My printers are so unpredictable. They won't just print.

My machines are so annoying I sometimes ask why I even bother with them.

When I print, I have to spend hours finely tweaking the settings to get really good prints. After enough tweaking it will finally give me an awesome print. If I save those settings and fire up the printer the next day etc.... The settings are worth s#%@. I have to tweak again. It's annoying.

Now... I think it may have something to do with my induction probe. I run my machines hot when printing PLA. 250deg for the extruder and 70deg for the bed. A hot bed prevents the part from breaking free from the bed and helps to prevent warping.

One thing I notice is that every attempt at printing, the extruder gets closer and closer to the bed. I'm wondering if this has something to do with the induction probe heating up or something.

During the very first print using previous settings... The first layer isnt sticking because the extruder is far from the bed. I have to move it closer. After a few attempts I have to dial in the machine so that it's extruding less and further from them bed because the extrusion is being smooshed.

I just bought a Bltouch to try it out. How ia it compared? Is it affected by heat or what?

I have a ton of stuff to print and I cant even print one damn thing.

Think I start tinkering with homing speed and ensure the end stop are solid and ain't any slight movement when homing after finishing.

You using pla+ just 250c seems a little extreme for pla and you shouldn't need a 70 bed either 40c ample I think

Edited 1 time(s). Last edit at 01/15/2021 04:40AM by jinx.

Quote
jinx
Think I start tinkering with homing speed and ensure the end stop are solid and ain't any slight movement when homing after finishing.

You using pla+ just 250c seems a little extreme for pla and you shouldn't need a 70 bed either 40c ample I think

I really don't think it's my homing speed. Its not really all that fast and it probes each point twice.

I have never had better results printing ever since I started printing at 250. The PLA doesnt burn at all evennif the extruder isnt extruding and is resting at temp. The 70deg bed does a great job keeping the print attached to the bed without glue, tape, etc. I wipe the glass down with acetone making sure theres no grease at all and start printing.

When I first start printing, the nozzle is to far away from the bed using the last settings I tweaked. I tweak the settings moving the nozzle closer tobget that first good layer. After a while it becomes apparent that the nozzle is getting to close so I start tweaking to keep the nozzle from getting to close and to prevent smoosh and overlapping the the extrusion width. Eventually I reach a point where the printer is printing perfectly. Its beautiful. But when I'm done and enough time goes by... I cant use those last settings because the first layer is crap. Not on the bed and won't stick.

I bought a BLTouch to replace the inductive probe. I'm really starting to think it's the probe heating up.

I have to agree with Jinx. Those temperatures seem way high. Did you check they are real? May have the wrong configuration settings so its reporting much higher than it really is.
I assume you are homing after the bed is heated.

I used an IR thermometer to check the bed and I'm getting 70deg. The extruder I cant get a reading with the IR because its small and insulated. I used to print PLA at 200 to 210. Then I saw a video of a guy recommending that prints should be done at much higher temps. so I tried it and holy hell yea. I don't see why the temp readings would be wrong. I know that the extruder is at 250 or about because of how long it takes to reach that temp. I actually tried to reach hotter temps but the 12v system wont go much higher than 250.

I am finally printing! I started up both printers not using the last settings I attempted for each machine but the some settings that I think are more appropriate for a cold start. That is if I'm correct about the induction probe losing sensitivity when hot. I got both printers running and they're both printing very well. Hmmm.

Yes I home and level the bed when the bed is at its operating temp.

Lets start with more information about your 3D Printers ?
It may also be helpful to have information on you 3D Printers firmware?

Though the numbers look quite high for PLA filament this could be a simple incorrect setting for thermisters / thermo couplers used.

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Computer Programmer / Electronics Technician

I have two mendal printers made by Alunar. They have M508 control boards that are were replacements for the original boards. They are running an older version of Marlin which I think is v1.1. I forgot which thermistor I specified in the firmware but I want to say I specified 1kΩ thermistors.

If the machine says the bed is 70deg, and so does the IR thermometer... I dont understand how anything can be wrong? If the bed is correct then I can only assume that the heatblock is correct too. Yes its hot, but it works really good. I get really good layer adhesion and bed adhesion too. I will upload a pic of the part I printed the other day.

The only issue I was having was with some stringing. I need to increase my retraction a bit more. The turn came out great though. No warping.

Another issue I'm having is with the machine printing small holes. I specified that i want perimeters printed slowly. It will print out perimeters slowly and some inner feature perimeters too but it seems to print some small holes faster and the hole perimeters get screwed up looking.

OK then which Slicer are you using.

I use the old an true Cura 15.04.6 and the New Cura 4.8.0 though finding that I like the PrusaSlicer 2.3.0 best of all.
It allows for modifiers that will allow me to give special attention to troubled areas photo below.




The Green in the above Photo.
I have adjusted the Printer Layer Height and Print Speed allowing the rest of the model to print normally while only giving special attention to this area that I was having problems with.
After changing the settings the model prints in 2 Hours not 6 hours and looks really great shown below. "this is a model I was helping another 3D Printer Forum user with.



Before doing this the Area in question looked like stairs when printing at 0.1mm layer height and took forever to 3D Print.
Now printing Model at 0.2mm layer height and change the layer height to 0.06 for this small area the continue printing at 0.2mm and prints in about 2 hours.

Though I can help you with the settings of any Slicer getting this Retraction and stringing problem solved I am suggesting that you switch to PrusaSlicer 2.3.0
My 3D Printer like yours is similar to the preset Ender 3 Slicer settings which made it easy to get PrusaSlicer up and running for me to print such good models.

Edited 1 time(s). Last edit at 01/16/2021 08:33AM by Roberts_Clif.

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Computer Programmer / Electronics Technician