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Uneven layers. Pleas look.

Posted by kaaveka 
Uneven layers. Pleas look.
February 01, 2017 08:25PM
Look at my prints, they are not smooth enough. What is the problem? Thanks smiling smiley
G-Code: [www.dropbox.com]
Printer video: [youtu.be]

Printer Specs
Tronxy i3 Reprap
Extrusion Width: 0.4mm
Layer height: 0.2mm
Nozzle: 0.4mm
Controller: Melzi 2.0_V5
Display: 2004A LCD
Fİrmware: Marlin
Filament: ABS
Bed temp: 85
Ext temp: 225
Slicer speed settings on the attaches.

Edited 5 time(s). Last edit at 02/02/2017 05:24AM by kaaveka.
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Re: Edges are not smooth. Pleas look.
February 01, 2017 08:47PM
Hi, welcome to the forum.

It's difficult for people to give you relevant advice unless you provide plenty of information about your printer and how you are using it. Photos of the printer showing it's construction and type would help, along with the type of filament you are using, and the print settings such as speed, temperature, layer height and nozzle size for example.

There's a page describing the sort of information that's needed here: [reprap.org]
Re: Edges are not smooth. Pleas look.
February 01, 2017 08:49PM
Sorry about that. This is my first topic.
Re: Edges are not smooth. Pleas look.
February 01, 2017 08:56PM
Yes, no worry. We've all been there at some point smiling smiley Just didn't want you to think you were being ignored.
Re: Edges are not smooth. Pleas look.
February 01, 2017 09:31PM
Is that okay now? Thanks for help smiling smiley
Re: Edges are not smooth. Pleas look.
February 01, 2017 09:45PM
Ok, so it looks like there are a couple of problems, one causing the horizontal bands and another for the diagonal ones. The diagonal ones are likely to be related to the extruder, possibly an off-center drive gear. The horizontal banding might be related to the Z screws. Is there any sign that they are bent and pushing the X axis side to side as they rotate? Another possibility is the bed flexing up and down as the heater turns on and off. If you have the option of turning the bed off for a few experiments that can be worth trying (easier with pla than abs).
Re: Edges are not smooth. Pleas look.
February 01, 2017 10:56PM
I didn't saw any issue. I record a video for you [youtu.be] if you want a specific place to look tell me i can record a video.
Re: Edges are not smooth. Pleas look.
February 02, 2017 05:48AM
Hey, i did what you said and print PLA without heatbed. Result is very good. So what should i do for my ABS prints?
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Re: Edges are not smooth. Pleas look.
February 02, 2017 06:59AM
Ok, that gives us somewhere to focus smiling smiley There are a few things that you could check/try:

- is the firmware configured to use PID control for the heatbed? PID gives tighter control of the bed temperature, and if the bed temperature is held steady it shouldn't flex much. The (common) alternative to PID control is called bang-bang which is a much less accurate method (intended for mains powered heaters controlled by a relay which can't cope with high frequency switching). Do you print from host software? If so, I think most of the host programs can show a graph of bed temperature so you can see how much it varies.

- you could try adding a piece of glass on top of the heat bed. If you clip it only on one side the glass should stay flat even if the bed bows. The downside is that the contact between the bed and the glass won't be very good, and the time taken to get to printing temperature will be much longer.

- part of the problem may be the design of the mounts holding the bed to the Y carriage. If they don't allow for expansion they may actually be causing the flex. You could look at redesigning the mounts to allow for bed expansion, possibly just using three points, making sure the screws are a loose fit in the holes and have smooth washers between the springs and the bed.

Edited 1 time(s). Last edit at 02/03/2017 08:25AM by JamesK.
Re: Uneven layers. Pleas look.
February 03, 2017 07:32AM
Just a comment here.

Not really having this problem but this is good information for the new printer guys.

Thanks from those of us that are on the steep learning curve!!!

eye rolling smiley
Re: Uneven layers. Pleas look.
February 03, 2017 08:38AM
I had a similar problem. But even with well-tuned PID on the heatbed, the flexing was still too much. So, instead of clipping glass to the PCB, I sandwiched the PCB under an aluminium plate, which is bolted on with the same mounts as the PCB. This way, the print surface isn't tied to the PCB. So if it flexes, it doesn't mess with the print. This introduces problems, though... The aluminium is REALLY thick- I should have gotten a thinner one. The Y axis has pretty bad chatter with the extra weight. It also takes 10 mins to heat up and stabilize.

Master Tinkerer
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