PETG on a PEI printbed (Lulzbot Mini)

Help with printing with specific plastic filaments.
Thinkdifferent
Posts: 9
Joined: Mon Feb 29, 2016 8:04 am

PETG on a PEI printbed (Lulzbot Mini)

Post by Thinkdifferent » Mon Feb 29, 2016 8:21 am

Hi,

I've got heavy problems with my PETG, printing on a PEI printbed (Lulzbot Mini): as I tried to pull off my print, I needed to use force. This ended in a destroyed PEI-sheet...
I use PETG from RepRapWorld (brand is REAL).
My former settings: 240° C, printbed 90° C.

As my printbed is destroyed only in the middle of the bed, I have 4 more efforts, to test other settings.
Should I use hairspray on the PEI? Or UHU glue-stick, to NOT GLUE the filament? Printing without heated bed was not successful: the object did not stick on the bed.

So - what are the best settings? Temperature and layer? Although the MINI has a self-levelling printerhead, I have the feeling, that the nozzle touches the bed - other to ABS and PLA...

I would appreciate any kind of help!!!

nopick
Posts: 991
Joined: Mon Sep 09, 2013 11:14 am

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by nopick » Mon Feb 29, 2016 9:33 am

I have printed PETG on my Mini a few times without issue. You might need to add a little positive Z offset in your slicer so the PETG is not squished onto the PEI quite as much, reducing the stick. That is where I would start.

Also, reducing the temp of the bed might help. I have been printing the PETG with PLA settings except for the nozzle temperature. I also slowed the print down a little from the PLA profile.

Thinkdifferent
Posts: 9
Joined: Mon Feb 29, 2016 8:04 am

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by Thinkdifferent » Mon Feb 29, 2016 9:48 am

Thanks for your quick reply!
I reduced the temperature of the bed down to 50° C.
But as you said: the filament is really squished onto the PEI.
Where do I set the positive Z offset in CURA???

kcchen_00
Posts: 1695
Joined: Thu Feb 19, 2015 12:42 am

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by kcchen_00 » Mon Feb 29, 2016 10:25 am

Look under the "Machine" settings in Cura to find the Z-offset.

If the surfaces touching the bed seem to be flaring out, then there may be a problem with the auto-level. Change the wiper pad, clean the nozzle and touch points with the appropriate solvents.

Thinkdifferent
Posts: 9
Joined: Mon Feb 29, 2016 8:04 am

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by Thinkdifferent » Mon Feb 29, 2016 10:48 am

There are no problems with ABS; therefore I don't think, it's a general Z-offset problem. Only with PETG this problem appears...

ttabbal
Posts: 298
Joined: Wed Nov 11, 2015 4:20 pm

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by ttabbal » Mon Feb 29, 2016 11:42 am

Some filaments are more prone to sticking when "squished" down. ABS is prone to coming off the build plate if you don't squish it, and the defaults for the Mini are conservative so you get squish. This is great for new users to ABS/HIPS. It sucks for PETG. Increase the Z-Offset for PETG and it will still stick fine, but come off without so much force. All the plastic types are a bit different and you have to adjust to them.

So you're right that it's not a general problem. It's just that every plastic is different. I've done a couple rolls of PETG now, and it's great, but if I forget and use the standard Z-offset, it's a pain to remove the parts.

Thinkdifferent
Posts: 9
Joined: Mon Feb 29, 2016 8:04 am

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by Thinkdifferent » Mon Feb 29, 2016 1:46 pm

With this answer I feel optimistic, that PETG and I will be friends - at some time... ;)
In the meantime I used some different settings (including Z-offset 0,2 mm); so far I'm not yet happy - but at least I could remove one object without destroying my PEI further...

C_Duncan
Posts: 42
Joined: Sun Feb 07, 2016 7:26 pm

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by C_Duncan » Mon Feb 29, 2016 2:56 pm

I am using Esun PETG and had delamination from the the PEI and warping issues on the borders. Ruined a few prints despite using brims to 20+.
This occurred at bed temps of 60, 70, 80 C, printing slow, with 240 nozzle temp.
Z offset was laying down a good squished first layer.
I sanded the PEI with 240 grit very very lightly and now I have at least twice the adhesion.

