What 3D printer...

[Onoff]

Quite possibly. This is why a lot of people use a BL Touch. It actually compensates for warped beds.

I don't get it...what is meant by "auto bed levelling"?

We can get a BL Touch for the i3 Mega S but you level it's bed with thumbscrews. Do some beds have say 4 micromotors rather than thumbscrews?

???

 

[Screwdriver]

Not for me. I am perfectly happy with the way it runs out of the box. I'm not going to be making decorative pieces. I see myself making boxes, cases, hinges, interesting mechanisms etc. but I am also happy to work around any precision issues with an externally fabricated additions. There is probably a geeky core of 3D users who need everything to be 100% 3D printed or it doesn't count. Nothing wrong with that philosophy but I'm not in that mindset. Give me practical functional items even if they're not "perfect".

Having said that, I will allow myself at least one T-Rex skull.

 

[Screwdriver]

I don't get it...what is meant by "auto bed levelling"?

We can get a BL Touch for the i3 Mega S but you level it's bed with thumbscrews. Do some beds have say 4 micromotors rather than thumbscrews?

???

My guess is a 3D map is used to compensate for your measured errors.

Won't compensate you for the hours it takes to constantly tweak it to work.

 

[ukracer]

I don't get it...what is meant by "auto bed levelling"?

We can get a BL Touch for the i3 Mega S but you level it's bed with thumbscrews. Do some beds have say 4 micromotors rather than thumbscrews?

???

I dont have one myself yet . Mine works fine BUT my bed is level as I use glass (although even that can bend slightly.) BUT I do use baby stepping every print.

As I understand BLtouch it find the variations in the level in the x and the Y planes and compensates for them in the firmware/processor.

So for example if the bed is level 1
20 cm from the front and 20cm from the back but in the centre its .02 lower its has intelligence to adjust the Z height from front to centre and centre to back.

 

[EBME2]

As others have said the BL touch does a map of your bed and compensates for. I have on mine and not 100% convinced on how useful it is, not convinced the algorithm works correctly and on top of this you then need to determine a Z height. You set the BL touch up to a height usually a couple of mm’s above the bed and then need to find a new Z offset based on how above the bed it is, I think this takes as long as levelling the bed properly. I have left mine on but if it packed in tomorrow not sure I would rush to replace.

 

[brewdexta]

I'm having trouble with some white PLA that isn't sticking to the glass bed properly and sometimes part of the print moves, I now have a polar bear with a club foot It only happens on prints with small bed surface areas.

I'll make sure the first layer is being squished down by checking the gap between the nozzle and the bed, but I've levelled it several times recently and use relatively thin economy printer paper so don't think its that.

So I've bought some Magigoo bed glue. I know some use glue sticks, some recommend water down PVA and we have loads of slugs in the garden, I could try rubbing the bed with one of those

Other than that I can play with higher/lower bed temperatures for the first layer etc. That will be easier once I have Octoprint installed, no rush, at the moment this is only an occasional annoyance and seems to be worse on this white PLA that came with the printer, not the loose free sample, my printer was bundled with 2kg on reels.

 

[Onoff]

I'm having trouble with some white PLA that isn't sticking to the glass bed properly and sometimes part of the print moves, I now have a polar bear with a club foot It only happens on prints with small bed surface areas.

I'll make sure the first layer is being squished down by checking the gap between the nozzle and the bed, but I've levelled it several times recently and use relatively thin economy printer paper so don't think its that.

So I've bought some Magigoo bed glue. I know some use glue sticks, some recommend water down PVA and we have loads of slugs in the garden, I could try rubbing the bed with one of those

Other than that I can play with higher/lower bed temperatures for the first layer etc. That will be easier once I have Octoprint installed, no rush, at the moment this is only an occasional annoyance and seems to be worse on this white PLA that came with the printer, not the loose free sample, my printer was bundled with 2kg on reels.

Print with a raft around the piece to increase the surface area stuck to the bed.

 

[Bladevane]

On mine (which has a 3mm borosilicate glass plate) I use PVA diluted 50% and PLA sticks really well BUT you need to let the glass plate cool with the print intact before trying to pry it off otherwise delamination can occur. My bed temperature is 70C for the Sunlu white I use but cooler (~58C) for other makes.

 

[Maker]

Just spotted these, can't believe 3d printing is strong enough!

