Heated Print Bed "Welding Prints" and Tolerance Issues

[huffworks3d]

I agree with the other users. Tune your Flow % in Cura down a bit and that should come out better. I run around 85% on nearly all my prints. May be a bit different for various filaments. But turning up the infill to 50% or so will help your top layers still come out nice.

[shall52]

Hi Jackson,

I have a few things for you to try.

Make sure the head to bed calibration is correct. It could be because the head is too close to the bed, causing the first layer to be flattened and fusing things together. I use Simplify3D which gives me much more control of the machine. You should check the first layer height, width and speed setting. Also, I’ve had to play with the Extrusion Multiplier setting and bring it down to as much as .8.

Try starting the print and stop it after the first layer to see if any of these things help.

Talk to you later,

Steve Hall

[Jackson_Moody]

Okay, thanks for the reply! I found in Cura that the nozzle WAS buried a little deep into the bed, and the starting layers were becoming squished. I can fix this problem in Cura. As for the first layer height width and speed, where do you find those settings in Cura? The extrusion multiplier also sounds like a great idea, and I will try that out.

Thanks for the quick response!

Jackson

[Jackson_Moody]

Thanks for the quick reply! Turning down the flow rate in Cura definitely sounds like a good idea. I will definitely try this!

Thanks for the suggestion!

Jackson

[Jackson_Moody]

Thanks for the reply!

I will definitely try to print with a lower extrusion multiplier, as a bunch of users seem to be suggesting this. As for the BuildTak, I haven’t heard of this idea before! However now that I think about it, having something on the bed itself would be a good idea! Do you think regular Painter’s tape would work? I know I have some in the garage…

Thanks for the great suggestions!

Jackson

[Jackson_Moody]

Thanks for the detailed reply! Man, everybody on 3D Hubs talk is so helpful!

As for Simplify 3D, I am definitely thinking about it. However, it still seems like a rather large investment for a software. I have also seen forums that say Simplify 3D has some trouble working with the Lulzbot Mini. For Simplify 3D, I would love to hear from a fellow Lulzbot Mini owner like you. If it isn’t asking too much, could you give me a rundown of how Simplify 3D works on a Lulzbot Mini?

As for the HIPS, I am open to other filaments, but I would prefer not to use eSun PLA. It is probably just because of eSun’s really cheap filament, but for some reason their PLA worked terribly for me! Maybe I will try Colorfabb or something.

In terms of the Z-Offset, are you reffering to the Initial layer width? If so, I will definitely try tweaking this, as it seems a little off. If not, which setting are you reffering too? As for the first layer width, what do you recommend changing it to? I have heard a wide variety of numbers, and I would love your opinion.

Thanks so much for the wonderful reply! You have really helped me a lot, and I can’t wait to try your suggestions!

Thanks Again,

Jackson

[Jackson_Moody]

Thanks for the reply!

I haven’t tried printing the 20mm cube, but that sounds like a good test print. I have heard about the Flow Multiplier, and turning it down sounds like a great idea!

Thanks for the suggestion,

Jackson

[Jackson_Moody]

Thanks for the reply!

I think my nozzle is at the right temperature, because HIPS has to be printed pretty hot. As for the fan, I will definitely look into turning up my cooling!

Thanks for the great suggestions!

Jackson

[Jackson_Moody]

Wow! I have received so many responses! This is my first time using 3D Hubs Talk as a support option, but it has worked really well! I am going to try every single response right now on my printer, until one works. I will let you know my results shortly.

I would also like to thank each and every one of you for at least taking the time to read this support post. I know all of you probably had better things to do, and I really appreciate your help! This issue has been bothering me for a little while, but I can’t wait to try your responses!

Thanks so much everybody, you can’t possibly imagine how much this helps me.

Thanks Again!!

Jackson

P.S Yeah, I know that sounded really sappy. But I would really like to thank everyone for all their amazing support.

[SSVT]

Let me prioritize my reply here:

Z-Offset:

Take a look at this thread here: https://forum.lulzbot.com/viewtopic.php?f=43&t=2494

The setting you are looking for is under Machine>Machine Settings>Z-Offset (mm) in Cura. I had to add just over a single layer height to fix the problem. You can also permanently adjust this in the firmware of your printer, but I was too scared to try it back then.

First Layer width and Height:

These are advanced settings under Cura. They are called Initial Layer Line Width (%) and Initial Layer Thickness (mm). Set the thickness to 0.0 or to the thickness of your normal layers(The tool tip will tell you those do the same thing). Set the Width to 100%. Beefier first layers help with adhesion in the same way printing with a brim does, more surface area to stick. But for mechanical parts, this ruins accuracy. Simplify 3D, for what it’s worth, seems to handle the calculations for the height a lot better than Cura, I’m not familiar with the Cura source code so don’t quote me, it could be they’re compensating for that thickness change too, but it caused me a lot more headaches with Cura.

That brings me nicely to Simplify 3D…

It works perfectly, right out of the box with the Lulzbot Mini. The one gotcha, is that for some reason they are using what I can only assume is an older out dated version of the auto-leveling sequence before the print starts. The major difference is that after the nozzle wipe, it pauses over the first contact point and waits for the extruder to reach a new temp, about a 20 second pause. Sometimes this little pause is enough to ruin the leveling sequence, driving the nozzle into the metal disk. It’s a pain when it happens, but it’s pretty rare. I’ve had it happen with Cura too, but it usually just means I need to replace the wiper pad. You can update this sequence pretty easily in the software, it’s just not done for you.

Other than that one thing, S3D works just fine on the Mini, and it works just like it does on any other printer. You can print directly from it while tethered, so it’s a drop in replacement for Cura.

