Upgrading Mini Kossel to Duet electronics I've written a couple of blog entries on how I upgraded my Mini Kossel to Duet electronics. Part 1 (Hardware) is complete and at http://miscsolutions.wordpress.com/2015/01/04/upgrading-the-mini-kossel-to-duet-electronics-part-1-hardware/. Part 2 (Software and Commissioning) is part-finished and at http://miscsolutions.wordpress.com/2015/01/05/upgrading-the-mini-kossel-to-duet-electronics-part-2-software-and-commissioning/. [img]https://miscsolutions.files.wordpress.com/2015/01/2015-01-05-15-31-10.jpg[/img] [img]https://miscsolutions.files.wordpress.com/2015/01/printerwebcontrolscreen1.jpg[/img] The main problem was that the Duet is too large to fit under the bed where the Arduino/RAMPS was. Increasing the lengths of all the top and bottom extrusions by 15 or 20mm would solve that, and give a little more print area. But I mounted the Duet on the Z tower instead. https://reprap.org/forum/read.php?178,451173,451173#msg-451173 Sun, 15 Mar 2026 17:19:08 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?178,451173,544356#msg-544356 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,544356#msg-544356 www.thingiverse.com]. The 3rd iteration of the mains inlet + Duet mounting plate is currently printing, and if it is a success I will upload that one too.]]> dc42 Delta Machines Mon, 10 Aug 2015 17:34:10 -0400 https://reprap.org/forum/read.php?178,451173,544324#msg-544324 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,544324#msg-544324
Thanks for the info.

I have ordered the ones from ETANG that you used £1 per motor just wasn't worth the hassle.

I have a 24V LED supply already so should be good to go for the next Delta (will be a smaller one geared up for finer prints)

Will be interested in your Duet mount as well.

Doug]]> dougal1957 Delta Machines Mon, 10 Aug 2015 16:02:18 -0400 https://reprap.org/forum/read.php?178,451173,544240#msg-544240 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,544240#msg-544240
Etang also sells these 24V 40mmx10mm fans [www.ebay.co.uk]. I got the 24V 30W heaters (to convert my E3Dv6 to 24V) here [www.ebay.co.uk] or you can get them from E3D.

I'll post the Ormerod extruder mount on thingyverse later this evening.

I now have a printed combined mains inlet & Duet mounting panel too.]]> dc42 Delta Machines Mon, 10 Aug 2015 12:59:17 -0400 https://reprap.org/forum/read.php?178,451173,544214#msg-544214 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,544214#msg-544214
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dc42
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shadowphile
Hi Dave, I have been relying on your kossel-to-duet blog and it has become my bible for this process, thank you! I have a bunch of parts on order so I'm still lining up my ducks. (or is that an American expression?)
You have suggested 0.9 degree motors but I have seen multiple comments that those and/or 1/32-step drivers are too fast.
I would think the Duet could easily keep up though, unless there is a limitation somewhere not related to the MCU speed or word size.

0.9 deg motors or 1/32 microstepping would seriously stretch an Arduino Mega or similar atmega2560 electronics on a delta. But I expect the Duet to handle them adequately. At worst, travel speed might be limited to 200mm/sec instead of the 400mm/sec that I currently achieve with 1.8 deg motors and 80 microsteps/mm.

I ordered some new motors a few days ago (3 x 0.9deg JK42HM48-1684 for the towers, and a 1.8deg JK42HS34-1334 for the extruder). They are due for delivery tomorrow or Monday. So I will soon know for sure how fast the Duet can drive them. I also have some firmware efficiency improvements planned to improve the maximum speed.

Dave

Do youu think that these 0.9 steppers would be suitable also could you post you Mount for the Ormerod Extruder please think I am going to go that route then just need to find the right 24V Heater/fan

Doug]]> dougal1957 Delta Machines Mon, 10 Aug 2015 10:59:50 -0400 https://reprap.org/forum/read.php?178,451173,538025#msg-538025 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,538025#msg-538025
For now I have removed one of the extruder drives from my Ormerod and printed a bracket to mount it on the Kossel. It uses a smaller and cheaper motor, and I think the 3:1 gear ratio is a better compromise between torque and acceleration than the 5:1 of the original. I have found the spring loaded variant of the Ormerod extruder drive very reliable. So in the longer term I plan to adapt this version of the Ormerod extruder drive for the Kossel, which basically just means removing the mounting hook.

