Hey there!
I am currently printing prototypes of extrusion profiles. Previously I was using the Makerbot Replicator 2 at school. I just got the Printrbot Simple Metal and started printing using it.
The Z-axis has a lot of striations and ridges, as seen in the photos below:
Comparison between Printrbot and Makerbot
Close up of comparison
Comparison of inside
The filament used is exactly the same. I was initially running the Printrbot at 210C and dropped it to 200C but there was no considerable difference. I’ve also decreased the step height from 0.2mm to 0.15mm and speed from 45mm/s to 30mm/s with no visible improvement.
Any clues about what might be happening and the tweaks I can do to make prints better?
Any help and suggestions will be very much appreciated!
Thank you,
Matthew
4 Likes
JATMN
2
Well for starters, that looks more like issues with your X and Y not Z…
Also your trying to compare prints from a $600 printer to prints of a $1,800 printer… Sorta like comparing a Honda Civic to a BMW. Your not going to get prints on the Printrbot that look as nice as the Replicator 2, there is many reasons its a lot cheaper. I have a Wanhao Duplicator 4 and a Ultimaker 2, no matter how much I try im not going to get prints on my D4 to look as nice as the UM2, its literally half the price. All I can do is tune the D4 as much as possible to improve the prints.
I would check your alignment and tensions on the X and Y see if anything is loose or needs adjusted…
Print a smaller part and see if it is bulging more on the left or right or more on the front or back it will give you hints where to look on your printer.
Also something else to consider… Replicator 2 is mostly contained printing environment, where as the Printrbot is wide open… this will play some factors as well.
Hey Jatmn,
Thanks for your tips. I know that the comparison isn’t necessarily fair, but I’ve seen prints online from the same model that suggest that I should be getting better prints. The striations are pretty significant and unlike most of what I’ve seen come out of Printrbot in online reviews.
Will definitely check on the X and Y movement. Thanks!
JATMN
4
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.
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
6
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.
Awesome - thanks for the link!
ianadan
8
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?
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.
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
11
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).
1 Like
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…
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.
1 Like
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!
Hi ASquar3D,
Appreciate your feedback. How did you go about diagnosing and fixing the issue?
TomV
16
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
17
where did you get it from and when?
Just got it from the printrbot online store over black friday cuz of the 15% deal.
Hey Tom, sounds good - I will definitely check it out.
Thanks!
ianadan
20
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.
1 Like
