Ebay SINTRON Kossel Mini full kit

Insulation is a good idea. I used to use a piece of cardboard with foil tape on top, but now have upgraded to a cork tile cut to the right shape (triangular, with the corners cut off).

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nebbian
Insulation is a good idea. I used to use a piece of cardboard with foil tape on top, but now have upgraded to a cork tile cut to the right shape (triangular, with the corners cut off).

but is it directly attached to the heated bed or is there air gap between?

There's an air gap in between. I don't think that it matters much, as I'm only using it to protect the electronics that are underneath. The heatbed is plenty powerful enough to reach ABS temperatures without any insulation at all.

Ok, I have a Smartrap and it is set up and prints well, but I was looking for a second printer. Ebay was my friend and I came across this printer, but decided to hunt around on the web for info before parting with cash. I read through 26 pages of this monumental tale and was going to hit the idea on the head, but then jumped to the last page and worked backwards. When I saw what SJN was producing on what appears to be a bog standard machine my eyes popped out of my head.

The Sintron Kossel that I am looking at is described as having the fixes included, so new T nut design and an M3 rod to avoid things hitting each other. Have they also upgraded the hotend, and arms (or do I still need Traxxas rods and ends?).

I am now at a crossroads, am I correct in thinking that thanks to the feedback that Sintron have received that they now produce a printer that works how it was supposed to? My only thought is that I would need to flash the 2560 with whatever code SJN has configured. Would this be correct.

I have to say that my 2 year old Smartrap, which has servo auto bed levelling and an old AluHotend, has been working pretty much flawlessly with PLA and no heatbed since the day that I bought it, but being a modeller myself, I look at what SJN is getting out of his Kossel and my heart and wallet are now locked in a fight to the death. I can print a box to hold the 2560 and Ramps, together with a cooling fan as I have the STL for the Smartrap. Then it seems that all I need is an extra fan/shroud to cool the print which is easy enough.

Dear Deirdre...what should I do?

Wibbles,

The choice of journey is up to you. If you choose the Sintron route, you will get a printer that prints parts relatively cheaply. However if you're like me, you'll spend the next year and a half gradually replacing and upgrading all the parts until the only thing that's left of the original kit is the aluminium extrusions.

A better starting point for a mini would be this one:
[www.robotdigg.com]

The biggest differences here are the metal corners, and the linear rails. Both will improve quality quite a bit, especially the metal effector and carriages. If your effector is printed, then it allows a lot more compliance than when using metal carriages and effector. Metal corners aren't quite the panacea that many believe them to be, as you can use diagonal bracing on printed corners to pull the frame into line -- however they do make it easier to get it reasonably straight.

I've enjoyed the journey, I've learnt a heck of a lot after buying the Sintron kit. However there are better options out there now. My printer now uses quite a lot of RobotDigg parts -- the linear rails and effector -- and after my latest round of updates I'm getting accuracy of within 0.2%. I think I can get this down to 0.1%.

Good luck on your project, whichever printer you choose

Forgot to add, the shopping list for a new delta if I were to do it again would be:

* Metal effector
* Metal carriages
* Linear rails
* Metal corners (although not strictly necessary)
* 0.9 degree steppers
* TMC2100 drivers or similar.
* Flying extruder
* Heated bed
* PEI build surface
* Turnbuckles to adjust the twist / squareness of the towers (there are a few options in the R/C car world)
* Zero slop ball joints (Traxxas ends are fine, if you buy more than you need and pick the best 12)

If money is no object, then the best controller is probably a Duet Wifi running DC42's RepRapFirmware, with a PanelDue attached to it. I have issues with their marketing strategy, though.
Other options include a Smoothie board, Re-Arm and probably some other 32 bit boards that I can't remember right now.

If going for a RAMPS/arduino setup, then choose Repetier for the firmware instead of Marlin, and avoid DRV8825 drivers. Even the venerable 16 uStep A4988 drivers give better results than the 8825's, especially when using 0.9 degree steppers.

I hope this helps.

I have only upgraded to the traxxas ball links :-)

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SJN
I have only upgraded to the traxxas ball links :-)

Thanks for the info, I was hoping that you would say that.

I can get one for £195 free postage, which by my reckoning is a bit of a bargain. The Smartrap kit cost me £280 2 years ago? Plastic parts do the job, as long as everything lines up properly, that much is down to the quality of the prints. The one thing that I did when I built the Smartrap was to tap threads through all bolt holes raher than just drill the holes out, and that little bit of effort resulted in a rock solid build. If this was my first printer I would probably be a lot more cautious, but knowing what I now know, I have lost that fear of the unknown.

I will go for it, and if the Kossel turns out small parts as good as SJN's I will look at converting the Smartrap to a large bed version using a mod on Thingverse. If there is one area where 3D printers come into their own it is in the world of RC models, I do 1/16 scale RC tanks, and the occasional boat.