 

[brewdexta]

Print with a raft around the piece to increase the surface area stuck to the bed.

While the bed glue is on its way I have started the print of the polar bear again but this time using "brim" in the bed adhesion part of Cura. It was set to skirt which just drawers a line around it but not touching it. The only point to "skirt" is that it shows if the bed is level I guess and if the filament is likely to adhere? So brim just puts a 1 layer thick skirt around the bottom of the print, I think that will be enough for the polar bear and sounds easy to remove. We shall see

Cheers
Andy

 

[brewdexta]

Success, well nearly. The skirt worked and the bears leg didn't shift but somewhere towards the middle of watching the original Return of the Pink Panther with the kids, probably when Kato jumped out of the fridge and attacked Closeau, the filament snapped and wrapped itself around the feeder.

I set it going again, originally thinking it may be problems with the filament diameter, but looking at what I dragged out of the the tube I think the feed roller pressure is set too high and its deforming the filament cross section too much. It's going ok at the moment so will leave it alone, however I will screw the adjustment in a tad to reduce pressure next time. Third time lucky with this piece..... maybe.

Cheers
Andy

 

[Screwdriver]

Just spotted these, can't believe 3d printing is strong enough!

So that's what 100% fill looks like. Amazing really, must admit the printed press tools I have seen have all been compression. That is impressive.

Haven't tried any destruction tests yet, a press tool must be on the cards soon. Meantime the only problem I am having is in the design. Whatever I think of is already on Thingiverse! I need a solution for a drooping iMacmonitor (it's printing now), I need a base riser for an overheating Mac Mini (Thingiverse), ok how about soe really useful hangers for USB cables ad the like, yep there's a million of them...

So instead of having to learn Fusion, I end up surfing for stuff on Thingiverse and wondering if what I really need might be another printer...

 

[brewdexta]

The bear printed 3rd time around, well half a headless bear as its torso is in two parts, a separate head and an arm that moves.

I'm now about third way through a 20 hour print. A tool drawer for the printer, mainly to how it prints tall things with thin walls as the drawer cabinet is printed end on with open end upwards.

 

[brewdexta]

Tardis turned out ok, the youngest assembled it today. Just got to stick the police box signs on.

 

[Screwdriver]

Oh well, it had to happen sometime. Looks like my luck ran out.

Not exactly bad luck, more like stupidity. I used Sketchup to hack together a quick bracket. The first bit went ok:

But when I made a new mounting lug, I ignored Cura moaning about "manifold error". It basically means Sketchup can produce something that looks like a 3D object but really isn't. The printer will print it anyway, even if such a thing cannot exist in the real world. Well it will try.

Got there eventually though there is an issue with having an interference fit between mounting parts! The part is always a bit bigger in one direction than the other and if the parts are not printed in the same orientation, those fractions of a mm mean they won't fit (easily).

Happy with it. Printed a couple of these "guide arms" but I actually like the blocky look you almost have to generate in Sketchup. The rounded end was a bit of a chore. Back to Fusion for the long term solution.

 

[brewdexta]

I did a 20 hour print of a frame of some drawers to keep bits of the printer in under the heated bed. Mainly to see how good it was, I was pretty pleased with the results. This was with the new hot-end because I screwed up the last one due to under-tightening the nozzle and the replacement came with a shiny new extruder to replace the plastic one.

Then I decide to print off some simple clips to tidy up the cabling as they get in the way and could potentially get tangled up. Same filament, no changes to setting and it all went pear shaped, very poor prints. Here's a clip cover that is proving a challenge, many prints, all died in various stages. The symptoms are that filament stops being deposited and eventually the filament snaps at the extruder.

The raft at the front was before I started looking into the problem. Its very poor and looks like a feed issuse. The other rafts are after I tinkered with the extruder.

This is close but no cigar, the print on the right failed about 5 mins from the end

After reading around the subject, it seems that the most common causes are extruder issues, heat creep and other types of hot end blockages. After watching the next print I first looked at filament feeding, there was the occasional big clunk as the roll of filament turned and lifted over the obstruction. This was not the cause but easily fixed, it turned out that when they spool the filament on the reel, there is some left sticking out on the inside, trimming this improved filament feeding.

