Printing in mid air...

Hello,
I am trying to get my first print.

I am using SFACT and Pronterface. I did calibrate the printer using the calculator from prusajr and the extruder extrudes just the right amount of filament when I tried it.
'
After the first layers (about 10) the printer start to print in mid air, the nozzle lose contact with the printed layers, looks like the PLA doesn't stick any more.. I have all the default settings of SFACT, using a 0.5mm nozzle

Any suggestions on what I should try?

Edited 1 time(s). Last edit at 08/26/2011 08:05PM by Kalle.

Your z axis calibration is probably off in the firmware.

I checked the Z axis movement telling it to move 50 mm and it did move for 50 mm looks like it's calibrated. Now I try increasing the flow rate in the firmware, I use sprinter.

Have you set your Z home and end stop to put the nozzle right on top of the bed?
I shoot for a mm off the bed.
Also make sure your firmwares Z_steps_per_unit value is set for your Z axis threaded rods.
Mine was set for metric and i have SAE and it was causing the print head to not move up enough and by the end of the print the head was buried in the printed object.
Be patient, believe me.
When you get that first decent print off,
you wont sleep for three nights.
lol
Cheers hope this helps.
-E

Edit_ i see your using sprinter.
So am i, the setting for the Z axis is under the steps_per_unit in the configuration file. And has 4 values X,Y,Z and E
Happy hunting

Edited 1 time(s). Last edit at 08/27/2011 01:08PM by 420e.

How about a closeup, high quality, in focus picture. Sometimes worth well over 1000 words.

Some possibilities (assuming your Z axis firmware is calibrated correctly):

1. Layer height is set too high, so with each pass the the distance between the extruder and the surface increases. 0.4mm layers may be a good place to start, that's assuming you are using a 0.5mm nozzle.
2. Flow rate is set too low. This might not become apparent immediately when printing small objects, especially if some filament has been extruded manually prior to the print. If the filament eventually loses consistency this might be the case.
3. If there is the slightest wobble in the Z axis this can lead to layers not being placed in perfect alignment – eventually causing a loss in average layer height. Make sure that the extruder moves perfectly straight along the Z axis. Any wobble, and the vertical rods might be fractionally too far apart.
4. Any slide from the pulleys can similarly lead to fractional misalignments, and eventual loss of height. Make sure that the pulleys are VERY tight, and also check that the timing belts have no looseness.

Good luck!

Edited 1 time(s). Last edit at 08/27/2011 07:20PM by Rook.

Thanks all of you for the answers, I did some more prints today using the raft and they look a little bit better, at least all the layers are printed but the sides are not flat (will take a picture later).

I feel like I am going in the right direction.

420e Wrote:
-------------------------------------------------------
> Have you set your Z home and end stop to put the
> nozzle right on top of the bed?
> I shoot for a mm off the bed.
yes it is like 0.3mm over the bed, I am using a raft now.

> Also make sure your firmwares Z_steps_per_unit
> value is set for your Z axis threaded rods.
Checked it's a metric

> Be patient, believe me.
> When you get that first decent print off,
> you wont sleep for three nights.
> lol
I belive you


> Edit_ i see your using sprinter.
> So am i, the setting for the Z axis is under the
> steps_per_unit in the configuration file. And has
> 4 values X,Y,Z and E
this are my values float axis_steps_per_unit[] = {80, 80, 2560, 1008};

Andrew Diehl Wrote:
-------------------------------------------------------
> How about a closeup, high quality, in focus
> picture. Sometimes worth well over 1000 words.

Will do one with the next print, the raft seems like a good idea.

Rook Wrote:
-------------------------------------------------------
> Some possibilities (assuming your Z axis firmware
> is calibrated correctly):
I checked and it is

> 1. Layer height is set too high, so with each pass
> the the distance between the extruder and the
> surface increases. 0.4mm layers may be a good
> place to start, that's assuming you are using a
> 0.5mm nozzle.
Yes I am using a 0.5 nozzle, the layer is set to 0.4


> 2. Flow rate is set too low. This might not become
> apparent immediately when printing small objects,
> especially if some filament has been extruded
> manually prior to the print. If the filament
> eventually loses consistency this might be the
> case.
I am experimenting with flow rate, the top layers bend a little bit, I do manual extrude when starting

> 3. If there is the slightest wobble in the Z axis
> this can lead to layers not being placed in
> perfect alignment – eventually causing a loss in
> average layer height. Make sure that the extruder
> moves perfectly straight along the Z axis. Any
> wobble, and the vertical rods might be
> fractionally too far apart.
I will check better on this

> 4. Any slide from the pulleys can similarly lead
> to fractional misalignments, and eventual loss of
> height. Make sure that the pulleys are VERY tight,
> and also check that the timing belts have no
> looseness.
I'll try to put some sort of belr tensioner

Edited 1 time(s). Last edit at 08/27/2011 11:45PM by Kalle.

Another big thing i had an issue with was the PLA i was using.
I was a dummy and used the free samples that came with it
Had ok results.
Changed to fresh blue out of the bag and wow.
No more issues,
no more bubbles, or blobs
If your not on good stuff, get some.
Its a silly chase trying to calibrate with garbage.
Also I had a little issue with lash in the Y carriage belt,
Caused little gaps between infill and perimeter but only on one side.
Also caused the print to "drift" where each layer was slightly over hanging the last.
But after tightening everything and playing with skeinforge settings, i am pretty happy with the results
Everything is squared off, parallel and connected.
Im printing the lid to a box that i printed earlier that only earlier today i had created in blender.
THIS THING IS AMAZING!!!
Hang in there.
Well get you there.
-E