Got to say that this thread has been an absolute goldmine of info, so many thanks to all of those who take the time and trouble to document their findings.

Rob

Here my Configuratin h file for the firmware downloaded from the Sintron site link when you buy the mini kossel.
I use the older Arduino 1.05-R2 software version, as the newer versions say there are errors or something when you try to compile the firmware.

This is the firmware that I printed all the stuff shown earlier with.


Its pretty crappy from sintron that when you download their firmware for their product that it is not set up at all to fit their mini kossel.

[www.arduino.cc]

Edited 1 time(s). Last edit at 01/14/2017 07:02AM by SJN.

You are a star, thanks, I'll download the file ready for when I have completed the build.

If anyone wants to know how to build the perfect printer, I highly recommend this guys videos on You Tube.

Kossel Build Videos , there are about 65 of them, and he goes into massive detail.

The problem with the Arduino errors is that some commands have been deprecated in the later versions, especially 1.8. It can be fixed by simply changing the syntax to the revised formats, but it's just as easy to use an older version. I use 1.6.

This is the the newset RC 8 version that is set up for my mini kossel.

It works just as well as the old one, but I did not like the way it ends a print compared to the old included firmware.
Now when a print is finished, the caragies return to end stops, and thn they move down and park themselves at the maximum print height.

The old firmware parks the carages against the end stops at the top, and leaves them there........ Im 100% positive that it can be changed somewhere......but im not smart enough for that yet :-)

And it does these things regradless of which end script you enter in the gcode in the slicer......so it is the firmware that is doing it.

With the latest RC8 marlin firmware, you can also use the latest Arduino software to compile the firmware...........but it wont make your printes any better anyway, so I use the old firmware :-)

[github.com]

[www.arduino.cc]

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Wibbles
You are a star, thanks, I'll download the file ready for when I have completed the build.

If anyone wants to know how to build the perfect printer, I highly recommend this guys videos on You Tube.

Kossel Build Videos , there are about 65 of them, and he goes into massive detail.

The problem with the Arduino errors is that some commands have been deprecated in the later versions, especially 1.8. It can be fixed by simply changing the syntax to the revised formats, but it's just as easy to use an older version. I use 1.6.

Thanks, I also saw those videos.

They are very good, but some of the things are a little overkill :-)
But he does a very good job.

@SYN
If you don't like the new behavior of G28 (for deltas) deactivate DELTA_HOME_TO_SAFE_ZONE.
However - G28 is not a move_to command. How about 'G0 X0 Y0 Zn', where n is your max_height.

Thanks for the info.

But since changing the firmware to a newer version does not make my ptints nicer, all just use he old one :-)

Is here any other reason to move to the new firware that I am not aware of ?

you may have to downgrade java runtime to older one.. at least if you are using mac

Mine was delivered yesterday, only took 3 days to get here.

I built 70% of it without downloading the instructions. I don't know about the early kits, but this one has good quality plastic parts, and all bearings etc are a good fit. The rod ends are all solid and don't come anywhere near rubbing on each other, I am going to try the originals before I decided whether to install Traxxas ones. Stacks of spare screws, cable extenders etc, the complete hot end was pre assembled. I seem to have 6 end stop microswitches, but assume that I only need the three at the top of each column.

My only gripe is the auto levelling, which seems to have been designed by a monkey with a mallet. It is a far cry from my Smartrap that has a completely automatic servo operated version, so once I have got this one up and running I will be looking around at the other options that are available. An LCD enclosure would have been nice but at the price I can't complain, I'll just print one.

Having built mine, I can see that the oz guy has gone a bit overboard on his problem solving, using sledgehammer to crack a nut, but then if he has an engineering background he probably gets obsessive about tolerances. I solved the height issue with the bed levelling micro switch by simply placing two half height M3 nuts between the effector and the rod holder to raise it by 2mm. The microswitch pins are now clear of the effector and the levelling rod is still way below the nozzle.

Should be able to do a test print within a couple of days??

Hi again

I have a problem with my kossel.. I have almost completed the building job. I have been tweaking this marlin
software that I grabbed somewhere from github (I post link later so professionals can evaluate have lost track completely)
I finally got lcd working and It shows that heat bed temperature is -26C so if I turn heat bed on from repertier host It won't do it due to safety feature

so I connected hot ends thermistor to heat bed thermistor pins and lcd shows temperature correctly (I tested this way that heat bed with external MOSFET works OK with this)
Also I tried to measure heat bed thermistor with multimeter with no succes..

Verdict heat bed thermistor is faulty

so could somebody help me and give me information about this component so I could buy new from local "radio shack"

Edited 1 time(s). Last edit at 01/20/2017 02:05PM by OG.