I would like to add to the discussion. Here are my print setting that result in the nicest PETG prints although it takes a long time. I would like to shorten it up some. Here is my CURA profile for my TAZ 5 for Esun PETG
Any recommendations or improvements would be highly appreciated!

Is there an expanded set of community verified Cura profiles other than the official AO hosted ones? I haven't found a good collection.
Again, I'm a novice relative to to many here.

[profile]
layer_height = .35
wall_thickness = 3
retraction_enable = True
solid_layer_thickness = 3
fill_density = 50
perimeter_before_infill = True
nozzle_size = .5
print_speed = 40
print_temperature = 0
print_temperature2 = 0
print_temperature3 = 0
print_temperature4 = 0
print_temperature5 = 0
print_bed_temperature = 0
support = Everywhere
platform_adhesion = Brim
support_dual_extrusion = Second extruder
wipe_tower = True
wipe_tower_volume = 15
ooze_shield = False
filament_diameter = 2.91
filament_diameter2 = 2.89
filament_diameter3 = 0
filament_diameter4 = 0
filament_diameter5 = 0
filament_flow = 100.0
retraction_speed = 10
retraction_amount = 1
retraction_dual_amount = 25
retraction_min_travel = 1.5
retraction_combing = All
retraction_minimal_extrusion = 0.02
retraction_hop = 0
bottom_thickness = .425
layer0_width_factor = 200
object_sink = 0
overlap_dual = 0
travel_speed = 160
bottom_layer_speed = 10
infill_speed = 20
solidarea_speed = 10
inset0_speed = 18
insetx_speed = 18
cool_min_layer_time = 45
fan_enabled = False
skirt_line_count = 2
skirt_gap = 6
skirt_minimal_length = 0
fan_full_height = .5
fan_speed = 40
fan_speed_max = 60
cool_min_feedrate = 7
cool_head_lift = False
solid_top = True
solid_bottom = True
fill_overlap = 10
support_type = Grid
support_angle = 45
support_fill_rate = 17
support_xy_distance = 0
support_z_distance = 0
spiralize = False
simple_mode = False
brim_line_count = 15
raft_margin = 3
raft_line_spacing = 1.0
raft_base_thickness = .5
raft_base_linewidth = 0.7
raft_interface_thickness = 0.2
raft_interface_linewidth = 0.2
raft_airgap_all = 0.0
raft_airgap = 0.22
raft_surface_layers = 2
raft_surface_thickness = 0.27
raft_surface_linewidth = 0.4
fix_horrible_union_all_type_a = False
fix_horrible_union_all_type_b = False
fix_horrible_use_open_bits = False
fix_horrible_extensive_stitching = False
plugin_config = (lp1
.
object_center_x = -1
object_center_y = -1
simplemodesettings =
simplemodeprofile = 2_normal
simplemodematerial = 1_pla
simplemodematerialtype = Beginner

wmgeorge64
Posts: 410
Joined: Wed May 27, 2015 7:28 pm

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by wmgeorge64 » Mon Feb 29, 2016 3:49 pm

For PETG I have always just used the defaults for ABS. But temps at Extruder 245, bed 75 and retraction (I don't remember the number) some use the fan, I never have but my shop and porch tend to be cool. Wait till it cools down before removing off the PEI. The stuff is stringy so need to find the sweet spot for retraction.
ULS Laser . Retired master Electrician in Iowa USA Lots of Hobbies

kingjamie
Posts: 35
Joined: Sat Feb 06, 2016 12:00 pm

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by kingjamie » Mon Feb 29, 2016 4:35 pm

I'm also using esun petg (various colors) without any delamination or problems removing from the PEI surface. I'm using 80 for the bed temp. See my profile on the first page (near the bottom) viewtopic.php?f=29&t=3037 also I've set my z-offset to 0.03 but you need to use a calibration test first to find your offset.

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