PLA not sticking to bed

Having spent years building and modifying my Ormerod 1 (original RS version) I thought I had got to the point where I could start printing something.
However, I cannot get the PLA to stick to the bed.
The bed has Kapton tape on glass as specified in the assembly instructions. I am trying to print the Calibration piece "Calibration 200x200.g" as supplied by reprap, which sets the bed temperature to 57 degrees and the nozzle temperature to 185 degrees.
I calibrated the Z axis by loweing the nozzle until it just gripped a piece of 0.1mm plastic film, then lowering the nozzle a further 0.1mm, setting the Z zero position to this point then raising the nozzle to give a reading of approx 600 on the sensor. The Z and P parameters were then written into config.g as 'G31 Z1.1 P596' and as far as I can tell the nozzle is touching the bed when the Z axis is homed.

When I start to print, the printing process starts, some PLA may (or may not) stick to the bed but then it is dragged off the bed and accumulates on the nozzle leaving a horrible mess.
I have tried cleaning the bed with nail polish remover (as recommended somewhere). I have tried spraying the bed with hairspray (as recommended somewhere else). (I get strange looks when I buy these in our local shop!!) I have tried (though not recently) diluted PVA glue, and printing on to the bare glass. None of which give 100% success.

I am willing to try any of these remedies again if anyone is convinced they should work. I am also willing to try anything else!

I would like to know how to fix the problem. Bed temperature up or down? Nozzle temperature up or down? Kapton tape or no Kapton tape? Bed cleaning agent? Adhesive?
Can anyone help please!

The symptoms indicate that the nozzle is too high. Set the Z zero position manually every time and do not use the Z sensor. Ensure there is no plastic blob on the nozzle before manually zeroing. Also adjust the bed to be as level as possible (so the Z zero position is the same at the edges and middle of the bed). If you cannot get it level, set up the bed calibration manually as well. If the first layer does not stick, cancel the print and set the Z zero position 0.1mm lower than before and try again. To set the Z zero position 0.1mm higher, simply send "G92 ZX.X" where "X.X" is 0.1mm higher than the height indicated. You could also try coating the kapton with a sugar solution (dissolve heaps of sugar in warm water). Let it dry before printing on it.

Dave

Quote
PeterSimpson

When I start to print, the printing process starts, some PLA may (or may not) stick to the bed but then it is dragged off the bed and accumulates on the nozzle leaving a horrible mess.
I have tried cleaning the bed with nail polish remover (as recommended somewhere).

Nail polish remover is not ideal as the Acetone often includes Glycerin and other chemicals designed to moisturise the nail and skin which will actually inhibit the PLA sticking. Acetone mixed with some offcuts is often used to help ABS stick, I don't think it will do much for PLA.

I have found for getting PLA to stick, the best solution (for me!) is to use Kapton tape cleaned with Isopropyl alcohol on a heated bed at 57⁰C. I apply the Kapton tape onto the glass after first coating the glass and tape with soapy water. Then squeegee the water out and let it dry for a couple go hours. It sticks so well I often have trouble getting the print off afterwards.

A level bed and the right height is critical. The symptoms you describe are probably because of the nozzle being too high, but it is possible it's too low. From your starting point try printing a single layer, see how it sticks. Remove the print, clean the bed and move the nozzle up or down slightly then try again. One thing to remember is to adjust the height when the bed and nozzle are at the temperature you will be printing at as heat expansion will make a difference.

A few hours spent methodically working out the best height and method of setting is well worth the effort and will save oodles of time and wasted prints later.

I print PLA straight onto glass

I use bed temp of 70 first layer then 65 for the rest.

Extruder temp of 205 for first layer and 195 for the rest.

I also coat the glass bed with extra hold cheap hair spray. It works an absolute treat. Got the hair spray from Super-drug

Good luck

Quote
dmould
....Set the Z zero position manually every time and do not use the Z sensor....

