I'm pleased to share a personal project of mine, where the initial design started in late 2018, and purchasing started in March of 2019. By no means is this complete, but I'm at a point where I'm excited to share the progress I have made so far.

Some background - My first real experience with 3D printing was in 2017 at the office; we had a Stratasys Dimension 1200es BST that wasn’t getting much use. I started printing practically anything I could think of, starting with a small hand tool, and progressing to much larger and more sophisticated designs. In early 2018 I got the go-ahead to propose search for a new 3D printer model that we would buy two of – because more is better, right? At that point I realized both the age of the Stratasys machine, as well as the wealth of hardware and software options for printers available at the time.

We opted to go with two BCN3D Sigmax printers – dual extrusion was a must, the IDEX technology had some potential uses, and the large bed width was attractive. I spent quite a bit of time learning how to effectively operate those machines (they are surprisingly a lot of work!); later I picked up a used Davinci 1.0 and flashed it with Repetier, built a MPCNC, and eventually the Stratasys went belly-up and made its way home with me.

My initial design objectives were to have a machine that…

• Has a rigid frame
• Has a limited number of 3D printed components
• Has an enclosed and heated chamber
• Has a large print area
• Is capable of printing high temperature thermoplastics
• Is capable of dual extrusion
• Is capable of fast travel speeds with reasonable accelerations

To start the design, I purchased two Rexroth ballscrews and 3x sets of IKO LWL12B 500mm rails with two ML12 each, sizing the frame to these components. Later on I purchased two LWHT15 200mm rails with a single carriage each for use with the ballscrews for the Z-Axis.

Other design and component decisions:
I wanted to utilize the Gates GT3 series of belts and compatible pulleys

• For the Y-axis I selected 3mm belt pitch, 15mm belt width
• For the X/U-axis, I selected 2mm belt pitch, 9mm belt width

I wanted to balance speed and resolution

• 16x microstepping, managing to achieve 100steps/mm in the X/U axis, 96steps/mm in the Y axis
• Y axis is geared down with a 2.25:1 gear ratio to compensate for the heavier axis
• X, U, and Y axis run at 300mm/s max speeds and 4000mm/s^2 acceleration

For the Y-axis and Z-axis, stepper motors are NEMA 23

• Oriental Motor PKP264D28AA2, .74 N*m, 2.8 A/phase, 1.5mH/phase
• Set to 2.4A in config.g
• Run super cool, barely feel warm to the touch

X and U axis use NEMA 17

• Oriental Motor PKP244D23A2, .48N*m, 2.3 A/phase, 1.9mH/phase
• Set to 1.8A in config.g
• These run quite a bit warmer than the NEMA 23s

Slice Engineering Mosquito and Mosquito Magnum for hotends

• Various nozzles (P3D, E3D NozzleX, Slice Vanadium
• Slice thermistors and heaters
• 12V Sunon fans

5/16” ATP 5 plate, 1000W Keenovo heater, SDF DF240S thermal cutoff (200°C holding temperature)

• TCO holding temperature may be a little high, but Keenovo recommended a maximum operating temperature of 204°C based on the 3M adhesive rating.
• Three-point bed leveling with probing
• Initially looked at a kinematic bed solution but opted for a fixed countersunk screw/spring combo, with two slotted countersinks sized and positioned to account for thermal expansion.

Bondtech BMG-M extruders

IDEX

• I do enjoy the IDEX technology on the BCN3D printers but wanted something a bit more structurally sound. Mechanically, lots of inspiration taken from the Stratasys Dimension 1200es.

Duet controller board(s) - Duet 2 Wifi, Duex5, PanelDue 7i

Snap action homing switches for X, U, and Y

• These have moved quite a bit as the design has evolved, I’m not happy with how they are mounted at the moment
• Had a homing “oopsie” where the U assembly crashed into the X carriage, actually moving the switch mounting block, and messing up my calibration!

Right now I’m looking at a print volume (single extruder) of 420mm x 450mm (475mm Y travel) x 210mm, losing ~100mm (to ~320mm) on the X and U axis for dual extrusion (lesson learned there!).

The project so far has been a blast, with many lessons learned along the way. The X-U axis has by far been the most challenging to build and design, I’m on the second major iteration and I’m still not entirely pleased, although I am getting satisfactory print results. As this is my first printer design and build, it was challenging to prioritize assembly design priorities. With this project, despite having a good idea of the components I wanted on each hotend assembly, it was the last item I designed and built up – ends up my build plate was a bit too big, leaving me little room to have nozzle wipe stations, purge buckets, etc. On future projects I for sure have a better idea of what assemblies to prioritize, making further decisions based on the size and function of said assemblies.

