Problem Printing

[figworthy]

Wanhao Duplicator I3

 

195C extruder temp

50C bed temp

 

I'm setting the clearance on the deck to be one thickness of standard printer paper, before heating, then cleaning the deck with meths, so hopefully I've got a clean level deck.  I'm also leaving the deck in pre-heat for a while before printing (I've seen suggestions elsewhere that the plate may not be heating universally, so this gives it a chance to catch up).

 

However, I'm having problems with my prints.  I have a regular thing where it seems to not quite print the first bit of the skirt, but otherwise is OK.  However I've had four attempts today at doing one print, attached is the most successful (or that should that be the least insuccessful).

 

 

The image is show with the front of the printer at the bottom.  The area in the blue rectangle is basically OK, apart from some missing diagonals, and an inconsistency in their diameter, and the bottom left corner of the rectangle is pretty much where the printer started laying down filament, although watching it, it looks as though it should have started a bit further to the left.  The centre and left hand side however are a complete mess.  The up and downs of the first layer were initially binding at the back, but not at the front, and the filament started lifting off the bed before the printer started to lay the diagonal layer.  Whilst today's efforts are an extreme, I regularly see less than perfect printing on the left hand side, but the printer usually manages to overcome that by the time it has finished the skirt. This is irrespective of where that left hand side is (e.g. whether the print is a narrow front to back, or a wide side to side)

 

I've tried using blue tape, but success rates with that are mixed.

 

One thing that might be significant, is that if I place a straight edge (300mm steel rule) across the deck, then in some places, it appears to be slightly dished, but I'm not sure that it is consistent.

 

I've spent quite a bit of time trying to find solutions to this, but I've run out of inspiration.  Any ideas welcome.

 

Thanks

 

Adrian

[Robin2]

I got better results by raising the temperature from 195 to 197.

 

I am using a piece of polycarbonate (NOT acrylic!) for the bed (and not heating it at all). The polycarbonate sits on the aluminium bed. I put a couple of pieces of paper under the polycarbonate at the centre of the aluminium bed to counteract greater clearance at the centre than at the edges.

 

I use Slic3r to do my slicing and I always use the option to print a skirt around the object as that gets the plastic flowing. If the skirt is not evenly printed it can be an indication of a problem at an early stage.

 

Provided I clean the polycarbonate with meths I have had no adhesion problems. However the polycarbonate is at risk of scratching with a knife when removing parts and of being marked by the hot nozzle if it comes in contact. I had hoped to use glass, but the adhesion was lousy.

 

...R

[AndyID]

Wanhao Duplicator I3

 

195C extruder temp

50C bed temp

 

I'm setting the clearance on the deck to be one thickness of standard printer paper, before heating, then cleaning the deck with meths, so hopefully I've got a clean level deck.  I'm also leaving the deck in pre-heat for a while before printing (I've seen suggestions elsewhere that the plate may not be heating universally, so this gives it a chance to catch up).

 

However, I'm having problems with my prints.  I have a regular thing where it seems to not quite print the first bit of the skirt, but otherwise is OK.  However I've had four attempts today at doing one print, attached is the most successful (or that should that be the least insuccessful).

 

P1010005a.jpg

 

The image is show with the front of the printer at the bottom.  The area in the blue rectangle is basically OK, apart from some missing diagonals, and an inconsistency in their diameter, and the bottom left corner of the rectangle is pretty much where the printer started laying down filament, although watching it, it looks as though it should have started a bit further to the left.  The centre and left hand side however are a complete mess.  The up and downs of the first layer were initially binding at the back, but not at the front, and the filament started lifting off the bed before the printer started to lay the diagonal layer.  Whilst today's efforts are an extreme, I regularly see less than perfect printing on the left hand side, but the printer usually manages to overcome that by the time it has finished the skirt. This is irrespective of where that left hand side is (e.g. whether the print is a narrow front to back, or a wide side to side)

 

I've tried using blue tape, but success rates with that are mixed.

