@Madman: This has been one of the best, most informative, and entertaining threads I have ever read through. I wish I had more expertise to offer help, but the folks who are helping are way smarter than me!
I’ll have to settle for cheerleading and waiting on updates. Best of luck sir, and gods speed on getting Alison rolling.
Thanks for the sentiment Geoffrey - Alison and I are going to be going to the “prom” one of these days.
Today is a “bit” frustrating - a public holiday here and I am sitting - need parts - shops closed…
The heated bed is not on yet - only putting that in when the print head assembly is done - and that has been “attacked” but a number of the previous owners - one of which even used a self tapping screw!!!
Some people do not have a clue!!!
All the best
Aubrey
Update:
She is all together and wired up.
The axis all work, homing and all the rest. (did that earlier in the week)
Then I had to put on the extruder and the bed.
The extruder assembly looked like dog cr@p but until I can print a new extruder mount plate and the fan holders and ducting, it is what it is.
She will have to accept that she has to help me to do her “makeup” ;>}
The bed: Yet another screw-up I inherited!!!
This printer must have been one of the first - you know - the ones that have not got all the bugs sorted out.
There are 2 pieces of acrylic, each with 2 bolts on the top of the carriage plate that hold the belt mount onto the bottom of the carriage plate.
The problem is that with the acrylic sandwiched between the bolt head and the carriage plate the space to the heated plate is at best “minimal”.
This may explain why the initial layers sometimes were sticking and sometimes not - the heater plate was bottoming out on these screws/acrylic pieces and probably bowing the center of the plate upwards which meant that bed to nozzle clearance was probably nothing in the center (where I was printing).
That may also explain why sometimes leveling took so long.
Every time I went from corner to corner around the plate it was way off compared to the last setting (I normally go around maybe 3 times to get things right).
Then I noticed that when you push the plate down so that the springs get compressed there was a sort of grinding sound - like the screw threads were rubbing pretty hard against the side of the holes.
So I removed the springs - sound gone!
it looks like the springs were “falling” partway into the holes (which HAVE been drilled out previously) and meshing with the screw thread, effectively jamming them up a bit which also contributed to the leveling process issues.
So I took 4 washers, on a piece of wood, and flared them a bit using a tapered thing I had and a hammer.
The side where the flare stood out was placed so that the springs centered themselves on the flare keeping them away from the thread - now that works pretty smoothly too.
I had to replace existing wires in many places on the extruder - they had been hacked, joined and generally screwed up by previous “owners”.
Unfortunately I only have one color wire at this time so that has to do.
I will try to see if I can get some of those small cylindrical markers that they use in commercial switchboards and use them for identifiers .
Until then its small pieces of paper attached to the wires or in the case of the extruder motor I cut small pieces of each color and attached them to each wire with a small piece of heat-shrink.
Messy I know but at least they are identifiable for now.
Maybe I will use small pieces of white heat-shrink and color them with suitable markers - we will have to see…
I would have liked to power her up but it was 2am when I got finished and today (Friday) I am with a client.
(side note: I HATE PRESTASHOP!!!)
Anyway, tonight we either get expensive blue smoke and start crying or we print something and shout and cheer.
Either way I think there is going to be a beer involved!
More later and thanks for reading and all the support and advice - this “newbie” is appreciative!
Hi All - been over a week - sorry about that!
STILL have not been able to get all the cap screws I need BUT I eventually decided to “order out” and that will take a while to get here so we are carrying on in the meantime.
One big thing that I still have to do is figure out what I screwed up as far as the cooling fans is concerned - so all these photos are of things printed with absolutely NO cooling whatsoever in 30 degree Celsius heat (you do the Fahrenheit math if you want)
So here is the first “fail” and next to it the first success which was the very next print.
[attachment file=56460]
The fist print lifted a corner off the bed so I stopped and tried again - with more glue stick.
The dimensions were pretty darn good, the hole is round and the inset is dimensionally equal so for now the “steps per millimeter” settings seem to be OK.
But what REALLY pleased me was the smoothness of the finish and the lack of “Z axis artifacts”!
