John's Mini-Kossel

[JohnStack]

Sorry, I've already built some Rostocks (and me have much love for them).

All that this is waiting on is wiring, hot end, and me figuring out how to hang an EZstruder off of it.

Features:
CF arms
Steel rails
E3d V5 HE (until I get my prometheus)
Smoothieboard 5

I bought some Chinese rails. I'm not sure about them. They seem to be a bit tight - but I'm hoping they ease up over time.

I am going to add Auto Bed Compensation but I figure that will be next month... I really want to see how this prints with a smoothie board.

[Polygonhell]

Terence Tam at open-beam is shipping Chinese rails, he used to sell them as is with lubrication instructions, but had a lot of returns, he now sells them pre-lubricated and claims they all work if lubricated properly.
I think the lubrication instructions are on the open beam site.

[mhackney]

There is a nice kossel ezStruder mount on thingiverse. I am using it on mine and the smoothieboard mount for kossel that uploaded to thingiverse yesterday. Makes for a nice compact package.

[JohnStack]

Thanks Guys!

On the rails: If you allow the truck to move past the end of the rail, the bearings come out...and I have shag in my office.

Doh!

Ezstruder Mount - definitely going to find it.

My primary motivation for building this is to have something really portable to take to clients. Stick it in a hard suitcase ala Maxwell Smart....

[Eaglezsoar]

John, you and Michael have to let us know the results of putting a smoothie board on the mini kossel. I am very interested.

[mhackney]

I'm ready to start testing smoothie but running into a problem. The board boots up when connected to USB and using the default firmware and config loaded on the card. If I then replace config with the Smoothieboard.Kossel config file it will not boot. Only the amber 3.3V LED is lit (none of the 4 green LEDs) which the troubleshooting guide says may be bad firmware or config file. I would think the firmware is ok since it boots the default config. This Kossel config came from GitHub and is the latest (edge). I looked through it and couldn't see anything that jumped out.

[mhackney]

Well, I built a new firmware from the edge release and flashed it. IMPORTANT TIP (and cool) - before you do ANYTHING to your smoothie board firmware, you can make a backup copy of it. Simply copy it from the SD card to you computer somewhere. This way you have a known good backup copy.

This new firmware reboots fine with the Kossel config. So now I can start to poet up the steppers...

[mhackney]

And we have movement:

[youtube]http://www.youtube.com/watch?v=P7Nu0t1VSbg[/youtube]

[gajtguy]

Congrats on getting that youtube thing to work too...!!

[Eaglezsoar]

You are getting it Michael. Good Job!

[Broose]

I just got my mini running with an Azteeg X5. Found a config that works for the X5 and am able to home and extrude. Just tweaking things in the config file and trying to figure out the best way to calibrate without the limit adjustment screws my Rostock Max has, since autocalibration is apparently not ready for prime time on the smoothie.

[gestalt73]

The three config settings that you'll want to use are:

Code: Select all

alpha_trim                                   0               # software trim for alpha stepper endstop (in mm)
beta_trim                                    0               # software trim for beta stepper endstop (in mm)
gamma_trim                                 0               # software trim for gamma stepper endstop (in mm)

the easiest way would probably to live edit the values in terminal, then save them off to the config file when you've got them dialed in

Code: Select all

config-set alpha_trim -0.010

[Broose]

gestalt73- Thanks for the tip on trim values- I'll try that- better than shimming the bed!

I am having an issue with the extruder temp display (at the bottom of the window and the temp graph display) on the Repetier Host Mac version. It shows the correct temp when I connect but does not update the temp unless I disconnect and reconnect.

[Eaglezsoar]

I just got my mini running with an Azteeg X5. Found a config that works for the X5 and am able to home and extrude. Just tweaking things in the config file and trying to figure out the best way to calibrate without the limit adjustment screws my Rostock Max has, since autocalibration is apparently not ready for prime time on the smoothie.

photo-13.JPG

Which extruder is that you are using and is it available on Thingiverse?

[Broose]

Which extruder is that you are using and is it available on Thingiverse?

Its the Richrap modified Greg's ( http://www.thingiverse.com/thing:60531 ) using an E3d bowden coupling from Filastruder.

