Full thin wall skirt? Alternative to printer enclosure?

[Mark-x 0]

I am having some warping issues with ABS and simmilar filaments that contract a lot. One remedy is to have a heated enclosure for your printer.

However i was wondering if there is a cura setting to print the skirt to the full height of the model as a thin single wall. This would act as a draft prevention and keep a higher temperature at the model when using the heated bed. Maybe an idea to implement if not already somewhere in the program. What do you think?

[gr5 2,072]

in cura it's called "enable draft shield" and you can set the distance from the part.  It will improve layer adhesion quite a bit at a cost of surface quality.

 

However, I don't recommend this feature as you don't need it.  What kind of printer do you have?

 

Are you having problems only with the first layer warping up?  Are you having problems with the part splitting?

 

Those are the 2 most common issues with ABS and both can be fixed without draft shield.  For parts not sticking/warping off the bed, see this video.  Yeah, I know, it's long at 20 minutes, but it's packed full of information that will make you an expert regardless of the material.  If it's the other issue let us know:

 

[Mark-x 0]

Thanks for the tipp and the setting in cura. I have been fiddling with different settings to get it to print better. However i can't make it stop 100% especially with thicker parts. I do get warping and splitting higher up in the print. Bed and layer adhesion is more than good, the forces are just too great. In the end I think it's down to the filament i have. I did make myself a test print today with an extra shell skirt. Helped a little bit. Anyway new filament is on the way.

[gr5 2,072]

A part with good layer adhesion will not split along layer lines.  You have lousy layer adhesion.  You fix that by lowering the fan (and it helps to raise the air temp).  You want the fan at the absolute minimum setting where it still rotates.  Have you tried that?  Have you experimented with what fan % results in what speed?  It also helps to have thick layers like around 0.2mm or more as that will melt more of the solid layer below.

 

Watch the video about adhesion to the bed.  Your part should never ever come loose even if using a hammer and picking up the printer by a 1 inch cube the cube should not come loose.  100C bed is not hot enough you really want 110C.  Watch my video please.

[Mark-x 0]

I did, i did. 😉 Picking up the printer by the part is no problem (interesting test). Ive tried fan off and ever so slightly on. I will go for the bed at 110 C. Only tried up to 90 C so far. Layer adhesion is usually good, even seen stress rips across several layers though, thats why Im still suspecting the material contracting way more than it should. The new batch of material will probably show a difference. I will report. Great video btw.

[gr5 2,072]

8 hours ago, Mark-x said:

even seen stress rips across several layers though,

Oh.  You mean one crack starts in a layer but rips through to another?  That sounds bad.  Maybe.  Although of course it started at a layer in the first place (almost surely).

 

What is your nozzle temp - you might have to raise it by 5C.

 

Regarding bed temp - ABS gets soft right about 99C (like hard clay at 99C).  You have to be above this temp - safely above - so 110C is about perfect.  This allows the stresses at the corners of the part to spread out more and not be concentrated in one spot - the part does indeed warp but too small to measure with a micrometer.  Certainly too small to see.  It warps just enough to ease the forces.

 

You might have an ABS that has a higher softening temp so it's good to do a test - take a few cm of filament and put it on the bed and heat the bed to various temps (start with 95C) and put a towel over the part.  AFter about 10 seconds on the bed reach under there (carefully - don't get burnt) and bend the filament.  At room temp and at 95C it should act the same.  Above 99C it should stay in it's new position.  I think I mention this in the video but with hot water (for lower temp materials like PLA or nGen or CPE).

 

[gr5 2,072]

I should add that enclosing the printer will really help a lot!  The Ultimaker S3 and S5 printers have a front door which is enough to make a big difference when printing ABS.  Just raising the air from 20C to 35C is a big help.  But really I don't like ABS.  It doesn't have any properties that I can't get with other filaments.

[gr5 2,072]

Your original idea of a draft shield could really help as well.  Did you end up trying that?