Strange anomaly when printing a cylinder

[asmunroh 1]

Hi,

 

I'm printing a modified cylinder on a quite new S3 using though PLA and PVA support (see picture). After about 1 cm a bump appears on the cylinder (x-y drift?), but after 2 cm the print is back on track. Looking back at previous prints I can also see the same anomaly. Any advice?

 

Thanks!

 

Åsmund 

 

[geert_2 557]

I guess that could be a cooling issue. When printing small items, the hot nozzle stays on top of the model, keeps radiating heat, and prevents the model from solidifying well. Causing deformation and overextrusion. This also happens when switching from a huge layer area to a tiny one, and the printer slows down to its "minimum layer time", for example when printing a thin exhaust pipe on top of a huge building.

 

Try printing much cooler, slow and in thin layers, so each layer has more time to cool. Or print two models next to each other, so the nozzle is moved away half of the time, allowing the model to cool down. Or print a dummy tower next to the model.

 

I am not totally sure this is the cause, but it is worth checking.

 

 

 

Printing a dummy next to the cones, reduces the overheating effect, but does not eliminate it:

 

 

 

 

Theoretical concept of a dummy tower to allow cooling, and keep printing time per layer as constant as possible:

 

 

 

 

A dummy cube in a real model:

 

 

 

 

 

[timotub 1]

Have you checked the g-code for this object? - Maybe the error has already been introduced by the slicer?

 

I have also observed peculiarities related to the start and stop seam of each layer after printing the object. For the example below I had expected that the seam would be at the same xy-position, but it wasn't.

 

Here we can see that the seam has been set to a slightly different location by the slicer:

[Torgeir 228]

Hi @asmunroh,

 

Hi Åsmund.

 

If you can share you "project" file, -someone may have a look at the model just to see if it's the file, -or your S3 is doing this.

 

Thanks

Torgeir