S3D is worth the money, only if you frequently run into problems with Cura. Especially things like thin walls, or support sticking to the model. If you’re making stuff that works well with Cura, just stick to that. I’m perfectly happy with my purchase of the software, but I don’t think it’s so much better that I would say you definitely have to buy it.

Oh and as for filaments, that’s another lesson that took me way too long to learn. It turns out that you do tend to get what you pay for, the cheaper stuff is just that. I haven’t tried ColorFabb, though I’ve heard good things. I use Verbatim PLA, and I buy it on Amazon. The stuff is really really good. The difference between it and something like eSun is night and day. It’s also twice as much for a 1kg spool. I’ve found the same for ABS and HIPS. You still have to do your research, but in general I’ve found the ‘higher end’ filaments are worth their weight in plastic.

-James

[SSVT]

Every single one of us here has been exactly where you are now Jackson. Soon you’ll be an expert on all the things you’re struggling with today an then you will get a chance to pay the community back.

-James

[Jackson_Moody]

Wow! Thanks for the detailed reply James! I really appreciate the support

I will try and post my replies to your replies here. (I know that sounds weird)

As for the Z-Offset, mine was set to 0. Is this normal? If so, should I increase it to .2? I am not quite sure what you meant by “a single layer height” I will definitely try adjusting the Z-Offset and Flow Rate, as that seems to be what a lot of people are suggesting.

In terms of the First Layer Width and Thickness, I had already set the Thickness to 0, as I had heard this would help on other forums I had read. With the First Layer Width, mine was set to 150. You were suggesting I turn this down to 100?

Finally, with Simplify3D, I am leaning towards buying it, just because of the reviews I have read. I am definitely having trouble with support material in Cura, and I have heard that Simplify 3D is very good with support material. I haven’t had too many problems with thin walls, but I have had a few.

Wait, and for the Filaments, I have already ordered some Colorfabb XT for my printer, which has gotten some great reviews. I haven’t heard of Verbatim PLA, but I will check it out.

Thanks again for the SUPER detailed reply! All this support is awesome!

Jackson

[stopaginn]

Hey there,

If your model can support it, I put a .5mm or bigger parameter chamfer around the edges that contact the build plate. This lets the melted plastic spread, but under the outline of the model. It doesn’t have to be .5, just adjust what works then trim the excess spread.

Also, look at FLEX3D.com. I just received a build plate that will stick any plastics without heat and you lift it off with your print attached then twist or bow the build plate to remove the parts. They have all different sizes to choose from.

Jim

[shall52]

I just received 2 FLEX3D plates too. Firing it up with an ABS print right now.

I hope it works as good as they say.

Steve

[Jackson_Moody]

Thanks for the reply Jim! I will definitely try adjusting my parameter chamfer, and see what that does!

As for FLEX 3D, I have heard good things about it! I might consider ordering one just to see how it performs on my machine.

Thanks Again for the great reply!

Jackson

[SSVT]

Careful with this Jackson. Fleks3D is not compatible with the either the PEI print surface on your heated bed, or the automatic leveling features of the Lulzbot Mini. You would need to do some serious modifications to try that out.

-James

[SSVT]

Hi Jackson,

Sorry for the delay. If you looks at the materials that Aleph Objects sent along with your printer there is a check sheet signed by the person who calibrated your printer. One of the values on that sheet was the Z-Offset that is hard-coded into your firmware. It’s slightly different for every Mini. What I would do is carefully watch the printer as it’s laying down plastic on the first layer, if it looks like the nozzle is too close or too far from the print bed, then adjusting the Z-offset in Cura is an easy way to fix that. Adjusting the filament diameter and feed % will sort of fix that problem too, but you won’t actually be fixing the root cause, just doing a work around, that will have a negative effect on all layers but the first layer. The Z-Offset parameter is how you fix height problems for the first layer specifically, which seems to be a good portion of your problem.

TLDR; Fiddle with it a bit, try different values, see if it improves.

Seems like you’re making progress. Let us know how it goes.

-James

[shall52]

I just tried the Fleks3D on my Lulzbot TAZ5 and didn’t turn on the heated bed. Of course I first tried a hard print in ABS and couldn’t get the first layer to stick. I’m a little discouraged with it at this point and might have wasted my money.

Any suggestions?

Steve

[SSVT]

I don’t want to come off as too negative, but I really seriously doubt you’ll get better results with the Fleks3D plates than you do with your heated bed printing in ABS. The problem with ABS prints sticking, has nothing to do with adhesion, or stickiness if you will. The problem with ABS is that as it cools the material shrinks, quite a lot. This causes the plastic to rip itself free of the build plate and warp pretty badly, the best way to combat this, no the only way to combat this, is to control the cooling process. A heated bed keeps the plastic from shrinking on the bottom couple layers, and thus it sticks well. A heated build chamber would keep the whole part from shrinking too quickly, and the deformation would be nice and uniform.

TLDR; No matter what marketing tells you, nothing beats heat for ABS.

And just in case this offended anyone, I’m not saying it’s impossible to print in ABS without a heated bed or build chamber, there is plenty of evidence of people doing just that, but you need to pay very careful attention to the entire process, including the model geometries you are printing.

-James

[thormj]

Out of curiosity, why are you using HIPS?

I’ve found:

PLA - Best dimensional accuracy, but shatters

ABS - Tougher, can warp a bit. Wears better than PLA.

Nylon - Really tough, tends to warp. I swear by Taulman.

HIPS - Nice dimensionally, nice quality, and ABS/PLA stick to it. But brittle…

I got HIPS originally for doing “lost foam casting”, but it doesn’t burn out cleanly enough, so it usually just sits on the shelf (If I’m burning out in an oven anyway, PLA smells much better).