- February 16, 2018 at 10:41 pm #53257
This is where I will be posting specifically about my CNC machine project.
I’m a retired artisan and often somewhat “weird” (hence my screen name) who had ALL his machinery and tooling (built up over years) consigned to a couple of skips by an idiot stepson.
BUT I NEED MACHINERY IN MY LIFE!!!
So I’m building myself a CNC mill.
It was difficult to decide which way to go as I literally don’t have tools – except for some spanners that fell into the spare wheel well of my car and many designs were way above the capabilities of what I have but about a week ago my luck changed and I was able to buy a 2nd hand I3 printer – so its going to be a MPCNC.
In South Africa we have a problem in that buying something from “overseas” sounds cheap but once you factor in delivery fees (a long way) and insurance (VITAL HERE) it is often simply not affordable.
So in many cases in my career I have had to use whatever is available locally and “make a plan” to get it working and I will probably be making MANY of these “plans”.
So I am going to post my trials and tribulations here.
I may be posting in the wrong place and if I am then if a moderator can let me know and if possible move it to wherever it should be.
In the meantime I need to get a couple of spools of PLA, a piece of pipe to test fit the parts to see if the dimensions are good and follow up on a lead I got for 2nd hand motors out of industrial printers at an affordable (for me) price.
And maybe tonight I will try printing my first part to see what is going on.
So, wish me luck as I will probably be needing it and to the guys who are more knowledgeable, please keep an eye here as I will definitely need more than just a little mentoring along the way.
Eventually the machine will be used to produce wood carvings and sometime in the future it (or its sister/clone) will probably get an A axis – and maybe the router will get more degrees of freedom but we will cross that bridge if and when we come to it.February 17, 2018 at 4:27 am #53260
So using the calculator at http://stevecd.github.io/mpcnc_calc_react/ I have gotten the following measurements:
Required swept length – 90 cm (900 mm)
Required swept width – 90 cm (900 mm)
Required swept height – 45 cm (450 mm)
Total pipe (25 mm od) required:
3 off 927.9 mm (X axis)
3 off 927.9 mm (Y axis)
2 off 470.1 mm (Z axis)
Total pipe 6507.8 mm cut as above
Z lead screw (M8x1.25) – 1 off 468.1 mm
2 off 945.7 mm (X axis)
2 off 945.7 mm (Y axis)
Total Belt 3782.9 mm
Now I don’t know what the values in the “Settings” section is all about so I left it at whatever the default values were – I suppose I’ll find out at some time or another!
My quest for 2nd hand steppers was a bust AND I had a run-in with the idiots in blue – long story, later but it cost me 500 bucks because something was 8 inches away from where it is SUGGESTED that it be placed – Year end coming, chasing the ticket quotas is my guess…
Anyway, going to try to print the smallest pieces – the ties that help prevent the belt roller bolts from misaligning.
Why? Well this will be the 3rd time I’m starting a print on the I3 so screw ups are bound to come my way – rather on a low volume print than a high volume print…
Wish me luck.
Attachments:February 17, 2018 at 8:10 am #53268
RyanKeymasterI may be posting in the wrong place and if I am then if a moderator can let me know and if possible move it to wherever it should be.
You are in the right place buddy, welcome. Can’t wait to see how you progress.So using the calculator at http://stevecd.github.io
That is an old one from a previous design. Do I still have it linked somewhere? This is the current one.inches away from where it is SUGGESTED that it be placed
Ohhhhh ya gotta learn to suppress that urge…99% of the time it just makes it worse. Can’t teach an old dogs new tricks I guess. I did watch a friend lose her mind on them once, they apologized and left. I felt like I was in the twilight zone, it was glorious.February 17, 2018 at 8:37 am #53272
I am expecting this to be a fun build to watch. No pressure.
I found this site to be pretty useful for describing what is failing on a print:
3D printing still requires a lot of skill, so don’t be afraid of a few dozen failures. The first layer is 10x more critical than you think. Hopefully you’ll get a hang of it before your stepson sells the printer.February 17, 2018 at 3:35 pm #53289
Its 1 am local…
The first part print was a disaster!!! Filament was not feeding off the spool so it started printing air.
