Filament will not stick right anymore

[Les]

I have Flashforge Dreamer about 7 mos old. (the one with the clear front access door/panel)
I am using ABS 230degrees @ Nozzle and 110degrees on the plate (after trying different settings) and all worked very well until one day it did not.
It started oozing filament a little more than usual and I removed it just before printing and all cleared up on the test strip except I noticed the test strip was not an even distribution at the start but cleared up at the end.

Next, as the print started, it would not lay down the filament but instead collected as a blob on the nozzle.
Thinking it might be a clogged nozzle, I changed to the Right nozzle which has almost no use and it essentially behaves the same. It makes some sense to change the heat of the plate or nozzle and/or feed rate but because it just started having problems one day, so seems to me something else might be at play. (I am using hatchbox filament and although it has been relocated outside of the machine, the filament is covered when not in use) ( It has been warmer here lately (SoCal) but not enough as compared to other days to think the filament was entering the nozzle that much warmer to make any difference. Humidity is within our normal range)
Anyone have any thoughts?

[ejcruz]

I would do the following:
1) clean the nozzle if the filament is sticking to the nozzle
2) level the bed
3) do a physical measurement of the filament diameter, and compare it to the slicer measurement

Hope this helps

[Les]

ejcruz - Thnx (this is my 2nd attest to reply, the first did not "stick" apparently

1) Tried that with acetone and scraping the exterior of both nozzles with not change - Is there are safe way to clean the interior? I have unloaded and reloaded several times w/o it making a difference
2) Did that and the center of the bed seems a little higher that the other 3 check points but the print starts at the outer edge of the plate - Do these plates warp over time? I did a small print at the extreme left/Front and there was less of a problem but it was a different print that those I had been doing
3) Have not done that yet, will do so and report back

[ejcruz]

1) Tried that with acetone and scraping the exterior of both nozzles with not change - Is there are safe way to clean the interior? I have unloaded and reloaded several times w/o it making a difference

When you do a reload check the filament is running out without sticking to the nozzle, if it is sticking to the nozzle that indicates the nozzle exterior needs cleaning. NB. if the nozzle is blocked you will need to remove the nozzle and soak it overnight in acetone (assuming you where printing with ABS)
I let the nozzle cool down then with a small wire brush dipped in acetone (I print with ABS) carefully clean the nozzle avoiding the heater ceramic tape.

2) Did that and the center of the bed seems a little higher that the other 3 check points but the print starts at the outer edge of the plate - Do these plates warp over time? I did a small print at the extreme left/Front and there was less of a problem but it was a different print that those I had been doing

Plates can warp over time, I use glass have been using it over a year without any issues.
When filament starts to accumulate on the nozzle it's an indication:
- exterior of the nozzle needs cleaning
- need to really clean the bed or replace the bed surface such as blue tape etc
- more then likely the nozzle is to far from the bed, hence the suggestion to level the bed
I use Simplify3D so before I actually level the bed, I go to "Edit Process Settings", then click on "G-Code", change the "Origin Offset" Z-Axis to -0.1 to bring the nozzle closer to the bed and do a test print

3) Have not done that yet, will do so and report back

Measure the diameter of the filament in several places and average the measurement then enter that into the "Filament Diameter" option

Hope this helps

[Les]

To ejcruz Fr Les I am curious, what is the consequence of changing the filament size on the setting? Does it change the feed rate or other setting related to dia. I checked several places on Hatchbox White and it was 1.75 but say I change it to 1.74 or 1.76 on the settings what would happen?

[ejcruz]

To ejcruz Fr Les I am curious, what is the consequence of changing the filament size on the setting? Does it change the feed rate or other setting related to dia. I checked several places on Hatchbox White and it was 1.75 but say I change it to 1.74 or 1.76 on the settings what would happen?

Yes, the feed rate is effected, correct filament diameter will also give you improved printing quality especially when you need to do precision printing such as printing a 10 mm cylinder to fit into a 10.1 mm hole. If your not concern with precision then adjusting diameter +/- 0.01 won't make much difference.

[curious aardvark]

the print bed needs calibrating.

simple as.

[Les]

Thnx Curious...

Is calibrating the same as leveling? if not where can I find the instructions to do so?

[curious aardvark]

yes calibrating is the same as levelling.

I use Simplify3D so before I actually level the bed, I go to "Edit Process Settings", then click on "G-Code", change the "Origin Offset" Z-Axis to -0.1 to bring the nozzle closer to the bed and do a test print

cheers for that. figured that might be an easier way to loosen calibration when it's a bit tight :-)

***
just used that - brilliant. I usuallly have the machine pretty tightkly calibrated and it leaves a rim on things. So when i don't want a rim - rather than moving the whole bloody printbed - i can just offset the print nozzle by 0.2 or 0.3 mm.
Works a treat.

***


Far as beds warping goes - yes.
Don't know what they put in the dreamer, but the 3mm aluminium plate they put in the creator lasts about 5 minutes. I put it down to the screws being steel and the plate being aluminium, so when it all heats up the screws expand at a different rate and the plate gradually buckles.
I dropped another 3mm aluminium plate on top of mine, attached with pet tape at corners and never had any more hassle with it.

[Geoff]

Yeah, Bed warp is just something you have to deal with with just about any Flashforge, that's why so many people go for a Glass plate or buy their own plates like Curious and put them on top. My plate is so bad after 5 years it is 1mm higher in the outer edges than it is in the middle.