Brand New Stock TAZ 5 - Horizontal Banding

[hockey1237]

I just received my TAZ 5 yesterday, which means I’m new to the forums. So I know this topic has been discussed, and I have done my research, but am just not familiar enough with printing yet to answer my own questions. Anyway, I have been printing countless calibration objects (mostly single/double/tipple layer squares, and cubes) to try and get my printer dialed in and learn what settings work best. I’ve printed several 20mm cubes and have found that I’ve got what seems to me to be pretty significant banding. I know there is a certain amount of banding that is to be expected, but was hoping to get some confirmation that what I’m experiencing is normal.

Below are a few pictures of my 20mm cubes. All of them were printed with HIPS out of Cura, and with my .5mm nozzle at 240 degrees, and bed at 110. Also all have .3mm layer height, 40% infill with 1mm shell and Top/Bottom thickness, and Initial layer thickness set to 0 and initial line width set to 100%. Speed was my big difference. From left to right the speeds were (in mm/s):

Cube 1 (Left): Travel 175, Bottom 15, Infill 50, Top/Bottom 30, Outer 30, Inner 35
Cube 2 (Center): Travel 175, Bottom 15, Infill 50, Top/Bottom 15, Outer 20, Inner 20
Cube 3 (Right): Same as Cube 2

What makes Cube 3 different is that while the first two cubes printed Infill before Perimeters, Cube 3 printed Perimeters before Infill.

So the middle cube, not surprisingly, is the best, but while the Front and Right faces aren’t that bad, the Back and Left faces are noticeably worse. So I guess I actually have 2 questions. 1) Is this amount of banding what is to be expected on a brand new TAZ 5?, 2) How do I fix it… I know there are a few mods I can do to reduce/eliminate banding, like piercet’s Anti Wobble Z Nut and Openbuilds v-slot Axis mods, but is there anything I’m just doing wrong?

Sorry for the long post, but thanks in advance for any help!

[piercet]

It looks like you have a couple of things going on here. You are getting much worse offset on one side of the cube than the other, which assuming the first picture is how they came off the bed, probably indicates something is loose or out of alignment on the left hand side of the printer. Possibly something got knocked loose in shipping. Z wobble will usually affect the entire part on all sides the same. In this particular case it looks like either the left Z axis rod or bearings are loose, the left Z axis leadscrew, motor coupling or bearings are out of alignment, or possibly the X motor belt or pulley setscrew is too loose and either the belt or the pulley is slipping slightly, but only on left side travel.

It also looks like your extrusion temperature might be a little warm, as the layers seem a little discolored in places. I’d try dropping 5 degrees and see if it looks crisper.

It also looks like you might have the layer starting on the outside corner of the cube, which is going to add a bit of extra extrusion at that point. See if you can tell the layer to start at a random location on an inner perimeter.

.

[hockey1237]

I thought there had to be something off for the banding to be offset like that. I will take a look at all of that and give some new settings a try.

Thanks for the quick response!

[hockey1237]

So I’ve done what I could tonight. I think I at least addressed the issues of things being loose or slipping. Although I’ll be the first to admit I may not be as familiar with the parts of this system as I’d like to think I am, so I may have not gotten the right screws, and I’m honestly not sure how to properly check the alignment. But anyway, here’s what I did:

I found that most of these screws were a touch loose. Again though, I’m not actually sure how to properly check the lead screw, motor coupling, and bearing alignment, but I did at least use a caliper to confirm that the screw and rod are parallel to each other and the frame. Is there a proper method for checking their alignment?

So before doing all of this I ran a 20x20x10mm cube with the nozzle at 235 degrees for a baseline, and then another after the above adjustments. Here’s what I got (Before on the Left, After on the Right):

There doesn’t seem to be much of a change. So while I’d like to think I addressed your proposed issues, I’m guessing I missed something.

I’m very much open to suggestions.

Thanks! And sorry again for another long one.

[piercet]

Hmm, you checked all the screws I would have checked. This could be a HIPS specific issue related to cooling. Maybe try adding some fan? I don’t print HIPS much but I know it can deform some like PLA due to temperature.

[hockey1237]

Good to know. I’ll give that a shot.

Thanks again!

[hockey1237]

Actually, thinking about it a bit more, that’s a really good call. It does make a ton of sense that given the position of the cooling fan the left and rear faces wouldn’t recieve enough air.

When I eventually graduate to printing abs I want to mod my extruder and get some better cooling. For now though I’ll find some way to get cooling back there and update with the results.

[piercet]

the Taz 6 prototype extruder carriage in http://devel.lulzbot.com/TAZ/Olive/production_parts/ and the right, left and center fans is a good upgrade to consider at some point.

[saramos]

I started out using HIPS when I first started using my printer. I found it hard to eliminate heat related issues on the side of my parts opposite the fan. Next I went to ABS, which is currently my go to plastic. Once I built an enclosure, I’ve been very happy. You might also try dropping your speed down a little too.

Scott

[hockey1237]

So a lot has happened since last week. I printed countless text cubes and progressively got more consistent results. I think the biggest thing that helped was adding Sebastian’s Dual Duct For Single Fan mod (http://www.thingiverse.com/thing:1349016). Airflow from both sides definitely made a difference.

However, while It’s helped, and the banding it a bit more consistent around the whole part, it’s definitely still more prevalent on the back and left sides. I’ve especially been struggling with trying to balance the airflow that seems to help with the banding, and maintaining good temps overall in order to prevent warping and lifting. I’ve printed parts now that have minimal banding, but the corners lift. And I’ve printed parts with no warping, but banding. Here are a couple of images for reference printed with the new fan duct.

In this image the cube was printed with the fan speeds set to min. 40%, max 60%. The banding is more consistent, but on larger prints I’ve had issues with corners lifting. The Benchy model was printed with the fans set to 30/40%. At this setting I haven’t been having as much of an issue with lifting, but the banding is a little more consistent, it’s still much worse on the back faces, again.

I think I’ve decided I just need to do an anti wobble Z nut mod if I’m going to get any real improvement. My next issue is eliminating warping and lifting, but that’s an issue for another thread.

Thanks again for all of the help.

[kcchen_00]

Try running the gantry up and down the length of the acme screw a few times. It may be a little more than a few times to be honest…

I suggest this because the horizontal banding which used to occur on my prints have gone away after almost a year of use. Its wear or the coincidence that my acme screws have synced themselves harmonically. Check that the gantry (x-rods) are level also… any binding could be contributing to the banding.

Just a thought…