Dave

Thanks Dave and Trevmas. I will try your suggestions.
How do you suggest I should set the Z zero position manually, without using the Z sensor? I find it very difficult (no, impossible) to see the nozzle when it is in close proximity to the bed, especially in the x-0, y=0 position. (my sight is not brilliant!).

BTW the mods I mentioned earlier were to replace the X arm with the aluminium version from davek0974 (DD Metal products); replace the bed support with the aluminium version (also produced by DD Metal Products) and to rebuild the base using aluminium end pieces in place of the acrylic ones.

Peter

After some tests time ago I never changed... PLA only on glass directly it's my choice.
With some filaments it's really difficult but others very easy.
With a dc42 sensor the problem can be only "forgetting how to set".... is always perfect!
DD Metal products.. a decisive good choice!
You're on the right track

Dario

---

Ormerod 187
Firmware Electronics: Duet 0.6
Firmware Version:1.18.1 (2017-04-07)
Web Interface Version:1.15a
Slic3r 1.2.9a and Simplify3D 4.0.0
[www.dropbox.com]

Quote
PeterSimpson

Quote
dmould
....Set the Z zero position manually every time and do not use the Z sensor....

Dave

Thanks Dave and Trevmas. I will try your suggestions.
How do you suggest I should set the Z zero position manually, without using the Z sensor? I find it very difficult (no, impossible) to see the nozzle when it is in close proximity to the bed, especially in the x-0, y=0 position. (my sight is not brilliant!).

BTW the mods I mentioned earlier were to replace the X arm with the aluminium version from davek0974 (DD Metal products); replace the bed support with the aluminium version (also produced by DD Metal Products) and to rebuild the base using aluminium end pieces in place of the acrylic ones.

Peter

To set the Z height manually, get the bed to print temperature, then move to the centre of the bed (position 100,100). Put a sheet of ordinary copier paper under the nozzle, and while moving the paper back and forth, lower the nozzle in small increments (0.1mm or 0.05mm) using the web interface until you can feel the paper being gripped firmly, but not so tightly that it does not slide at all. You will probably feel the fan vibration through the paper. At that point send the command "G92 Z0" to set it as the zero position. If the print shows that it is still a bit too high, you can repeat the process but this time send "G92 Z0.05" or "G92 Z0.1" Be careful to hold the paper at the edge in such a way that you are not putting any pressure (weight) on the bed. If you need to manually set up the bed compensation points, first set the zero height as above, then use the same paper technique on each of your chosen calibration points, but after finding the height where the paper is gripped, read off the Z height instead of setting it to zero.

The firmware will not normally allow you to lower the nozzle below zero. I therefore usually start off by sending "G92 Z100" to ensure that the indicated position doesn't get to zero before touching the bed.

Dave

Quote
Ormerod187

With a dc42 sensor the problem can be only "forgetting how to set".... is always perfect!

Dario

I did a search on the forum for 'dc42 sensor' and found this from author dc42:
[forums.reprap.org]
which links to a mini-height sensor board at [miscsolutions.wordpress.com]
Is this what you are referring to? - if not what?
Is this board directly electrically compatible with the original board?
It looks to me as though the mounting is different from the original which presumably would require a different or additional plastic part (which obviously I can't print!) Are stl files available for this/these parts to enable me to get someone to print them for me?

I don't understand your statement: '"forgetting how to set".... is always perfect!' could you please explain.

thanks
Peter

Quote
dmould
To set the Z zero position 0.1mm higher, simply send "G92 ZX.X" where "X.X" is 0.1mm higher than the height indicated.

Dave

How, if at all, does the G92 command interact with the other commands for z axis manipulation, such as the G1 Z0 command or the G30 command?
Should the G92 command be executed before any of these other commands (as a command line in Pronterface), or after these commands - used in homing and bed compansation and possibly within a design file in which case it would presumably require editing of the design file. When, and how is the offset created by the G92 command reset to zero?

