[Cura 13.11.2 ignores Minimal Layer Time]

What would really help for these sharp tips to print correctly is if the printhead would retract and move away a little, so that no longer the hot-end is touching (and heating) the model, and the print time will actually result in cool-down time. Preferrably the head is moved a little away from the model with the fan on, to let the fan cool the model during the ' minimal layer time' .

Can I add this feature request somewhere?

 

[New support material method.]

Any news on the support implementation?

I'm running Cura 13.11 and actually I am not happy at all with the new support structure. It works great for parts that have 'open' areas that needs support to the outside of the part, but it destroys parts that need support in enclosed parts. The horse and bird posted in this thread are excellent examples (I had another bird destroyed http://www.thingiverse.com/make:55256) due to this problem. The same goes for support of replacement fan bodies. These need internal support structure, which just doesnt work with these solid settings.

Could configuration be added for support type? Or if it's possible to judge the topology of the needed support structure you could implement the solid blocks to the outside of the model, and the old lines to the inside or enclosed areas of the model.

The key issue is that the old support structure can be bent, causing it to be broken away easily, while with the new one this is no longer possible.

 

[Trouble making Soft PLA prints]

Quick update:

Spent most of today cleaning out the printer: opened up the hot end, pushed some PLA through it, scraped it empty with screwdriver, gave it the candle treatment, put it in a cup of acetone and cleaned it out thoroughly.

Will post pictures later/tomorrow.

Afterwards assembled the whole kit again and pushed some 'normal' pla through by had, to get a feel for the pressure in the hot end. Afterwards did the same with the soft PLA. Even though manufacturer states a print temperature of 210C, it starts feeling the same as PLA at about 240C. Will do testprint tomorrow to see if everything is fixed.

Learned/tried a few things along the way:

1. Rotate the large gear manually to get feedback on the pressure/friction when melting PLA, this really gives a lot more info that trying to extrude a few mm's more using printrun.

2. Remove the extruder spring assembly when leaving soft PLA in the machine. I've first done this today, but as I have seen a lot of creep in normal PLA, I suspect leaving it in the springforce and knurled bolt for a long time might also play a role in it not moving correctly through the extruder.

3. Playing around and just getting your hands dirty is the way to go to learn working the Ultimaker... it's not as mature and well documented as I would want it, but with the tips people give you around here and on the wiki you can get into it, and that way you get a lot more deeper understanding of the machine, making you able to troubleshoot it a lot better (which will be necessary regularly!). This should be an important part of the sales communication of Ultimaker, since if people expect to get a machine that always works perfectly they will be disappointed...

3a. what I learned: by having just the hot end (brass/alu parts) heated outside of the normal head (holding it with pliers) and then manually feeding PLA through it, you can really see the pressure required, at what kind of feedrate it starts melting back out on the rear side, etc. etc. This has really shown me the kind of problem that might take place inside the head during normal printing.

3b. Another one: by manually pushing the soft PLA through the bowden tube throug the hot-end at different temperatures you really get a feel for the amount of pressure that is built up (and how this slowly builds up). This gives me an indication how to start my next print (perhaps manually building pressure first, or adapting the gcode to slowly extrude some material before starting the print).

Will keep you up to date when printing starts, and how my settings/start code will end up.

Gr5 thanks for your great tips, I originally kinda dismissed them as I had already been fiddling with speed and temperature for the soft pla before the whole thing started going awry. However, after cleaning the head out, and manually turning the gear did I really get your tip. This is such a good way to get a feel for the pressure/resistance and the associated flow.

 

[Trouble making Soft PLA prints]

After some months of printing normal PLA with the Ultimaker I ordered some Soft PLA from FormFutura to make some parts to dampen the amount of noise the Ultimaker produces. However, trying to print with Soft PLA has really been a hell compared with regular PLA.