I hunted down a simple clip over spool holder that would fit my machine, sliced it and began setting the machine up.
I suspect that the heated bed may be warped as the adjuster at home position needs to be loosened more than it can be (the nut is no longer in contact with the surface).
Eventually got it more or less set up.
Then the filament started to grind – cleaned it all out.
Then I noticed that the extruder fan would not switch on – the other blower did..
Unwound the spiral cable holder – THE DARN THING WAS NOT EVEN CONNECTED!!!
To make matters worse all the places to plug wires in are used – NOW WHAT?
So I doubled up on the switchable fan connector. evidently the extruder fan runs when the machine is powered up but this is better than nothing!!!
Then I noticed that the positive side of the power supply cable pair was loose – It had just been stripped and twisted – out with the soldering iron and tinned the wires – heated bed power wires too.
Put everything back together – Evidently the board was changed at some point BUT its a crappy design, no space and mounted right up against the frame (the side with all the wires – USB port on the other side so can’t turn it over – last resort was to mount it with 2 screws but moving the right hand holes to where the left hand holes should be and wrapped everything up again.
And the little display on the machine frame does not work – needs to be updated (firmware) I had been told.
Started the spool holder print – forgot to replace the silicon extruder heat shield and the workpiece cooling shroud but let it go on.
So far so good – THEN just before it was about to do the closing on the top layer it lost communications…
Hope THIS is not going to become an issue!!!
So the first port is a dud – but its usable…
Put all the missing pieces back, cleaned the bed, rubbed Pritt (glue stick) all over it again and started on the 2nd one.
Then remembered that I had not checked the bed levels again…
Oh well, too late – but the bottom layer looked OK so I let her run.
It has just started to close the holes and when its done its sack time…
While I was typing this it finished – top layer too this time.
It does not look too bad but I think that just maybe I’m not pushing out enough material as you can see the boundary lines between the passes – little creases but not holes or drop-aways so I must remember that.
BED – NOW – Goodnight…February 17, 2018 at 11:35 pm #53294Hopefully you’ll get a hang of it before your stepson sells the printer.
Oh don’t worry, I’ll get the hang of it all right!
As to the idiot stepson, his biological father gave his mother her first failed marriage and he gave her her second. I’m in Cape Town and she is “captured” in a situation and up in Johannesburg.
Hell has a special place for idiots like him – and I have an aluminium baseball bat (normally used to “keep the peace” in my boarding house) that I would dearly like to take for a test drive.
Mr Moderator: what is the policy here for placing links to off subject material?
In any case, I am attaching an image of a sculpture that had me crying like a baby for over an hour the first time I saw it – It lit a fire that is sending me down the path I am on as far as this project goes – I HAVE to make my own version of it to pay homage…
What the heck, Here is a link to more info
Attachments:February 17, 2018 at 11:44 pm #53296
OK – when I posted the last entry I got a “Gateway not found” error (not uncommon on a WordPress site) so I hit the reload button – then I got this:
ERROR: Duplicate reply detected; it looks as though you’ve already said that!
But I can’t see a “Yes it is duplicated” button to dump it so I’m overwriting the duplicate post (I hope!!!!)February 18, 2018 at 12:34 am #53297
WHAT IS WRONG WITH THE UNIVERSE? ;>}
Just when I thought it was safe to “go back in the water” I discover that the 57 mm hole in the spool allows the spool to drop on the axle which allows contact between the rim of the spool and the machine frame.
I also show the “failed side arm print” in the photo – the infill sure looks “nice” ;>}
So off to Thingiverse and I found THIS
A bit “adventurous” for a newbie?
But that is how you learn!!!
Attachments:February 18, 2018 at 2:37 am #53299
First print: unmitigated DISASTER !!!
The piece around the edge didn’t even bother to adhere.
So it was started again and while it was in the final warm-up stage I hit the bed with the Pritt stick in a VERY liberal fashion.
Well, the bit around the edge stuck OK.
HOWEVER the first layer was all over the place.
The individual lines were not lying flat and parallel to each other, there was gaps all over the place – it was a mess!!
And in the center it looked like the wall of the hole was drooping off to the side – NOT GOOD!