Thanks
Peter

Quote
PeterSimpson

I did a search on the forum for 'dc42 sensor' and found this from author dc42:
[forums.reprap.org]
which links to a mini-height sensor board at [miscsolutions.wordpress.com]
Is this what you are referring to? - if not what?

Is this board directly electrically compatible with the original board?
It looks to me as though the mounting is different from the original which presumably would require a different or additional plastic part (which obviously I can't print!) Are stl files available for this/these parts to enable me to get someone to print them for me?

I don't understand your statement: '"forgetting how to set".... is always perfect!' could you please explain.

thanks
Peter

yes it is [miscsolutions.wordpress.com]
yes fully compatible with the original board
you can find all the links for stl on the same site or Thingiverse
after the first setup done I never had more problems with the Z probe ... even better than many branded printers in my opinion.
time ago I made this video showing a start and time to be ready [www.youtube.com]
the sequence is:>home all>print a file

Ipswich UK ...so far from you?

Dario

Edited 1 time(s). Last edit at 10/14/2016 09:05AM by Ormerod187.

---

Ormerod 187
Firmware Electronics: Duet 0.6
Firmware Version:1.18.1 (2017-04-07)
Web Interface Version:1.15a
Slic3r 1.2.9a and Simplify3D 4.0.0
[www.dropbox.com]

Quote
Ormerod187
yes fully compatible with the original board
you can find all the links for stl on the same site or Thingiverse
Dario

On your website you provide a number of links to Thingiverse for modified plastic parts:
One for a E3Dv6 hot end on a Kossel (suffix mk and rd)
One for a Kossel dual fan J-head hot end;
One for a E3d Chimera;
One for a E3d v6;
One for a Kossel J-head hot end; (older version 1.0 boards)
and One for a Kossel E3d v6 hot end (older version 1.0 boards)

Which of these should I use for my Ormerod 1, as none of them look anything like the existing fan duct! Please don't say 'none!' as I have already ordered the mini-height sensor board!

It's not my web site! I'm not David (dc42). I am not involved in any business with him.
anyway.. take a look on [www.thingiverse.com] or [www.thingiverse.com]


Dario

---

Ormerod 187
Firmware Electronics: Duet 0.6
Firmware Version:1.18.1 (2017-04-07)
Web Interface Version:1.15a
Slic3r 1.2.9a and Simplify3D 4.0.0
[www.dropbox.com]

I found the most problematic sticking with 100% infill... but so far solved with a second fan.

Ormerod forum is a goldmine!
The best community for a 3D printer!


Dario

---

Ormerod 187
Firmware Electronics: Duet 0.6
Firmware Version:1.18.1 (2017-04-07)
Web Interface Version:1.15a
Slic3r 1.2.9a and Simplify3D 4.0.0
[www.dropbox.com]

Quote
Ormerod187
It's not my web site! I'm not David (dc42). I am not involved in any business with him.

Dario

Sorry for the confusion, but thank you for the links
Peter

If you want to use my mini height sensor, you may find this thread helpful [forums.reprap.org].

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
PeterSimpson

Quote
dmould
To set the Z zero position 0.1mm higher, simply send "G92 ZX.X" where "X.X" is 0.1mm higher than the height indicated.

Dave

How, if at all, does the G92 command interact with the other commands for z axis manipulation, such as the G1 Z0 command or the G30 command?
Should the G92 command be executed before any of these other commands (as a command line in Pronterface), or after these commands - used in homing and bed compansation and possibly within a design file in which case it would presumably require editing of the design file. When, and how is the offset created by the G92 command reset to zero?