Ok, I have it all assembled and I've been testing it from the lcd screen using the move axis option in Prepare.
The motors were running in the wrong direction, so I turned the X and Y plugs around. The Z can't be reversed because of the plug, so I popped the pins out of the plug and reversed them (There are two black ones so if you do this make sure that you reverse them).
I can move each axis up and down.
If I select home all three will move up until they bounce on the end stops, and then stop completely.

Questions:

I tried running the extruder motor from the lcd but doesn't move, so does anyone know if it should? I don't have any filament in there at all.
I just need to check that it is also running the right way, rather than retracting.

When selecting + and - movement, should + move down, and - move up?

OG, have you selectred the correct probe in the marlin firmware ?
Try use my config.h file, and see what happens.


Wibbles, the extruder will only move when the hotend has reached the temperature preset in the marlin firmware :-)

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SJN
OG, have you selectred the correct probe in the marlin firmware ?
Try use my config.h file, and see what happens.


Wibbles, the extruder will only move when the hotend has reached the temperature preset in the marlin firmware :-)

I thought it would be something like that, thanks for the info.

I'll try testing the levelling, Z height and all of the other parameters tomorrow.

If anyone knows where there is an 'easy to bolt on and set up' sensor that will be a neater solution to the bed sensor supplied, please post details.

Wibbles, you just have to reverse the direction in the firmware...way easer that messing around with the hardware........you WILL be compiling your own firmware anyway :-)

Downloading the stock marlin firware from the marlin site will not work without setting up all the parameters for the sintron mini kossel.

You will need to replace the stock Marlin Configuration.h and Configuration_adv.h with the delta files in the example_configurations folder. Then modify those to match your config. SJN is correct you can just modify the settings in the config file instead of re-wiring your hardware.

I took my marlin firmware from here

there is >"example configurations folder >delta>kossel mini" there is quite good example configs (configuration.h and configuration_adv.h) files that you can copy to main marlin folder.. but you still need to configurate some parameters like DELTA_SMOOTH_ROD_OFFSET

guess you guys know these..


SJN: I eyed your configuration file and your thermistor setting for bed was 1 and mine was 11

I will check this thing tomorrow

somewhere I red that this thermistor is maybe EPCOS B57560G104F THERMISTOR, 100K
and that choice #1 is for epcos 100k thermistor

so I hope this is maybe the reason that does not work

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SJN
OG, have you selectred the correct probe in the marlin firmware ?
Try use my config.h file, and see what happens.


Wibbles, the extruder will only move when the hotend has reached the temperature preset in the marlin firmware :-)

There's a g-code, M302 or M303 or something close to it to enable cold extrusion, should be useful for testing.

Thanks for the extruder gcode info.

I grabbed SJN's config.h file and swapped that into my marlin files, and I am hoping that this will be a closer start point than the Sintron version. Time will tell, I will be back on the case tomorrow hopefully. My initial test via the LCD was to confirm that the motors, speed controllers and end stops were all on the correct plugs and that they functioned. I hooked up the red wires so that I could see the led's coming on, it looks whizzy so I will leave them that way. Swapping the four pins around in the Z motor plug only took about 60 seconds, I do it all the time on radio controlled models, so it was a doddle for me to do it that way. If I am editing the firmware I may well swap them back again and do it from there to keep the code consistent.

I checked the frame over and it seems pretty straight, all angles pretty close etc. The rods and the difference in width between the roller bracket and the effector may yet prove my undoing, I'm not one for washers, so may have to take things apart and do a bit of filing, the snag with that method is that although the width may be identical, there may still be a difference between the centreline of each component and the ball joint, eg 24mm one way, and 26mm the other, so even though the effector mount may be 50mm, the roller mount could be 26mm and 24mm. Both would be 50mm and the rods would be parallel, but they would be at an angle between the two components.

The acid test will be actually printing something??

If you aer using my file, just remember to swap back the wires you changed, because I did not do that.
I only reversed the connector for the extruder motor, as it was feeding backwards.

Good luck on the tests.


Remeber to define that you are using a delta printer in the slicers, and if you are using simplyfy3d, make sure you move the center co ordinates to the middle of the build plate :-)

This is a complete noob question, but how is the print bed secured to the frame? There are three screws, three square nuts, and three springs, plus a black allen bolt.

I cannot figure out how to keep it securely in one place, and can't find anything on the web that shows how the screws and springs should be assembled so that it is.

I'm not using the heated bed as I will only print using PLA. I'll just stick a Buildtak mat on there.

If anyone has any pics I would be very grateful.

I just use the T nuts, springs, and some washers to keep up the tension, so it does not move around.



Edited 1 time(s). Last edit at 01/21/2017 07:40AM by SJN.

Anyway, with springs installed the heat bed is still a bit movable (when nozzle scratches over printing model). So, I threw springs away and replaced then by some plastic spacers instead.



Edited 1 time(s). Last edit at 01/21/2017 08:09AM by GrAndAG.

I have installed mine so that I can use adjuster nuts to level the bed. See Picture.