Next syptom was that a few minutes before the print failed, the extruder started clicking, this is where the rollers are exerting pressure on the filament, but the filament can't feed so eventually it slips in the roller, the click is when the feed roller tension is suddenly released. Below is the new extruder, same feed roller and motor, just aluminium not plastic body.

It only happens just before the print fails so I don't think this is the root cause, but after looking up causes the roller nearest, although on a bearing, several people have reported that loosening the bolt slightly so the roller can move a bit and line up with the feed hole helps. So I did that and increased the roller tension. This did improve the overall feed and the better raft shows that, but prints still failed.

If you leave the extruder clicking long enough, the toothed feed roller wears through the filament and it snaps. just where the filament enters the hole leading to the bowden tube. You can see the groove being worn in the filament below.

What I did notice is that I couldn't manually feed the filament and get anything out of the nozzle when the issue hits. However, its not a nozzle blockage, if I heat up the hot end, pull out the old filament, replace it, immediately the filement exused from the nozzle. So onto problem solving in the bowden tube and hot end.

First up the bowden tube needs to be pushed right up to the extruder and the hot end, no gaps between extruder body and tube, or hot end and tube. I checked both ends, no issues and it still happended. if it was heat creep, that is heat from the hot-end creeping up to the heat sink and melting the filament before it gets to the nozzle, I would have thought that this would also show up when I pulled out the filement whiel herating the hot-end and replaced it. So discounted that for now.

I tried different filament temps, the box was printed with PLA at 200c, the problem started with the same PLA at 200c. so I lowered it and raised it a few, same issues. I've tried it from 190 up to 205c and given I can feed the filemt manually through the nozzle at 185c I don't think this is a root cause.

Although I have changed the extruder, this was before I made the box and it is virtually identical to old one, just better quality materials. However I wlll calibrate the feed by measuring how much filament is fed when the printer thinks it has pushed 100mm into it. There's also some calibration about how much the extruder reverses the filement to play with. Its 26c in the office during this heat wave, that may be playing a part....

EDIT

Although I've learned a lot from this, my finger just fell on the buy button for the micro-swiss extruder/direct drive hot end. Life's too short and I want to get printing Its supposed to get rid of any heat creep issues and other feed related problems. I will have to calbrate the stepss per mm feed with this but it will also print a wider array of filament types as it can go hotter without heat creep so I can tinker with stuff that stock bits can't handle.

Cheers
Andy

 

[Screwdriver]

My first thought was feed issue. I had some problems with the filament being reluctant to rotate off the roll and by the time it got to the feed roller, it was coming in at right angles because the straight pull came down vertically. Moved the filament roll to the far left of the top rail and made up that little anti-drag bracket above. The filament now goes into the feed roller at no worse than 45 degrees but due to the stiffness of the filament, almost a perfect straight in as it bends.

Your feed roller pressure looks way too high, my filament is barely even marked by the roller, yours looks squashed flat!I have been an expert in this field for almost a whole week now, so these comments are really what I would do if I saw that happening. The urge to tweak and upgrade is almost irresistible though and most of my projects have been parts for the printer.

I made these though (I made them off Thingiverse!).

It's a bodge bracket for my new (to me) iMac which has the traditional droopy screen, it's the 27 inch version, I forgive it. Plus the chap before couldn't be bothered to fix it so gave it to me. Thank goodness for that particular issue.

Again, I am a bit sad this item works so well. It is a great design and free but it really doesn't encourage me to design anything myself...

Anyhow, I hesitate to post this next picture but, WTF, it sort of relates to this amazing new iMac which is in fact 8 years old (!). It replaces the Mac Mini which disgraced itself by not being video edit friendly but only after I bumped up the RAM and installed SSDs. They ported over to the iMac (24Gb RAM total !) and I needed to fix the keyboard issue.

Err, so I downloaded this...

Did anyone spot the key cap puller?

Well, like I said, it sort of relates to the iMac because I have been using this keyboard for more than a decade. Time for a bit of gardening...

 

[Screwdriver]

Did you make this thing yet?

Stops you dropping stuff into the fan slots.

Curious as to why you printed your clips vertically. I did mine flat on their backs, no raft and like the cover above, at high speed 75mm/s. Also bed temp 70 degrees (for PETG).

 

[Seadog]

Now all that you need to do is download the keyboard cleaner

 

[Screwdriver]

Now all that you need to do is download the keyboard cleaner

She was too busy ironing.