Thanks
Peter

The G92 command tells the controller what the current position of the relevant axis is, and the G1 command tells the controller to move the axis to the position given. The controller uses the position that it "thinks" the axis is to calculate how far and in what direction to move the axis, so effectively all moves will be relative to the last known position given by a G92 command. The homing macros send a G92 command giving the position that the homing switch triggers for each axis, thus setting the reference used for all other moves. Often this is used to set the zero position - e.g. move the Z height until the nozzle is just touching the bed (using the method I described), and then send "G92 Z0" to tell the controller that the nozzle is at a height of zero. But it can be used to set any height (or XY position). So if you find that the nozzle is a bit too high, then you can see what the current height is, (perhaps 0.25mm for the first layer), and then tell the controller that the height is 0.1mm higher (0.35mm) by sending "G92 Z0.35" If you then send the command "G1 Z0.25" or re-start the print, it will cause the nozzle to print lower by 0.1mm (because you have re-defined the reference). Similarly you can move the XY position by hand to put the nozzle over the geometric centre of the bed and send the command "G92 X100 Y100" to give the controller a reference XY position instead of homing the axis.

Dave

Thank you all for your help. I have ordered the mini height sensor from dc42 and a getting Treito's plastic parts printed (http://www.thingiverse.com/thing:1395051) so hopefully when they arrive, and with your advice, I will be able to start printing!
Peter

A lot has been said above about the problems of getting the PLA to stick to the bed and I am sure we have all experienced these difficulties at some time during printing attempts.

I think first and foremost as many have said above is the nozzle height above the bed surface, I have always used a thin piece of white paper to set nozzle height, this is 0.09 mm thick, in fact a nozzle height of between 0.08 and 0.1 will work just fine.

I start my print head temperature at 225 degrees and drop it to 210 degrees after the base layers.

I always start the print with three outlines offset from the part by 4mm, this gets the extruder and nozzle flowing nicely.

The above setup printing on glass worked most of the time but not always so decided to look at the print bed surface itself as the caption tape is a bit of a nuisance and does need repairing from time to time. To this end I invested in a GeckoTek Build Plate, Link Here.

I have now been printing on the Gecko for nearly a year and to date have not had a single failed print, they always stick! I heat the bed to 50 degrees. The model I bought is one of the HT plates which is supposed to work for ABS as well, although I did not have much success with ABS. It will need a bit of change to your bed setup but is quite easy to do, I will never print PLA on any other surface again!

Brian

I gave up printing on Kapton too. Now I print on plain uncoated glass on my Ormerod. Surface preparation is key. On my delta, I print on PEI.

Edited 1 time(s). Last edit at 12/10/2016 06:22PM by dc42.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Same i always print on just glass ,but i always clean it while its hot(just before it starts printing) with Alcohol.

Quote
dmould

To set the Z height manually, get the bed to print temperature, then move to the centre of the bed (position 100,100). Put a sheet of ordinary copier paper under the nozzle, and while moving the paper back and forth, lower the nozzle in small increments (0.1mm or 0.05mm) using the web interface until you can feel the paper being gripped firmly, but not so tightly that it does not slide at all. You will probably feel the fan vibration through the paper. At that point send the command "G92 Z0" to set it as the zero position. If the print shows that it is still a bit too high, you can repeat the process but this time send "G92 Z0.05" or "G92 Z0.1" Be careful to hold the paper at the edge in such a way that you are not putting any pressure (weight) on the bed. If you need to manually set up the bed compensation points, first set the zero height as above, then use the same paper technique on each of your chosen calibration points, but after finding the height where the paper is gripped, read off the Z height instead of setting it to zero.

The firmware will not normally allow you to lower the nozzle below zero. I therefore usually start off by sending "G92 Z100" to ensure that the indicated position doesn't get to zero before touching the bed.

Dave

After 3 months of struggling, I went back to basics and followed dmould's suggestion for zero-ing the Z axis.
Having fitted the Mini Height Sensor I could now do the calibration in the centre of the bed (as suggested) without having to fiddle about in the corner.
I did exactly what dmould suggested as far as sending the G92 Z0 command. To set this as the home position I raised the nozzle by 5mm then sent the G30 S-1 command to lower the nozzle until the mini height sensor triggered and noted the Z height (1.2mm) which I then put into config.g as 'G31 Z1.2 P500'
The filament still fails to stick.
Out of interest I repeated the procedure then after sending 'G92 Z0' I replaced the paper under the nozzle and lowered it in 0.1mm increments expecting the nozzle to just grip the paper at Z=0.
However, it gripped the paper at a height of 0.4mm which suggests that the Home function is actually setting the height to 0.4mm below Z=0!
I have repeated this a number of times and get the same results!
What is going on here??