The 0.9deg motors I bought are JK42HM48-1684 and the extruder motor is JK42HS34-1334, both from Etang Electronics which sells on ebay UK. Total cost was £50.80 + VAT. These motors don't have flats on the shafts, so I ground flats on them. Also, they have flying leads instead of connectors.

I subsequently discovered [www.omc-stepperonline.com] which sells the 17HM19-1684S. This is the 0.9deg version of the motor I was originally using and would probably be my preferred choice if I hadn't bought the other ones. From the picture, it looks like it does have a flat. The 17HS13-1334S looks to be a suitable choice for the extruder drive. The prices are low and it looks like they ship direct from China, so delivery may take a while.]]> dc42 Delta Machines Mon, 27 Jul 2015 06:01:20 -0400 https://reprap.org/forum/read.php?178,451173,537994#msg-537994 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,537994#msg-537994
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dc42
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Koenig
Might I ask why you choose a smaller motor for the extruder?

The 17HS19-1684S has too much torque for the geared extruder that came with my T3P3 Mini Kossel kit. To get the right amount of force (so that it the nozzle gets temporarily obstructed, it skips steps instead of grinding through the filament), I have to reduce the current to 400 to 500mA. However, this reduces the available extruder acceleration, because of the high rotor inertia of this long (48mm) motor. So I have a choice:

1. Keep the motor, but use a lower gear ratio, or even direct drive.

2. Keep the gearing as it is, but use a shorter motor with lower rotor inertia.

I chose (2) partly because it means that I can sell a set of 4 motors along with most of the parts from the Mini Kossel kit I started with. Also because the motor I chose is the same one used in my Ormerod printer, and I may copy the geared extruder design from that.

OK!

I was just curious.

Do you mind sharing where you got your motors from?

I have thoughts about upgrading my kossel to 0.9 steppers, have been waiting to hear your thoughts about it though.

Not sure I can wait any longer, I have an itch in my tinkering-finger.... ;)]]> Koenig Delta Machines Mon, 27 Jul 2015 05:19:32 -0400 https://reprap.org/forum/read.php?178,451173,534272#msg-534272 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,534272#msg-534272
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Koenig
Might I ask why you choose a smaller motor for the extruder?

The 17HS19-1684S has too much torque for the geared extruder that came with my T3P3 Mini Kossel kit. To get the right amount of force (so that it the nozzle gets temporarily obstructed, it skips steps instead of grinding through the filament), I have to reduce the current to 400 to 500mA. However, this reduces the available extruder acceleration, because of the high rotor inertia of this long (48mm) motor. So I have a choice:

1. Keep the motor, but use a lower gear ratio, or even direct drive.

2. Keep the gearing as it is, but use a shorter motor with lower rotor inertia.

I chose (2) partly because it means that I can sell a set of 4 motors along with most of the parts from the Mini Kossel kit I started with. Also because the motor I chose is the same one used in my Ormerod printer, and I may copy the geared extruder design from that.]]> dc42 Delta Machines Sun, 19 Jul 2015 09:27:00 -0400 https://reprap.org/forum/read.php?178,451173,534255#msg-534255 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,534255#msg-534255
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dc42
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shadowphile
Hi Dave, I have been relying on your kossel-to-duet blog and it has become my bible for this process, thank you! I have a bunch of parts on order so I'm still lining up my ducks. (or is that an American expression?)
You have suggested 0.9 degree motors but I have seen multiple comments that those and/or 1/32-step drivers are too fast.
I would think the Duet could easily keep up though, unless there is a limitation somewhere not related to the MCU speed or word size.

0.9 deg motors or 1/32 microstepping would seriously stretch an Arduino Mega or similar atmega2560 electronics on a delta. But I expect the Duet to handle them adequately. At worst, travel speed might be limited to 200mm/sec instead of the 400mm/sec that I currently achieve with 1.8 deg motors and 80 microsteps/mm.