Almost aborted the print when I had a brainflash: IDIOT!!! There is a thread in the middle of this thing and that is the start of it!!! (Carefully removed the cursor from the “Abort” button)
So I increased the flow rate to 106% (sounded like a nice enough number) and on the 2nd layer things started to look better, everything was smoother so I let it run and had breakfast.
Thinking about the crappy first layer I came to the conclusion that something was definitely out so I sat eating and thinking (sometimes I multi-task – what can I say!)
Then it hit me: The problem is with my setup procedure!!!
I home the machine, lift the Z a few millimeters, Go X0 Y0, home Z again and use a piece of paper as a feeler gauge to adjust and repeat on the other extremities and do this a few times.
BUT THE BED IS THE THICKNESS OF THE PAPER BELOW MACHINE X0 !!!
So the first layer is not being extruded “into” the bed but rather above it!!!
That means bad adhesion and 1 layer’s worth of material having to try to take up the volume of its own layer PLUS the layer represented by the thickness of the paper !!!
I was given Repetier Host v2.0.5 with the printer and I remembered that there ar some pre-defined and programmable functions available (and the print seems to be doing well as I write – SEXY thread!!!) so I am going to use 4 of them for setup purposes.
Basically, I will home the machine and each function will move Z whatever the thickness of the paper is above Z and then to the X and Y coordinates of the corner I’m busy setting up.
Then repeat until I’m happy with the bed leveling.
That way the first layer will be extruded INTO the bed, ensuring better contact and “stickiness” to the bed and the extruder nozzle will be able to “wipe it to the correct height which will squash excess material a little sideways into the material next to it.
While writing I went to have a look at the progress – IT STOPPED EXTRUDING!!!
Something is jammed up SOLID – I can’t even get the filament out!!!
So it looks like I will be getting intimate with the extruder head.
As I suspected, the first layer is a mess – if you hold it up to the light you can see daylight in places so after I troubleshoot the extruder I’m going to use the new setup procedure and try again.
I’ll be back later.
Attachments:February 19, 2018 at 8:31 pm #53403
While I have been having an “enforced” period of down time due to technical reasons I have been doing some thinking (DANGEROUS!!!)
Anyway I got to thinking about the design of the extruder head and I am wondering about a couple of things.
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!!!
It is NOT designed to be a traction device and is in fact a pretty lousy shape to be a traction device IMHO.
It has rounded edges that are IDEAL for creating slippage at the least provocation.
Why is this? Or is it simply using whatever is at hand to sort of get the job done?
The next thing I was wondering about (mainly because it is the actual thing that is causing my down-time) is the piece of M6 threaded stainless rod with the hole in the middle that in my case has a PTFE liner which is actually the problem in my case – clogged and stuck solid!!!
What is the use of the liner – it is simply another point of failure that has been introduced into the system!
Someone told me that it is a legacy thing from the days when the “standard” filament size was over 3mm and when things moved to the 1.75mm diameter they simply put in a “spacer” to make up the difference.
But is the PTFE not then also acting as a heat barrier and reducing the efficiency of the heat transference from the metal part to the plastic that is being melted?
So would a design that is closer to the 1.75mm standard not be better?
It could be reamed to a smooth and tapered bore to help with extracting blockages.
Like production injection molders (which are cyclic as opposed to 3d printer heads which are continuous) it is all about hydraulics.
In printer heads the “ram” is the filament entering the enclosed system through a fine tolerance orifice and once it is inside, melts and becomes part of the “fluid” that is extruded out the nozzle.
So would a smaller (not too small) “melt reservoir” not work?
If it was not semi-insulated by a chunk of PTFE then the transference of heat from the SS part to the material would be faster and everything would happen more efficiently.
I have also been lurking around YouTube and was particularly interested in a number of videos about “making your own filament” and the problem that everyone seems to be having is keeping the diameter of the extrusion to within a very fine tolerance around 1.75mm and this is understandable given the fact that the filament needs to “seal” the orifice through which it enters the melt chamber so that the required hydraulic pressure is maintained which forces the melt out of the actual print nozzle.
