Author Topic: Another 3D Printer  (Read 24103 times)

Offline Joules

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Another 3D Printer
« on: January 16, 2016, 07:55:56 AM »
Never really sure where to put an article on 3D printers, here, under plastics, or somewhere else.

Anyhow my current 3D printer road map got derailed through one thing and another.  The next printer is actually going to be a trip back into my printing past.

https://www.think3dprint3d.com/3D-Printer-Kits/complete-3D-printer-kits/Kossel-Mini-3dPrinter-Kit

This is a Kossel Mini delta printer, I started out with a Rostock Max before moving onto cartesian machines.  The Kossel is more a stop gap machine to take some load off my workhorse whilst it has a refit.  The other thing about the Kossel is the new controller it uses, this one is 32bit (very important for smooth interpolation of the delta motion) and a built in web server.  The development work has been done, so I can fairly cheaply see if the benefits would be worth me swapping over my other machines to the same Duet controller.   I very much like the idea of checking and setting jobs via an iPad or Android device.  I just need to shoe horn extra hours into each day for the build now.
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Offline nrml

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Re: Another 3D Printer
« Reply #1 on: January 16, 2016, 10:58:08 AM »
Have you had a look at CNC machined aluminum bits for the mini Kossel on Aliexpress? I bought a few bits including an extruder and toothed pulleys for my next printer (a corexy with a duet board) and I am amazed at the quality for the price. I had no issues with any of my Aliexpress orders but my project is bogged down by ebay orders not turning up, the ensuing the dispute resolution process and having to re-order.


Online BillTodd

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Re: Another 3D Printer
« Reply #2 on: January 16, 2016, 01:47:54 PM »
Joules,

Your 3d printing posts have inspired me now you have me thinking about either making or , if you are impressed by it, buying one :-)

So, please report back with your experience with this machine :-)
Bill

Offline Joules

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Re: Another 3D Printer
« Reply #3 on: January 16, 2016, 02:15:58 PM »
OK Bill will do.  I am not a fan or user of ebay but I do like the option of metal parts for the frame corners.   Just wish someone in the UK would stock them and they be of known quality.  Guess they could be fabricated from laser cut sheet.
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Online BillTodd

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Re: Another 3D Printer
« Reply #4 on: January 16, 2016, 04:23:36 PM »
I've been looking at various kit for kossel type printers on ebay etc. what makes the one you mentioned better than some others?  I've seen ones that use linear bearings and metal bases that look sturdier for less money.

Are there any plans available for a diy version?




Bill

Offline Joules

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Re: Another 3D Printer
« Reply #5 on: January 16, 2016, 04:35:55 PM »
Bill, the Kossel is open source, what you see and what you get off ebay in my case have never been one and the same.  I like to support UK business, as any problems I like them to support me.  The money spent on the Kossel I posted also helps fund its development.  Buying from overseas tend to be into one persons pocket as they rarely contribute back to the community that developed the idea.

The Duet is not standard to the Kossel range yet, and prior to it I wouldn't have bought the Kossel as a serious machine.  Things like linear bearings and metal parts can be added later if required, and can be manufacture/fabricated in house if you have the facilities.

Oh, the other important point for me, this version uses an E3D V6 printhead, and that's not to be sniffed at if you want decent quality work.
« Last Edit: January 16, 2016, 05:03:01 PM by Joules »
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Online BillTodd

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Re: Another 3D Printer
« Reply #6 on: January 16, 2016, 05:10:12 PM »
Quote
I like to support UK business, as any problems I like them to support me.
:thumbup: Fair enough :)

I'm giving this serious thought ,  it only costs about the same as one refill for the works Objet30 (which is great but ,so slow and stupidly expensive to run)

BTW have you tried vapour or plasma smoothing ?  (I came across it while youtubing)
Bill

Offline Joules

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Re: Another 3D Printer
« Reply #7 on: January 16, 2016, 05:28:02 PM »
Nah, I use H2O MOX abrading....    :med:

Rub it with damp wet and dry paper.
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Offline Joules

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Re: Another 3D Printer
« Reply #8 on: January 18, 2016, 08:12:46 AM »
A medium sized heavy package turned up this morning.  So once another  :coffee: open it up.



 :bugeye:  STREWTH, I've been had it's really dense newspaper !!!



Pulling away tear soaked paper revealed the goodies, and so to unpacking.



