3D Printers

[Stub Mandrel]

30 minutes ago, Chriske said:

Most (almost all) beginners underestimate the strength of printed parts.

Absolutely right, I printed a guitar effects box with the lid hinged on two M3 screws. It happily takes my full 13 stones standing on it.

[Stub Mandrel]

9 hours ago, Chriske said:

Before I decided(that was years ago) which filament I was going to use for most of my parts I did tests on solid parts. It was a completely different test I also did to test what colour would be best to use in sunny conditions).  Anyway that test-part was 100x20x10mm, I made 5 of these parts each all with different infill and a few different materials. All parts had 3 perimeters. It took me almost 2 days to test all these different materials/infills.  ABS(I never use it myself). but did add that in my test because my friend Marc asked me to.
Half of the length of that test-part was clamped on my workbench, the other half was hanging free above the floor. Hanging on that part above the floor there was a bucket that I filled with brass, lead,...  The most promising infill (for PLA) was 'Line infill' at 40%. After about 30kg that small part started to bend. It needed 55 kg before it eventually cracked. To be clear, that bucket was not hanging close to my workbench, but at the very tip of that part.

 

I did some similar tests on 1x10mm bars.

The setup for a test

Please bear in mind that these were all based on single samples, except test 1 which was done twice, giving similar results.

Tests 1 to 3 were performed PLA test bars, printed with 0.2mm layers, a shell thickness of 0.8mm (using a 0.4mm nozzle), a top/bottom thickness of 0.56mm and a fill density of 20%. Test 4 used a bar with 40% fill.

Table 5.2 - Test Results

Bar	Fill	Direction of layers	Direction Force Applied	Force to flex ~3mm	Force at failure	Type of failure
1	20%	Along length of bar	Normal to layers	3kgf	11kgf	Brittle
2	20%	Along length of bar	Sideways to layers	4kgf	10kgf	Brittle
3	20%	Across bar	Sideways to layers	3kgf	10kgf	Brittle
4	50%	Along length of bar	Sideways to layers	7kgf	21kgf	Brittle

 

 

[Stub Mandrel]

A striking difference between the bars was in their stiffness. Bar 3 was much more flexible, presumably this was because of the direction of the fill being along the length of the bar, whereas in the other bars the fill effectively divided it into many short compact cells rather than a few long ones.

Increasing the density of fill from 20% to 50%, fig. 5.35, both stiffened the bar and resulted in a significant increase in strength.

Thread Strength

Very simple tests were performed to see how strong screw threads are. Test pieces were printed with close fitting threads in them, using 40% fill, a reasonable amount to use for structural parts.  The threads were not ‘tidied up’ in any way and were tight but it was not difficult to insert the screw, fig. 5.36.

Ordinary cap screws were fitted and given a total of ten turns – the head of the screw was NOT tightened up against the test block. The pull-out strength of the screw was them tested using the same spring balance as for the fracture tests, this limited the maximum force to 35kgf (75lbf). The test was then repeated with the screw wound out to five turns of engagement.

Table 5.3 – Thread Strength

Thread	Material	Engagement	Force	Result
M6	PLA	10 threads	35kgf	No effect
M6	PLA	5 threads	35kgf	No effect
M5	PLA	10 threads	35kgf	No effect
M5	PLA	5 threads	35kgf	No effect
M4	PLA	10 threads	35kgf	No effect
M4	PLA	5 threads	30 kgf	Surrounding bulk of print failed
M3	ABS	6 threads	25kgf	Plug of material broke out around thread
M6	PLA	8 threads	240kgf	Gradual failure of surrounding material

The M6 test was done with a lever giving 10:1 advantage, 240Kgf is nearly a quarter of a ton...

 

Edited October 13, 2019 by Stub Mandrel

[PeterW]

Steel or harder nozzles with the carbon fibre stuff, printed a block once and the whole end of my brass nozzle “vanished”... like ended up 3mm in diameter rather than 0.4mm.

i never use rafts as they either don’t stick or stick far too well. I print onto the bed and use a brim that I can trim off. That way rectangular plates don’t peel off. I adhere with glue, though buildtak, hairspray etc are also good. For higher temp materials I like Dimafix... smells amazing too. With a 100C bed I can print ABS/PC/PVDF with no issues.