The prints are based on the profile posted by Daid for soft PLA on the google groups:

 

[profile]
layer_height = 0.1
nozzle_size = 0.4
wall_thickness = 0.8
retraction_enable = True
solid_layer_thickness = 0.6
fill_density = 20
skirt_line_count = 1
skirt_gap = 2.0
print_speed = 20
print_temperature = 220
support = None
enable_raft = False
support_dual_extrusion = False
filament_diameter = 2.89
filament_density = 1.00
machine_center_x = 100
machine_center_y = 100
retraction_min_travel = 2.0
retraction_speed = 40.0
retraction_amount = 4.5
retraction_extra = 0.0
travel_speed = 150
max_z_speed = 5.0
bottom_layer_speed = 20
cool_min_layer_time = 5
fan_enabled = True
bottom_thickness = 0.3
enable_skin = False
model_scale = 0.093069064273
model_rotate_base = 0
flip_x = False
flip_y = False
flip_z = False
swap_xz = False
swap_yz = False
plugin_config = (lp1
.
raft_margin = 5
extra_base_wall_thickness = 0.0
cool_min_feedrate = 10
fan_layer = 1
fan_speed = 100
fan_speed_max = 100
raft_base_material_amount = 100
raft_interface_material_amount = 100
support_rate = 50
support_distance = 0.5
infill_type = Line
solid_top = True
fill_overlap = 30
bridge_speed = 100
sequence = Loops > Perimeter > Infill
force_first_layer_sequence = True
joris = False
retract_on_jumps_only = True
hop_on_move = False
model_rotate =
print_bed_temperature = 70
gcode_extension = gcode
object_center_x = -1
object_center_y = -1
alternative_center =
add_start_end_gcode = True
model_multiply_x = 1
model_multiply_y = 1
flipx =
flipy =
flipz =
model_matrix = 1.0,0.0,0.0,0.0,1.0,0.0,0.0,0.0,1.0
object_sink = 0.0
[alterations]
start.gcode = ;Sliced {filename} at: {day} {date} {time}
;Basic settings: Layer height: {layer_height} Walls: {wall_thickness} Fill: {fill_density}
;Print time: {print_time}
;Filament used: {filament_amount}m {filament_weight}g
;Filament cost: {filament_cost}
G21 ;metric values
G90 ;absolute positioning
M107 ;start with the fan off
G28 X0 Y0 ;move X/Y to min endstops
G28 Z0 ;move Z to min endstops
G92 X0 Y0 Z0 E0 ;reset software position to front/left/z=0.0
G1 Z15.0 F{max_z_speed} ;move the platform down 15mm
G92 E0 ;zero the extruded length
G1 F200 E3 ;extrude 3mm of feed stock
G92 E0 ;zero the extruded length again
;go to the middle of the platform (disabled, as there is no need to go to the center)
G1 F{travel_speed}
nextobject.gcode = ;Move to next object on the platform. clear_z is the minimal z height we need to make sure we do not hit any objects.
G92 E0
G91 ;relative positioning
G1 E-1 F300 ;retract the filament a bit before lifting the nozzle, to release some of the pressure
G1 Z+0.5 E-5 F{travel_speed} ;move Z up a bit and retract filament even more
G90 ;absolute positioning
G1 Z{clear_z} F{max_z_speed}
G92 E0
G1 X{object_center_x} Y{object_center_y} F{travel_speed}
G1 F200 E6
G92 E0
end.gcode = ;End GCode
M104 S0 ;extruder heater off
M140 S0 ;heated bed heater off (if you have it)
G91 ;relative positioning
G1 E-1 F300 ;retract the filament a bit before lifting the nozzle, to release some of the pressure
G1 Z+0.5 E-5 X-20 Y-20 F{travel_speed} ;move Z up a bit and retract filament even more
G28 X0 Y0 ;move X/Y to min endstops, so the head is out of the way
M84 ;steppers off
G90 ;absolute positioning
switchextruder.gcode = ;Switch between the current extruder and the next extruder, when printing with multiple extruders.
G92 E0
G1 E-5 F5000
G92 E0
T{extruder}
G1 E5 F5000
G92 E0
replace.csv =
support_end.gcode =
support_start.gcode =
cool_end.gcode =
cool_start.gcode =

However, most prints fail after the first couple of layers. It looks and feels at the extruder as if no more PLA is being fed into the hot end. Two evenings were spent trying to tune settings and the bed to overcome this, but this evening I first checked the extruder and found the Soft PLA 'bunched up' there, See the attached picture. I cut off the PLA and inserted a fresh end.