First out the electronics, very nice well packed and the wiring loom complete with labelled plugs etc.  The hot end is assembled and wired with localised connections.  I will be able to swap the entire head to try different materials without fear of cross contamination.  The re-purposed Dell PSU is a beast, 12vdc @18amp.



The heated bed, glass and bag of test PLA, spiral wrap for wiring and ptfe tube for bowden feed of filament.  The heater is assembled and of good finish, they have removed the burrs off the top where the countersink screws are fitted.  Good attention to detail and ready to be used.



ABS printed parts, I still have no regret using PLA for my prototypes.  The parts seem good, not warped a little clean up in places wouldn't go a miss, but not a requirement to use them as is.  The extruder is assembled and the one component I would exchange for an all metal extruder.  I doubt anything will be wrong with this extruder and have confidence it will perform, but I just like the control an adjustable all metal extruder offers.  NO, not a cheap China extruder they have some nasty design flaws, such as lack of support for the filament coming too, and exiting the pinch roller, allowing the filament to buckle then suffer feed failure.



And here's why I am happy to pay that little extra, genuine Misumi 2020 rails, they should be dimensionally accurate, STRAIGHT and hard anodised.  I have seen some awful rails and it's attention to detail and quality thats going to give you the fighting chance of decent prints.

Now going over this machine it looks a good deal for the money, big support community online and it's in constant development.  Downside for some, its going to be for smaller prints (though big enough to do the Quorn components).  The working bed is 170mm diameter, giving you a block of 120mmx120mmx245mm and you have to build it yourself.   I would really suggest looking at the Rostock Max V2 if your requirements are for a larger machine of this style.   Box now sat in office awaiting time to start construction.  I am happy with what I got as a kit, only time will tell if the print quality will be enough for my demands, but once built I doubt I would loose money selling it if I can't get the print quality I am after.




Missed the picture of fasteners, steppers, GT2 timing belt and they even include the tools required to build the machine.
« Last Edit: January 18, 2016, 10:22:01 AM by Joules »
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Offline Will_D

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Re: Another 3D Printer
« Reply #9 on: January 18, 2016, 09:38:56 AM »
That looks dangerously desirable.

I see why they named it after a genetiscist! Can just see the DNA spiral being printed!

I note on the page that there is an optional touch screen is that needed?

Also what resolution do you expect, they state 100 steps per mm in all 3 axes(10 micron) and repeatability of 30 microns.

What is the minimum layer thickness it can lay down?

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Offline Joules

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Re: Another 3D Printer
« Reply #10 on: January 18, 2016, 09:56:45 AM »
Will, no need for a touch screen, use a PC/laptop whatever to do direct communication with the thing.  For me I will be using the network port so I can send jobs direct from my CAD machine or via one of the tablets that will also be used to monitor it and progress.

Your other questions, I have no idea until its built and I can measure things myself.  However I see no reason to doubt their claims.  The big jump in resolution comes from moving away from 8bit to 32bit controllers.  The old Rostock I have really moves across the bed in a sort of sinusoidal  slither as the 8 bit controller doesn't have the grunt to calculate and deliver the in between vectors.  This is my gamble on the Duet delivering much improved performance.  The fact it can also handle a bolted on web server at the same time just adds to the confidence.
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Online BillTodd

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Re: Another 3D Printer
« Reply #11 on: January 18, 2016, 12:43:59 PM »
All the parts look nicely made from here:-) 

Are we there yet?....
Bill

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Re: Another 3D Printer
« Reply #12 on: January 18, 2016, 01:43:17 PM »
Very cool Joules  :thumbup: 


Rob

Offline nrml

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Re: Another 3D Printer
« Reply #13 on: January 18, 2016, 02:45:58 PM »
I've bought one of these to connect my duet board to my wireless network http://www.amazon.co.uk/Vonets-VAP11G-WiFi-Bridge-Dongle/dp/B0050AI804
I tested it on my laptop and it does what it says on the tin - converts any device with an ethernet port to a wifi device. I would suggest getting one if you haven't decided on a wireless connection device already.

Offline Joules

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Re: Another 3D Printer
« Reply #14 on: January 20, 2016, 06:46:59 AM »
Sorry guy's, my hearts not really in this build at the moment as I have a really sick puppy.



