Another 3D Printer

[Joules]

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.

[nrml]

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.

[BillTodd]

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 :-)

[Joules]

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.

[BillTodd]

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?

[Joules]

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.

[BillTodd]

I like to support UK business, as any problems I like them to support me.

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)

[Joules]

Nah, I use H2O MOX abrading....   

Rub it with damp wet and dry paper.

[Joules]

A medium sized heavy package turned up this morning.  So once another  open it up.



   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.

[Will_D]

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?

[Joules]

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.

[BillTodd]

All the parts look nicely made from here:-) 

Are we there yet?....

[RobWilson]

Very cool Joules   


Rob

[nrml]

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.

[Joules]

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   

[awemawson]

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

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  )

[Joules]

So would all that be at the same vets practice ?   

[Pete W.]

Hi there, Andrew,

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

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  )

I hope that both operations have a good outcome. 

[awemawson]

So do we Pete 

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 

.. sorry Jules - we'll go away and leave your thread uncluttered now 

[Joules]

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"

[Joules]

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.

[PeterE]

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 

/Peter

[SwarfnStuff]

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. 
John B

[Joules]

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.

[PeterE]

PLA is different from ABS so one possible cause out of the way.