 

One thing that might be significant, is that if I place a straight edge (300mm steel rule) across the deck, then in some places, it appears to be slightly dished, but I'm not sure that it is consistent.

 

I've spent quite a bit of time trying to find solutions to this, but I've run out of inspiration.  Any ideas welcome.

 

Thanks

 

Adrian

 

Hi Adrian,

 

There are many little things that can upset a 3D printer so it's hard to tell exactly what's going on with yours without a lot of information. I'm using a slightly different printer, so please ignore any of the following if it does not apply.

 

I don't think you want so much clearance between the nozzle and the bed when you "zero" the Z axis. If you can get hold of some metric feeler gauges, first zero the Z axis (so that it hits the limit switch) then using the manual controls step the Z axis up to, say, 0.2 mm. Now test the gap with your 0.2 mm feeler so that it just "tickles" the nozzle and the bed. Keep adjusting the limit switch until it does.

 

That way when the controller finds the zero vertical datum the nozzle should actually be just touching the bed. The software only extrudes filament from the nozzle after it has raised the nozzle to the height of the first layer.

 

Another thing that you might do is try printing five test boxes as one print job. Position one in the center of the bed and the other towards the four corners of the bed. There's not much point in trying to print anything complex until you can get all the boxes to print consistently.

 

Regards,

Andy

[Robin2]

Just remembered ... when setting the gap between the nozzle and the bed make sure there is not a piece of hard plastic sticking out of the nozzle. That would mean that the real gap was much bigger than you thought.

 

I set my gap at the thickness of a piece of regular 80gsm paper.

 

...R

[figworthy]

Thanks to Robin and Andy for their comments.

 

I thought I'd have another go with it this morning (hoping that a good night's sleep might have left it in more co-operative mood), however when I put it into pre-heat, I noticed that whilst the extruder was warming up, the bed wasn't, it remained at the ambient temperature.  Turning it off and on again didn't make any difference.  As is still less than a year old, I shall be having a chat with the supplier (Amazon).  What I didn't notice yesterday was what the bed temperature was when I gave up.

 

With that in mind, if I'm offered the choice between a refund and a replacement, should I go for the former, and then get a genuine Prussa ?  Whilst it is a useful thing to have, it's not something that is getting continuous use.

 

Adrian

[Robin2]

I have an ANET A2 which I bought last October. It was cheap and I am very pleased with it.

 

...R

[big jim]

Check the connections to the bed aren’t loose before writing the printer off or looking at an exchange

 

Regards the initial problem, I had a similar issue when trying to print a raft on a print I was doing with my Aldi printer (which is the i3 with a different name) and i think it was simply the bed wasn’t completely level so when it come to put the next layer down it also pulled up the previous one as it caught on the extruded, once that happened there was no going back!

 

I have found that adding blue low tack masking tape to the bed also helped with futher prints as they seem to stick to it better

[figworthy]

Check the connections to the bed aren’t loose before writing the printer off or looking at an exchange

 

Regards the initial problem, I had a similar issue when trying to print a raft on a print I was doing with my Aldi printer (which is the i3 with a different name) and i think it was simply the bed wasn’t completely level so when it come to put the next layer down it also pulled up the previous one as it caught on the extruded, once that happened there was no going back!

 

I have found that adding blue low tack masking tape to the bed also helped with futher prints as they seem to stick to it better

 

Thanks Jim.

 

I've had a look, and it isn't a loose connection, it is a broken one !.  One of the power leads has broken off where it is (was) soldered onto the plate.  I'm guessing that it is a metal fatigue issue as the wires bend when the plate slides backwards and forwards.  In theory that is easy to fix, but it is "big soldering iron" job, and I don't have one.  But I think I might know someone who does.

 

Regarding the blue tape, sometimes that works for me, other times it doesn't, and there doesn't seem to be a pattern to it.

