MF Pegasus Print Quality Issues

Although I am aware that there aren't many people here with the Pegasus hopefully someone with an i3 has seen this issue. The first print I did on the printer, on the left, came out pretty well. I have since switched from ponterface to Repetier use and am using sli3er inside of that. What could be causing the issue on the right with the banding look? It isn't just popping out in one axis those outcroppings go all the way around the print.

I'm printing pretty slow too, maybe 35mm/s. My nozzle should be set right at .4mm, temp at around 195C in PLA.

Attachment 7681

I had the same issue and switched to PID and an aluminum Y bed. Take a look at this thread:

http://3dprintboard.com/showthread.p...-bed-relay-PID

Thanks for the reply! I do already have an aluminum Y bed. Maybe I just need to run a PID auto-tune on the machine, I can't remember whether or not I had done that on this one. I'll run one once this print finishes and post an update. I was racking brain with what the issue could be. I had checked mechanical tightness thinking there was some kind of resonance with the frame or maybe some loose belts but for the banding to be so even didn't make since to me. After reading that it seems like every 5 layers my temp must be falling then going 5 layers and raising back up which totally makes more sense than anything I was thinking. I appreciate the comment and will post an update either way.

In order for the PID tuning to work well on the bed you need to have a Solid State Relay installed. I am not 100% certain of this on the Pegasus. maybe the board can support PID operation. That i cannot answer. I know I had to replace my relay board with a SSR on my 12" iv3 in order for it to work properly. Once completed, it works extremely well and I highly recommend using PID when ever possible.

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Originally Posted by FDM_Process

Thanks for the reply! I do already have an aluminum Y bed. Maybe I just need to run a PID auto-tune on the machine, I can't remember whether or not I had done that on this one. I'll run one once this print finishes and post an update. I was racking brain with what the issue could be. I had checked mechanical tightness thinking there was some kind of resonance with the frame or maybe some loose belts but for the banding to be so even didn't make since to me. After reading that it seems like every 5 layers my temp must be falling then going 5 layers and raising back up which totally makes more sense than anything I was thinking. I appreciate the comment and will post an update either way.

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You need a SSR installed to run PID, the mechanical relay that comes with Makerfarm Kits will not work.

Sounds about right. I do have an SSR that I can salvage off my old run down modded Solidoodle 3. The problem I am having is with the PID values and entering them in. I think I was able to manually enter them with gcode but on the Rostock Max, in Repetier, I can edit the PID values in the EEPROM settings. With the Pegasus I am not getting the same EEPROM settings. Does anyone know why that is?

Also, I am having a hard time believing that I need a SSR for my hotend when the three other printers I have running right now aren't using one and are running just fine. My issue has to be something else. While I certainly believe that a SSR is better I don't think that it will make enough of a difference to really matter for what I do and again the object on the left was printed on the same machine.

What kind of board are you running?

Ramps 1.4 for the Pegasus.

I have a feeling this is some serious z-wobble. I can literally see my right z-rod wobbling when I move the hotend up and down. I need to find a way to stabilize that before I go messing with the electronics. Try the simplest things first and then move from there.

The Z rod wobbling can be a source of wobbles. the axis itself is constrained bu the Z extrusions. If those (Or the V-wheels) are loose the rod can force the Z towers to move. Ig everything is tight however, I don't think the rod can cause that degree of banding. All this is said without seeing how much your rod is moving. Can you see the actual z carriage moving side to side when you move the z axis up and down.

I had made some bearing holders to hold the Z rod at the top and keep it from moving. My quality severely went down. Once I removed them and added a SSR my prints got quite a bit better.

The SSR is not for the hotend. It is for the heat bed. The issue is by default the bed uses a bang bang heat control the turns on the heat at a level and turns off at a different level. My bed would swing in temps sometimes by 5 degrees! That difference in degrees will cause variations in bed thickness which shows up in the banding. To use PID tuning on the bed you have to have a SSR as the relay included in the kits (mechanical) is not capable of running a PWM signal.

I know I am saying quite a bit wrong but the gist is there. The SSR is for the heat hed, not the hotend.

Well that makes more sense because that was how I had my solidoodle setup. However, I only switched to a SSR because my original heated bed died and I replaced it with a more powerful one.