Some parts on closer inspection had signs of delamination, a possible problem due to under heated extrusion or cooled layer below, but not unexpected on ABS.  The simple fix is a blade mounted in an iron to  weld and smooth the areas affected.  No biggy really, considering I wouldn't print one part for the cost they are doing the full set.  The parts are adequate for the job, I just like to over engineer things.  The ABS is so much softer than PLA, but they print the parts at 0.2mm, probably with a 0.4mm nozzle. My own feeling is never print over 0.15mm layers with a 0.4mm nozzle, you want a good layer squash to guarantee a good inter layer weld and even then my prints can still suffer occasional delamination.



The little Tee nuts can be a pain, but assembling the machine on its side allows the nuts to be slide along side ways than hoping they turn when you tighten them.  Golden rule, "measure" all the way through the build.  What it measures doesn't matter, the fact that the relative measurements are all the same DOES.





A bit of a jump ahead, and frame assembled, follow the instructions and measure that all beams are the same distance apart and components in the same plane, i.e limit switches, top section.  To within 0.5mm should be OK in this area.

 

This is where it gets more critical and I would be aiming for 0.05mm for the legs.  This determines how level your printhead is and will affect the geometry as you move towards the edges of the print area.  Keep in mind you have plastic parts and over time they will change shape so what you measure now may not be the same in a month or two, but at least you should be good to get started.



I may still have an issue here later in that my measurements are close, but may not be relative to the centre, they could be displaced laterally and that will have an effect on the geometry, wait and see.



These are a bugger to tension evenly, you really are after a dull twang, not something you could kill a deer with at 100 paces.



This is where I am at for now.  Overall still happy with the build, I would buy another but print my own parts to a higher quality and denser than those supplied in PLA   :thumbup:
« Last Edit: January 20, 2016, 07:37:35 AM by Joules »
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Offline awemawson

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Re: Another 3D Printer
« Reply #15 on: January 20, 2016, 06:54:14 AM »
Joules, sorry to hear about the puppy - far more important than these workshop thingies  :thumbup:

My younger dog is in for an operation tomorrow (inflamed paw) and I'm more concerned about that than the fact I'm having another hernia operation myself at the same time (but different medics  :lol: )
Andrew Mawson
East Sussex

Offline Joules

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Re: Another 3D Printer
« Reply #16 on: January 20, 2016, 07:01:13 AM »
So would all that be at the same vets practice ?    :lol:
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Offline Pete W.

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Re: Another 3D Printer
« Reply #17 on: January 20, 2016, 07:47:45 AM »
Hi there, Andrew,

Joules, sorry to hear about the puppy - far more important than these workshop thingies  :thumbup:

My younger dog is in for an operation tomorrow (inflamed paw) and I'm more concerned about that than the fact I'm having another hernia operation myself at the same time (but different medics  :lol: )

I hope that both operations have a good outcome. 
Best regards,

Pete W.

If you can keep your head when all about you are losing theirs, you haven't seen the latest design change-note!

Offline awemawson

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Re: Another 3D Printer
« Reply #18 on: January 20, 2016, 07:56:48 AM »
So do we Pete  :clap:

It's Penny I feel sorry for - first she drops me at the hospital, then picks up the dog and drops him at the vets, then home to feed the animals and muck out the pigs, then on stand by for both of us for collection, while I'm drifting off into some distant place dreaming of nurses  :ddb:

.. sorry Jules - we'll go away and leave your thread uncluttered now  :thumbup:
Andrew Mawson
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Offline Joules

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Re: Another 3D Printer
« Reply #19 on: January 24, 2016, 02:48:02 PM »
Mini Kossel not easy to setup and calibrate.  However once you get over that, the print quality is astounding using the Duet board.  More info to follow, below example a "rough test print"

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Offline Joules

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Re: Another 3D Printer
« Reply #20 on: February 02, 2016, 09:24:10 AM »
After my initial success with the printer I am now having problems.  I have just tried doing the Dremel gear I designed and seeing the head loose position during the the first two attempts at printing.  It looks like the head is snagging on the lower layer and getting offset.  I have now altered my layer height to 0.15mm and trying another print, the quality is not what I had to begin with and my suspicion is falling on the hot end having worked loose.  Once I finish the print I can investigate further.   During the build I was concerned by the fact they rely on bolts into plastic to trap the hotend.  I am going to look at this and see if I can make a proper alloy part thats tapped to take the bolts.   Shame, but I just seem to be having a run of bad luck as lots of things going wrong at the moment   :(




