Got any pointers on the Bowden Extruder?

[fredini]

I'm using Slic3r, printing at .2mm layer height.
Extruder temp is set to 240. Previously trying to drop that to 230 did not work, but can try playing with that again.
I'll try the solid cube tonight. thx.

[fredini]

What software are you using to slice with?
Can you print a 100% infill test cube (the 20x20x10 one) with no retraction at all, and the minimum layer time set at 30s (or with a fan blowing on it) that's usually the clearest indication of how well the extruder esteps are set, it should produce a nice crisp top layer, if you are extruding too much the extruder will start dragging through the plastic part way through the print.

Where in Slic3r do you set the minimum layer time? I am not finding this setting anywhere.

[Polygonhell]

What software are you using to slice with?
Can you print a 100% infill test cube (the 20x20x10 one) with no retraction at all, and the minimum layer time set at 30s (or with a fan blowing on it) that's usually the clearest indication of how well the extruder esteps are set, it should produce a nice crisp top layer, if you are extruding too much the extruder will start dragging through the plastic part way through the print.

Where in Slic3r do you set the minimum layer time? I am not finding this setting anywhere.

It's part of the cooling settings, same place to set when to turn a fan on.
I haven't use slicer extensively since 0.7.2 and it's changed a lot since then.

[fredini]

[img]http://farm9.staticflickr.com/8370/8362881595_2744c28b45.jpg[/img]
Rostock Max calibration cubes by fredini, on Flickr

Left one printed at 230 degrees(some morse code action going on there), right one at 240. The right one looks pretty good to me. WDYT?

[Polygonhell]

I think it looks pretty good, I can't really see the layers in the picture, but if you have a slight wave in the side and you don't have that on a single wall test print, you might want to turn your esteps down very slightly.
I ended up doing all my ABS printing at 240, and using a fan to cool anything with a significant overhang.
Currently I'm still playing with PLA, printing at 210 with a fan on.

[fredini]

This was looking so good when I went to bed last night....
[img]http://farm9.staticflickr.com/8336/8365066454_62ab12e8aa.jpg[/img]
Print fail by fredini, on Flickr

[Polygonhell]

Yeah, ignoring the failure it does look good, some marginal stringing, but the layer alignment looks good as far as I can see and the plastic seems to be going down consistently.
Do you know why it failed, or was it one of those come down to a blob of plastic moments?

[fredini]

Not sure why it failed- It was going well and up to the waist by the time I went to sleep. This model is one of my favorite scans that I've done as it prints quite nicely. The red flourescent plastic is hard to photograph, but the print quality is miles ahead of my Printrbot+.
http://www.thingiverse.com/thing:32816

[lazerusrm]

As someone who has printed almost 4 spools through his Rostock MAX, and the first to have a functional printer besides the prototypes (as far as i know!) i believe i can offer some input.

So i've noticed a few problems when trying to calibrate the bowden extruder. The real problem lies in finding the exact correct tension on the extruder bolts. If it is too tight, the filament gets squished to a very small diameter, and looses

strength in the bowden tube. This can cause the filament to BREAK OFF in the extruder gears during retraction.

On the other hand, if the extruder is too loose, it will just sit there and grind a flat spot in the filament.

The best way i've discovered to tune the tension on the extruder is to prepare a print, set your hotend to 230-240C (hotter is unnecessary) have your filament tension screws just snug enough to begin engagement with the filament.

You will also want to have plenty of light so that you can examine the knurled extruder gears.

Begin a print (does not matter what it is)

Slowly tighten each screw 1/4 to 1/2 a turn at a time (turn tension on both screws) untill you start to see extrusion out of the hot end. You are getting close.

Once the hot end begins to extrude, you will then want to clean off the filament shavings on the knurled extruder gears.

Once you clean them off, look to see if the filament is still being ground up. you will see evidence of this by small particles of plastic buildup in the knurled grooves. If this is the case, give both bolts another 1/4 to 1/2 turn, and clean

the gears.

I've had success cleaning the gears during a print by using a toothbrush to remove the plastic particles so i can re-examine the bolts for plastic grinding.