In extreme cases the filament can jam up going in (filament too large) or not provide enough sealing (filament too small) in which case the melt will be forced back up along the path that the filament is entering the melt chamber and solidify, thus causing a jam up that way.
So as it stands now, the diameter of the filament as it comes off the spool is critical to the success of the whole process as it provides a seal (or leak) to the melt chamber AND allows the accurate calculation by the software of the volume of material that is being extruded out the print nozzle.
But is there not a way that this can be worked around?
Would it not be great if a printing head could accurately and “clog freely” work with a filament of minimum diameter 1.75mm and maybe up to about 2.00mm?
Maybe I should give some thought to this issue while I am eventually waiting for the components of my MPCNC to print…
And while I am waiting for the MPCNC mill to finish the jobs it will be running.February 19, 2018 at 9:23 pm #53405
RyanKeymasterWhy is this? Or is it simply using whatever is at hand to sort of get the job done?
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.But is the PTFE
PTFE makes printing with PLA a breeze. I have throats with no liner but the settings are more finicky. The reason yours went bad is it was overheated and baked the PTFE dry. No more than 260C and even then mine only last about 1 year. Luckily a set of 2-3 new liners a about $2.But is there not a way that this can be worked around?
The extruder will handle all sorts of size variances, the print will look like crap though. But yes again this has been solved as well, you can get a device that measures the average diameter as it goes in and adjusts the feedrate accordingly. As for making your own filament…not that easy. Plastic can only be cooked so many times, and you always need new fresh material and nowadays it cost just as much a laser calibrated professionally made filament. Not to mention the drying that needs to happen.February 20, 2018 at 7:59 am #53419
Hi Ryan – points all well taken!
I was kind of ranting a little bit – I tend to do that hence the name.
While I was wondering around in my boredom I did come across some guy that was experimenting with using something like a drywall screw to move the filament.
His argument was that there would be no slippage due to multiple points of contact.
Anyway, thanks for the replyFebruary 20, 2018 at 9:23 am #53428
I have come to the conclusion that I bought someone else’s pile of spares!!!
A spare frame, spare bits and pieces – got it all working sort of – and sold it to me.
Why do I say this?
Well, there is not a single washer on the Alison (thats her name now – she can be a b1tc# but if you treat her well she works…) and there are an assortment of miss-matched cap slotted and cap screws all over the place.
And I’m not going to even talk about the wiring…
Another big thing that I noticed is that the fan was in the wrong place!!!
In the photo I have mounted the motor to the right of where it was and drawn a line to show that it was cooling the extruder gear and the stepper motor but nothing was getting to the cold end (?) because the bottom of the extruder assembly was blocking any air movement to that destination.
So the Stainless Steel “melt chamber” was getting hot and the “cold end” was too which supports what Ryan said earlier about frying the PTFE liner.
But the show must go on – I need to get my spool holder printed so that I can carry on with the MPCNC parts but it looks like I have to find a cooling shroud for the “melt chamber” to print first – and maybe some harness clamps to control the rats nest of wires rubbing all over the place and bending where maybe they should not be bending…
But in the meantime I cobbled together a bit of a Heath Robinson contraption to get the air from the fan to where it is needed.
Here it is – its NOT pretty!!!
And a view from below…
But to carry on trying to get Alison to print anything without some sort of cooling down there would be a waste of time and filament – so it is what it is!
The first thing that I desperately need is to finish off the filament spool mount and that means printing the universal spool holder.
The other day printing the small part of that assembly lead to the blockage disaster but now things that should be cooled are being cooled.
So I set up the job (using a modified setup procedure that seems to have gotten rid of the first layer problem) and printed the nut part again.
That came out pretty nice in my inexperienced view – seems that the nozzle is sort of smearing or smoothing out the line if material as it is laying it down which begs the question “Is that a good thing?”
I think that maybe it is because it is forcing the new layer into hard contact with the previous layer which probably means good layer adhesion.
Or maybe it is NOT!!!
I started the “bolt” part of the assembly and made what is probably a rookie mistake – I didn’t flip it over so that the large part was at the bottom.
Which means that I started printing the narrowest (43mm) part and the widest (80mm) part would be at the top.