So now it was time for something a little bit more challenging - lets see what she can really do!
Now the “3D Benchie” is the “thing” that everybody does - I must have started printing 20 or 30 of them so far and to be honest, BORING!!!
So I decided to print Alison herself. Or at least the sexy wench I think she can be.
Off to Thingieverse and found a suitable model, put it through Cura and started printing.
DISASTER!!
All sorts of issues with the first 10 or so - never got more than 1 or 2 millimeters off the bed.
They came loose, nozzle got totally blocked, partially blocked, once the filament got hooked up on the spool holder, all sorts of issues!
Oh Yes, AND a power failure…
VERY disheartened!!!
Simply could NOT get her to come up more than 5mm no matter how nicely I talked to her!
But while waiting for prints to fail I had been all over YouTube and had seen a couple of slicer software comparisons - I knew that the Repetier package had a few of these so I tried one - the Slic3r “vanilla” and the Slic3r “Prusa Edition” were there so I decided to try the Prusa Edition - Alison is a Prusa clone after all.
Well, my ancient HP Note-thingie just has not got what is needed - kept hanging all over the place.
So I tried the vanilla Slic3r - and it managed to get thru the process.
Run the g-code - hit the power button!
In my haste I had used whatever the default settings were and in this case, one of them was 3mm filament diameter and she was spitting out large blobs of plastic all over the place.
Anyway, went thru all the settings and made sure they were as suitable as I thought they could be, pulled all the speeds down to max 30 mm/sec, leveled the bed, purged the extruder (which gave me yet another blockage, fixed that and tried again.
Under-extruding!!!
Spaghetti all over the place!!!
Then I had an idea - molten plastic is a fluid - a very viscous fluid BUT subject to all the laws of Fluid Dynamics - a less viscous fluid flows more easily and the only way to get the extruded material less viscous is to up the temperature.
And seeing as she had absolutely NO cooling whatsoever I was a “little bit” hesitant but what the heck - I went for it.
I bumped the temp up to 200 - just to see what happens.
She blocked again.
How I wish that I had access to a mean solvent like trichloroethylene or something - yes I know, “DANGEROUS STUFF” but it is getting to be desperate times!
So after the umteenth extruder strip and re-setup I fired her up again, at 200 degrees.
At about 2mm she started her nonsense again so I took a pait of long nose pliers, grabbed the filament just above where it goes into the release bar and gave a GOOD push down.
Well, a big stream of plastic suddenly squirted out and I could see there were little black specks in the yellow plastic and she started behaving herself - FINALLY.
so I let the print run, just to see what happens.
MEET “ALISON”
[attachment file=56461]
Sexy little wench isn’t she?
Yes, there are definitely still a bunch of issues to be sorted out but without cooling? I would say that it came out pretty good.
On the top of the buttock it looks like the same sort of delamination type issue that you get on the bow of the Benchie and there are layer lines on her bum and thighs but those are slice thickness issues.
The carbuncles on her shoulder-blades are probably ooze wipe-off happening when the nozzle moves from the leg to the torso - a retraction issue I think.
And at the bottom is remnants of the blocked/partially blocked nozzle issue that seemed to clear when I got a bit forceful with the filament.
Other than that, except for the groove around her one leg in the vicinity of the ankle she is not too bad to my newbie eye as far as finish goes.
The overhang support structures that Slic3r puts in seem to be adhering a little bit more than is desired but that is also probably settings related.
And she has even got all 10 toes!!! AND 5 fingers on the hand that is fully view-able…
So even though technically this is a failed print, I am considering it a big success simply for the reason that it shows that with all the adjustments and setup that I made to her, Alison is more than capable of producing a good print with a good finish when she does not have extruder indigestion.
Judging from the marks on the actual extruder nozzle I am probably the first one to use an actual spanner on it - there are all sorts of jaw marks and rounded edges on it - the orifice is probably not round anymore either - think I must hunt down a new one…
{Quick addition to the post}
I have just gone and made some tea for myself and as I was waiting for the kettle I decided to do another print using the saved settings to see what happens.
