calibrations cubes etc. This problem occurs with large and high objects.

btw: I will let this print finish.