Protopasta steel fill makes good weights too. Wood fill is only for those with infinite patience who have too many spare nozzles and like a challenge.

peter

[johninderby]

I use 3M blue masking tape on the bed. That way the tape can come off with the raft when I slide a palate knife under the raft and it pops off.

[Gina]

I just use clean glass.  Mainly borosilicate glass but I have also used float glass as used in windows.  I clean the glass with IPA (isopropyl alcohol) though with a glass plate that is removable, washing up liquid and warm water, well rinsed off and dried with clean kitchen paper works well.

I've tried all sorts of goo applied to the glass but for PLA and PETG nothing I've tried is any better than clean glass and mainly worse.

Edited October 13, 2019 by Gina

[Chriske]

Louise has a new problem now.
We all try to help Louise(or other 3D-printer starters) by writing down our way of working with our own printer. We all have our own way of working thinking it is the best way. There are dozens of things that could be done differently. We all have our own criteria how good a print supposed to look like. We all have our own optimal set of slicer settings. We all have our own method how a print should stick onto the bed...and so on...

For a  newbie like Louise this must be all incredibly confusing. I'm not saying stop posting info/tips.
Problem is all printer-users here (and around the world) had that same problem/dilemma when they started their own endeavour to find the correct way. So did we 6 years ago. In the end we decided to forget all about printer-forums and go our own way because after a while we didn’t know what or who to believe anymore. Reason : Yep...they all have their own way of working thinking it is the best way...

What I didn't find on the net back then was a set of 'standard (basic) rules' how to use a printer. Not a specific printer 'X' or 'Y' brand, just a printer.
A mini manual how to start and most of all how to correct errors like quality problems. That is what Louise and all other starters need.
Lucky for all these starters these days there are a few (non brand related) sites were you can find very good info, 'How to' and 'How to fix'
This is just one of many. It has to the point info what to do in case of bad printing. (The one in this link sells Slicers but the info is free.)
 

[Gina]

Although rigid.ink have stopped selling filament their website is still working and they have lots of useful info.

[Chriske]

10 hours ago, Gina said:

I just use clean glass.  Mainly borosilicate glass but I have also used float glass as used in windows.  I clean the glass with IPA (isopropyl alcohol) though with a glass plate that is removable, washing up liquid and warm water, well rinsed off and dried with clean kitchen paper works well.

I've tried all sorts of goo applied to the glass but for PLA and PETG nothing I've tried is any better than clean glass and mainly worse.

Glass is indeed the best surface to print on. Parts printed on glass have that smooth and glossy surface.
I always use plain float and clean it with glass cleaner instead. Then I rinse with hot water(not cold!)
And as Gina said, dry with clean kitchen paper.

No towel or anything else that came out of a washing machine is used to dry the surface..! Rubbing the glass surface dry with a towel or cloth will undo the effect of Isopropyl or glass cleaner completely. Freshly washed cloths still have traces of soap in it. Drying a glass surface with it, at the same time you put a very faint soap-film onto that surface.

Anyway after glass-cleaner and hotwater-rinse parts sticks like hell. That's why I have several glass sheets for each of my printers. When a print is done I take glass (+ part(s) still on it) of the printer and replace it with a new and clean glass sheet. After a few minutes the finished print starts making cracking sounds while releasing itself from the sheet of glass. I always put it angled against a cabinet or wall allowing it to cool faster. After a few minutes the parts fall of by itself. Very large parts takes longer.

There's that issue of using hot water to rinse the sheets of glass. I've tested it several times using cold or warm water. A warm water rinse makes the glass surface more sticky compared to a sheet that has been rinsed with cold water. Very strange, did some research on the matter, and I still don't know why.
As a matter of fact when a glass-sheet is freshly cleaned I'm able to print very small parts on it without the need of a skirt at all. Even when the first layer is just 2 or 3 lines wide..!! (PLA, not PETG)

[Chriske]

Just watched the newest Angus YouTube movie.
He was testing that Sidewinder-X1 printer. To my astonishment at min. 5.25 he said about that blue cat he just printed with that Sidewinder-X1 : 'it's still a great result, compared to many machines I've reviewed...'