After everything warmed up I gave the extruder a purge and all it did was make a rats nest at the nozzle - so I did an "assisted purge.
This is what I got coming out the extruder! (sorry but my phone is no good at close-ups)
[attachment file=56462]
I can actually feel it with my finger!!!
That means that either the filament, which is in a re-branded box (from a supplier that has proven themselves to be shysters) is cr@p (the reel says “ZEN” but it is probable that it is fake)
OR there is carbonized plastic hiding away in the nozzle and that is randomly being extruded!
So - Off I go to hunt down a new, better nozzle.
Thanks for reading my sometimes long winded posts and a special thanks to all those that have shown an incredible amount of support and advice - I really appreciate it!
Those stringers look like under extrusion. If you’re getting burnt plastic, then you definitely have a partial clog.
They make filament cleaner that is jist filament that is molten at a huge temperature range. You can do a cold pull and get that gunk out.
PEI is a great surface to print on. Really sticky for pla and consistent, because you arent responsible for adding the right amount of glue.
You need a cooling fan on the extruder all the time, but the part cooling fan should only be on the overhangs. It should be off, usually.
Its hard to judge any of the print surfaces with a clogged nozzle, but I had a bunch of those warts from the usb just not being fast enough. It would drain the buffer and pause waiting for new commands. Thats especially true for highly detailed prints where one line of gcode means less than 1mm of path. The solution is to print from an SD card.
Slic3r can run from the command line. You’ll have to make the ini file, but this is what repetier is doing under the hood. You can try the prusa edition this way.
Hi Barry
Part of my “start up procedure” has now become :
But lets face facts here, Something is NOT RIGHT!
Half my life ago I was working for a company that made snacks - things like potato and corn crisps etc and they developed a new product based on whet ground corn.
The corn was prepared and then sent through an extruder and straight into the fryer.
The problem was that it had “stones” in it - small pieces that were rock hard and the public were complaining bitterly - some people even broke teeth.
So I was put in charge of sorting it out - everyone else in the maintenance department had tried but nothing helped.
So I ran the machine and then switched it off without going through the shut-down procedure and when it had cooled I started to strip it down BUT inspecting everything minutely as I went.
As it turns out, the plate that was bolted onto the end of the screw barrel had a hole quite a bit larger than the hole in the screw barrel.
This was because the nozzle had a thread that was also larger than the hole in the screw barrel and it only went half way into the plate.
So between the nozzle and the barrel there was a cavity that the material filled BUT it just stayed there, getting dried out and baked by the heat caused by extrusion pressure and mechanical friction.
The useless “procedure manual” told the operator to “unscrew the nozzle and clean out all material” - and that is what they had been doing.
So we redesigned the plate and the nozzle so that there were no “dead areas” to trap the product and all of a sudden there were no “stones”. Put the public had had a bad experience with the product and it had a bad reputation and it died - pity, it was actually pretty nice…
My experience in the plastic injection molding industry is that you NEVER have anywhere that material can be trapped in - if you do you have got a “problem” injection molder because in theory ALL the plastic going in SHOULD come out as quickly as possible.
Plastic at melt temperatures starts to degrade relatively quickly - a minute or two is enough sometimes.
With the snack thing, the “degradation” was drying out and forming the “stones” I was talking about.
With plastic, ESPECIALLY PLA which as far as I know has its origins in organics (wheat or corn I think) and the degradation process is probably a lot quicker than in most of the oil based polymers.
So now the PLA is degrading and carbonizing and every now and so often apiece breaks off and you get a nozzle blockage of some sort.
Now I have noticed that her nozzle blockages happen either during or shortly after printing an area that does not have high material flow requirements.
Low flow means a higher heat buildup and because the trapped material is on the outer edges of whatever “hole trap” there is, it gets the full brunt of the heat being transferred from the heater block, degrades, and as soon as high flow is resumed, breaks free - and you have yourself an issue!
That is why a lot of people ONLY use genuine parts (like nozzles and the Teflon lined threaded tube because the knock-off parts cause cr@p!
