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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.

3d-printing
First Print (failed)

 

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 partEstimated time from Ideamaker was around 55H and consumption 750g filament. 3Layers  and 30% infill
New partEstimated 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!

redesign part
redesigned part
First part printing again without raft.
First part printing again without raft. around 2h

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 PTEG with brim
Printing PTEG with brim
Printing PTEG with brim
Printing PTEG with brim

 

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

12h printing
12h printing
12h printing
12h printing

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.

Layer shift
Layer shift

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).

Cracking on shell
Cracking on 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.

 

 

 

 

raess

Chief Technology Officer with a demonstrated history of working in the internet industry. Skilled in Business Planning, Computer-Aided Design (CAD), Quality Process Development, and SolidWorks. Strong business development professional with a Higher Education Diploma with specialization in Mechanical Engineering focused in Product development from Blekinge Institute of Technology.

http://valify.se

4 thoughts on “Printing the first part (updating as we go)”

  1. You should not need raft or a connected brim for PETG, perhaps you are not starting low enough, I get great prints on glass, 80C and ~230C at the hotend.
    On a clean glass bed, coat with cheat hairspray, then Elmers purple gluestick where the part is to be printed.

    -The then fix the glass print bed by scraping with a razor blade and spray glass with water to “reset” all the glue and spray for next part, again, use fresh glue stick for next part.

    Printbed glass can be cheap hardware store glass, does not need to be Borosillic/Pyrex

  2. Good question, I dont have any experience with PEI.
    Keep the build plate hot, dont drop from 80C after first layer, dont use cooling fans. unless your part is tiny, like the size of a coin.

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