While working on this project, I did not initially intend to share the design files, however because of all that I learned from the fantastic content and individuals on this community and others, I figured I should give back and contribute this project.

https://drive.google.com/drive/folders/12TOxGG-kKjuYwNuwhYpwor9TGhdfy2mg?usp=sharing

The Google Drive link contains a Solidworks (19-20) pack-and-go, as well as assembly parasolids (.x_t) and IGS files. A (very!) rough BOM and various images and videos of my progress are also available.

How have I done so far?

• Has a rigid frame - definitely nailed this one! Almost entirely end tapped extrusions with fasteners + access hole
• Has a limited number of 3D printed components - making progress, but not quite done. Y axis bearing holders, most of the hotend carriage assembly is still 3D printed
• Has an enclosed and heated chamber - making progress on enclosure, have not installed+tested active chamber heating (excluding built plate)
• Has a large print area - pretty satisfied
• Is capable of printing high temperature thermoplastics - goes hand in hand with the heated enclosure, no issue with extruding 9085 PEI, but I have not tested an actual PEI print (the volume above the build plate stabilizing at 50°C without being fully enclosed, which is pretty neat, but not enough for PEI)
• Is capable of dual extrusion - accomplished
• Is capable of fast travel speeds with reasonable accelerations - accomplished

Many thanks to Slice Engineering, PrintedSolid, and Filastruder ( @elmoret ) for fast shipping, excellent communication, and great customer service when it was needed, as well as to the Duet team for a fantastic product.

@BlueDust said in IDEX anyone?:

I am thinking about building an IDEX printer as a 2nd printer. Few questions...
Could I use a filament sensor on each extruder?
Using a Duet2, would I also need a Duex5 to run an IDEX?
Is best practice installing a bed level sensor on both hotends?

Are there any considerations or limitations I should be aware of in regards to building an IDEX printer and it's use?

Thanks!

I'm running an IDEX, and I do enjoy the flexibility of it. Some advantages when compared to single extrusion - multi material, mirror/ditto print, and different diameter nozzles in the same print (walls vs infill, etc).

You will need an expansion board when using a Duet2, I'm using a Duex5, but I think you can get away with a Duex2.
I only have a bed leveling sensor on one hotend, I calibrate the second within the config.g to line up with the first hotend.

Like any multi extrusion setup, it gets expensive. The mechanics and design considerations of the gantry holding the two hotends gets a little more complex, and you have additional hardware to sling around. Whenever you change your nozzle setup, you will need to re calibrate both hotends, as there are minute differences in nozzles.

@TheBasedDoge said in Many issues after upgrading to 3.0 RC-12:

Ok, here it is. thank you!

; Configuration file for Duet WiFi (firmware version 3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v2.1.8 on Sun May 10 2020 13:55:08 GMT-0400 (Eastern Daylight Time)
; Axis Limits
M208 X0 Y0 Z0 S1                                       ; set axis minima
M208 X300 Y0 Z0 S0                                     ; set axis maxima

M208 X300 Y0 Z0 S0 ; set axis maxima

That looks like a mistake - Y300 right??

@dc42 Alright, what am I doing wrong? Likely something simple

Duet2 Wifi +Duex5
Duet Web Control 3.3.0-b3
RepRapFirmware for Duet 2 WiFi/Ethernet 3.3beta3 (2021-04-22)

Wiring diagram (tried some variations of this, including using duex.cs5, duex.cs6). Green LED on each of the boards tested.

M955 P0 C"spi.cs3+spi.cs4"
Error: M955: Accelerometer not found on specified port

Update - I'm quite confident the cable assembly was good, but likely was too long (~11ft). Trimmed 4ft off the Duet side, re-terminated and now we're good to go.

Some mechanical updates (and lessons learned)! When this thread was posted, the X-U axis was on its second major revision. The initial design placed the steppers, belts, and idlers on the backside of the axis.

On the 'low' side of the axis, a third ML12 block was used to join this axis to the Y-axis guide blocks and belt, with the intent to mitigate alignment or expansion issues. The issue with this X-U axis design was that the print area was limited because of the space occupied by the stepper motors and idlers.

The second iteration placed the steppers, belts, and idlers on top of the axis.

Previously the idlers were supported on both ends via a rotary shaft and two ball bearings, however the change in belt routing necessitated a change in how the idlers were mounted.

Misumi configurable shoulder bolt, washers, idler, with flanged bearings. The problem here is that I had selected a 4mm shoulder diameter, and had the option to either select an M3 or M4 thread at the end - I opted to go with M4, and thus sized the through-hole in the plate to that diameter. When tightening the stackup, I compress the bearings, idlers, etc to the plate instead of just the threaded portion of the bolt to the plate (below left, area in red can be tightened).