And I can see why - the “pirate” parts are only “more or less” dimensionally the same as the genuine parts.
Yes, the orifice, thread, length etc are identical BUT these pirate parts introduce all sorts of miss fitting issues that then start messing you around.
Here a good example is the hole on the back of the nozzle - the one that everyone wishes was bigger so that they could get a bigger screwdriver blade into it to clean out the “gunk”.
That hole right there is probably where the problems come from!!!
If I still had my machinery I would love to have made my own tube and nozzle, and get rid of the heat barrier Teflon tube - that would increase the heat transference from the outside of the tube to the plastic quire a bit.
But reamers are expensive, ESPECIALLY ones as small as 0.4mm so that is not on at this time in my life…
Thanks for the comment
Thanks for the comments and advice there Jeff! Appreciated!!
“Cold Pull”
I do it all the time!!!
But the blocking is the result of the problem, I want to fix the cause - that is just me though!
“PEI is a great surface to print on.”
I believe so!
And mounting PEI on a spring steel plate seems to be the answer for rapid turn around because all you have to do is remove the one with the prints on, mount a newly prepared plate and hit “Start” - good if you are in production.
“You need a cooling fan on the extruder all the time, but the part cooling fan should only be on the overhangs. It should be off, usually.”
[attachment file=56550]
I know!!!
I have managed to get one fan sort of working - but you have to “kick start” it - the other one is totally dead.
And on the bed I’m printing cable chain pieces - the first row all lifted (which accounts for all the spaghetti).
[attachment file=56551]
I have already printed the shroud for her new parts cooling fan.
After I get 2 new fans I will print up a nice extruder cooling duct for her.
“I had a bunch of those warts from the usb just not being fast enough.”
Had a similar problem with USB - the HP would go into sleep or energy saver mode and comms would go down - made a pile of scrap!!!
“Slic3r can run from the command line.”
NOT a "command line person!!! ;>}
“You can try the Prusa Edition”
I tried it - Hangs the HP - Did it on my PC - but just got confused!!!
I should really learn how to set up different profiles etc - maybe this weekend. ;>}
Anyway, thanks for the comments, interest and advice - REALLY appreciated!!!
Have a safe Easter weekend!
Aubrey
Update:
“Space Invaders” are attacking Alison!
[attachment file=56556]
Actually the links for a wire management chain that I promised her ;>}
And this is probably the first time the print area is TOTALLY full.
The last batch was “only” about 24 - and unfortunately a bunch of them sort of came loose - which had me sitting there for about 4 hours with a long nose pliers fishing out spaghetti so that it didn’t mess up the ones that were still sticking.
And if my calculations are correct I will have to print up another batch…
I have bumped the feed rate up to 125% and everything still looks OK and Alison is jiving away quite contentedly - so we will see.
Why didn’t someone tell me that printing takes so long? ;>}
Anyway, busy downloading Fusion 360 at this time - I hope they accept me as a “personal use” user - cant afford a license…
When the MPCNC is done I will be using mainly Blender to produce the models but in the meantime I have got a whole bunch of small bits to print so it is now time to learn a new CAD program - the last one I used was pre-Windows so essentially I am a newbie there too.
Looks like “retirement” is pretty much like going back to school, learn learn learn…
But that is cool.
Noticing that the nut that you have double bolted to your lift looks more like an anti-backlash nut, which would normally have a spring between it and the plastic block. Well, that’s how it works on my 2418 CNC. Maybe for a 3D printer anti-backlash is not needed…
Hi David.
That there “thing” you pointed out is my way of getting the lead screw not to fight the guides and the other side lead screw.
When the component was printed in the factory it started to lift off the bed resulting in the surface that the nut should be attached to causing the nut to go out of alignment when tightened up.
so now the nut is sort of hanging on those 2 screws and I put lock nuts on so that the length does not change around.
Not the most elegant solution I will say BUT at least now she is not arm-wrestling with herself and since I did all the fixups (and some temporary work arounds) at least the Z axis is not binding any more and the print wuality and finish has improved dramatically!!!