 

Adrian

[Robin2]

as the wires bend when the plate slides backwards and forwards. 

 

That's part of the reason why I don't use the heated bed

 

...R

[eldavo]

As has been suggested trying using the thickness of a sheet of normal printer paper as your feeler gauge when levelling. Almost every problem comes down to bed levelling unfortunately. It's a pain to get right on a lot of printers.

 

If you are using PLA then try a nozzle temperature of 200 with or without heating the bed (50 degrees is normally fine). I always use ordinary masking tape or Kapton tape on my print bed but blue painters tape is fine. Wipe the surface of the tape with some IPA before you start printing to make sure there is no sign of grease or contamination.

 

Most Prusa i3 designs can be made to give good results, the design is pretty good, so don't give up on it too soon. Best of luck.

 

Cheers

Dave

[Fen End Pit]

I have a Wanhao Duplicator i3 plus.  Looking at your picture it doesn't appear as if the first initial outline of the shape was laid down properly. As a result the diagonals of the raft had no 'ends' to join up with. It might be worth look when the job starts whether there is a delay before the filament actually starts getting extruded.

 

David

[figworthy]

I have a Wanhao Duplicator i3 plus.  Looking at your picture it doesn't appear as if the first initial outline of the shape was laid down properly. As a result the diagonals of the raft had no 'ends' to join up with. It might be worth look when the job starts whether there is a delay before the filament actually starts getting extruded.

 

David

 

Thanks David, that is exactly what appears to be happening.  The extruder head is moved into position, but it always (every print ever done) appears to move some distance from what I feel ought to be the first point at which it lays down filament to the point at which filament does start to appear.  I was starting to wonder if it was deliberate, so as to give an easy point at which to get the scrapper in to lift skirt off the bed once finished.

 

Adrian

[Robin2]

, but it always (every print ever done) appears to move some distance from what I feel ought to be the first point at which it lays down filament to the point at which filament does start to appear.  I was starting to wonder if it was deliberate, so as to give an easy point at which to get the scrapper in to lift skirt off the bed once finished.

 

Can you post a photo of the failed print while it is still on the print bed - i.e. with the skirt and everything else in place.

 

And there are dozens of helpful YouTube videos about 3D printing, including problem solving

 

...R

Edited January 30, 2018 by Robin2

[AndyID]

Thanks David, that is exactly what appears to be happening.  The extruder head is moved into position, but it always (every print ever done) appears to move some distance from what I feel ought to be the first point at which it lays down filament to the point at which filament does start to appear.  I was starting to wonder if it was deliberate, so as to give an easy point at which to get the scrapper in to lift skirt off the bed once finished.

 

Adrian

 

Adrian,

 

Try enabling a "brim" around the print. That will flush out the nozzle before it starts the real print job. I usually set the brim to make three circuits around the job. And if the brim is not adhering properly by the second circuit I abort the job.

 

Andy

[Robin2]

Try enabling a "brim" around the print. That will flush out the nozzle before it starts the real print job. I usually set the brim to make three circuits around the job.

In Slic3r that is referred to as the "skirt". I have been assuming that it is what @figworthy means when he says "easy point at which to get the scrapper in to lift skirt off the bed once finished"

 

...R

[Fen End Pit]

You could try adding some custom Gcode to do a 'nozzle wipe' prior to starting your job. I found a few articles online with some examples.

The standard Cura install for the Wanhoa gives you the options for skirt and raft, but in the case of your print with raft is failing and you need something to push some filament out of the nozzle before the raft starts to print.

 

David

[AndyID]

In Slic3r that is referred to as the "skirt". I have been assuming that it is what @figworthy means when he says "easy point at which to get the scrapper in to lift skirt off the bed once finished"

 

...R

 

Ooops! My mistake - you are quite correct.

 

Andy

[figworthy]

Can you post a photo of the failed print while it is still on the print bed - i.e. with the skirt and everything else in place.

