3D printing problem - Wanhao Duplicator I3

[figworthy]

When I set this up last month, it successfully printed the sample item that comes with the software.

 

Now, I've had several attempts at printing my first design, and they've all been a failure.  In a couple of cases, the filament has failed to stick to the bed either completely or has come loose almost immediately, leaving an unholy mess of fused filament (even after I'd carefully set the height of the deck as per the instructions).  However, on a couple of occasions, things have been a bit more subtle.  The picture below shows what is happening.

 

 

I'm trying to print a section of fencing, which is intended to go on a slope, hence the parallelogram shaped base.  As you can hopefully see, the right hand side is sticking down OK, but on the left hand side, the bottom edge has lifted off the bed.The blue tape is freshly laid, and was dusted off immediately before the printer started.  The filament is the PLA stuff that comes with the printer, and the temperature settings are the default for PLA.

 

Why is this happening, and how do I stop it ?

 

 

Thanks

 

Adrian

[thegavs]

Looks like a bed leveling issue, try to relevel the bed.

 

Also I find printing with a skirt helps.

[Marbelup]

If, as you say, the bottom edge is tapered, then you need a support structure below the bottom edge as the printer can't print something which starts in mid air. Your printer software will probably be able to generate supports automatically, although you may well find it adds supports where not really needed. Another alternative is to create supports as part of your 3D drawing (e,g. on a different layer).

[figworthy]

Looks like a bed leveling issue, try to relevel the bed.

 

Also I find printing with a skirt helps.

 

The bed has been re-leveled every time I started a print.

 

Sorry, "Printing with a skirt" ? Not a phrase I've come across before.

 

If, as you say, the bottom edge is tapered, then you need a support structure below the bottom edge as the printer can't print something which starts in mid air. Your printer software will probably be able to generate supports automatically, although you may well find it adds supports where not really needed. Another alternative is to create supports as part of your 3D drawing (e,g. on a different layer).

 

I'd already rotated the design through 90 degrees, so the fence is being printed as though it was laid on the ground.  My comment about the parallelogram is because the fence panel is intended to go on a slope, rather than on the flat (which would make it a rectangle).

 

Thanks

 

Adrian

[thegavs]

The bed has been re-leveled every time I started a print.

 

Sorry, "Printing with a skirt" ? Not a phrase I've come across before.

 

 

 

 

In your slicer there are options for build plate adhesion or something like that.  I use Cura and there are 3 options raft, brim, skirt and none.  Putting a skirt on makes the nozzle draw an outline around the part but not touching it.  Helps as often the first few cm are not a good as the rest but the skirt is sacrificial.

 

G

[figworthy]

In your slicer there are options for build plate adhesion or something like that.  I use Cura and there are 3 options raft, brim, skirt and none.  Putting a skirt on makes the nozzle draw an outline around the part but not touching it.  Helps as often the first few cm are not a good as the rest but the skirt is sacrificial.

 

G

 

Thanks for the explanation.

 

I'm using Cura (the version supplied with the printer), and whilst it doesn't appear to have the above options, it does start by putting down a sacrificial layer and then printing on top of that.  It is this sacrificial layer that isn't being sitting on the bed properly.  If I let it continue, where the layer is good, the print it good, the problem is the rest of it end up looking like a plastic model that has been melted.  The picture shows it several slices before it starts to print the fence.

 

Adrian

[thegavs]

https://ultimaker.com/en/products/cura-software

 

is the later versions well worth upgrading to 2.7 which I use with no problems.

[Fen End Pit]

I've had similar issues with my wanhao duplicator i3 plus when the bed is slightly too low. I tend to find when using a raft that going too high is better than too low. leveling with a paper thickness rather than a business card seems too work.

 

David

[Spitfire2865]

In my experience, ditch the tape and just use a glue stick, spreading liberally over the area which will hold the print.

Cleans up relatively easily with a scrub of hot water and soap, if its needs cleaning at all.

But yeah, it definitely looks like a level issue, which might be stemming from your use of tape or incorrectly leveling the bed.

[figworthy]

I've had similar issues with my wanhao duplicator i3 plus when the bed is slightly too low. I tend to find when using a raft that going too high is better than too low. leveling with a paper thickness rather than a business card seems too work.

 

David

 

Thanks David.

 

I've been round all four corners of the deck and the middle, 2-3 times checking the clearance (with normal printer paper), and I can just move the paper.  I'll try it again with it even tighter, but that is likely to be Friday at the earliest.

 

Adrian

[Hyper Aus]

The gaps between the pieces of tape aren't going to help either. I had similar issues with my delta printer.

 

I now have 100mm wide kapton tape but it isn't the best for PLA. More suited for ABS printing at higher temps.

 

A lot of people recommend using a piece of glass on top of the heated bed and using hair spray as the adhesive.

[AndyID]

Assuming the bed is level I think you might just be having an adhesion problem.

 

Blue tape works quite well if you sand it down slightly between prints. I use fine grit wet and dry paper for that (use it dry.)

 

The other thing that's critical is to get the first layer right (again, assuming the bed if properly leveled). I cheat the height of the extruder so that it's really slightly closer to the bed than it "thinks" it is. That helps the first layer to adhere but it does leave a little flash around the edge of the printed part.

Edited October 7, 2017 by AndyID

[figworthy]

I had another chance to have a look at this today.