To me : This print is a disaster.!!!
Ok, agree, it is a cheap printer, and I would not expect great things or super quality using this kind of printer. But saying about this 'great result' Is a bridge to far imo.

[Gina]

The perimeters are certainly rather rough but I've seen worse.  I don't think I would go so far as to describe this print as "a disaster" - it certainly isn't good though.  The support material around the cat's face looks very strange.  Is that the real disaster?  It certainly isn't right.

I would also comment on his statement 'it's still a great result, compared to many machines I've reviewed...' .  If that is so the others must be dreadful!

Edited October 14, 2019 by Gina

[Chriske]

Well Gina, on this one I must disagree with you about that word 'disaster' I did use.
It is a 400+$ printer, I've expected far more clean prints for that kind of money.

37 minutes ago, Gina said:

....If that is so the others must be dreadful!

That was my second thought too...😱

[Gina]

Ah!  Didn't realise it cost that much, something gave me the impression of more like 150-200!

[Chriske]

This is the one he's testing.

[RolandKol]

Hmm,

but doesn't it depend on the print speed also? maybe he was too lazy to wait and printed on 80mm/s? in this case, - result is quite Good!

with my Mega-S, I can get very clean surface or similar to this one

Edited October 14, 2019 by RolandKol

[Chriske]

Nope, speed has nothing to do with it Roland. This printer has a major Z-axis problem. It's a well known problem btw.
With my printer I can go even faster without any degrading perimeters.

[Gina]

How big was the cat print?  If it was a couple of cm (miniature) that may not be too bad though my little test prints of cats I did years ago were better than that and I thought 3D printers had advanced a lot since then (mine certainly have).

[Chriske]

I think somewhere between 150 and 200mm.

My hand is 204mm long(starting from the wrist)
So I think closer to 200mm

[Gina]

That should have printed much better then!!

[Thalestris24]

Oh well, I ordered an Ender 3 Pro earlier and via Amazon I did glance at the slightly more expensive CR-20 Pro but wasn't sure if it was worth the extra plus the search for ideal devices can become never ending!  Also ordered some Sunlo (Korean) filament - hope that's ok... Will see how I get on with it all. What's the worst that can happen?? I think my main problem will be finding the time! Plus, I registered with Autodesk for their Fusion360 software but not downloaded it yet. I said I was a student for the next 3 years .

Louise

[RolandKol]

6 minutes ago, Thalestris24 said:

Oh well, I ordered an Ender 3 Pro earlier and via Amazon I did glance at the slightly more expensive CR-20 Pro but wasn't sure if it was worth the extra plus the search for ideal devices can become never ending!  Also ordered some Sunlo (Korean) filament - hope that's ok... Will see how I get on with it all. What's the worst that can happen?? I think my main problem will be finding the time! Plus, I registered with Autodesk for their Fusion360 software but not downloaded it yet. I said I was a student for the next 3 years .

Louise

Gratz!

Just once you assemble it, - do Not Press "HOME All" button! 
Level the bed properly  

and better if you level it once its pre-heated up to your preferred bed printing temp, which will most likely to be 60C, if you will print PLA.

[Thalestris24]

1 minute ago, RolandKol said:

Gratz!

Just once you assemble it, - do Not Press "HOME All" button! 
Level the bed properly  

and better if you level it once its pre-heated up to your preferred bed printing temp, which will most likely to be 60C, if you will print PLA.

Ok, thanks for the tip! What does 'Home All' do that I wouldn't want it to? I won't get it before Friday and may not have time to assemble it until the following Friday. Still, something to look forward to - early Christmas ha ha

Louise

[PeterW]

Heads up Prusa just announced a Mini version that’s simple to put together, but smaller build bed, 380 (ish currency units.... have to see what £). Available in a month or so... very interesting as that have a very strong reputation. 
 

PEter

 

PS watched a colleague end a job today with millimetres of filament hanging out the extruder when it finished.... lucky?!

[Stub Mandrel]

26 minutes ago, Thalestris24 said:

What does 'Home All' do that I wouldn't want it to?

If you haven't adjusted the stops yet, it can plunge various bits into other bits.

Setup instructions should let you get the stops set right and then you can home the head with impunity.

[Dr_Ju_ju]

Glad to hear it Louise, if you need any help, you know where to come.....