I ordered some new motors a few days ago (3 x 0.9deg JK42HM48-1684 for the towers, and a 1.8deg JK42HS34-1334 for the extruder). They are due for delivery tomorrow or Monday. So I will soon know for sure how fast the Duet can drive them. I also have some firmware efficiency improvements planned to improve the maximum speed.

Might I ask why you choose a smaller motor for the extruder?]]> Koenig Delta Machines Sun, 19 Jul 2015 08:50:27 -0400 https://reprap.org/forum/read.php?178,451173,533834#msg-533834 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,533834#msg-533834 thanks]]> shadowphile Delta Machines Fri, 17 Jul 2015 19:55:05 -0400 https://reprap.org/forum/read.php?178,451173,533788#msg-533788 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,533788#msg-533788
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shadowphile
Hi Dave, I have been relying on your kossel-to-duet blog and it has become my bible for this process, thank you! I have a bunch of parts on order so I'm still lining up my ducks. (or is that an American expression?)
You have suggested 0.9 degree motors but I have seen multiple comments that those and/or 1/32-step drivers are too fast.
I would think the Duet could easily keep up though, unless there is a limitation somewhere not related to the MCU speed or word size.

0.9 deg motors or 1/32 microstepping would seriously stretch an Arduino Mega or similar atmega2560 electronics on a delta. But I expect the Duet to handle them adequately. At worst, travel speed might be limited to 200mm/sec instead of the 400mm/sec that I currently achieve with 1.8 deg motors and 80 microsteps/mm.

I ordered some new motors a few days ago (3 x 0.9deg JK42HM48-1684 for the towers, and a 1.8deg JK42HS34-1334 for the extruder). They are due for delivery tomorrow or Monday. So I will soon know for sure how fast the Duet can drive them. I also have some firmware efficiency improvements planned to improve the maximum speed.]]> dc42 Delta Machines Fri, 17 Jul 2015 16:38:00 -0400 https://reprap.org/forum/read.php?178,451173,533754#msg-533754 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,533754#msg-533754 You have suggested 0.9 degree motors but I have seen multiple comments that those and/or 1/32-step drivers are too fast.
I would think the Duet could easily keep up though, unless there is a limitation somewhere not related to the MCU speed or word size.]]> shadowphile Delta Machines Fri, 17 Jul 2015 14:03:55 -0400 https://reprap.org/forum/read.php?178,451173,460634#msg-460634 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,460634#msg-460634 github.com].

In version 1.00b I have added support for IR Z probing on deltas for accurate height determination (M558 and G30 commands), however this is largely untested at present. Bed probing and compensation (G32 and M557 commands) is also implemented in theory, but completely untested. I will do further work on this when I have fitted an IR probe to my Mini Kossel.

I could add support for the mechanical switch Z probe of the Mini Kossel, however that would require implementing macros files to extend and retract the probe. So unless there is any demand from users for that support, I'll concentrate on the IR probe support. It should be possible to use FSRs in the bed supports in place of the IR probe, as all that is required by the software is an analog input that rises when the probe approaches or contacts the bed.]]> dc42 Delta Machines Sun, 25 Jan 2015 19:07:26 -0500 https://reprap.org/forum/read.php?178,451173,460201#msg-460201 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,460201#msg-460201 dc42 Delta Machines Sat, 24 Jan 2015 16:36:39 -0500 https://reprap.org/forum/read.php?178,451173,460147#msg-460147 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,460147#msg-460147 paveldvor Delta Machines Sat, 24 Jan 2015 15:20:48 -0500 https://reprap.org/forum/read.php?178,451173,459868#msg-459868 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,459868#msg-459868 dc42 Delta Machines Sat, 24 Jan 2015 05:59:58 -0500 https://reprap.org/forum/read.php?178,451173,459650#msg-459650 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,459650#msg-459650
I've improved the accuracy of the algorithm to reduce the maximum error to around 3us, and I now have moves at 500mm/sec speed and 5000mm/sec^2 acceleration working on my Mini Kossel. I've also reduced the minimum step interval to 10us. I'm doing some test prints and looking for other possible similar problems before I release the changes.]]> dc42 Delta Machines Fri, 23 Jan 2015 14:23:05 -0500 https://reprap.org/forum/read.php?178,451173,459448#msg-459448 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,459448#msg-459448
EDIT: I just managed to provoke this software trap on my Mini Kossel by increasing the XY accelerations to 5000 and generating moves at 500mm/sec. I'll check that the calculation is correct, and reduce that 15us figure appropriately if it is.]]> dc42 Delta Machines Fri, 23 Jan 2015 07:10:49 -0500 https://reprap.org/forum/read.php?178,451173,459438#msg-459438 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,459438#msg-459438 The homing is of cource just as you said - i didnt realize it is this dependant - i have just the 250mm up and my Z height is aprox 350mm.
I'm not at home yet and i will test it in the evening ang post results - I 'll try to lessen the accel and max speed to your values and than after more testing try to increase it.]]> paveldvor Delta Machines Fri, 23 Jan 2015 06:57:47 -0500 https://reprap.org/forum/read.php?178,451173,459364#msg-459364 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,459364#msg-459364
I have my Delta pretty much built and just have to do the electronics. While I want to use the Duet in it, I think for now I will start with the Smoothieboard and switch over in the near future. I am going to need the Ormerod to print a few parts for one thing, such as mounts for the electronics. I also thought it might be a good idea to get it up and running with a known working firmware, which will hopefully help eliminate any build and setup errors when I do the switch.