 

I re-taped and then re-levelled the bed, and set it off, and at the first pass, I had adhesion problems.  So I removed the tape, levelled the bed again, and set it running.  About half an hour later I had a section of fencing.  I then repeated the process with another section of fencing (for the other end of the platform), and that worked as well.

 

 

And here it is, propped up with a bit of blue tack.  It looks as though the lower of the cross rails is too high (compared to the existing bit of fence), and of the wrong depth, but apart from that, I think for a first attempt, it isn't that bad.  I hadn't noticed the height discrepancy until I saw the picture..

 

The print did need a bit of cleaning up.  There was a bit of filament between the slats, both at the top and the bottom from where the head moved between slats, and a couple of other places, but that was relatively easy to do.  Looking at the picture, it looks as though the fence isn't the only thing that needs cleaning up.

 

Thanks for the advice and assistance.

 

[edit]

I forgot to mention the gaps in the tape.  When I put the tape on, the edges were tight together, but that was with the plate cold.  As the plate warms, it expands, but the tape doesn't (or not as much), so gaps appear.

 

Adrian

Edited October 7, 2017 by figworthy

[AndyID]

Adrian,

 

Do you have a glass plate on the heated bed? If you do you should not need tape or anything else. I give the glass a good clean with a paper towel and methanol between prints.

 

Andy

[figworthy]

Adrian,

 

Do you have a glass plate on the heated bed? If you do you should not need tape or anything else. I give the glass a good clean with a paper towel and methanol between prints.

 

Andy

 

No I don't.

 

A number of glass plates (a bit smaller than the printer bed) were left behind in the house by a previous owner, but I don't know if they would be any good for this job.  They are 165 x 262 x 8 mm.

 

Adrian

[AndyID]

No I don't.

 

A number of glass plates (a bit smaller than the printer bed) were left behind in the house by a previous owner, but I don't know if they would be any good for this job.  They are 165 x 262 x 8 mm.

 

Adrian

 

I suspect 8 mm is too thick. I'm running a Prusa I3 which I believe is pretty much the same as your printer. They recommend 1/8 inch thick glass (about 3 mm).

 

I've found it's very important to get good repeatability on the Z axis reference (microswitch). If it's sloppy the first layer thickness can vary from print to print and that messes up adhesion. I made a simple modification to the z-axis microswitch. I'll post a pic later.

 

Andy

[AndyID]

Here's the pic.

 

 

Your printer might be a bit different and it might be better than mine, but this should give you an idea of what I'm on about.

 

I added the screw and set it up to hit the microswitch. That lets me make fine adjustments to the Z-axis zero position by turning the screw by fractions of a turn. The screw is held in place by a piece of PLA attached to the vertical carriage with CA adhesive.

 

It's not very obvious from the pic but the end of the screw is set-up to hit the microswitch at its button rather than at the end of its activator arm. That reduces uncertainty about where the switch will toggle.

 

Andy

 

EDIT: I think I need to do a bit of dusting.

Edited October 8, 2017 by AndyID

[figworthy]

I suspect 8 mm is too thick. I'm running a Prusa I3 which I believe is pretty much the same as your printer. They recommend 1/8 inch thick glass (about 3 mm).

 

I've found it's very important to get good repeatability on the Z axis reference (microswitch). If it's sloppy the first layer thickness can vary from print to print and that messes up adhesion. I made a simple modification to the z-axis microswitch. I'll post a pic later.

 

Andy

 

Thanks.  I had a feeling that my glass would be too thick.  3mm seems rather thin for most uses.  There is (or at least used to be) a company doing "glass stuff" the other side of town, I could ask them if they have an offcut of the right size.

 

Here's the pic.

 

DSCN3455.JPG

 

Your printer might be a bit different and it might be better than mine, but this should give you an idea of what I'm on about.

 

I added the screw and set it up to hit the microswitch. That lets me make fine adjustments to the Z-axis zero position by turning the screw by fractions of a turn. The screw is held in place by a piece of PLA attached to the vertical carriage with CA adhesive.

 

It's not very obvious from the pic but the end of the screw is set-up to hit the microswitch at its button rather than at the end of its activator arm. That reduces uncertainty about where the switch will toggle.

 

Andy

 

 

Thanks.  Mine appears to be the other way up (the Z axis motors are at the bottom, so the microswitch acts at the top of the travel, I haven't seen a lower end one yet.

 

Adrian

[AndyID]

Thanks.  I had a feeling that my glass would be too thick.  3mm seems rather thin for most uses.  There is (or at least used to be) a company doing "glass stuff" the other side of town, I could ask them if they have an offcut of the right size.

 

 

Thanks.  Mine appears to be the other way up (the Z axis motors are at the bottom, so the microswitch acts at the top of the travel, I haven't seen a lower end one yet.

 

Adrian

 

I bought the glass at a local glazier. They did charge me to cut it. I imagine the thickness is something of a compromise. Thicker will resist bending more but it will also take longer to come up to temperature. You could always try the 8 mm stuff and see how it goes.

 

 

The switch on your Z-axis might just be some sort of limit switch. Your printer might be using a different method to determine Z-zero.

 

Andy

[AndyID]

I wondered if it might be possible to print lattice signal posts, so I took a shot at it. Needs work.

 

In terrifying close-up -

 

 

It's was actually printed flat then folded.