Well, something happened – the nozzle somehow climbed sideways off of the piece, the steppers skipped a whole bunch of steps and proceeded to print in mid air…
Fortunately enough of the part had already been printed so that it would at least be functional!!!
On the left is the first failed nut, center is the “good” one and on the right is the the “failed but usable” bolt piece.
I’m using Repetier-Host with the extruder set to 190 degrees, the bed set to 50 degrees and I’m using glue stick. Even though there was a collision between the piece and the nozzle, nothing broke free from the bed.
EDIT: THIS IS INCORRECT !!!
However the “Feed Rate” is set to 100 and I think that maybe I should dial that back after the first few layers have been printed and the infill starts happening.
I THINK THIS IS CORRECT !!!
At some point or other I must have enabled “Easy Mode” which hides the “Flow Rate” setting. I am going to have to rectify that and see what it is set to and play around from there.
Anybody got any thought?
Attachments:February 20, 2018 at 10:27 am #53437
What are you using as slicer software? I use the prusa modified slic3r:
Ryan has some settings for the normal slic3r, and they are a very conservative, but good starting point:
Generally, you want the first layer to be slower, and the outside layers to be slower, and the infill to be as fast as you can get it without making mistakes.
The first layer is critical. When it cools down, if there is a fat part and a skinny part, they will cool at different speeds, and cause warping on bigger parts. The first layer should be smooshed a little, but not really smooshed. I don’t know a better way to describe it with words, but if it’s not able to extrude the plastic it’s trying to, or it’s smooshing it enough that it’s flowing out the sides, then that’s too much smoosh. When you get it close, a smooshed part will have bell-bottoms or elephant feet on the bottom because the first layer will be too smooshed.
Are you printing PLA? I really like printing on blue painter’s tape instead of gluestick. But a lot of people like the glue stick too. When you get better at getting the bottom layer right, you can move to PEI, and be really happy. But if you smoosh into PEI, it will really stick, and you’ll ruin the PEI getting the part off. PEI sticks to the scent of PLA. If your bed isn’t flat enough for the larger parts, you can add a brim. It’s a hack, but it does help with the warp.
Here’s some more info that’s pretty good, to keep you busy:February 20, 2018 at 10:18 pm #53459
Hi Jeff – I’m busy enough but I will get to all the links.
I’m using Repetier Host to run everything, Cura to slice and PLA.
Look, I know that it is early days on the printer but at this point I need to get the machine and myself to the point where I can start printing the bits and pieces for my MPCNC.
Some of those parts have got MASSIVE print times and I will probably be able to hunt down a lot more info on the net while I am waiting…
I am actually pleasantly surprised that of the 8 prints I have run up to now.
I have had 4 “fails” but 2 of them were “usable”.
My biggest shock was seeing just how “well” Alison performed even though she has a lot of issues (some pretty serious) that I still need to sort out.
Once that is done and I know more about setting up for a print (I need to get a dial gauge to get the leveling process spot on) , I will probably give her a major service and lube job and start the printing marathon.February 21, 2018 at 3:01 am #53460
Oh my Giddy Aunt Mary!!!
I printed the little boat test model and it is an unmitigated disaster!!!
And to make matters worse, I don’t have a CLUE where to begin sorting it out!!!
I have seen this test model looking “not so good” but maybe I have set a new standard of “LOUSY” ….
Attachments:February 21, 2018 at 7:56 am #53469
That looks like severe under-extrusion and/or a partial clog resulting in not enough and intermittent plastic actually making it out of the nozzle!February 21, 2018 at 9:45 am #53481
Yea, I agree with Vincent, under extruding. Usually the filament has suggested temp range on the spool. I usually print 10 degrees hotter than the lower temp.February 21, 2018 at 10:00 am #53483
I have basically spent the whole day printing benchies – most of them big failures and the last one, although a failure, is definitely getting in the right direction.
And what you say is starting to make sense.
A number of failures happened when it just stopped extruding plastic. To get it going again I had to remove the filament and cut of a bit because the front 10 or 15mm was noticebly thicker than the “virgin” filament.
Eventually I bumped the extruder up to 210 degrees and the “Flow Rate” up to 110% AND turned off the retract function and the material cooling fan just for luck.