I am still looking around for the stl files for that pair of parts (Afinibot) and as soon as I get hold of them, new parts get printed.
Thanks for the comment
Aubrey
Those cable chains work a little better if you print some in each direction, so any small errors are canceled with the next link.
Printing on the whole bed is a pretty good indicator that you’re doing something right.
Hey Jeff,
That print took FOREVER to finish and all components were usable I’m glad to say.
At the moment she is printing 2 new Z axis pieces (the ones that holds the axis that the extruder is on) and that one was also going to take forever even though I increased the “normal” speed to 45mm/sec (I know, probably too conservative!!!)
At about layer 8 (of 300) I decided to go for broke to see what other problems there may be and I pumped it up to 200%.
Well, at least there was enough filament being processed so that we did not get carbonization and the resultant blockage and it went OK for about 20mm (finish “not so good”) with her throwing the extruder all over the show - but she handled it speed-wise.
Then she got a radial artifact sort of like what the YouTube guys show when they get skipping steps on X or Y.
And maybe 8mm later it went away and everything came back into line vertically.
The finish is rather cr@ppy but then I noticed that as you get higher it gets better.
(I will post a pic when it is done.)
My thinking is that the guide rods are not parallel.
That was one thing that I didn’t check because I don’t have accurate measuring equipment large enough but I’ll figure out some way of doing it with what I have.
I also noticed that the X and Y belts bounce around quite a bit at high speeds but the machine construction is such that things start to bend if I take the tension any higher - tried to do that on assembly and had to back down a little on both.
The new pieces have bolts that screw up against the end of the guide rods on one side - the current ones are just interference fit so any excess belt pressure simply gets transferred to the guide rods and flexes them - not good!
But if you think about it, you are trying to throw around a hot end AND stepper motor - the stepper motor is heavy - no wonder the guys with the Bowden type setups get better quality prints all other things being equal - they are not throwing “half a ton” of stepper around!
Another thing I must remember to do is see if I have filament retraction on and what the setting is because there are all sorts of “blob wipe” type artifacts and thin stringing.
But I think for now after the new axis blocks are fitted, the cable management and fans I must go back to the MPCNC.
Hopefully the steppers and drivers will be ordered in the new month [;>}
All the best and have a happy and safe Easter.
Aubrey
Wrap a string around them in a loop and tie tight, then slide it up to the top and see if it’s just as tight. Needless to say you’ll want to make sure it’s horizontal at both positions…
FOUND AT LEAST ONE OF THE PROBLEMS !!!
On a much earlier post I made the following statement:
Firstly, on most of them that are available commercially I notice that the part that actually engages the filament and forces it into the “melt chamber” is an actual gear.Really? – The shape of a gear tooth is designed TO BE A GEAR TOOTH!!!
Many things have been tried. Have a look at the extruder wiki. There are hundreds of attempts. The gear needs to pull equally in both directions without cutting the filament in half and engaging well. As long as one of the gear or the bearing has a grooved surface it is actually a great option. Some are even geared on both sides.I should have stuck with my instincts!
It seems that the high feed rate has got all sorts of slippage going on!!!
The “gear” drive simply does not have the mechanical means of providing the high level of pressure on the filament so it simply starts slipping.
But that may not simply be the end of the story really.
Alison’s hot end is pretty much your "standard setup meaning the brass nozzle has a thread length of maybe 10mm - and that is the “melt chamber”.
Now if you think about it that is not much of a melt chamber at all really.
Now if you have got a high feed rate on the filament, is 10mm enough length to allow the filament to fully melt during its travel?
Maybe not!!!
So the outer layers of the filament are melted but what about the inner core?
That 0.4mm or 0.5mm of filament is reaching the nozzle orifice in an unmolten state and that is definitely not good.
It will cause a momentary “blockage”, the “gear” drive will slip a bit while the melting process carries on and eventually the nozzle will clear and the extrude will start flowing again.
BUT there will be a length of the layer that has been skipped!!!
