Weird problem trying to 3D print a large flat panel

[CircleTech]

Maybe someone who has 3d printing experience knows how to fix this.

 

I am printing a 3mm×250mm back panel with 5mm holes for a custom electronics enclosure, and the print layers are not coming out flat. The layers have random bumps, and its affecting the print. Interestingly enough, as the print continues, the bumps start going away. Then they return later as the layer cools while the print head moves onto another portion of the print:

 

 

 

I am using a Tevo Tornado and Hatchbox 1.75mm PLA with a nozzle temperaure of 200C and a print bed temperature of 60C. My layer height is 0.2mm and the infill was set to 100% by default because this is such a thin piece to begin with.

 

Based on the research ive done, my printing temperature is too high. The question is do I lower the nozzle temperature, or the print bed temperature? Because the first print I ever did was a spool holder, and it turned out great. But this piece not so much.

[James Evens]

200°C and 60°C is standard. So no obvious problem there. 

Never used painters tape so no plan if you can clean it with IPA or need to replace it.

[CircleTech]

20 minutes ago, James Evens said:

200°C and 60°C is standard. So no obvious problem there. 

Never used painters tape so no plan if you can clean it with IPA or need to replace it.

Correct. Its standard. But whats not so standard is really large very thin prints. 

 

Ill try reducing the print bed temperature by 5C for the next panel. I need to do four of these.

[MaverickMP]

Stop using painters tape. Kapton and hair spray is the way to go unless you have the cash for a whambam

[James Evens]

24 minutes ago, CircleTech said:

reducing the print bed temperature by 5C

Won't help. The problem is a bad print bed adhesion in the areas which aren't flat so expect in the next print the same issues in the identical position.

[CircleTech]

Uodate:

 

The print has about 3 hours left. There was about 0.5mm of infill, and the weird uneven surface is gone. I dont know if its because the infill added just enough Z-height to go over the bumps, or for some other reason I can't think of. Ill see how the bottom looks after I remove the print.

 

[CircleTech]

7 hours ago, MaverickMP said:

Stop using painters tape. Kapton and hair spray is the way to go unless you have the cash for a whambam

Don't have kapton tape, but do have some hairspray.

 

Removing the blue tape will require me to recalibrate the print bed. Ugh.

[MaverickMP]

Correct. You can order the kapton sheets from Amazon. They are super cheap. I think shaxxon makes it. They come in packs of 5.

[UrbanFreestyle]

I had this exact issue with layer 2 looking better. Turned out it was a TINY TINY bit too close to the bed and causing pillowing.

This was using Flex build plate and PEI. since adjusting no issues.

[tikker]

In my experience it's either an uneven print bed, nozzle being (slightly) too close to the bed (which can tie in to the uneven bed) or overextrusion. It makes sense that it "goes away" because the molten plastic of the next layer can adapt and after enough layers you'll get something flat and nice.

[W-L]

On 3/18/2020 at 10:36 AM, CircleTech said:

Uodate:

 

The print has about 3 hours left. There was about 0.5mm of infill, and the weird uneven surface is gone. I dont know if its because the infill added just enough Z-height to go over the bumps, or for some other reason I can't think of. Ill see how the bottom looks after I remove the print.

Bit late to this but usually on the first layer if you get that rippling effect it's usually due to bed unevenness if it's not perfectly flat where the nozzle could be slightly closer to the bed surface. Very small changes can also affect how the filament lays down and then creates somewhat of a snowball effect where it can cause the next lines to ripple out or expand due to the slightly extra material.