I got this:
As it was printing I was very pleased to see that the bow was looking pretty darn good and small details like the anchor chain ports, the ?exhaust? hole in the stern and ?fish pole holder? above it were not looking too shabby at all.
But here is the thing: The nonsense only starts when the nozzle has to move many and far distances without extruding – thats when the stringing starts and once it gets to the upper portion where extrusion happens at a more or less continuous and constant rate things start looking a heck of a lot better again.
And at least with the retract turned off it was not clogging.
So I think that I have either got a “made up of parts” extruder here which is not working very well or like I mentioned in a previous post, that “gear” (which is showing more than a little wear and tear) is not up to the task any more.
The cheapest option is to replace the gear and see how much difference it makes and thats what I’m doing tomorrow.
Attachments:February 21, 2018 at 10:14 am #53487
Dialing in a printer that is an unknown quantity can really be a pain and is an exercise in patience and creativity. From what I can tell from the pictures, it does look like you had a vast improvement, until it came to the point where there would have been a lot or retracts and non-print moves. I know you said you turned retraction off, but it really does look like it was retracting and then not priming sufficiently before beginning the next extrusion. In Repetier there is a setting to add a slight additional advance when it finishes the retraction move to combat this. With retraction all the way off, I would expect to see extra filament from oozing in the form of strings and little zits where it moved over a previous layer while continuing to ooze.
That said, your extruder does sound like a piece of work! For one, it is critical that you have adequate cooling on the cold end above the heat break. When the nozzle is at temperature, you should be able to touch above the heat break and feel no heat. Should be cool to the touch. If not, you need better cooling up there. Also, in a previous post you mentioned that the PTFE liner was probably cooked. Rather than decreasing friction, a bad liner will increase it and make your filament more prone to jams, especially during retract moves.
As for overall extrusion, did you accurately measure your filament diameter in several places and then input into your filament profile? That can make fine-tuning difficult or require extra multipliers to get right otherwise. Also could be an issue with steps/mm in the firmware, since this is a cobbled together printer and may not be using a standard drive gear. Optimally you should have perfect extrusion with the multiplier at 1.0 (100%). Anything else is an indicator of something not being set right.
Once you overcome the inconsistent extrusion issue, they rest should be a matter of dialing in settings.February 21, 2018 at 10:36 am #53489
My vote is not enough cooling on the cold end. Extruding cools things down, because it takes energy to keep the plastic. When you’re extruding less, the cold end will heat up, and if you don’t get it cool enough, your gears will be against squishy plastic and you won’t get extrusion.
W.r.t. steps/mm, you should calibrate the incoming filament, extruding 100mm in the air should result in 100mm going into the extruder. Do this at temp, in mid air. You can also look at the outgoing filament. It should be coming straight out. Partial clogs will cause the filament to come out the side. Pay attention when extruding for skipped steps (crunchy or popping noises) and you can put a finger on the incoming filament and feel that it’s moving consistently. If it’s skipping, or not moving smoothly, calibrating your steps isnt going to work.February 21, 2018 at 11:26 am #53492
The best thing I’ve found for troubleshooting printer issues is to leverage the experts for your hardware if there is such a group. The Prusa forums for my Prusa, the vendor for my 1st printer which was a Prusa clone. Typically, they’ve seen the most common reasons for the issue you’re having. If I comprehended what I read, this is an i3 clone originally built by someone else. Did that person show you any prints that were successful? Are you able to get a gcode file from them that worked for them? I learned to use my 1st printer by looking at the gcode the vendor provided and which would print correctly. I wasn’t using the right slicer settings at first, but thought I was… That said, when I built my 2nd printer, there was a piece of gunk (probably ptfe) inside the ptfe tubing and it took me 2 weeks to figure that out.
We’ll keep tossing ideas out too, I’m sure. Good luck.February 22, 2018 at 1:50 pm #53550
Thanks for the comments etc
I eventually went out and bought a new extruder.
WHAT A JOKE !!!
