Strange first layer

[rcg4 0]

Hello.

I have never seen this before.  I was trying to reduce some stringing (using PLA) and corner curling.

Original temp was 200c. reduced to 198-not a huge change.

I suddenly get this weird "ocean wave" look.  I seems to be getting covered up with subsequent layers and smoothing out.

Bed temp is 60 and using painters tape as you can see.

Cooling is off for the initial layer and on at layer 2

Thank you for any advice/suggestions.

 

RG

[Crusty 0]

Not quite sure what you mean by an 'ocean wave' look but if you are printing a straight line and it ends up wavy then quite likely your nozzle is much too far away from the bed. Check your nozzle to bed gap using a piece of paper as a feeler gauge - you should just detect some resistance to movement of the paper when it is just trapped under the nozzle and for most 80gsm weight papers that will give you a gap of around 0.1mm.

Also check on your Cura print settings under the quality section that you haven't specified an inappropriate initial layer height.

[geert_2 558]

My guess is one of the following:

- overextrusion,

- blue tape coming off the bed, with air being entrapped below it,

- the filament not sticking to the tape for whatever reason.

 

If you watch closely while it is printing, maybe you can see what happens.

 

[Smithy 1,146]

Why do you need the BlueTape when you have a heated bed? 

[rcg4 0]

Thanks for the replies so far!

Smithy- I am using the blue tape in an attempt to fix the corner curling I mentioned. I had started with a bed temp of 50c and have increased to 60c ans noted. I have since read in other forums that I may need to go as high as 70c or so (without the tape)with PLA, so I will try that.

 

Crusty- this is what I mean, the area in the middle looks like waves it supposed to be smooth(ish) more like the bottom area of the photo.  as you can see the larger image the initial skirt looks correct.

RG

[Umo_Alex 4]

Curling at the corners is often due to the printer head being too far off the bed.

Pretty sure Crusty's right. 🙂

I.e., calibrate your print-bed.

 

Edited July 20, 2019 by Umo_Alex
Typo

[Crusty 0]

15 hours ago, rcg4 said:

Thanks for the replies so far!

Smithy- I am using the blue tape in an attempt to fix the corner curling I mentioned. I had started with a bed temp of 50c and have increased to 60c ans noted. I have since read in other forums that I may need to go as high as 70c or so (without the tape)with PLA, so I will try that.

 

Crusty- this is what I mean, the area in the middle looks like waves it supposed to be smooth(ish) more like the bottom area of the photo.  as you can see the larger image the initial skirt looks correct.

RG

Hi RG

Your photo doesn't seem to have downloaded so it's difficult to comment further. However, having looked more closely at your original photo, are we looking at an infill over the large rectangular surface? If that is so then perhaps you should try to reduce your infill density and see what happens. Also, what is the underside of the first layer like when you remove it from the bed? Maybe you have an adhesion problem.

I wanted to try blue painters tape but I haven't been able to find any stockists here in the UK although it seems to be advertised everywhere in the USA. I tried some Scotch green tape which is used for road markings and PLA seemed to adhere well to that but being a crepe paper base the tape it has a tendency to de-laminate at the edges leaving the base of the print warped. I had a lot of success with the 'salt method'. My prints would stick firmly to a glass bed at 60deg. and would just ping off as the bed cooled down. The underside of the prints were perfectly flat right up to the edges and had a glass finish with the exception that under a magnifying glass minute crystals of salt could be seen embedded in the surface. My perfect solution to adhesion is 'Kapton' tape. Adhesion is effective right up to the very edge and although I haven't tried it yet, it should be possible to get full adhesion without the need for a brim. I am still using a narrow brim simply to get a good flow of PLA going before the print proper starts. The finish is glass smooth but because there is no 'stretch' in the tape it is not the easiest of materials to apply single handed without some practice. I stick it down at one end first and then gently squeegee along using the edge of a credit card to remove all air bubbles. Once it is on it will last for many prints.