I'm not seeing how this would cause a z-banding issue like the one imaged above, especially near the top of the print where the heated bed would have absolutely no bearing on the actual print.

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Originally Posted by FDM_Process

Well that makes more sense because that was how I had my solidoodle setup. However, I only switched to a SSR because my original heated bed died and I replaced it with a more powerful one.

I'm not seeing how this would cause a z-banding issue like the one imaged above, especially near the top of the print where the heated bed would have absolutely no bearing on the actual print.

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People have proven that the heat bed toggling on and off causes the print surface to move up and down with the toggling of the heater. With bang-bang control, the slow toggling can lead to artifacts through the entire print as the bed surface moves up and down. Going PID with an SSR allows the toggling to be fast enough that the up and down movement is negligible.

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Originally Posted by FDM_Process

Well that makes more sense because that was how I had my solidoodle setup. However, I only switched to a SSR because my original heated bed died and I replaced it with a more powerful one.

I'm not seeing how this would cause a z-banding issue like the one imaged above, especially near the top of the print where the heated bed would have absolutely no bearing on the actual print.

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It doesn't matter if your print is 10mm or 10X10^10mm's tall. If the base (Heatbed) fluctuates up and down by 1-2mm's then the whole print is moved up and down 1-2mm's.

Okay, well let's test this. Since I'm printing in PLA anyway I'll just turn the heated bed off and see what happens. I will report back.

I am curious to see. Adding the SSR helped my prints come out nicer. I didn't have the banding to that degree however. I did at first. The firmware provided from Colin had me over extruding quite a bit. Only once I had my machine calibrated better and then adding the SSR was I happy with the prints.

I think in this case adding the SSR will help. If you still have banding issues (The may be smaller) you might have a extruder calibration issue too. I still chase that number all the time. It is why i have modified my firmware so that the knob on my display adjusts the extruder multiplier instead of the speed while printing.

I'm about halfway through printing the "okay" model with the heated bed off and the banding is to the same extent (I will post a picture when it's finished). I will calibrate the extruder again but I think I have it pretty dialed in and I'll also see if I can't get a small video of the carriage moving up and down to visualize whatever amount of z-wobble I have.

I'm at a loss here because the very first prints came out rather well with little to no sign of banding at all.

Alright, printed with the heatbed off. No change. I raised the height of the z to the top and homed it and watched for wobble in the carriage assembly and it looked pretty good. I checked for mechanical tightness which was also good. I calibrated my extrusion settings, also good. I am now trying Simply3D instead of Repetier/Slic3r and seeing how that goes.

Here is a picture of the old print and print with the heated bed off, side by side. Old print on the left, current on the right.

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Wow that is some crazy banding. I really thought the heated would be the issue. It was for me. What layer height are you printing at? I am not 100% on the construction of the pegasus, does it use 5mm z rods?

Also, I now am using matter control and am getting much nicer slices than with Slic3r and cura. It doesn't have as many settings as slic3r but the prints are much better. It is free and may be a good alternative to paying for S3d. If you have already paid for s3d then use that. it is expensive!

That actually might be a layer height/model resolution issue. Try printing that tower test object again, the one you initially had good results with and see if it comes out like this.

I've used both Repetier and Simplify3D to print the hand. Same sort of banding (although the simplify 3D one came out a little better because I was printing at .15 mm). I really like all the options Simplify3D has and even switched our Rostock Max v2 over to it. I was getting some surface layer issues with Matter Control and they didn't have a setting for extrusion width in there, overall I've found Simplify3D to be worth the price after using Repetier, Slic3r, Cura, etc...

The hands in the image are .2mm layer height. The Pegasus uses M5 threaded rods for the z. Honestly, I doubted it was the heated bed but was hoping that it was because that is something I could easily fix. I have the parts available.

I will stop in the shop later today and print out the tower object from the sd card. It came pre-loaded from Makerfarm so that should be a good fail-safe print.

I'm thinking it something firmware related? The only thing I've changed though is the PID settings for the hotend and that was well after this started happening. Very tempted to reflash the electronics but I'm keeping that as a last resort. Thanks for the help everyone, it is much appreciated. I will update with an image of the tower when I can.