The following print came out very nice for the first 2-3mm (a lot more than the first few layers I was getting before), but afterwards still failed on lack of material. See below...

 

How can I fix this problem? I am thinking it might be the dreaded plugged hot end and I am really not looking forward to opening it all up and cleaning it out, but this is probably what my weekend is going to look like anway. Any other tips?

 

[Struggling with 20mm boxes]

Wow, seems like your tip was right on. I used the printed z-adjustment screw to lower the bed a little bid (using the leveling screws seems kinda risky due to skewing the bed as well). And the flared bottom problem is gone.

Now I can actually see what my gcode was doing too... the z-height reset actually did nothing (trying to move the bed 1.6mm before the print didn't work. Besides, the retract I added at the start of the print is apparently only added after the raft has been printed, so it only resulted in the bottom layer of the print not getting any PLA. So all gcode reset to basic version and back to printing again!

[Struggling with 20mm boxes]

What do your settings looks like?

I calibrated the z-height in this second instance by having an A4 below the printhead,and adjusting the z-end stop in such a way as to when it's I can feel a little friction when pulling the paper away (not totally free, and also not so much that you really have to use force to get it away).

I have now adjusted it in the start gcode to zero at 1=+0.1mm (which is also my layer height). So basically I have the thickness of a sheet of paper + 100 mu as the zero height when I start the print. Is this comparable to what you are doing?

[Struggling with 20mm boxes]

My ultimaker has been running for a while now, printing fluorescent green, after calibration of the steps per E setting with 20mm boxes giving great infill and quality. However, I always had problems with the bottom flaring out, and was not able to fix this.

I recently changed to transparent dark green PLA (3mm), which caused some problems:

Keeping the steps per E the same and just changing the measured diameter of the filament resulted in the bottom layer being too thick, so in the 2nd or 3rd layer there was so much plastic that the head would bump in to it and scar it.

Print settings are:

0,1mm layer height

0,8mm wall thickness

0,2mm bottom/top thickness

Fill 100%

skirt

150mm/s speed

225 C print temperature (PLA)

No support, no rafts, just simple 20mm boxes

Bottom layer speed 20mm/s

Initial layer thickness was originally at 0,2mm, later changed to 0 (same as normal layer)

Z-height was adjusted with the aluminum multimeter trick and http://www.thingiverse.com/thing:11033

Changing the initial layer thickness to 0 was the fix for the problem posted above.

However, before finding that out I thought the steps per E might be the problem, so I also lowered that 30%. After the first box was printed it was clear that infill was very far away from 100%, so I started printing more boxes to get the infill exactly right:

The dark green ones are getting better and better infill. The last one however, is not completely filled, and is suffering from two other problems:

- the sides are starting to get 'wobbly'

- the bottom of the box is still flared (which all boxes suffer from)

The last box actually has 30% more steps per E than the fluorescent green baseline setting.

Closeup:

Two questions remain to get my print quality better:

1. The knob I had found to fix the top infill (adjusting steps per E), has now been exhausted, because I start getting back other problems from it (the wobbly side). What is the correct approach to get a properly filled top?

2. The flared bottom is something I have not been able to change in any of the print. I tried the following:

- Adding some retraction at the start code (hypothesis: pressure buildup during raft/initial layer printing)

- Offsetting the z-height a little (setting +0,1mm to 0)

- printing at faster bottom speeds (ruined the print)

- Printing the bottom layer at the same thickness as the other layers

I get the feeling that the gcode does not account for the slower bottom speed, or that something else is going on. Has anyone seen this? What have you done to fix it?