[Tinyhead]

I've really wanted to build a mini-kossel. Other than the cost of the smoothieboard and printed parts, what is a rough estimated cost to build one of these? I notice some have bearing cheapskates like the rostock, some have the bearings that slide on the round rails, Broose has a different sort of sliding system it looks like... Any kind of ballpark figure that someone could toss out there?

[mhackney]

It depends! The original design uses linear guides that are about $240 for the set. I used them but my son is building another that will use the new - and cool - ball bearing carriages that Johann posted last month. They will be about $20 for 3. I have not seen a mini Kossel with round linear guides, the corner pieces are not designed for it, i think that was the full size Kossel. All the minis use the tower extrusions or linear guides attached to them.

I just priced this out for my son and a friend. Here's what I came up with:

Mini Kossel Printer parts

Mechanical

1. 3D printed parts (make or buy for $45)
2. frame: aluminum extrusion kit (precut to length) (black $55, silver $50)
3. fasteners (screws, nuts, etc) (kit $16 or buy individually and save a little and get extras)
4. Bearings for carriages (6 per carriage * 3) about $10
5. Delrin for bearing covers about $5 (and need to be machined) or substitute 4 & 5 with pre-made units for $50
6. 4 meters GT2 timing belt $10
7. pulleys for top and bottom of belts $14 or substitue 6&7 with this belt and pulley kit for $48
8. 6 push rods and ends kit $21 or assembled for $40
9. $13 borosilicate glass plate (Amazon backing pan!)

Electronic

1. 4 Nema17 stepper motors $40
2. Arduino based stepper controller card RAMPS $50 on eBay
3. optional LCD display $40 but I have 3 you can use
4. 3 endstop microswitches $7
5. 12v 5A power supply $8 to $25
   Hot end J-Head $60 or other hot ends form $40 to $100
6. 1.5M PTFE Bowden tupe $7.50
7. hot end fan $10
8. Wade's extruder hardware kit - I have most of the stuff to make these

Total: $321 to $450 depending on how much you buy vs build

or a complete kit for $699 but this includes linear rails instead of the Mechanical 4 & 5 items. These cost about $140 for 3 of them

[Eaglezsoar]

Michael, do you have more info on the "Amazon baking pan", I paid $30 for my glass and could use another.
I now have all the parts, just need the time and be in a less painful condition, these spring rains also brings the pains.

[mhackney]

Here you go Baking Pan

Should work fine on an Orion too.

[Tinyhead]

Ha! I really like that pan idea.

Thanks for the awesome list! Most of the hardware and bearings I could get through work, so that would cut down on costs, but what would really drive the cost up is shipping. Most of this stuff would be out of the states and the shipping would destroy the project. It's stuff like ordering a hobbed gear for the extruder at 9 dollars with an 18 dollar (US) shipping charge that kills me.

Again, thanks for the list. It'll help at least get a few things together. I was also looking at the 3D Printer Kit at Maker Geek, but it seems to be geared more towards building a reprap (even though it mentions you could build the mini-kossel). Things like only 2 GT2 pulleys and Z axis couplers...

[mhackney]

I get a lot of the stuff from TriDPrinting - you could at least minimize shipping because they have all the basics. i hear you about shipping. I sell my fly fishing reel kits and books all over the world and feel awe full when folks in Australia have to pay $30 to ship a $25 book.

[Eric]

I saw the recirculating bearing ball bearing concept as well, and ordered 300 acetel balls two days ago to give it a try. It'll be a few weeks before they get here, sadly.

[youtube]http://www.youtube.com/watch?v=UTxivqmK4s0[/youtube]

[mhackney]

Where did you order your balls? (don't laugh)

[mhackney]

Looks like 20 balls per side or 40 balls per carriage times 3 = 120 balls. I see amazon is backordered. Cancel your order and get them at McMaster Carr - http://www.mcmaster.com/#balls-(made-with-delrin-acetal-resin)/=rz9d5s

In stock and they are ultra quick with the shipping.

[barry99705]

Wouldn't airsoft pellets work? They come in 6 and 8 mm.