Had I gone with an M3 thread with the 4mm shoulder diameter (above right) the shoulder would have been tightened to the plate (via the hex nut or even a tapped hole), with the shoulder length specified to be equivalent to the washer, bearing, and idler stackup. As it is now I have to be mindful when tightening this section.

Interesting design note, in order to match the bearing size, shoulder diameter, and idler counterbore, I needed to select (I believe) a minimum of a 24 tooth pulley. I designed the stepper mounting plates such that the belt segments the hotend carriages clamp to are parallel to the gantry.

With the new X-U stepper and idler locations, I was able to center the 550mm length rail, however this required a short linear guide to be installed on the low side of the axis. Of course, with the stepper motor plate on the low side now mounted to a linear guide, I'm now tensioning the belts against a sliding surface... yes ultimately that side is mounted to a fixed surface (Y-axis guide), any misalignment would result in varying belt tension as the gantry travels up/down the Y-axis.

I recently removed this short guide and have seen no ill effects, however the impact of thermal expansion cannot be discounted and should be investigated further.

Some other neat stuff, build chamber is nearly completely enclosed, with the localized build envelope temperature stabilizing at 68°C with the print bed at 120°C. Some work is still needed on that front.

Just yesterday I setup the tool needed for duplication printing - not the prettiest ABS prints (steep overhang, high print temperature, and no print cooling fans ) but it worked well! Some goofy movements at the start and end, which I attribute to my tool change files, but overall pretty easy.

https://www.youtube.com/watch?v=5FNhITS6L6I&feature=youtu.be
An issue I am having is with the filament tubes and cable assemblies for each hotend bending and pressing down on the X and U belts. Somewhat self inflicted with the limited clearance above the hotend carriages, but still working through this issue.

@Nxt-1 said in Delta stepper upgrade - advice welcome:

@sebkritikel Thank you for the suggestions. Do you have any experience with either of the motors you suggested?

I have also found these from the same supplier:

PKP266MD28BA

• Rated current: 2.80 A
• Holding torque: 1.32 Nm
• Inductance: 3.90 mH
• Rotor inertia: 290.0 gcm²
  (6.35 mm shaft)

PKP266MD28B2

• Rated current: 2.80 A
• Holding torque: 1.40 Nm
• Inductance: 3.00 mH
• Rotor inertia: 310.5 gcm²
  (8 mm shaft)

These see to be the longer versions of the ones you linked (54 mm vs 39 mm)

I don't have any experience with those models, however I do use two PKP264D28AA2 NEMA23s (2.8A/phase, 1.8°, 39mm, 74Ncm, 1.5mH inductance) on my printer, and they are fantastic.

I see you're trying to hit 200steps/mm with a 2mm pitch belt @ 16teeth on a pulley... I don't know how realistic it will be to find a pulley with 16 2mm teeth, and 6.35mm or greater shaft bore

Excerpt from Misumi's 2mm PowerGrip GT3 catalog listing

@gnydick said in Pressure advance limits?:

@engikeneer thanks. Yes, I'm aware of the distinction. From my pictures, you can see the ghosting only happens after sharp feature changes. That's why I believe it's PA.

I may be missing something, but I don't believe its PA, and I do believe it is DAA, M593. Have you configured M593?

I think you're conflating a PA "fix" at 2000 mm/s^2 when really the system doesn't create ringing at 2000mm/s^2.

I would recommend running your same test, but with an appropriate value of M593 configured. Verify the speed at which your outer perimeters are set to (stock print speed doesn't always equal the perimeter speed... make sure you double check), and divide that by the "peaks" of the ghosting ripples.

@bot said in Tips to mitigate vertical artifacting Duet 2 Wifi:

Well, I wasn't able to find any ready-to-go off-the-shelf idlers from Misumi (that are more than 5 or 6 mm), but I've always wanted to try using one of their customizable pulleys for idlers: See info here.

You can choose a wide range of sizes of pulley there, and you can get stepped holes made which should allow for easy placement of bearings. They have a variety of options and you can have the stepped hole sized how you wish. See:

snip

[Edit: this photo is slightly misleading, there are more options to configure to get a full part number. Still playing around with it ]

I've done that on my machine, and it works quite well (albeit the assembly stackup can get pricy quick!). Must carefully select parts based on all the appropriate parameters.

