Ebay SINTRON Kossel Mini full kit

Has anyone else had problems with their carriage roller wheel bearings? Some of mine are OK, but some have a lot of play in them. One can wobble more than a mm at the outer edge, when the centre is locked solid.

*sigh* Back to Bunnings today I guess.

Nebian,
Sorry, about the only thing that worked right out of the box was the carriage.

I got my Traxis rod ends today. I am going to use the supplied metal rods with jam nuts. I will use this fixture (on Thingyverse).

I have another commitment so won't be working on the Sintron for a couple of days but will keep reading. Hopefully some of you will get ahead of me and solve any outstanding problems before I get there.

Do any of you have any thoughts on the Arduino Due and Ramps-FD shield. $55 for the pair on Ebay. What firmware would I use? Is it worth doing?



Roger

Quote
Miamicraft
Nebian,
Sorry, about the only thing that worked right out of the box was the carriage.

I got my Traxis rod ends today. I am going to use the supplied metal rods with jam nuts. I will use this fixture (on Thingyverse).

I have another commitment so won't be working on the Sintron for a couple of days but will keep reading. Hopefully some of you will get ahead of me and solve any outstanding problems before I get there.

Do any of you have any thoughts on the Arduino Due and Ramps-FD shield. $55 for the pair on Ebay. What firmware would I use? Is it worth doing?

[attachment 60495 DUE.JPG]

Roger

That Ramps-FD is the Geetech v1 board which is known to have serious problems There are plenty of threads re it in the controllers section of the board.

Some of the flaws are actually quite dangerous in that under a crash situation they can enable all the heaters at full output = severe fire risk.

You would be much better going for the DUET Board from Replikeo for like $60 and use DC42 firmware on it

HTH

Doug

Hi everyone. I have just bought this kit as well. I have also had the problems with the extrusions not fitting which resulted in me snapping one of the parts! Not cool.

Anyway, I have sorted the frame out now but I have just read through the issues you are having with the rod ends not fitting the roller carriage and again I have this problem. I don't have access to a printer so I can't print out any spacers etc. Has anyone been back to ask for a refund on the parts as I am a bit reluctant to start altering the printed parts which I have paid for to be working straight away.?

@azz00
You can use washers instead of the adapter plate to make your carriers work. Or use TRAXXAS joints.
Nevertheless, you should ask Sintron for a replacement of the snapped corner. It might be still usable, when you can fix it with glue.
At least you can try to make your print work and then print some better corners yourself.
-Olaf

Good point. I will use some washers for now until I get the carbon tubes etc. And yes I will try the refund now and I may be able to glue the corner back together as well. Thanks!

I made a jig for the diagonal arms today, and as expected there is quite a lot of slop with a 3mm bolt inside the ball end. It was pretty easy to adjust the rods to all be the same size (estimate that all are within 0.05-0.10 mm of each other). I'd also expect that this method is more precise than gluing, because you can adjust the rods after the fact. If a rod is slightly off, you can still twist the rod ends to get the adjustment you need (the rod ends don't need to be perfectly in line with each other).

When I was done, all rods fit easily on the jig, and could be wiggled around the same amount as if only one end had a bolt through it..


Also when you're putting the main 2020 sections together, use an angle finder! The first time I tried, I got angles of 60.4, 59.8 and 59.8... after a lot of manipulation I got them all to 60.0 degrees with only minor dremel work required. The top triangle (with only one layer of 2020) was easier than the bottom.


In less successful news, Bunnings doesn't have those rollers. The only place I've found will deliver in a couple of weeks. The slop in some of my rollers is completely unacceptable, those bearings are shot. A couple of them are tight, most are loose, and a couple are really bad. I can wiggle the worst one through a good 10 degrees

I've emailed customer support asking them for some replacements.

I´ve been looking for those "shower door" rollers myself and some vendors spec´d them ABEC-1 which is the worst quality.
Now I get an idea, why the official v-rollers are so expensive.

Any chance to replace the bearings? Or print the rollers yourself and use better bearings?
-Olaf

Doug,
The DUET Board from Replikeo is on sale for $50. Bought one for $60 including shipping. Will commission machine with the Arduino and upgrade after bugs are worked out. Thanks.

Nebbian,
Would it be quicker (not easier) to just replace the bearings? Sort of good news is you can get machine up and running as is and change out wheels later. The quality control on this kit really sucks. Believe it or not have ordered a lot of stuff from China and this is the first time I've had problems.

o_lampe,
Robotdiggs metal corners and Traxis ends would resolve your current problems but would add $60-$70 to the cost of your budget kit.

Off to do real work,
Roger

@ Miamicraft;
I have done another redesign of the carriage also using Kossel-Linco effector and changed to 12mm in openscad.
My printer is not able to print the GT2 teeth for some reason? (UP! Mini)


If anyone is going to use the magnet kit (12mm/10mm balls).

