Irregular and uneven ridges and striations on Z-axis throughout print

JATMN · 2015-12-04T05:27:58.000Z

Yea check your X and Y for slopping around… check the belts for too much or not enough tension…

Also make sure your printing on a solid surface, AKA not printing on a wobbly table.

Print a 20x20x10 calibration cube… many of us have printed this dozens of times to get our printers where we want them.

matthewlim · 2015-12-04T05:34:40.000Z

Haha sounds like I will be spending a lot of time with my Printrbot Simple then.

Cool, I’ll find an .stl to start that process. Will also move the Printrbot to a more stable surface.

JATMN · 2015-12-04T05:42:44.000Z

Yea stable surface with help a lot of trouble shooting, and yes your going to spend a lot of bonding time with your Printrbot.

http://www.thingiverse.com/download:5839 - This should work for you.
I would recommend you get your hands on a caliper as well if you dont already have one.

Even a $5 one from china will be a good start, you dont need a super expensive one to get you going.

matthewlim · 2015-12-04T05:51:19.000Z

Awesome - thanks for the link!

ianadan · 2015-12-04T10:14:59.000Z

try a layer height of 0.1984mm and check the belt tension. should be firm, but not overtight. Did you build it or was it already assembled?

Flavio_Camus · 2015-12-04T12:04:47.000Z

Seems to mi the threaded rod is wiggling around. the spacing of the anomalies is the same as the pass of the the rod, periodical and even. That happens when the rod that rise the Z axis is excentric from the axis of the step motor.

you can check making a rise of the z axis and watching how much the z axis rod spins.

A simple solution is put some tape to make the union more fit. then check again, and make sure if the wiggling stops. If not. add some tape (one layer) on oposition og the two bolts that fix the rod to the step motor.

ASquar3D · 2015-12-04T13:17:07.000Z

Make make sure the acme screw is co-linear with the output shift of the NEMA stepper motor. Your problem is most likely all stemming from the flex coupling. Mine took quite a bit of elbow grease before it was set perfectly. Hope my $.02 is worth while

TomV · 2015-12-04T13:42:37.000Z

Hi Matt, Simple Metal isn’t the best printer under $2000 regarding smooth surfaces, but these ridges are too much. As it looks the pattern is not homogeneous, check again your X and Y belts first – they need to be tensioned well (precise position repeatability) and secured by clip (two are better than one, do not smash the belt). Altough I have nice prints from my Simple Metal as you pointed out (gallery with samples: 3dhubs.com/brno/hubs/tom) I have also one very painful area which can cohere with your problem. I have to change (proprietary and with shipping and clearance costs to EU quite expensive) bearing blocks and rods quite often as the bearings are squeaking and scratching the rods, even with quality PTFE lubricants and from day one. As I have the 3rd pair of bearing blocks I presume the problem maybe somewhere in the construction (innaccurate holes on metal Y arm etc.).

But back to your problem: Check well, if your X and Y moves with ease. Then check your belts if the teeth are not squeezed (too much of tension or after some time running). Then tension the belts properly and lubricate the rods (lubricant needs to work with metal and plastics, some of them can harm plastics; I use PTFE spray). As @JATMN proposed, lay your printer on some sturdy table, or try the floor when testing. Temperature is not a main problem with vertical walls (I print PLA on 190 °C, but I have E3D V6 hot end upgrade and added 120mm area fan). Try to pick up model with thin walls (0.8mm is good enough for 0.4mm nozzle) and try to print it when calibrating. I use my own model (check the attached picture) or you can use these great test models: www.thingiverse.com/thing:533472/#files (those for resonance tests).

There are always some small wobbles on prints from Printrbot Simple Metal, but with right adjustment they look more like negligible pattern. I wish you luck you quickly find the source of problems (if you build Simple Metal from the kit, just check all mechanical joints).

Tom's_40x40_test_cube.JPG1600×900 608 KB

matthewlim · 2015-12-04T14:19:56.000Z

Hey ianadan,

This particular print used the Getting Started .ini file, which means the 0.1984mm layer height you mentioned. I will check on the belt tension - is there a good way to determine the right firmness?

That’s probably the most frustrating part of my experience thus far - I got an assembled printrbot. It might have gotten mishandled during shipping possibly. The part that holds the extruder came not parallel to the print bed. When I tried making my first print the print head dug into parts of the frame. After that, I read in other places that the bent issue is a no-go so I proceeded to bend the sheet metal to make it close to parallel as possible. In the process of doing so, I’m not sure if I might have messed something else up…

matthewlim · 2015-12-04T14:27:33.000Z

Hey Tom,

Thanks for your reply. Do you have a picture of the clips securing the X and Y belt? Would love to see how it is done properly.

The prints look really good! Hope I would get there soon.

matthewlim · 2015-12-04T14:40:28.000Z

Hi Flavio_Camus

That was my initial guess as well. I’m not sure if this is significant but I can notice that the z axis acme screw wobbles a little at the top when it runs. The base of the screw where it meets the coupler is actually quite snug. I assumed that the top of the screw wobbling would be counteracted with the guide shafts - is there a way to determine that the wobbling on mine is not normal?

Will try your suggestions, thanks!

matthewlim · 2015-12-04T14:42:46.000Z

Hi ASquar3D,

Appreciate your feedback. How did you go about diagnosing and fixing the issue?

TomV · 2015-12-04T14:58:42.000Z

Hi Matt, even you have completed Printrbot (not a kit), check the original online documentation of manufacturer: i.tvit.cz/1XNxwok. It is VERY handy if you need anything to change or justify. Clips on belts are also there. I only use two (one more) on both ends to secure belt. Some say the bigger tension the better, but too much can lead to structural deformations or tearing the belts. (In the worst case GT2 belt is quite cheap and universal accross more 3D printers.)

ianadan · 2015-12-04T14:59:53.000Z

where did you get it from and when?

matthewlim · 2015-12-04T16:09:45.000Z

Just got it from the printrbot online store over black friday cuz of the 15% deal.

matthewlim · 2015-12-04T16:16:16.000Z

Hey Tom, sounds good - I will definitely check it out.

Thanks!

ianadan · 2015-12-04T16:26:52.000Z

open a ticket on the PB support site for Bent Y Arm. Mention my name in the ticket - Ian Lewis and i’ll pick the ticket up.

matthewlim · 2015-12-04T16:57:02.000Z

Awesome, will do. Thank you!

ASquar3D · 2015-12-05T01:54:57.000Z

Banding, as it is normally termed in additive manufacturing, is always due to the Z axis. This is mostly identifiable by the “waviness” in the part, which is often representative of the pitch of your Z-Screw. The problem can be very easily remedied be re-aligning the Z-Screw with the NEMA motor.

The Easiest method is to loosen the set screws on the flex coupling and apply some pressure to the top of the ACME screw in order to set the coupling. If the screw comes into contact with the output shaft of the NEMA motor then separate slightly in order to allow the backlash to be absorbed by the coupling. After all is said and done you should have no troubles printing at even .1mm resolution.

Also a tell tell sign of banding caused specifically by the Z axis is that regardless of resolution the banding will be the same since it is caused by a misalignment of your Z-Screw. Please let me know if there is anything else I can do to help.

Joerg_4 · 2015-12-10T15:24:09.000Z

you should also check the accelleration settings in the firmware.

afaik it is M204 command
M501 for listing all values.