I am VERY busy at the moment but as soon as I can I’ll post about it – its almost a bigger disaster as the one I got with the machine…
And when I took it back (they actually know my machine) they told me that the problem was that I had bought a bowden extruder by mistake – I ASKED THEM WHAT THEY SUGGESTED AND TOOK THEIR ADVICE!!!
Oh well – maybe its time to start looking around for a more “client friendly” company to do business with.
For example, when the nut is on the extruder tube it blocks off one of the mount holes – nonsense like that!!!
TOTALLY CR@PPY DESIGN !!!
Now I have to make some sort of adapter somehow… with no tools (long sad story)
Alison (I name ALL my machines) will be done right by… I promised her…February 22, 2018 at 8:20 pm #53585
Dui, ni shuo de duiParticipant
Your clogging issues are due to an insufficient cooling of the cold side of hotend.
You can try several things:
-Put a more powerful cooling fan (cheap and easy)
-watercool the nozzle (a bit more complicated, plus it adds weight, but solves totally the issue)
-Lower quite a bit your hotend temperature
-increase your travel speeds (to reduce the time when it is not extruding)
-lower your retract distance
-Put some thermal paste on the threaded insert tube linking hotside/coldside of the extruder to better evacuate the heat (this usually works quite well)
-put some kind of insulator (kapton, silicone or whatever) in the tiny space between the hot side and the cold side of the extruder, to limit radiative conduction
Good luck, this is usually a relatively easy fix and once done your prints should be ok.
No need to change the hotend in my opinion. All the hotends are basically the same, even the crappiest ones should work ok (I had various hotends, even the cheapest of the cheapest worked fine). If your hotend is clogged , let it heat, then take it apart and finally burn down all the crap from it using a gas burner.February 23, 2018 at 2:22 pm #53593
Went to the local 3D Printer suppliers – bunch of wanker ripoff artists!!!
Showed them the bits and pieces of the extruder (had stripped it off Alison) – they didn’t have the exact unit so they “SOLD” me a “drop-in” replacement.
Yea – RIGHT!!!
When I took it back because there was no way to mount it they told me that “I HAD CHOSEN THE WRONG ONE“!!!
Evidently it was for a Bowden style setup.
I didn’t “choose” anything, I bought what they recommended!!!!
No refund, no swop – told me to manufacture an adapter bracket, turned around and left me standing in the middle of the shop.
Guess where I WON’T BE BUYING IN FUTURE!
Not not having any tools (long story) is a pain!!!
Eventually I managed to figure out an angled bracket that did the job (made out of the plastic cube that most people have on their desks full of paper squares.)
Anyway, once I got it mounted and working (more “cube” plastic and hot glue to mount the hot end fan) and I did a test print.
The roof supports were still a disaster – but a lot less so – and when the bow was being printed I could see it curling upwards and being pressed back down as the nozzle passed over it.
At that point I only had one fan blowing on the hot end, nothing cooling the print!!!
Obviously the print cooling fan is a must but the shroud was not going to be properly fitted using any of the available holed – BUT IT WAS NOT CLOGGING!!!
I think that the new drive gear has a lot to do with that. The old one had significant wear.
So more “cube” plastic and hot glue and I had that rigged up as well.
That print looked pretty decent to me – the roof supports were still an issue but…
In the post above “Dui, ni shuo de dui” mentions using water cooling on the extruder – and I just happen to have an old fish tank water pump lying around so a small block of ally, tap an 8mm hole for the extruder bore and for Festo pipe connectors and drill in a manifold sealing extra openings with epoxy and we should be good to go …
Then I noticed that the threaded rods holding the machine together had a bunch of loose nuts!!!
Obviously forgotten to tighten them when the seller threw the thing together.
At the same time I tightened the belt that pulls the print head around – it was pretty slack.
My butt was itching to do a “real” part so I sliced the foot piece and set it up and let Alison have at it.
About a third of the way in she simply stopped !!
I’m using an old HP Notebook that I bought back in ’02 and at that time it was an “End Of Series” unit.
I had reservations right at the start as to whether it would be powerful enough but it had handled the boat OK and looking at the logs I saw that the “comms” had failed.
So I uninstalled everything I could off the HP, rebooted everything and tried again.
So tomorrow I am going to connect it to my big PC and try again.