Ideally, your gears should not build up plastic in this area, plastic on the gears mean that the filament is not tight enough. The goal is to to get it tight enough, but NOT ANY TIGHTER. Otherwise, on retractions, the filament can easily

end up snapping or getting weak, or not extruding properly.



Now, the other problem i ran into after learning this tuning process, is that the geared assemblies inside the extruder were not tight enough, and it left the inner knurled gear assembly spinning, and not actually pushing on the filament.

im talking about the gears seen in the middle of this picture here:

[img]http://reprap.org/mediawiki/images/thumb/b/ba/ExtrudBottom_02.jpg/800px-ExtrudBottom_02.jpg[/img]

http://reprap.org/mediawiki/images/thum ... tom_02.jpg

this was MUCH harder to diagnose, because the filament will feed just dandy through the bowden tube, and then once it gets to the hot end it will not put force on the filament. I ended up taking my extruder back apart, and making

sure the internal two knurled roller assemblies were very tight so as to ensure ZERO slipping in this area. ---This had a monumental influence on print quality and consistency.


At this point, i now am getting fairly confident about leaving prints run. My longest successful print this far was a 20 HR print of an AR-15 Lower Receiver. Printed without serious issue in ABS (minor warping but thats another issue.)

I've attached a few photos of some recent prints to show you the part quality i am now getting with my Rostock MAX W/ 1.75 MM ABS Filament. @ .2MM Layers.

I Print on a GLASS Heated bed (Onyx) and i print on 3M PET TAPE (lulzbot) Prepped with an mild ABS/Acetone solution rubbed on it.

I slice all my parts with CURA 12.12A -- NOTE! Older versions of cura have problems with small or slow parts sometimes totally ruining prints. Use 12.12A or NEWER!

Another note, on your first time setup wizard, because the center of the bed is at 0,0 you must set your bed size to X 1MM Y1MM Z (Your Z Height) otherwise your prints will be messed up. also note, when adding files, you must manually set your SCALE to 1 (it will autoscale incorrectly because of the bed dimensions) It will however, slice just fine!

Another Note: I have a fan mounted to my rostock hot end. it helps a lot with small areas or small prints, etc.

Here are my settings:

Layer Height .2MM

Wall Thickness 1.0 MM

Bottom/Top Thickness 1 MM

Fill Density (Various)

Print Speed (20MM/sec - 75MM/Sec)

Printing Temp: 0 (Using Autotemp, set print temp to 0 then add this code in start [M109 S212 B255 F0.4] This is in my start code below)

Bed Temperature (At least 70 Degrees *C)

Filament Diameter 1.73

Packing Density .85

Nozzle Size .5MM

Line Count 1

Start Distance 1.5

Retraction:

Minimum Travel 5.0

Speed 68MM/Sec

Distance 11MM

Extra Length on Restart .6MM

Travel Speed 275MM/Sec
Max Z peed 275MM/Sec
Bottom Layer Speed 20MM/Sec

Minimal Layer time 13 Seconds
Cooling Fan Enabled

Initial Layer thickness .4MM
Duplicate Outlines <No>

Expert Settings:

Extra Wall Thickness 1.0MM

Minimum Feedrate 13MM/sec

Fan on layer 2

Fan Min Speed 15

Fan Max Speed 100

Raft:

Extra Margin 8MM

Base Material 100%

Interface material amount 100%

Support:

Material Amount 70%

Distance from object 1MM

Infil: Grid Hexagonal

Solid Infill Top <Yes>

Infil Overlap 38%

Bridge Speed 20%

Joris <no>

Retract on jumps only <yes>

Enable hop on Move <no> (only with prints with lots of tall, small separate areas)

My Start code:

Code: Select all

;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
M106 100                ;Quickly Enable Fan, Then Turn it Down to Low Speed
M109 S212 B255 F0.4    ;AutoTemp Enabled
G28 X0 Y0 Z0            ;move X/Y/Z to min endstops
M106 16                 ;Turn Fan to Lowest Moving Setting
;G92 X0 Y0 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 E7              ;extrude 3mm of feed stock
G92 E0                  ;zero the extruded length again
G1 F{travel_speed}