Now this will of course look like a blocked nozzle because that is exactly what it is however the “blockage” is NOT being caused by foreign material, carbon, dirt or whatever but by filament that is not getting up to the desired temperature all the way through its diameter in the 10mm long melt chamber.
I have looked at the “volcano” style of nozzle which has a far longer melt chamber length along with the associated heater blocks which is simply a “standard” lead block rotated 90 degrees to apply heat along the entire length of the much longer nozzle/melt chamber which all things being equal, will ensure that the filament is completely melted and up to temperature by the time it gets to the nozzle orifice.
The standard heater insert probably has enough power to supply all the heat required although the duty cycle will be a much higher percentage than the short version.
So it looks like I will have to track down a supplier locally that can sell me the “volcano” style parts without ripping me off - unlike the a$$h0le that sold me a Bowden style drive when what I needed was a direct style drive.
And then would not refund me or swap it out for the correct style drive - IDIOT!!!
But maybe I will have to deal with him - but I hope not!!!
I am sure that I am not the first one he has ripped off like that - nor will I be the last.
Anyway…
I have started to figure out where and how to fit all the cable management tracks - unfortunately not everything is a “direct fit” but that is OK, I’ll figure it out.
At the moment all the high amperage wires have got a pretty big strand diameter which means that over time they will work harden and break.
So maybe I will use some auto speaker wire - just as thick in the overall total cross section but the individual strands are much smaller diameter so it should pass current better and last longer.
Thanks for reading, more later, all the best, Aubrey
Remember that when you say ‘high feed rate’ with a standard 0.4mm nozzle and 1.75mm filament you are feeding the filament into the heating chamber at a 0.04 : 0.765625 ratio (proportional to r squared), or about 1:20. That means you are feeding into your extruder with the filament moving at a 20th the speed of the X/Y movements. With a 10mm melt chamber you should have no trouble melting fully within the time elapsed moving the head 200mm.
Point taken there Bill.
So now the question is “WHY are things still going weird?”
But I think that a longer melt chamber is a better idea anyway so I’m going to go down that route and then start trouble shooting from there.
Once I have my MPCNC built then I will be fitting a 1mm nozzle and rapid prototyping the work pieces on the 3D (as big as I can get it to fit on the bed) to see if everything “looks” OK before firing up the mill.
For the final product (on the mill) it will be all about the aesthetics and I really do not want to spend 2 days milling only to find that it “looks” off for some reason or other so within reason the high layer height during that “pre-milling” process is good.
However for the printing of the mill pieces it has to be done at a small layer height without all the layer skipping, under-extrusion or whatever is actually going on here.
Long story short : Gotta get it right!
The standard hot end design has a block that heats and wraps around the throat and tip. Both the tip and the portion of the throat that’s in the block get hot, so the depth of the melt chamber is the thickness of the block. Above that block the throat goes through some sort of cooling device, typically a finned heat sink and fan, but sometimes more exotic like water cooled. If your cooling isn’t working right the heat from the block will travel up the throat and you’ll get partial melting up higher. The partial melted plastic tends to stick to the sides of the throat, or worse yet partially melts the PTFE tubing inside the throat, and that blocks smooth movement of the filament. Your issues sound to me more like improper cooling than improper heating. Try upping your game in that area to make sure it’s cooling efficiently, or pull the hot end apart and look for signs of melted plastic above the top of the block.
You said earlier that you are using some kind of shitty filament, with big impurities in it. So it is very likely that your nozzle is clogged. Check that again and never use this filament from now on.
Also, and more importantly, it seems like your extruder is quite basic, with not much possibilities for cooling it since it is just some kind of threaded rod. The fan you attached will cool it down a little, but in my opinion this is nothing close to what you actually need. So I suggest you swap it for a “normal” one, they are super cheap and it will take out a lot of troubleshooting guess work for you.
Hey there Madman,
I know this does not help with your 3D Printer issue, but if you would like I could print the parts that you require for the MPCNC and ship them to you.
I am in JNB so I am more than willing to assist in that regard. At least in this way you can work on getting the MPCNC up and running.
At some point I need to find time to build me one of these too.