A couple of layers got displaced, so ruining the print, this was third attempt with more relaxed settings.  I need to figure out if it's a mechanical fault, firmware or software, but above this the print quality is OK.  However its messy below, especially in the area the head starts the next layer, this is what makes me think the hotend may have some play and allow it to dig and stall the steppers.  This could mean I need to increase the stepper current as the motors are still pretty cool at the end of the print.   Lots of possibles to look at and try.
« Last Edit: February 02, 2016, 10:10:14 AM by Joules »
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Offline PeterE

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Re: Another 3D Printer
« Reply #21 on: February 04, 2016, 04:36:52 PM »
Joules,

For what its worth. My friend who printed my first parts for my 3D printer also used black filament as you seem to have done here.  I do not know what material you are using, but I wanted ABS and his machine was set up for ABS as well. Good we thought because he had had no problems before, but now with the black variant the prints did not come out well. Not compared with red or yellow! Much the same effect as on yours actually.

We guessed that it may be due to the black colouring that is probably done using a carbon additive of some sort, and that carbon changes the filament properties enough to alter the settings for other colours.

Could your problem have the same source????

My bits turned out way better in red  :bugeye:

/Peter
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Offline SwarfnStuff

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Re: Another 3D Printer
« Reply #22 on: February 05, 2016, 01:36:00 AM »
Peter,
  You would be correct in assuming carbon being the most likely pigment for black. In a past life I worked in a plant that made and blended pigment for the paint and plastic industry. I don't recall us using anything else for black except carbon, usually broken down with Barium Sulphate to make it easier to weigh out. That is, by adding the Barium Sulphate we could give the customer a powder to weigh in grams per kilogram of polymer rather than miligrams.

  Whether it modifies the melt characteristics I have no idea but as you intimate, interesting that it was with the black filiment you had trouble.  :doh:
John B
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Offline Joules

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Re: Another 3D Printer
« Reply #23 on: February 05, 2016, 04:15:20 AM »
Sorry guys, it's not the black pigment causing the issue, as this PLA works fine on my cartesian printer.  I now only buy good quality, in this case UK blended filament, as it's not been baked or soaked travelling half way round the planet.
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Offline PeterE

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Re: Another 3D Printer
« Reply #24 on: February 05, 2016, 04:27:34 AM »
PLA is different from ABS so one possible cause out of the way.   :thumbup:
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Offline Jorkki

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Re: Another 3D Printer
« Reply #25 on: February 09, 2016, 08:51:12 PM »
Joules,

Just waiting for the same Kossel Mini  kit myself (my first), so can't really give any expert advise.
I have used the waiting time to do some reading though and from what I have read, probably  the most common reasons are the retraction settings.
Just thinking about it, if it was a mechanical issue, the printer probably would not recover to properly print the upper layers.

If the Bowden tube would be loose at either end, you would probably also have the issue everywhere.

So it may have something to do either with a too large retraction or a positive value on the 'Extra length on restart'.
Alternatively it might be that the printer is doing short moves and retracts before arriving on the perimeter to continue.
It might make sense to test with the 'Avoid crossing perimeters' and 'Only retract when crossing perimeters' settings.

Also putting 'Random' in 'Seam position' might make a difference.

For delta printers I have also seen a recommendation to put a small value (e.g. 0.1mm) to 'Lift Z' if the nozzle keeps catching the already laid filaments.

Hope you get everything sorted soon!

Jorma

Some links:
http://manual.slic3r.org/expert-mode/fighting-ooze
http://wiki.e3d-online.com/wiki/E3D-v6_Troubleshooting

Offline Joules

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Re: Another 3D Printer
« Reply #26 on: February 10, 2016, 05:12:31 AM »
Hi Jorma and welcome to MadModders, I finally found the problem and it was the hotend being loose.  It has caught on the prints and loosened.  I wasn't keen on the method of bolting into plastic to clamp the hotend, so I will either make an alloy part or some little threaded bushes to reclamp everything, and increase the Z lift   :thumbup:
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Offline Pete49

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Re: Another 3D Printer
« Reply #27 on: February 10, 2016, 09:15:00 PM »
Glad you found the problem Joules as I knew the software was good as I had no problem with the print even though I used ABS (black).
Pete
oops..........oh no.........blast now I need to redo it

Offline Joules

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Re: Another 3D Printer
« Reply #28 on: February 11, 2016, 05:47:33 AM »
And here is my problem, screwing M3 bolts into ABS was never going to be a good idea, but you can't say I didn't give it a try.