 

And there are dozens of helpful YouTube videos about 3D printing, including problem solving

 

...R

 

Not at the moment.   As mentioned up thread, one of the power leads to the heater bed has broken off, and my soldering irons aren't up to the job of remaking the join.

 

What probably won't help is that at the moment I've only got black filament, and that on a black bed won't show up very well.

 

Adrian

[figworthy]

You could try adding some custom Gcode to do a 'nozzle wipe' prior to starting your job. I found a few articles online with some examples.

The standard Cura install for the Wanhoa gives you the options for skirt and raft, but in the case of your print with raft is failing and you need something to push some filament out of the nozzle before the raft starts to print.

 

David

 

Once I'm back in business, I'll have a look at that.

 

In Slic3r that is referred to as the "skirt". I have been assuming that it is what @figworthy means when he says "easy point at which to get the scrapper in to lift skirt off the bed once finished"

 

...R

 

I'm still getting my head around the terminology of this.  What I'm calling the skirt is a four layer base where the first layer is a broad weave, followed by another broad weave at 45 degrees, followed by two full layers, one front to back, one side to side, with the print itself starting on top of that, but taking up a smaller area.  What is shown in the picture above is where the first two layers have gone horribly wrong.

 

Adrian

Edited January 31, 2018 by figworthy

[Robin2]

I'm still getting my head around the terminology of this. 

I don't want to give the impression that I am an expert on it. I have selected the option in Slic3r that causes it to print two rows of a circle (approx) about 10mm outside any part of the object that I am making. Laying down the circle gives lots of time for the plastic to start flowing and usually shows up adhesion problems before time or plastic is wasted. See this image taken from Slic3r.

 

 

...R

[Marbelup]

For what it is worth, I have discovered that some blue tapes are better than others. After using 3M 2093 tape for some time, the next roll I bought was 3M 2090 which has significantly better adhesion. I think the difference is due to the slightly textured surface.

 

I use a Makerbot dual head printer, with original aluminium platform. I mainly use ColorFabb PLA/PHA blend filament, which I found has minimal warping for large prints, and sometimes pure PLA.

[AndyID]

Hi Richard,

 

I have a heated glass bed but I've also printed on an unheated glass bed with blue tape. Both methods seem to work quite well. One idea I got from the web is to rub the tape with very fine sand paper between prints to remove residue and key the surface a bit.

 

Andy

[eldavo]

Once I'm back in business, I'll have a look at that.

 

 

I'm still getting my head around the terminology of this.  What I'm calling the skirt is a four layer base where the first layer is a broad weave, followed by another broad weave at 45 degrees, followed by two full layers, one front to back, one side to side, with the print itself starting on top of that, but taking up a smaller area.  What is shown in the picture above is where the first two layers have gone horribly wrong.

 

Adrian

 

That sounds like a"raft".  Often used to help prevent warping of the print.  Personally I rarely use a raft but always use a "skirt" and a "brim".  The skirt runs one or more lines of plastic around the outside of the print but not part of it.  This gets the extruder going before starting the print proper.

 

The "brim" (think of the brim of a hat) lays down a number of loops of filament around the print and attached to it to help with adhesion and lessen warping.

 

None of these will help unless the bed is correctly levelled and clean. Personally I mostly use ordinary masking tape on the bed to help adhesion but if I want a very smooth finish I use Kapton tape.

 

Cheers

Dave

[AndyID]

 I mainly use ColorFabb PLA/PHA blend filament, which I found has minimal warping for large prints,

 

I had not heard of that filament before. Sounds like it might be great for printed turnouts (PLA is OK, but something with a bit more strength would be better.) I've ordered some to try it.

 

Andy

[AndyID]

I mainly use ColorFabb PLA/PHA blend filament

 

That was quick! It arrived today. I printed some track samples and it's definitely stronger than pure PLA.