My End Code

Code: Select all

;End GCode
M104 S200                     ;extruder heater Low
M140 S60                     ;heated bed heater Low (if you have it)
G91                                    ;relative positioning
G1 E-5 F4000                            ;retract the filament a bit before lifting the nozzle, to release some of the pressure
G1 Z+2.5 E-12 X-20 Y-20 F{travel_speed} ;move Z up a bit and retract filament even more
G90                         ;absolute positioning
G1 X0 Y0 Z352.0
G28
;M84                         ;steppers off

This first item is something that is currently printing, its the reprap LCD case. it is shaping up very nice. i'll have to post some pictures of it here for reference of the quality you should be getting with a Rostock MAX

[img]http://imageshack.us/a/img824/9206/dscn0967d.jpg[/img]

[img]http://imageshack.us/a/img546/518/dscn0964f.jpg[/img]

[img]http://imageshack.us/a/img717/5295/dscn0962r.jpg[/img]

Uploaded with ImageShack.us

[fredini]

Lazerusrm- thank you for the AWESOME feedback! I didn't have time to print anything tonight- got home too late and this machine is pretty loud, so my wife doesn't love it printing overnight as it wakes her up. Hopefully tomorrow I can continue tweaking.

I have found that this thing really needs a fan going on it while it prints- even with ABS. I just have a little USB fan pointed at it for now but if you have some time to post an image of your fan mount on the extruder I would appreciate it. I think I may want to try this. The other thing I was considering was to just mount a fan on one of the cheapskates so its angled toward the extruder. I guess I thought the weight on the side of the extruder might throw the print off, so the cheapskate solution seemed like it could cause less interference.

[lazerusrm]

Fan? I forgot to even get into that problem. to use a fan successfully and reliably, i had to insulate the hot end from the fan, otherwise it would cool off too much.

You should be able to print just dandy without a fan for many things, as long as the parts are not super tiny. Lower the temperature some.

My hotend is insulated with Hi-Temp Stove and Gasket Cement that i bought from the local hardware store. Once heated it forms a ROCK HARD insulation layer around whatever you put it on.. but beware, if you ever have to replace

anything, you must use a new thermistor as the leads snap right off. (done this twice now) i just ordered my 3rd set of thermistors etc for the next time i break them.

Right now my fan setup is just cobbled together as i have been SLAMMED with work.... but this is what i used...

http://www.thingiverse.com/thing:28412

But instead of mounting it flush, i used a longer bolt and threaded it into one of the far end holes on the cheap skate, and right now am just using a peice of masking tape to prevent air from being blown over the hot end. this seems to

work fairly well. its light enough it has no effect on the print.

I'll have to post a video of a print. maybe i'll take one as soon as im done printing this case ( ETA 5 seconds...) !

[fredini]

First Successful Print!
[img]http://farm9.staticflickr.com/8183/8369756704_78c601de30.jpg[/img]
Red Rostock Max Katie vs. Printrbot + Katie prints #3DPrinter by fredini, on Flickr

[img]http://farm9.staticflickr.com/8233/8368881739_15957b436c.jpg[/img]
Rostock Max first Print by fredini, on Flickr


Rostock Max Print vs. Printrbot+ prints:
[img]http://farm9.staticflickr.com/8334/8369756932_e7870b40a4.jpg[/img]
Red Rostock Max Katie vs. Printrbot + Katie prints #3DPrinter by fredini, on Flickr

[lazerusrm]

share more details of your print!

Temperature

Slicer

Speed

Slicer Settings?

[fredini]

Some more prints and some settings today.
I had a couple instances of printing failures- The settings are more or less the same as the settings below. On all prints I am running a small fan just setting next to the printer after the first couple layers.

