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First layer doesn't stick for long, flat parts.

Posted: Wed Nov 25, 2015 4:00 pm
by hcdbey
Does anyone have a suggestion as to what might be causing this poor first layer? It happens on parts with long straight runs of filament. Other parts that are more vertical than they are horizontal print nicely.

I'm using a Rostock MAX V2, ABS at 235 degrees on a bed at 100 degrees. I believe most, if not all, other settings are at the default values when I first started using the printer.

Thanks,
Hank

Re: First layer doesn't stick for long, flat parts.

Posted: Wed Nov 25, 2015 4:07 pm
by mhackney
Are you printing on a raft? That looks like more than a first layer.

If you are printing on a raft, then your actual first layer seems to be doing pretty good. Your part first layer not sticking to the raft could be due to a number of things:

1) make sure the tip of your nozzle is clean and polished (see my signature links)
2) make sure you are actually at 235°C - it looks to me (bad photo though) that you are not getting good bonding. This is *usually* due to low temperature. Your hot end might not be properly calibrated. Which hot end are you using? Have you verified the temp? The other contributor is contaminated filament. Do you have another filament to try? Silicones can have this effect, have you sprayed silicone lubricant near your printer?

Re: First layer doesn't stick for long, flat parts.

Posted: Wed Nov 25, 2015 10:32 pm
by nebbian
Which way is your hot end fan blowing?
I had a problem with certain long thin parts curling up when printing in ABS, which turned out to be the exhaust from my hot end fan blowing on the part. I put a shroud underneath the fan, and reoriented those parts to print at 90 degrees to the exhaust direction -- problem solved.

Re: First layer doesn't stick for long, flat parts.

Posted: Thu Nov 26, 2015 7:54 am
by hcdbey
mhackney wrote:Are you printing on a raft? That looks like more than a first layer.

If you are printing on a raft, then your actual first layer seems to be doing pretty good. Your part first layer not sticking to the raft could be due to a number of things:

1) make sure the tip of your nozzle is clean and polished (see my signature links)
2) make sure you are actually at 235°C - it looks to me (bad photo though) that you are not getting good bonding. This is *usually* due to low temperature. Your hot end might not be properly calibrated. Which hot end are you using? Have you verified the temp? The other contributor is contaminated filament. Do you have another filament to try? Silicones can have this effect, have you sprayed silicone lubricant near your printer?
Yes, I am printing on a raft.

Because of my inexperience, your next two sentences are contradictory for me. The first layer isn't sticking so I consider the first layer not to be pretty good. Please help me understand.

I have read through your signature links. I'm not sure what “polished” means. I normally clean the nozzle with an acetone dampened cloth before printing. Do you mean something different when you say polish?

I plan to get a thermocouple to check the temperature on the outside of the nozzle.

We received only one spool of filament so far. I am in Africa and tonight, a woman returning from the States is hopefully bringing us a reel of ABS and a reel of PLA both from SeeMeCNC.

No lubricants of any type have been used in the vicinity of the printer.

Thanks for your suggestions, I will let you know what I find out with the thermocouple.

Re: First layer doesn't stick for long, flat parts.

Posted: Thu Nov 26, 2015 7:55 am
by hcdbey
nebbian wrote:Which way is your hot end fan blowing?
I had a problem with certain long thin parts curling up when printing in ABS, which turned out to be the exhaust from my hot end fan blowing on the part. I put a shroud underneath the fan, and reoriented those parts to print at 90 degrees to the exhaust direction -- problem solved.
So far, I have been printing only ABS and the only fan that is installed is the PEEK fan.

Re: First layer doesn't stick for long, flat parts.

Posted: Thu Nov 26, 2015 8:48 am
by geneb
The "first layer" is the very first layer that the printer lays down on the glass. It doesn't refer to the first layer printed upon the raft. Your actual first layer appears to be excellent.

I think what I'm seeing is that there is a gap between the raft and the top surface of the raft. I see an inset perimeter that follows the raft and then there's a thin, warped, layer beginning to bridge across that perimeter. ABS is finicky when it comes to bridges. Can you post a screen shot of what the underside of the part you're trying to print looks like? I'm willing to bet it's got a lip around it.

g.

Re: First layer doesn't stick for long, flat parts.

Posted: Thu Nov 26, 2015 8:52 am
by Xenocrates
What he means by first layer is the layer which adheres to the bed, rather than the first layer of the final part. I might check your "air gap" setting, if you're using mattercontrol, as a high setting for that may cause one layer to not adhere to the next because they are insufficiently squished together. I find most of the time one layer height works for me.

Also, is that Red ABS from Hatchbox by chance?