I am trying to print PETG on PEI and I can not get the first layer figured out to save my life. I have my z height set to .14mm all around and the bed is level. I am practically printing the first layer at 10-20mm/s yet after about 40 seconds into the layer the nozzle clogs and the extruder starts skipping.
Now if I include a raft, the rafts default settings which I have no idea what they are, will print nice thick lines that stick and the nozzle doesn't clog.
I have tried moving First Layer Height up to 200%, First Layer Width to 200%, First Layer Speed down to 20 seconds and when I try to print without a raft, I start to get decent lines then it clogs up.
I wish I knew what settings Raft uses by default so I can try to derive my own first layer settings from it
Re: First Layer Settings, Height, Width etc question
You can figure it out pretty easily by looking through the gcode. My raft with default settings prints around 220% height, 200% width, and nice and slow to make sure it sticks. That's using default medium settings with 0.4mm nozzle and 0.2mm layer heights. I imagine that if you are printing at a lower layer height like 0.1mm, the first layer height would actually be double that (closer to 400%) as that would equate to the same thickness.
Re: First Layer Settings, Height, Width etc question
griff, i want you to print something normally at .2 layer height with first layer width and height set to 100. when it jams on you stop the print and take a very clear and closeup picture of the first layer and post it here so i can see it. like i said i have not printed on pei before BUT i have printed probably atleast 30-35 spools of petg now, maybe more. i have that stuff pretty much figured out lol. i need to see how that first layer is going down then ill be able to tell you what to do. also post an fff for the print. it does sound like your printing too close though.
Re: First Layer Settings, Height, Width etc question
jimc wrote:griff, i want you to print something normally at .2 layer height with first layer width and height set to 100. when it jams on you stop the print and take a very clear and closeup picture of the first layer and post it here so i can see it. like i said i have not printed on pei before BUT i have printed probably atleast 30-35 spools of petg now, maybe more. i have that stuff pretty much figured out lol. i need to see how that first layer is going down then ill be able to tell you what to do. also post an fff for the print. it does sound like your printing too close though.
Awesome, I will do that later today or tomorrow. I ran the same print in Cura last night and got it to print, so I know it has to be some fine setting tweaks. I really love the look of this PETG and hope to be able to print it
Re: First Layer Settings, Height, Width etc question
Here is my FFF for mt prints with the PETG. I was able to get a print last night using S3D, it wasn't as good as I would like so maybe you can look at my settings and see if there are any tweaks you recommend.
Thanks,
Chris
Thanks,
Chris
Re: First Layer Settings, Height, Width etc question
Bump as this will get lost in all the 3.0 happiness 
Re: First Layer Settings, Height, Width etc question
What has got lost is your fff file.Bump as this will get lost in all the 3.0 happiness
Nobody can give you all that much advice at the moment.....
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net
Re: First Layer Settings, Height, Width etc question
dohdkightley wrote:What has got lost is your fff file.Bump as this will get lost in all the 3.0 happiness
Nobody can give you all that much advice at the moment.....
Re: First Layer Settings, Height, Width etc question
Here is my FFF. I just can't seem to dial in the temps for this PETG. I am getting terrible stringing and can't find a good combo of retraction settings to help. I am on a Bowden setup
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Re: First Layer Settings, Height, Width etc question
petg tend to be a little stringy. prints will usually have alot of micro fine hairs. this can be normal. all you do is blow the part with a heat gun or run a lighter or flame quickly over the part and they disappear. i dont notice too many thing really over the top with your profile. if your filament dia is correct then your multiplier seems a bit high but that can vary printer to printer. mine is at 98. i assume you have run a thin wall calibration to dial that multiplier in? if your overextruding that will increase the stringing from the extra psi in the nozzle. 255 is ok for the temp but try dropping that to 245 and see what that does for you. again that can vary from printer to printer as well. i never used a bowden so i cant really comment on your retraction but overall it should be similar settings to your abs profile. couple of other things is your speeds seem a little odd. print speed can be up toward the 3600-3800 range. xy movement speed could be a little snappier as well. 9000-12000 maybe. these speed will vary also from printer to printer but yours just seem extremely low. the other thing is those first layer settings. man for a .2mm height those are pretty extreme. i could easily see if you increase your speed that you will never be able to extrude that amount of material without stripping the filament or jamming the extruder. at a .2mm layer height there is no reason to have that higher than 100%. the width maybe 100-125% or so. if that width is greater than the little flat spot on the tip of the nozzle you are just going to make a mess. a first layer like that is completely unnecessary.