Keep up the good work.

Les]]> Pointy Delta Machines Fri, 23 Jan 2015 04:22:02 -0500 https://reprap.org/forum/read.php?178,451173,459262#msg-459262 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,459262#msg-459262
If you think the problem you observed is due to a firmware bug and it is repeatable, then please do the following:

1. Connect Pronterface via USB. Send command M111 S1 P4 and start the print. Capture any error messages that it displays and post them.

2. Identify the location in the gcode files where it happens, produce a smaller sample gcode file that demonstrates the problem if you can, and send it to me.

Otherwise, if your printer is missing steps, it may be that the accelerations or maximum jerk rates are set too high in config.g. I had the values from the Mini Kossel/Marlin firmware in there for a while, but they were way higher than the Ormerod values and the printer sounded really bad. So I reduced them in the config.g file that I checked in with version 0.80k. Or it may be that you need to increase the motor currents to better suit your motors.

If your printer has a Z range greater than about 230mm then you will need to edit homedelta.g. Change the three instances of 320 to a larger value, around 90mm more than your Z range. This figure defines the maximum distance that a carriage will travel up when homing.]]> dc42 Delta Machines Thu, 22 Jan 2015 19:48:30 -0500 https://reprap.org/forum/read.php?178,451173,459258#msg-459258 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,459258#msg-459258 Also both prints i made today stopped working, it behaved as if missed steps on one tower (it started to print in air a little off (cca 5mm) from the layer below), but i din't hear any missed steps.
I didn't havy any issues like this with the 80j firmware. I'll probably try to reflash to 80j tomorow to test if it is consistent.
Please let me know if you happen to have the same issue.]]> paveldvor Delta Machines Thu, 22 Jan 2015 19:29:34 -0500 https://reprap.org/forum/read.php?178,451173,459075#msg-459075 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,459075#msg-459075
The binary is here: [github.com]. I have also made some changes to the config.g file at [github.com].

I've added a Part 3 to my blog series on converting the Mini Kossel to Duet electronics, to cover calibration. It's available at [miscsolutions.wordpress.com].

Next on my list for this firmware is re-testing it on Cartesian printers, then I will move the current code to my main dev branch. After that is some more work to support additional Panel Due features (e.g. print time estimation). So it may be a couple of weeks or so before I start work on supporting a Z probe (probably an IR one) and implementing auto calibration.]]> dc42 Delta Machines Thu, 22 Jan 2015 14:02:38 -0500 https://reprap.org/forum/read.php?178,451173,458711#msg-458711 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,458711#msg-458711
I will publish a firmware update and Part 3 of my blog series later today. I haven't implemented support for the Z probe yet. I have almost run out of differential IR sensor boards, so I am considering designing a new version for the Mini Kossel and other deltas. It will probably be just a sensor, with no illumination, fan control or hot end indication and a 3 pin Molex connector. It will be short enough to fit below the effector of the MK. It would be compatible with the sensor on the board you already have.]]> dc42 Delta Machines Thu, 22 Jan 2015 01:44:17 -0500 https://reprap.org/forum/read.php?178,451173,458670#msg-458670 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,458670#msg-458670 today i installed your newest firmware 0.80j and i'm printing my first calibration ortogonal test piece on my Duet delta.
Thank you very much for your hard work.
It is printing nicely and i love it.
One thing i noticed is that you have to have some kind of hardcoded max continuos move of any carriage, my delta has 347mm homed height and if i try to home from Z0 it stops at around 270mm and i have to press the home button again.
The same occurs when homed and I send a G1 Z0 command.
One more question, i have a working differential Z height sensor from you mounted on my kossel, is it already possible to use it for Z homing? If so, how should i enable it in the config?
I tried some experiments my self, but i could not make it work.