The advice to tighten gently  :lol:  into plastic.  It failed in use, I tried over tightening the bolts once I had it out and the difference between snug and pulled out is very small, too small to feel if the delta plate your fixing too is a little tight on the bolts.  So, this part is getting a redesign to take an alloy insert that is tapped to take the bolts properly and clamp things firmly.

At this point a cnc mill would be nice.
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Offline mattinker

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Re: Another 3D Printer
« Reply #29 on: February 11, 2016, 06:09:15 AM »
The thread is far too fine, something like self tapping screws or wood screws work much better in plastic!

Regards Matthew.

Offline tom osselton

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Re: Another 3D Printer
« Reply #30 on: February 11, 2016, 04:47:25 PM »
Could you not drill through and use some of the threaded inserts used in woodworking that are capped?

Offline Joules

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Re: Another 3D Printer
« Reply #31 on: February 11, 2016, 05:27:11 PM »
Could you not drill through and use some of the threaded inserts used in woodworking that are capped?

I looked at those inserts, but decided on a horseshoe shaped alloy fitting with the five threaded bosses machined in, so none of them can spin and I get good clamping force.  The whole  part above is having a redesign as its a pretty course print, I can route the wiring better and improve the filament cooling fan supports and reduce its footprint with better clamping.   Just juggling time and jobs as a rather nice robot arm got delivered a few days back and could be a major distraction if I'm not careful.  8-)    But that's another story.
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Offline Jorkki

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Re: Another 3D Printer
« Reply #32 on: February 12, 2016, 07:47:12 AM »
I received my my kit and have been going through and preparing the parts for assembly.
The hotend mounting really is not something that gives a warm and fuzzy feeling even if I'm not a mechanical engineer.
To complicate that, my effector piece seems to be a not so successful print with deformed rod end mounts so I'll have to trim it down and use some additional washers to make the rod distances equal.

I think the best option would be to order an effector made of aluminium.
At least this one has a 3mm set screw that tightens the hotend directly to the effector plate.
http://www.robotdigg.com/product/396/End+Effector+for+Kossel

Another thing I have noticed  is that many of the Traxxas ball joints have quite a bit of play. I know this is a fairly common issue that people have tried to solve by using rubber bands or springs to pull the rods together to lessen the effect, but annoying nevertheless. We'll see how it will affect the accuracy.

Jorma

Offline Joules

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Re: Another 3D Printer
« Reply #33 on: February 12, 2016, 08:04:56 AM »
Jorma, you can ignore the play in the ball joints, gravity is working in your favour.  The weight of the hotend keeps enough tension to stabilise everything.  The only time you will have a problem is when you ramp the speed up.  I would suggest this is not a fast printer, but when properly setup, a very precise printer.  All my tests indicated very good repetition and quality printing till the hotend worked loose due to crap clamping method.  I am working on a solution now.

Wow, I really like that effector plate solution, you have just changed my design focus.   :thumbup:
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Offline Joules

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Re: Another 3D Printer
« Reply #34 on: February 14, 2016, 01:53:34 PM »
Best laid plans of mice and men.  I figured I would get this redesign of the hotend clamp nailed, when work rudely interrupted, since last year was very hit and miss, earning toy money has become the priority.  So the design got shelved and a quick fix sorted.  I modified the original STL file to take a 5mm diameter x 4mm long knurled bush.  These are set into the 3D print 2mm from the clamping surface.  If anyone wants the new STL file, just give me a shout.



I had to work quick in the workshop as it was freezing and I had about 20mins before my hands stopped working, so no pictures of them being machined.  Back inside and warmed up I made use of a cheap table vice I picked up from Aldi, on Friday.  Very handy it is too, for holding small stuff like this.  Each bush tapped 3mm and the faces cleaned of burrs with a needle file.



I used some packing to spread the load on the working face of the print and pulled the bushes in with a 3mm bolt.  The bushes are about 0.15mm oversize with the knurl so they bite well into the 3D print, but hopefully don't stress the walls too much as I wouldn't want them to break loose when clamping this all together.



Here they are all installed and ready to reassemble, then go all the way through calibration again.  This I hope will fix the printer for now.....  Others plans for update have been pushed well back on the back burner.