What filament are you using? One roll of filament I bought (Jet PLA) fails to stick to anything. OTOH a roll of Rigidink PLA+ I bought sticks so well to both plain glass and PET that I find it unusable

Edited 1 time(s). Last edit at 12/30/2016 03:26PM by dc42.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I am using 1.75mm white PLA from FilamentPrint. It is the reel which was supplied with the kit which I bought from RS components exactly 3 years ago!
which leads me to wonder - There has been a lot of discussion here about the effects temperature and humidity have on the PLA filament breaking.
Could it be that being exposed to typical room temperatures and humidity that the filament has deteriorated to such an extent that it no longer sticks? My filament often breaks between the reel and the extruder during printing (attempts)!

Edited 1 time(s). Last edit at 12/30/2016 05:01PM by PeterSimpson.

There are at least two issues here:

1. Filaments absorb moisture and this affects their printing properties. This is more a problem with ABS than with PLA. But if that filament has been open to the air for 3 years, I suggest you write it off.

2. Some PLA filaments become brittle once off the reel, even after just a few hours. If you can break the filament easily by bending it, unwind it to see if it is more flexible underneath. If the whole reel is brittle, throw it away.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Ok. Thanks
I will get a new reel of filament and see what happens. At least that will eliminate one unknown!

Quote
PeterSimpson
After 3 months of struggling, I went back to basics and followed dmould's suggestion for zero-ing the Z axis.
Having fitted the Mini Height Sensor I could now do the calibration in the centre of the bed (as suggested) without having to fiddle about in the corner.
I did exactly what dmould suggested as far as sending the G92 Z0 command. To set this as the home position I raised the nozzle by 5mm then sent the G30 S-1 command to lower the nozzle until the mini height sensor triggered and noted the Z height (1.2mm) which I then put into config.g as 'G31 Z1.2 P500'
The filament still fails to stick.
Out of interest I repeated the procedure then after sending 'G92 Z0' I replaced the paper under the nozzle and lowered it in 0.1mm increments expecting the nozzle to just grip the paper at Z=0.
However, it gripped the paper at a height of 0.4mm which suggests that the Home function is actually setting the height to 0.4mm below Z=0!
I have repeated this a number of times and get the same results!
What is going on here??

Dunno, but an easy fix would be to just accept it at compensate those 0.4mm in your G31 settings

Erik

Quote
dc42
There are at least two issues here:

1. Filaments absorb moisture and this affects their printing properties. This is more a problem with ABS than with PLA.

Yes - ABS sucks :-)



Erik

Hi Peter,

I'm using 2 Ormerods for a number of years now. I print PLA on a heated bed of 60 degrees Celsius with Kapton sheet, nozzle temperature 205 degrees. Perhaps there are better ways, maybe you don't need the Kapton or this bed temperature, but I printed a total of about 25kgs of filament now and it works for me. So I don't intend to change it.

Reading what has been written above my 2cts:

Cleaning the bed is key!
I use pure Isopropanol. It works best if I clean while the bed is already heated (somewhere between 40 and 60)
Pay attention to what you use to wipe the bed with. A cloth or anything similar is never 100% clean. I 'stole' a roll of kitchen paper towel (I think it's called) from our kitchen. That paper (at least whay I use) is absolutely clean and contains no solvents or other substances.
I once grabbed a roll of toilet paper because my kitchen paper towel ran out and I was to lazy to go downstairs. I had been printing for half a year without any substantial troubles and now suddenly my prints were not sticking to the bed anymore. Not at all! It took me 2 days, I replaced the Kapton twice. Nothing seemed to help. Until I reverted back to the original kitchen paper towel! The toilet paper seems to contain some kind of oil to keep your b#tt soft!