Pavel]]> paveldvor Delta Machines Wed, 21 Jan 2015 18:45:38 -0500 https://reprap.org/forum/read.php?178,451173,454858#msg-454858 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,454858#msg-454858 It fits, but only when insulation cover is not pressent, with insulation cover the rods touch the insulation when in the outside perimeter of print bed. I have about 50mm separation (40mm on effector and the rest on ball-links), im considering increasing the separation or insulate the board with kapton tape only - which i'll try first.
Some pictures attached, i can upload the scad files if anybody would by interested.]]> paveldvor Delta Machines Tue, 13 Jan 2015 14:42:28 -0500 https://reprap.org/forum/read.php?178,451173,454853#msg-454853 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,454853#msg-454853
Dave Mail on the way re the single extruder differential sensor.]]> dougal1957 Delta Machines Tue, 13 Jan 2015 14:35:26 -0500 https://reprap.org/forum/read.php?178,451173,454842#msg-454842 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,454842#msg-454842
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dougal1957
I am going to be using a E3D V6 and its fan is very quiet as well and I haven't yet needed a print cooling fan and that can be controlled from the duet anyway can't it?

Doug

Just connect it to Fan0 on the Duet and then it can be controlled by M106 & M107.

Regards,

Les]]> Pointy Delta Machines Tue, 13 Jan 2015 14:25:15 -0500 https://reprap.org/forum/read.php?178,451173,454841#msg-454841 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,454841#msg-454841
EDIT: I just found that it is 28mm wide.]]> dc42 Delta Machines Tue, 13 Jan 2015 14:24:57 -0500 https://reprap.org/forum/read.php?178,451173,454822#msg-454822 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,454822#msg-454822
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dc42
I have a few single-nozzle sensors left, however I think they are too tall to fit on a Mini Kossel. Also the thermostatic control of the fan isn't really needed, because the fan on the MK is so quiet. However, once I have got the delta firmware fully working and sorted out a few other things, I intend to look into a couple of options for a better Z probe. One option would be a smaller version of the differential IR board, probably without the thermostatic fan control. Another would be a solenoid operated probe, which I considered for the Ormerod but didn't really fit (but it would fit on the MK).

Some people use FSRs under the bed mounts to detect contact from the print head. This appears to be a nice solution, however I have seen it said that this is not compatible with the heated bed option. Presumably this is because the FSRs need to be kept cool and/or because of the extra weight of the heated bed.

Ok well I wont be building a MK but a Cherry Pi4 which is larger but in essence is a larger version of the Cherry Pi3s but with a fairly solid effector/nozzle arrangement and the nozzle will only protrude under the effector by approx. 15 mm so something else will be needed to mount one anyway but if you are thinking of doing a simple one that would be Ideal.

I am going to be using a E3D V6 and its fan is very quiet as well and I haven't yet needed a print cooling fan and that can be controlled from the duet anyway can't it?

Doug]]> dougal1957 Delta Machines Tue, 13 Jan 2015 13:57:01 -0500 https://reprap.org/forum/read.php?178,451173,454793#msg-454793 Re: Upgrading Mini Kossel to Duet electronics https://reprap.org/forum/read.php?178,451173,454793#msg-454793
Some people use FSRs under the bed mounts to detect contact from the print head. This appears to be a nice solution, however I have seen it said that this is not compatible with the heated bed option. Presumably this is because the FSRs need to be kept cool and/or because of the extra weight of the heated bed.]]> dc42 Delta Machines Tue, 13 Jan 2015 13:15:38 -0500