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SoliForum - 3D Printing Community → Help/Repair/Maintenance → How to fix blobs
Blobs causes the object to decrease size.
I already did the following:
Calibration of the extrusion stepper,
Calibration of the flow rate,
Calibration of the Z wobble,
Change the extruder,
Change de temperature,
What more else?
Thanks.
Photos?
[img][/img]
what's your print speed?
You've got some pretty serious Moire going on there so I'd start with your extruder VREF.
here's the spec,
; generated by Slic3r 1.0.0RC3
; layer_height = 0.3000
; perimeters = 3
; top_solid_layers = 4
; bottom_solid_layers = 3
; fill_density = 0.2
; perimeter_speed = 45
; infill_speed = 60
; travel_speed = 60
; nozzle_diameter = .35
; filament_diameter = 1.75
; extrusion_multiplier = .87
; perimeters extrusion width = 0.42mm
; infill extrusion width = 0.42mm
; solid infill extrusion width = 0.42mm
; top infill extrusion width = 0.42mm
; first layer extrusion width = 0.42mm
thanks,
Nelson
If you have a .35 nozzle, the value should be .42 to allow for expansion.
Also, if you have not just yet, level the bed and adjust your Z height...you want to first layer to be fat and flat like a ribbon.
AZERATE,
what should be .42? The layer_height?
Thanks.
Your filament settings look fine since the SD3 has a 0.35mm nozzle. You need to:
1, balance your bed
2. Tighten and/or align your belts (I see backlash)
3. Calibrate your extruder steps per mm
4. Calibrate your extrusion multiplier.
5. Adjust VREF on your extruder motor (Turn it down until the moire disappears).
If you google or use the search function on this forum you will learn how to do all of this. Do *all* of this (you can't skip steps in 3d printing), and report back. If you get stuck along the way, we're happy to help.
I know you said you did all of these things, but do them again. I've done it so many times on my machine it makes me sick, but it's the only way you're going to improve your prints, which is the goal, right?
The reason I say this is blobs are the least of your worries based on that print. You have a lot of calibration to re-do first. A lot of the things I mentioned above can in fact *cause* blobs, so fix these things first.
AZERATE,
what should be .42? The layer_height?
Thanks.
Nozzle diameter. You want to allow 20% for expansion.
For exapmle, if you have a .4 nozzle, the setting should read .48
There are a couple things off, but nothing simple calibrations can't fix 
jagowilson's previous post is a great way to start and diagnose.
jagowilson + AZERATE,
thanks for the tips. i will try and give you feedback.
Nelson
Good luck
Your filament settings look fine since the SD3 has a 0.35mm nozzle.
FYI not all SD3's came with a .35 nozzle. Sometime between August and October of 2013 they started to ship with the .40. I think that's the correct timeframe.
They've been shipping 0.4s that long and RH still has the wrong settings on install? Damn. Mine sure did if you recall.
In that case OP you should double check that!
Yep, it seems as though SD adjusts for everything with the extrusion multiplier. At least they have for the last year and a half.
Doesn't work as well as they would like. My prints came out much better once slic3r knew my nozzle diameter and desired extrusion width. Handicaps new users imo.
Absolutely, software design has always been an afterthought for SD.
I done the following:
1. balance bed
2. Tighten and/or align belts
3. Calibrate extruder steps per mm
4. Calibrate extrusion multiplier.
Is slightly better , but still having strings and therefore to compress the object (see photo compared with a printed before start of the problem ) .
The nozzle is .35 mm and i bought the SD3 in May of 2013.
I kept the nozzle diameter at .42
What should I do now ?
Thanks in advance .
If the print on the left is after the adjustments, you are looking at moire. This can be fought on a couple of attempts:
1) You should have a Sanguinololou board, which means you can interchange stepper drivers. You can upgrade to a DRV8825 driver for the E chip which allows 1/32 microstepping. At stock components, you are stuck at 1/16.
2) Upgrade to a Bulldog XL extruder...this smashes moire with 1/32 microstepping.
3) Simply adjust your E VREF by ear using a ceramic/non-conductive screwdriver
Also, it looks like you are having some backlash from the Z rod. There are many printable designs on Thingiverse to combat this. If you go this route, bare in mind that the stock Z rod is 5/16".
I don't like to adjust extruder VREF by ear, hard to hear it over fans in my experience. You can touch the filamen close to the extruder entrance and feel the moire.
I recommend starting a calibration cube print with relatively long walls (try 50mmx20mm and let the 50mm side face the side where you will be when you adjust VREF). Turn VREF down (Moire indicates too high in my experience) on E in *small* increments. Give yourself time to look for differences. By the looks of it it's not too far off, so go slow. You may want to run a few calibration prints and look carefully. As AZERATE mentions, you are using 1/16 steppers so you will never eliminate it 100%, but you will come close.
And by the way, DRV8825s can be purchased for $10 in some places. I strongly encourage you to upgrade. For all 4 motors you're looking at $40+shipping, but if you don't want to spend that start with E. Upgrading them all will definitely improve the quality of your prints as well .
Hi everyone,
Things I done after last post (2014-11-01);
1) I printed a anti-blackslash;
2) Ajust E VREF and Z VREF;
The improvement was huge, but still have some minor problems to fix. I need more advices.
Thanks in advance.
Looking good! See what a little elbow grease can accomplish? 
For the sections that are sagging, you can try a couple of methods:
1) Print at lower layers. If you are printing that at .3mm, printing it at .1 (for example) would take 3 times longer, but you would have as drastic of an overhang.
2) Under speed settings in Slic3r, check your "Bridges" speed. Stock runs at 60 mm/s. Increasing the speed for bridging would allow the overhanging filament to cool faster. I don't know if the top sag is a bridge or a perimeter, but you can try this and see if it helps. If it doesn't, just scale the speed back to whatever setting you prefer.
3) Mount a fan to your hotend. This is pretty much mandatory for printing PLA if you want good results, but it can also come in handy for some ABS prints
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