I hope that it is a lack of processing power issue and not the driver board!
Who the heck knows where I will find a supplier that has stock (NOT going back to the extruder sharks again!!) and mail order is simply too expensive when you add postage in – often the parts you are getting cost less than the postage.
Which raises the question:
Just how difficult would it be to switch over to an “UNO and RAMPS” setup?
At least those are available here in SA at “almost” reasonable prices.
Any comments people?
More later and thanks for reading.February 23, 2018 at 3:18 pm #53595
You’re printing via USB, using the computer to drive it? Sounds like it. That never worked well for me. Printing from SD seems far more reliable. I don’t know if you have an SD since I don’t know which board you’re printer is using. It seems like it would already be ramps based if it’s an i3 clone, but who knows, it could be lots of things. I guess you wouldn’t want to switch to ramps if it was already ramps. 😉
Ramps are cheap and pretty easy to use. I guess it all depends on how it’s all wired to the current board. If it’s all Dupont style or screw terminal stuff it should be fairly easy. I fried the first 3 ramps boards I ever used and finally figured out my heated bed was pulling more current than it should. I switched to using a solid state relay to drive the heat to the bed and that was very reliable.
The low-cost LCD controllers make using the printer a lot easier and they’re compatible with nearly all the boards that control printers. I got the one I’m using for like $8US on aliexpress with free shipping. They have SD card slots in them too. Maybe just get one of those to hook up to what you have? Just get the text version, not the full graphic, the full graphic isn’t as compatible.February 23, 2018 at 3:20 pm #53596
Of course, you’d want to see if the LCD could be used with your current board before getting one, or just get a ramps set that includes the LCD as well…February 23, 2018 at 3:32 pm #53598
Even after you sort out all the hardware issues, there’s still some stuff about 1st layers that can be tricky to sort out when you’re new to this. You also might have to check your z adjustments after every print, you’ll just have to figure it out based on how your printer behaves.
The thing that helped me the most with troubleshooting first layers was to find something that’s like 10cm x 10cm and print the first layer of it. This is a good exercise to just model up a box and then print it (use tinkercad or fusion 360 or some other method). You can stop it once it has printed enough to see how it’s behaving. You should get a first layer that’s a solid piece of plastic and that stays stuck to the bed the whole time. If it’s good for like 1/2 of the print, your bed isn’t level enough.February 23, 2018 at 9:55 pm #53609
Thanks for the info SquidPlan.
Here is a pic of the brains.
I had to go back into the history of the chat on FB Messenger to confirm but the seller said he used the SD card all the time.
He also said that he needed to have a PC hooked up to initiate the job because the LCD on the machine had the “wrong firmware” for the board which had been replaced at some stage.
If this is true or not I have no idea – it may be a blown LCD unit that he gave me.
Thanks for the heads up about using a relay for the bed heater – I will need to remember that…
So I guess I am going to get an SD card and try that before I start moving everything around to hook Alison up to my big PC.
My setup procedure is as follows:
- Make sure the 2 Z axis bearing holder/guide pieces are at the same level – I use the glue stick as a measure between the bottom of the bearing holder/guide piece and adjust the right hand one to match the left hand one.
- Then I switch the machine back on, fire up the bed and extruder heaters and home the machine.
- When everything is up to temperature I use buttons 1 to 4 (programmed them to take the head to X10 Y0 Z0 and then to Z0 and the same for other extremities) and do the paper feeler gauge thing.
- I load the stl file, slice it and then extrude some plastic just to make sure the nozzle is OK then let her rip.
One question here: Should I not maybe use Z0 PLUS the thickness of the paper in this procedure and not simply Z0?
Maybe the way I am currently doing it makes the first layer the paper thickness higher than the 0.2mm that it should be and this may account for some of the bad first layer issues.
But I have to say that using glue stick, when it does adhere to the be IT ADHERES TO THE BED!!!
So I think that I’m going to the phone shop to get a micro SD, then slice the part and save it to the SD card, reset reboot and set up the machine and point it at the SD card and see what happens.
Thanks SquidPlan for the comments and advice and to everyone else for reading.
Attachments:February 23, 2018 at 10:33 pm #53612
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