Extruder Nozzle too far from surface

Hi Guys,

First post here, so I do apologise if I have posted in the wrong area or missed something.

Before I get into it I will give you a bit of back story, so you can fully prepare for how dense I am probably being.

I have wanted a 3D printer for ages, the world of possibilities of being able to model something and then get a physical output has appealed for a long time. However, unfortunately I don't have an expansive bank account, so I have always thought this would have to be done on a budget.

I was scrolling through ebay when I found a diy kit based on the i3 Prusa for £160. Bargain!

I had hoped (In my naivety) that as long as I put it together, after a small bit of calibration (Making sure that the X axis is level and the bed is flat) things will just happen. unfortunately this was not the case. After a bit of work, I have managed to get it to make the motions of printing, but, the nozzle doesn't get close enough to the bed for the filament to adhere, and instead it just squirts out like someone (very slowly) standing on a tube of toothpaste.

I have used Cura 15, and this doesn't appear to have any settings to resolve this within the model. Likewise I have tried SLic3r which does have a setting to account for any Z axis offset, but this does not seem to do anything.

In the hopes that I was over complicating it, I simply tried to raise the print bed, but it seems to know and remained about 3mm above the surface not printing.

Simple question, what am I missing?

I accept this is probably a very silly question for which I apologise but I am getting a bit irritated now as I just cant work it out!

Any help would be greatly appreciated.

The printer itself says it is a Euroway 3D printer, with directions to the CTC website. The control board is 2560 Rev A. Not sure what more detail is needed, please ask and I will do what I can to fill in the gaps.

Kind regards,
T

Does not matter what soaftware you use, without a properly calibrated printer you won't get any prints.
So do the entire setup and calibration for the machine, then try a print and do the finetuning.
If you buy a dirt cheap kit you can't expect it to work like a 1000$ model

Hey downunder35,
You struck a key point there that I may have missed. I thought (based upon my best guess at the calibration/set up guide... It was a poor translation) that I had set it up. Based on the issue described above, are you able to venture a guess at what I may have missed? Is it purely z-axis calibration or do I need to start messing around with settings?

Cheers,

Maybe this helps.
The head home and print position is referenced to the Z end stop position. You can't drive the head below the end stop. You probably need to lower the z stop. This can be pain on cheap machines as its held on by a couple of screws through slots and the head doesn't move with it.
I guess you can :- lower the bed to near its lowest adjustment. Loosen the z stop switch and move it realy low. Use small steps to move the head down to about 1-2mm above the bed. Lift the z stop up until you can hear the switch activate and lock in position. Home the Z axis so it reacts to the stop switch. Now adjust the bed to paper clearance. Slicers z offset does work and negative numbers are for the gap between the head and bed but I don't know if there is a max value you can use. You may need to have another go at the Z stop as its not easy to hold it still when tightening the screws. Many people will tell you to do the last bed adjustment with the bed and hot end at temperature.
For info, there are parameters in the firmware that are often set to identify the home position relative to the end stops. When the head is at this location the travel is set to zero. So home is not where the end stop switch is. When slicing all distances are from the home position not the end stop.

couple things if your printer is like mine (diy prusa i3 from amazon for $360)

DO NOT

want to loosen the heat bed screws in order to raise the bed. This can very easily cause the tension on the springs to be too lose causing binding on the y-axis linear bearings.

INSTEAD

adjust your z end stop like the guy said above me. simply lower it SLIGHTLY and hit the z-home button to see how it goes. rinse and repeat until you can barely slide a piece of paper between bed and nozzle.

ALSO

if your z endstop is all the way at the bottom already, so you cant lower it, then you probably have the hot-end set too high in the extruder. If its anything like mine, there is a little set screw holding the hot-end barrel which can be loosened to allow the hot end to slide up or down.

MY PROCEDURE

loosen hot-end set screw on extruder. make sure it slides loosely, push it up all the way, set your z end stop roughly 1cm above the lowest setting, put a piece of paper under where the hot-end will lower, hit z-home button, slide hot-end down so its touching paper, tighten set screw, remove paper, make adjustments to z endstop as necessary. Just make sure your z endstop is close enough to the heat bed so that you dont have to lower the hot-end TOO much. Each item has nice margins so its not hard to get them in good spots.

LAST RESORT

if you must raise the heat bed by loosening the screws then put 2-3-4-5 washers under the springs to keep the same tension.


BY THE WAY

Fancy $1000 printers use the same hardware and materials as our diy printers do, They dont have access to some magical programming or tools we dont have. There is no reason why your diy printer should not rival more expensive printers as long as its properly calibrated. a common misconception is that a cheaper printer means cheaper quality prints. WRONG WRONG WRONG. Cheaper printer means more work to get it properly calibrated, but has nothing to do with the capibilities of the printer itself!!!!!! I would gladly save $700 in order to have to make my own adjustments to a device i built myself anyway lol....Last note...im only using a .4mm nozzle (nothing fancy) and people have asked me many times after seeing my prints "how much was your printer" "whered u get it" etc. They have no idea its not a $1000 prebuilt

Edited 4 time(s). Last edit at 01/23/2016 12:27PM by davidbananas999.

Hi guys,

Thanks for the advice, still having trouble getting it right. thought i got close made a minor adjustment and now its back to where it was. Also, i think one of my motors is dying as well. making a weird noise and randomly stops turning :/

I guess your peoblem might be the understanding between z-offset, platform height and start height for a print layer.
Although the procedure of calibrating is straight forward if done incorrectly it only makes things worse.
Try it this way to get a base to move on:
Start a print with no z-offset defined, just simple basics.
Stop the print as soon as the nozzle moves over the printbed.
Now check the distance between nozzle and bed.
It works best to set a first layer height that corresponds to whateven you have to measure it - e.g. a postcard is roughly 0.1mm thick.
Adjust the z-endstop bit by bit until your distance between nozzle and bed is the same as set for the first layer height.


Biggest beginner fault is to set the z-height from the zero postion.
Effectively that means you set up a distance between bad and nozzle that seems to be correct.
Only problem with that approch is that you actually adjust for whatever your first layer height will be PLUS the distance you just calibrated

Hi,

I bought the same printer & the instructions for the z stop screw aren't the clearest....

Put a nut each side of the zslider so you can adjust the length of screw sticking out below the hits the micro switch.

That way the nozzle can go down to the bed.

Apologies if you know all this.

Thanks for the advice. I think I narrowed down the issue. The motors I had kept cutting out or making some pretty alarming noises. I took a chance and replaced them. The thing now lays down the first layer alright. Things go squiffy after that so I think it's either a temp thing or maybe my z axis is still a little bit off. Only got it back together late yesterday eve no not properly looked in to it yet.

Thank you to everyone that helped!