I still need to wait for my parts to arrive to see if files are right, unsure when it'll arrive.

I will post the STL soon (need to make sure its right).

Edited 1 time(s). Last edit at 08/23/2015 06:44PM by kingoddball.

Thanks for the ideas guys. How easy would it be to press out the bearings? Do you think that the wheel would be molded around the bearing, or just pressed in after the fact?

I don't have access to a working printer yet, so can't print any replacements sadly.

By the way, if you're using the Traxxas ends then you'll still have to do a bit of dremel work to get the rod ends to clear the carriage:



And since I've just figured out how to add pictures to my posts, here's a gratuitous shot of how "together" mine is right now:



If anyone has gotten up to the end stop switches, then try holding up the plastic spacer to the switch PCB. You'll laugh your head off.

For giggles did a search on DLT-180. It looks like a close relative of the Sintron. The assembly instructions show Traxxis type ends and cut belts. The carriages are slightly different with the joint horns centered. Don't know if that would affect clearance. The end stop switches are plain lever micro switches which may be why holes don't line up.

Some comments on parts not fitting... surprise surprise....

Roger

I mentioned it in another thread, but here it fits as well:
The bearings aren´t meant to take sideloads. A roller design similar to the small black one would be a much better fit.
It would have two bearings and rolls on the face of the extrusion. The slot would only act as a guide.
-Olaf



Edited 1 time(s). Last edit at 08/24/2015 02:45AM by o_lampe.

I believe the best way to strip the roller from a shot bearing is to put it in hot water. But still a quality replacement bearing isn´t meant to take sideloads, it´s only a bit stiffer...
-Olaf

Hello "friends" of the SINTRON Kossel Mini full kit,

so i ordered the kit and last Tuesday it arrived. Only one week delivery and no taxes --> nice.

First impression: everything was well packed. Didn't notice any bend pins on the electronic. Every part seems ok.

Assemble: Well yes, i was warned by this thread. So overall i think the parts will work. I allready assembled the frame and the roller-carriage. Hardest part i think was to find out which screw goes were. The T-Nuts dont hold the short aluminium extrusions well, because of the little "integrated spaces" in the printed parts. But they hold well enough (i hope).
The long extrusions i hammerd with a little hammer in and they did go in with little force. For me this is ok.

The belt clip i think will hold strong enough. The belt fits in very tight so i think it won't come loose.

Problems so far: the ball joints REALLY don't fit on the print head and the roller-Carriage. I installed the spider with the original ball joints and they move but not very easy and affect each other or with the roller-cariage. Solution: i switched to TRAXXAS. Nice fit and now the print head easily moves in every direction.

The normal M5? nuts on the Roller-carriage sometimes gets little bit loose resulting in a little play. If they are in place i have no play on the roller-carriages. Will replace them with nyloc or use a second nut as conter.

The wrench in the z-probe won't go down. But when i look at the "Printed Parts Preperation" from [www.think3dprint3d.com] i think this will be fixed by me.

Questions so far:
How to assemble the complete print head? Looked at the parts and i can't imagine how they fit well together (for now) and which screws i will choose.
Why i always think there are too many screws left? Replacements? (e.g. Carriage assemble)
Why i read everywhere to not use all three connectors on the endstops? If you connect the delivered endstops right to the ramps then everything should go fine or not? (Would love to see the led light up on the endstops )
Are there any screws for belt tensioning left?
Should i really connect the delivered cable to the power-supply and burn down my house?

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Should i really connect the delivered cable to the power-supply and burn down my house?

What´s wrong with the cable? Any pictures?
-Olaf

No no, nothing wrong with the cable. I'm just a little bit scared to connect 220 Volts to the "open" connectors of the power-supply. For savety i think i will connect a three-wire cable with a ground wire and try to isolate them somehow.

PS.: i'm not a native speaker

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Rossini
No no, nothing wrong with the cable. I'm just a little bit scared to connect 220 Volts to the "open" connectors of the power-supply. For savety i think i will connect a three-wire cable with a ground wire and try to isolate them somehow.

Doesn't the kit include an enclosure to guard the mains terminals and provide strain relief for the mains cable?

I'm guessing that the PSU they provide is a generic Chinese 12V LED/CCTV one. In which case you can print an enclosure similar to this [www.thingiverse.com] when your printer is working.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

nope .. kit doesn't include a enclosure.

Thought I'd post a couple of tips I've come across while building this kit.

Parts preparation

* Remove the anti-lift pads, and any extra strings left lying around:


* Bevel the edges of the hole where the 2020 will be inserted


* After driving the 2020 through the corner with a mallet, it will create these shavings. This is fine.