First I had a print that I aborted- the machine took a weird jog in the x and y. I know it was previously suggested that this could be something overheating in the Rambo Board, but I'm also wondering if I have some kind of loose connection with one of the wires that connects to the Board.... not sure.
[img]http://farm9.staticflickr.com/8499/8373997254_5b46c4bb47.jpg[/img]

[img]http://farm9.staticflickr.com/8464/8372926355_5b737cbd7e.jpg[/img]

The print after this was the one I previosuly posted - a 122mm tall figureine, that came out pretty well. Still some blobbing. Settings pretty much identical to below but retraction was set to 7mm @ 55mm/sec
[img]http://farm9.staticflickr.com/8088/8373979372_affca5f4e0.jpg[/img]

I then ended the night by dialing up retraction to more like your settings 10mm retraction, 68mm/sec and went to bed with a 161mm tall version of the same model printing. The filament never kinked, but here is what I found in the morning-I think it is a metaphor for my psyche!:
[img]http://farm9.staticflickr.com/8507/8373978218_b17b330941.jpg[/img]

The next night I resolved to try the bigger print again- 161mm tall. Here's the print and the settings used. The print is really nice in comparison to my Printrbot, but I still get some blobbing and threads in the gaps between the legs...

[img]http://farm9.staticflickr.com/8506/8373270995_b105552cba.jpg[/img]
[img]http://farm9.staticflickr.com/8516/8374344952_4d63fb4f57.jpg[/img]
[img]http://farm9.staticflickr.com/8468/8373271935_301759b8d3.jpg[/img]
Settings:
[img]http://farm9.staticflickr.com/8233/8374366646_f6daec48a9.jpg[/img]
[img]http://farm9.staticflickr.com/8233/8373293537_9e4aef352e.jpg[/img]
[img]http://farm9.staticflickr.com/8213/8374366602_6bf2a6f880.jpg[/img]
[img]http://farm9.staticflickr.com/8075/8373293531_806b12fcdb.jpg[/img]
[img]http://farm9.staticflickr.com/8330/8374366562_0b850a606b.jpg[/img]
[img]http://farm9.staticflickr.com/8491/8373293491_42cdb006e2.jpg[/img]
[img]http://farm9.staticflickr.com/8376/8373293475_3a50489e41.jpg[/img]
[img]http://farm9.staticflickr.com/8473/8373293467_c5fafc20df.jpg[/img]
[img]http://farm9.staticflickr.com/8465/8373293463_ae8c176aea.jpg[/img]

Any advice on reducing the blobbing/stringing? Next up I am playing with setting retraction back up to 10mm at 68mm/sec and tweaking the tension on the extruder rollers- I get a very tiny bit of plastic dust on the rollers, but not bad at all.

[slausonm]

I read through the posts and did not see the answer to the original very first post. I am going through the calibration for the hot end on my Rostockand got a similar error message at the end of the process. I am trying it again as I type this.


Edit... Just finished. Same error message again. AFAIK the thermistor is seated properly in the hot end. I used automotive grade Silicon RTV to create the thermister assembly. I didn't have the silicon gasket material so I bedded it in normal high temp gasket material. The hot end seems to be comming up to temperature as it is going through the process, and I am getting a message in the box below the log that gives me a temperature, although it is now back to room temp and it reads 200.
Whats's up?

Thanks, Matt

[barnett]

If you're talking about the "Error:Line Number is not Last Line Number" message at the end of an autotune run, I thought someone said a newer marlin firmware version would fix this. But I haven't tried it and I still get this error. Doesn't seem to cause a problem though.

[slausonm]

Thanks, Just looking for confirmation that I'm not messing something up. We downloaded the newest software...I think. I will try the settings I obtained and carry on until the next problem/ question.

[jesse]

What's supposed to keep the bowden tube from popping off when the filament enters it from the extruder?

The tube just gets pushed upwards.

[Polygonhell]

What's supposed to keep the bowden tube from popping off when the filament enters it from the extruder?

The tube just gets pushed upwards.

The quick connect fitting should hold the tube so it can't move.

[JakeCShake]

What's supposed to keep the bowden tube from popping off when the filament enters it from the extruder?

The tube just gets pushed upwards.

Check out this thread for visuals....we had issues with this as well....

http://forum.seemecnc.com/viewtopic.php?f=42&t=978

[jesse]

Thanks for responding.

Here's a photo of the problem.

[img]http://i.imgur.com/jMISNtS.jpg[/img]

[fredini]

You need to push the Bowden tube further into that fitting. Once properly seated, there's little teeth in there that grab the tube and prevent it from pulling out.

[jesse]

Thanks, that fixed the problem.