Something that has started to interest me is the possibility of moving to a cnc lathe.  With my hands being hopeless in these temeratures I am looking at desktop Denford and Boxford slant bed lathes.   Anyone local (South Yorkshire) with similar machines fancy guiding/training me in return for CAD design work.  If anyone also knows of a working machine requiring a good home  !!!  I am on the look out for one.
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Offline awemawson

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Re: Another 3D Printer
« Reply #35 on: February 14, 2016, 02:31:32 PM »
I have a Traub that could be re-homed if you are brave and reckless  :lol:
Andrew Mawson
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Offline Joules

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Re: Another 3D Printer
« Reply #36 on: February 14, 2016, 03:30:25 PM »
Sounds great, so that will go on the kitchen table then.    :bugeye:
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Offline Joules

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Re: Another 3D Printer
« Reply #37 on: February 15, 2016, 01:21:15 PM »
Re built the head, and found lots of gap between the clamp and the hotend.  I ended up putting an O ring on the hot end and compressing it against the effector plate.  Everything now calibrated and running some test prints.  Auto bed level worked even with the old setting so I am probably within 1mm of the old Z height.
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Offline Jorkki

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Re: Another 3D Printer
« Reply #38 on: February 15, 2016, 03:22:22 PM »
Good progress there Joules  :thumbup:

Mine is printing as well after some initial battles.
All in all a very nice kit with some very good components like the controller and the IR probe. Also everything is very nicely packaged and marked and the instructions are good.

The gripes I have with the kit are:

- some of the printed plastic parts are not of best quality (like my effector plate)
- the use of ordinary 3mm metal screws with ABS plastic, some are even too short (3 for the effector plate have very little grip) and some cause delamination because of the bad print quality.
- some of the Traxxas ball joints are quite loose
- one of the aluminium verticals was a tiny bit bent

The geometry is so complex that it's a little bit hard to pinpoint what exactly caused my difficulties in calibrating the printer.
The good thing is that the IR probe is quite reliably and repeatably triggering at the same height all over the building plate. What is not so good is that the height of the nozzle is varying quite a bit indicating that the effector is not staying exactly level across the build area.
Fortunately the calibration algorithm is quite good and by putting in height offsets in the configuration file I have managed to get decent results.

Joules, you should try to print the spiral test file that is on the SD card. You will very soon see if you get a spiral or just a mess of angel hair like I did on the first try.

Offline Joules

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Re: Another 3D Printer
« Reply #39 on: February 15, 2016, 06:38:37 PM »
Jorma, I was having trouble getting my prints to stick till I realised my Z probe offset was out by 0.2mm.  I also increased the current to the motors by 10%.   I am still having some slippage on my own test prints, but I think that may be down to a problem in my slicer !!!  As everything else prints OK.

I would suggest for any parts you have issue with, reprint them on your machine at something like 0.15mm layer.  You will get a much better part then exchange it on your machine.  Do you have access to a lathe, as making the brass bushes for clamping the hotend to the effector plate made a big difference in print quality.  I just need to see how it holds up long term.

         Joules
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Offline Jorkki

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Re: Another 3D Printer
« Reply #40 on: February 16, 2016, 11:47:24 AM »
I had some head banging myself due to too fast printing speed on a small layer so the plastic did not have enough time to cool.
I got better results after I switched from Slic3er to MatterControl. Actually I'm not sure if it was the slicer switch, because I set the Z-lift to 0.15mm and increased the retraction length to 4mm at the same time, but there may be other subtle differences between the slicers.

If you have Z-offsets in the print head height paper test and you can't fix them mechanically, you can do the same as I did and put the offsets in the bed.g file.
The idea is to adjust the Z-offset to 0 at P9 (origin) by adjusting the probe offset in config.g (in the G31 command) and put the offsets for other test points in bed.g.

My values are as follows:
G30 P0 X-73.6 Y-42.5 H-0.10 Z-99999   ; X tower
G30 P1 X0 Y-85 H-0.15 Z-99999      ; between X and Y towers
G30 P2 X73.6 Y-42.5 H-0.10 Z-99999   ; Y tower
G30 P3 X73.6 Y20 H0.10 Z-99999   ; between Y and Z towers
G30 P4 X0 Y67 H0.05 Z-99999      ; Z tower
G30 P5 X-73.6 Y20 Z-99999   ; between Z and X towers
G30 P6 X-36.8 Y-21.25 H-0.05 Z-99999   ; half way to X tower
G30 P7 X36.8 Y-21.25 H-0.05 Z-99999   ; half way to Y tower
G30 P8 X0 Y42.5 H0.05 Z-99999      ; half way to Z tower
G30 P9 X0 Y0 Z-99999 S6      ; centre

The sign is so that e.g at P1 my my bed is high, a 0.10mm paper read 0.25mm on the Z display and at P3 it's low so the 0.1mm paper read 0mm.