Initial height is key!
First the bed needs to be perfectly level. It is really worth the effort to give that plenty of attention. Bed level compensation is good to get rid of the last tiny differences, but it should already be mechanically level. Differences before electronic compensation shall be less than 0.5mm.
I gave up using automatic sensors, because they don't work for me. And 0.1mm or even 0.05 is far to coarse for me.
My setup procedure:

- Home axes
- Up 1 mm (so the head is 100% certain free from the bed)
- G1 X100, Y100 (center)
- Put some 80g printing paper under the nozzle
- Lower in steps of 0.1mm until it grabs the sheet
- Up 0.1 mm
- Move the X-arm +10mm and -10mm to settle the print head again (because it was pushed up a little by the paper. The friction of cables etc apparently keeps it just a little above the "free hanging" position)
Repeat:
- G92 Z0.02
- G1 Z0
Until it just grabs the paper
- G92 Z0.02 once more
(maybe your last step should be 0.01 or 0.03 or whatever. Experiment what works best. I have two printers and the optimal setting is different for each printer. Don't ask why.)
- Print!

Depending on your Ormerod software level some of the above steps can be grouped by "macro's", so it works faster. The finetuning then does not have to take more than half a minute or so.

Best regards,
Leon

Geronimo! ....well, almost. I have finally got the PLA to stick to the bed!
Thank you for all your suggestions about levelling, cleaning and temperature, all of which I have taken into account.
Having exhausted all your suggestions without any improvement, I looked into the possibility that the bed was not reaching the required temperature. I invested in a thermocouple probe for my multimeter and stuck it to the glass printing surface. With the web interface showing a temperature of 55C the thermocouple was indicating 50C, meaning that I had been trying to print with a bed temperature of only 50C.
I replaced the thermistor (with an Epcos B57861S0103F040 device) and drilled a 2mm hole half way through the aluminium where I fitted the thermistor with heatsink compound to ensure good thermal contact between the thermistor and the aluminium plate. However, all this made no significant difference - the thermocouple was still indicating 5C below the thermistor.

I don't know whether this is significant, but one of my modifications to the printer was to replace the 3mm aluminium bed with one made of 6mm aluminium, arguing that it would give a more rigid bed, and that being of larger mass the heat would be distributed more evenly over the area of the bed.

Not being able to resolve the discrepency between the thermistor and thermocouple, and trusting the thermocouple more than the thermistor, I increased the temperature settings in my design file.
Following the recommendations above I set the bed temperature to 65C (actually 60C) and the nozzle temperature to 205C for the first layer, reducing to 60C (actually 55C) and 195C for subsequent layers.

The PLA now sticks to the bed!!!!!!!

The reason I say "...well almost" is that after printing the first 10 or so layers I could see (and hear) the nozzle bouncing over the previous layers suggesting that the nozzle height was lower than the height of the previous layer, and it seemed to get worse as the printing progressed - to such an extent that I had to do an emergency stop after 27 layers.
The object I am trying to print is the 'Calibration 200 x 200.g' file supplied with the original kit. The nozzle is raised by 0.3mm between layers and the nozzle size is 0.3mm ....

... I have just discovered that the nozzle mount has parted company from the z-axis bearing. I wonder why!!

Glass doesn't conduct heat very well, so you get a temperature drop of at least 5C across it at 55C, and 10C at 100C. I print PLA at 65C indicated bed temperature on my Ormerod.

If you want a filament that sticks very well, try PLA+ from rigidink. I print PLA on plain glass, and PLA+ sticks to it so well that I can't get it off.

The STL for the X carriage printed part was modified some time ago to have a pimple that locks into the slot in the bearing.

Edited 1 time(s). Last edit at 01/07/2017 02:57PM by dc42.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].