* To get the aluminium extrusion out of the corner piece, you can open the jaws of a vice to be slightly larger than the 2020, and rest the corner on the jaws. Then using a socket, you can tap the extrusion back out.
(Note: the top corners need to be a lot looser than the bottom, because the belt tensioners need the corner to be able to slide up and down without the use of a mallet.)


* The T nuts won't grip the aluminium extrusion properly if the corner pieces are left as-is. I found that removing the pad where the T nut sits meant that I could get a good amount of tension into the T nut.

Traxxas rod ends

You will need, clockwise from top left:

• A small dish with ice, water and salt
• A cup of boiling hot water
• A packet of rod ends
• A chopping board

Pay careful attention to the rod ends. The side with a shiny ring is the side you want the ball to slide into, as it is wider than the other side. The one on the left has a shiny ring showing.



Dump the metal balls into the ice bath, and with some tweezers hold a plastic rod end in the boiling water for 30 seconds. Then simultaneously take a ball out and put it on the chopping block, while putting the hot plastic part over the top. Press down with your fingers until you feel it click into place.



The finished article should have no slop. If you hold the rod end by the ball, the plastic part should stay sticking out horizontally, not flop down. Here the top one is bad, while the bottom one is good.



Finally, tap the rod end with an M4 tap.

Getting your frame lined up


When first putting your frame together, a really handy tool to have is a digital angle finder. I picked this one up from my local hardware store for around $25.

You need to go around your frame, making sure that all your angles are exactly 60 degrees. When I first tried this, one angle was 60.4, the others were 58.8 despite trying to push the extrusions fully in.
Loosen the T nuts, and see if your corner brackets are twisted or warped. Some light work with a dremel can sort this out. Only continue when all angles are exactly 60 degrees.
A little bit of time spent here will save you days of calibration frustration later on.

Rod end length

It helps if you make up a jig to get all your rod ends the same length. Here is one I made from some bits of aluminium angle, with screws and T nuts provided in the kit. Try as hard as you can to get all your rod ends exactly the same length.

End Stops

The mounting method recommended by Sintron isn't exactly stable... there are a number of issues with this. I wasn't happy with the design anyway.

So with a couple of round washers, some small screws and nylon M3 hardware, I was able to fabricate some brackets that seem a lot more sturdy.

When you put the endstops right to the top, you aren´t able to print full width at that height.
In order to use the full print envelop you have to allow the carrier to move past the endswitch. ( and disable max_software_endstop )

I´m gonna use optical sensors to achieve this, but haven´t thought of a bracket yet.
-Olaf

Quote
o_lampe
When you put the endstops right to the top, you aren´t able to print full width at that height.
In order to use the full print envelop you have to allow the carrier to move past the endswitch. ( and disable max_software_endstop )

I´m gonna use optical sensors to achieve this, but haven´t thought of a bracket yet.
-Olaf

Good point, although the carriages can't physically move past the top corner piece. Perhaps the best idea would be to mount the endstop switch so that it triggers a mm or so before the carriage is physically stopped by the corner piece. That way you don't need to disable max_software_endstop, as you know that the carriage can't go past the endstop anyway.

More progress:

The top bearings seemed a little bit too close together for me, as the belt seemed to hit the flanges slightly. So I added a thin 3mm washer between the bearings. The belt rides nicely now.


Here's how I'm attaching the belts to the carriage. More dremel work *sigh* Half the teeth are removed, and the lower end of the belt is set up to grip the teeth of the top end of the belt. This means that the bearings are rubbing on the flat side of the belt, rather than the side with teeth. You could use an idler pulley, but I don't have one, and can't print one out.
This also means that you need a half twist in the belt as it goes between the top idler bearing and the bottom pulley. You need to ensure that this is around the right way so it doesn't rub on the carriage (even so, more dremel work was required here). I know that not many people will set things up this way, which is fine.


The hot end bracket didn't seem to fit properly either. I'm not sure whether they printed out one that is set up for a different hotend, or if they just didn't measure properly. Anyway it needs some dremel work as well.




Here it is attached to the hotend. Rossini I hope this helps.



Also please let me know if you think I'm spamming up this thread with too many pictures. I'm sort of getting a bit snap happy!

The provided Z sensor attachment object was too big, it was fouling on the hotend.


So I replaced it with a small terminal block:



Much better!


It seems to retract and trigger properly now.

One of the first things you're going to want to print with your printer is the bracket that holds the RAMPS and arduino board in place.

I don't have a printer (yet) so had to make do with some scraps of aluminium angle.



I'm still not sure whether to put the electronics in the top or the bottom. The top is sort of better because you don't have to run your cables as far, and also don't have any worries about heat.
But there's not much room up there with the filament roll in place.

Your stepper motors are on the bottom, that is where you want the short cables.

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
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