I do have access to a lathe at my brothers, but I think I'll gather some experience first and see what else I'll learn.
I just printed Emmett's Gear Bearing from Thingiverse to test. It's a quite nice example of things that you can't build or take apart, you have to print it.





Offline Joules

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Re: Another 3D Printer
« Reply #41 on: February 16, 2016, 05:11:25 PM »
You got really good print quality there Jorma.  That's what's making the niggles worth solving.  This little printer is capable of very high quality work.   My fear about the extruder was justified when a filament jam popped the large gear and pinch roller out  :bugeye:

I hope it was just a one off, but I still have an all metal extruder on my upgrade list.  That said, a second Mini Kossel will probably join this one shortly.
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Offline Jorkki

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Re: Another 3D Printer
« Reply #42 on: February 16, 2016, 05:55:34 PM »
Outch!
Can't really beat metal for certain applications.

Of the printed ones, the coolest looking I have seen is Drew's planetary geared extruder:
http://www.thingiverse.com/thing:39138

Also I kinda like the simplicity of the design that Builda3dprinter.eu has in their kits.
The guy is showing the build in this video:
https://www.youtube.com/watch?v=u3npxBuSv0Y
They sell the geared motor and stainless steel spur gear on their web site as well:
http://builda3dprinter.eu/shop/page/2/
The plastic part stl file is in the information/downloads section.
I have no idea of it's durability though, probably would be a good idea to print a spare or two just in case.


Offline Joules

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Re: Another 3D Printer
« Reply #43 on: February 17, 2016, 04:33:29 AM »
Ha I printed Drews planetary extruded when he first released it with the intention of using it on a Rostock Max.  I like the YouTube video and extruded design might exchange the printed part for alloy machined part.  I do like the other Kossel machines on that site, but won't ever go back from a 32 bit controller now.

Setting the printer up for another test print.
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Offline Joules

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Re: Another 3D Printer
« Reply #44 on: February 17, 2016, 06:18:09 AM »
First test print with everything dialled in.  These are shell prints, in effect a spiral movement to print a single layer.  The objects you see are nose cones for a small model glider.



The print on the left when I produced it about a year ago was thought to be pretty damned good.  The print on the right is from the Kossel, you see a grain effect where the 8 bit controller interpreted steps on the left.  The right print barely shows the steps, you really have to see these to get a full understanding of the increase in resolution in printing.

My other concern was going to be tolerance from machine to machine as I have a few printers now and will be printing multiple parts and in different colours, so things like snap shut lids could be a problem.



Not a worry...  The translucent white print was from another machine over a year ago, and the black section below is a failed print from last night on the Kossel, they are mating parts printed on different machines and the grain in each print is alined, so you can see the difference.  The failed part has the snap lock printed on it, so it makes a good test part.  They clicked together just fine, I am so pleased with the tolerance I am seeing so far.   Yeah other issues with the printer are getting resolved and worked around, but the print quality is just outstanding and it's still early days.
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Offline Joules

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Re: Another 3D Printer
« Reply #45 on: February 20, 2016, 04:47:45 AM »
Oh well, I hate been right....  The extruder mechanism is pants.  The lower bearing is a rattle fit on the end of the 3mm bolt holding this all together, it should have been longer to at least take a lock nut, that would have stopped the extruder wheel grinding a helix and jacking itself out of the printed body.  So another part for redesign and thinking through a better solution.  Now I need to make two, as another Mini Kossel is on it's way.   Despite the hiccups, I really like what this printer can do, and the above mods will be done before I even assemble the next one.
Honour your mentors, and pay it forward.

Offline nrml

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Re: Another 3D Printer
« Reply #46 on: February 20, 2016, 07:23:03 AM »
The difference the Duet board and the DC42 firmware have made is amazing. It is nice to see a direct comparison. I never thought it would be such a big improvement.

