Used to get near perfect prints - Was it only a dream???

[mitchfx]

I've had my two Dremel Idea Builders for about 5 months now. When new they both were producing some amazing prints but slowly got worse over time. After countless hours calibrating, testing and even swapping out the PTFE liners (which finally solved my extrusion issues) I am still not able to get anywhere near the quality as before. I've tried every combination of extrusion multiplier, temperature, speed, infill, etc etc but nothing seems to get me close to the "good old days". At this point I'm leaning towards two possibilities...

1. Warmer weather. My most successful prints were done in the spring when the temperature and humidity were lower. I'm in Los Angeles so it never get's super humid but the ambient temp in my workshop is probably 10f warmer on average now. However my prints take on average 16-22hrs each so you would think that the day vs night fluctuations would have also wreaked havoc with the older prints as well if this were the true culprit.

2. Mechanical wear and slop. Maybe these units have simply started to get out of tune and the belts, rods, etc are just not as tightly aligned as before. I do semi-regular maintenance like lubing the rods, cleaning and tightening the bolts but nothing beyond that.


Here are two images. One is an "average" print from when I first got the Dremel. The other is the best I can seem to eek out these days. Any ideas you guys have are appreciated.

Older prints - Looks Great!

Newer Print...YUCK!

[JoeJ]

Well, first of all, I would try to change software settings since that it just adding additional variables. If you truly want to figure out what's going wrong, then print the exact same g3drem file you printed 5 months ago. Don't change any settings. You have already seen how that file should print, so now you can focus on why the machine is producing different results with the exact same file.

Other ideas to add to your list could be the filament itself - perhaps it is a different brand, or even if it's the same brand maybe the manufacturer made modifications. It's also possible a roll of filament degrades over time as it soaks up moisture from the air. So maybe try opening a brand new roll that was sealed and print with it to see if it makes a difference.

Was there any firmware updates that you did with the machine? It's very possible that could also have a big affect here depending on what they changed.

The extruder may also be degrading over time. You may want to try replacing it or disassembling and cleaning it our REALLY well to try to remove any foreign debris that may be stuck inside or any leftover plastic that shouldn't be there. Also possible that the extruder drive gear tension has changed, so it isn't consistently pushing the filament like it used to.

Either way, don't try to mess with software settings too. You already know what settings are supposed to work well, so no need to experiment more on that front. Just print the exact same file and then focus on these other possible causes.

[LeonMF]

Generally, layer alignment issues like that are not software.

My experience with my machines is that it is most often caused by loose belts. It could be something else mechanical but the only way to tell is to inspect the machine.

The best way I've found to look for slop is to enable the motors and then press gently to mildly firmly on the axes with your fingers. That will expose loose couplings, belts and other worn components. Also, pay attention to things like directionality of defects as the problem is often only on one axis.

Good luck!

[mitchfx]

Well, first of all, I would try to change software settings since that it just adding additional variables. If you truly want to figure out what's going wrong, then print the exact same g3drem file you printed 5 months ago. Don't change any settings. You have already seen how that file should print, so now you can focus on why the machine is producing different results with the exact same file.

These are using the exact same gcode file. That was the point of doing comparison tests.

Other ideas to add to your list could be the filament itself - perhaps it is a different brand, or even if it's the same brand maybe the manufacturer made modifications. It's also possible a roll of filament degrades over time as it soaks up moisture from the air. So maybe try opening a brand new roll that was sealed and print with it to see if it makes a difference.

Yes, this test is using same PLA but a brand new roll freshly unwrapped.

Was there any firmware updates that you did with the machine? It's very possible that could also have a big affect here depending on what they changed.

No firmware changes.

The extruder may also be degrading over time. You may want to try replacing it or disassembling and cleaning it our REALLY well to try to remove any foreign debris that may be stuck inside or any leftover plastic that shouldn't be there.

Extruder has been cleaned and the PTFE liner changed out just a couple of days before this test. Some previous extrusion issues I was having were solved by this new liner and the old tube was definitely visibly degraded. The Gear tension is another thing I've not thought about however. Interesting.

Either way, don't try to mess with software settings too. You already know what settings are supposed to work well, so no need to experiment more on that front. Just print the exact same file and then focus on these other possible causes.

That is what I'm doing by using the old gcode and same brand PLA. Thanks for your help trying to solve this.

[bbinnard]

It looks like mechanical wear & tear to me. I'm in the LA area too so I don't think climate has anything to do with it.

Try this - if you don't already have one, get a digital micrometer (they cost about $12) and print a couple of 50 cm cubes. Place the cubes at different locations on your build plate. Then measure the results. That might help you identify what's going on.

[JoeJ]

I've tried every combination of extrusion multiplier, temperature, speed, infill, etc

You said you were trying different software settings, so that had me thinking you were adding that into the tests as well. Glad that's not the case.

At this point, sounds like extruder and mechanical issues are your most likely causes. Lots can change with an extruder over time if the tension changes, screws loosen, friction builds up, etc. And for mechanical stuff, belt tension and wear can definitely cause extra slop in the movement which will clearly show up in the prints.

Keep investigating and let us know what you find!

[AndersE]

Check the diameter of the filament also, so it doesn't vary too much in the roll.
Also check for wobbling z-axis.

[tenaja]

...I'm in Los Angeles so it never get's super humid...

"Super humid" is all relative. To me, that is anything over 60% or so. To others, it has to be over 80%. To plastic, however, it is anything over something like 2%.

This week alone, you are seeing levels near 80% every day in Los Angeles, with 9hrs a day exceeding 70%. Sure, the humidity drops as the marine layer burns off, but even then, it is still over 40% all day long. That is enough to degrade plastic that absorbs moisture, if not protected and/or dried.

I am not saying for certain the material is causing your issues, just sharing a "reality check" on your humidity.

[PinballGeorgio]

What happens if you lower the speed settings by 50%?

[mitchfx]

What happens if you lower the speed settings by 50%?

I can try that but I'm already at 18mm/sec for outlines, supports and solid layers (30mm/sec for infill).

A little update as well. After changing the liner in my other Dremel's extruder I was able to get a little closer to my original quality but still heavier lines and more errors. I will post a photo of that later for comparison.