I appreciate your stand on supporting local businesses whenever possible, but it might be worth a look at these for your next mini kossel. Some of them might save you a bit of hassle and possibly improve the end product.

http://www.aliexpress.com/item/3D-Printer-Accessories-Aluminum-Alloy-Full-Metal-M3-Delta-Kossel-Fisheye-Effector-Hammock-3MM/32437620404.html

http://www.aliexpress.com/item/4Pcs-Lot-3D-Printer-Accessories-Hot-end-Round-Fixed-Aluminum-plate-Sandblasting-Oxidation-Reprap-Kossel-E3D/32314904596.html?spm=2114.10010108.0.124.C1oOhW


http://www.aliexpress.com/item/New-Black-Color-Reprap-Kossel-All-metal-Aluminum-Corner-Piece-Frame-Vertical-Base-Delta-Top-Bottom/32473624719.html?spm=2114.01010208.3.47.P7Uyy2&ws_ab_test=searchweb201556_2,searchweb201644_3_505_506_503_504_502_10001_10002_10017_10010_10005_10011_10006_10003_10004_10009_10008,searchweb201560_1,searchweb1451318400_-1,searchweb1451318411_6449&btsid=0ea26ee5-c1d1-4a60-b03b-063b6a8c0376

http://www.aliexpress.com/item/3D-Printer-Accessories-Full-Metal-M4-Delta-Pulley-Tackle-Moving-Block-Hammock-Effector-20MMx20MM/32434034394.html

http://www.aliexpress.com/item/5Pcs-Lot-3D-Printer-Accessories-Reprap-Kossel-Prusa-Bowden-Step-42-Stepper-Full-Metal-Remote-Extruder/32426938444.html?spm=2114.10010108.100007.18.0UhbRQ

There are a lot of other very interesting products in the 3D printer parts category.

Offline Jorkki

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Re: Another 3D Printer
« Reply #47 on: March 03, 2016, 04:58:08 AM »
I found myself using a head torch constantly to see how a print is coming along.
I decided this is a good opportunity to start learning a little bit of the openSCAD software and decided to design a small clip to put on the hot end fan where a short strip of LEDs could be mounted to shine some light on the work in progress.

This is what I came up with.

I have also changed the hot end heater cartridge to enter from the front side as the leads were pressing against the cooling fan hood and that tended to unscrew the hot end loose.

At the same time I replaced the original 3mm machine screws that hold the hot end carriage to the effector plate with 3.5mm deep threaded universal screws (as I could not easily find the special screws made for thermoplastics). Not as good as Joules's threaded inserts, but a huge improvement anyway.
Might be a good idea to try and get some of these http://www.tappex.co.uk/trisert-inserts or something similar for future projects.


Offline Jorkki

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Re: Another 3D Printer
« Reply #48 on: March 13, 2016, 01:19:45 PM »
I have done some further improvements to my Think3DPrint3D Kossel Mini.

I noticed that to get better retraction performance, it is essential to lock the Bowden tube better in place.
At the extruder end the pneumatic connector seems to be solid, but at the hotend the connector collar will move back and forth with the tube no matter how hard I tried to push the tube in.
The solution is to lock the collar in place with a C-shaped spacer under it.
I printed some in PLA with the ID of 5.1-5.2mm, OD 7.8mm, thickness 1.3-1.6 and 270 degree coverage.
Seemed to fix the issue.

My hotend cooling fan quit, so I used the opportunity to upgrade it with a better one.
I chose the Sunon HA40101V4, which seems to be a very nice one with magnetic bearings.
http://www.tme.eu/en/details/ha40101v4/dc12v-fans/sunon/ha40101v4-000u-999/
Very quiet and practically no vibration.
At the same time I replaced the print cooling fan with a bit beefier Sunon, but I think there is a bit too much back pressure from the small airway opening in the guiding tube to be able the realise the full potential.
http://www.tme.eu/en/details/mb40101v2-a99/dc12v-fans/sunon/mb40101v2-000u-a99/
An axial blower type fan might be better  here.
I have also soldered a 220nF capacitor across the print cooling fan terminals because the fans do not like the PWM signal. The Fan used to start at 100% only, now it starts at around 10-12% and has a quite nice adjustment range.

I have also gone back using springs to pull the carbon fibre rods together to reduce the effect of play in the Traxxas joints. Seems to make the print quality a bit better, but for sure joints with no play would be better.