Something to look out for is there is an issue on Misumi's site it seems, where you cannot select all the options on the left side (for example, with the Gates MR2 page, the "T" parameter does not show up. As an example, filling out all the available options can give you "GPA30MR2090-A-Y4-Q6-R6-S3", so copying and pasting that P/N with the addition of "-T3" into the search pulls up a real part.

For this case, do we want GT2/GT3 (Gates MR) or the 2GT series?
Looking at 2GT
Looks like something like 26teeth would match the 16mm OD (16.04mm OD, 16.55 PD). However the max 'shaft' hole for this size is 6mm, and the max counterbore is 8mm. However, it looks like the site gets stuck at GPA26GT2060-A-Y6, and we cannot configure past that.

• Force = Mass times acceleration. Understanding acceleration is a big piece of the puzzle
• Torque drops to 71% when using microstepping
• To keep motion lag under 1/16 microstep during acceleration, multiply by 9.8%
• Stepper motors in our cases are typically run at 85% the rated current - multiply rated torque by 85%

Ok, CoreXZ - you have the stepper motor, with the 20 tooth pulley on it right? That is then belted to the 60 tooth pulley correct?

I guess I'm not entirely sure where the reduction is taking place - but I'll mock up something else, which might point you in the right direction.

Good reading here:
https://forum.duet3d.com/topic/6/stepper-motors-for-corexy/4
https://forum.duet3d.com/topic/6853/maximum-acceleration-calculator

A tool:
https://wilriker.github.io/maximum-acceleration-calculator/

I am saddened by the news. While I had limited direct interaction with Danal, his posts were always insightful and his projects an inspiration. He will certainly be missed in all the communities he participated in.

@RogerPodacter said in IDEX Setup Macro Issues:

@Proschi78 thank you so much. removing that H2 seems to have fixed almost all of my issues. damn. let me try running some tests and see how this is working.

Hope it fixes it! Its been a second since I reviewed the why for the H2 in my files, but I could see how in a CoreXYish/Markforged that would mess you up FWIW I use the more Cartesian IDEX approach - I'll have to keep an eye out for differences like that in the future. Some similar discussion on 'H2' here: https://forum.duet3d.com/topic/29180/possible-bug-observed-after-v3-3-to-3-4-1-update/5?_=1672696734502

Glad someone was able to find the issue!

@RogerPodacter Hmmm right now I'm not seeing anything stick out to me. The gcode file looks mostly fine now, and the T0/T1 sections all look expected to me (it does look like in the new gcode file T0 is used to print both calibration set's first layers, but that shouldn't be causing tool changing issues).

Any chance you can try and upload a video or two of the tool changing behavior using the above print file and tool change files?

If, without a print running, if you select T0, jog it to the center of the machine, and then select T1 - what happens? Same for T1 - select it, jog to the machine center, and select T0 - what happens? Same behavior or different? Perhaps possible to upload quick videos of that as well?

Not a huge help, but here is how my machine responds after doing the above test for T0 - first run is from my posted files from earlier, second run I include restore points commands (copied from your tpost files).
https://www.youtube.com/watch?v=9vC4J3762Sk
https://www.youtube.com/watch?v=87awKG0txCY

@RogerPodacter Can you verify your firmware version?

Some notes

• tfree0.g - You have G1 S2 ... 'S' is deprecated for this use type (instead use H2).
• I don't think, for your use case, you need to have anything in your 'tpre' files. When calling a tool (say T0), tpre0 executes before tpost0. In this case you're asking the machine to move in a more negative direction (from -69, defined in tfree0, to -70, in tpre)

Comments above also apply to your tfree1.g and tpre1.g.

Looking at your gcode file - I don't see a tool called prior to you purge line, is that correct? It appears as if you set some temperatures, home all axes, set temperatures again, prime 'a' nozzle, and then select your initial tool. Can you also post your homeall.g? My recommendation for a start of print file is to set temperatures, home each axis (it may make sense to deselect all tools during homeall.g), select your initial tool, prime the nozzle, and then start printing. It seems that your print file is not selecting a tool until the model is about to begin.

It looks like you're setting the active/standby temperatures for T0 using the M568 command, but I don't see one for T1. I may be missing something based on other macros you're calling early in the print file.

@RogerPodacter said in IDEX Setup Macro Issues:

, then tool T1 begins clicking extruder for about 10 seconds, where the gears just click and i can visibly see the gear clicking. at this time temperature is at proper printing 205C

Are you saying that, while the T1 temperature is at 205C and parked, when it executes the tpost1.g G1 E6 F900, the extruder is not working properly?

Here are my tpre, tpost, and tfree for T0 on my IDEX machine

; tpre0.g
; called before tool 0 is selected


; If the printer hasn't been homed, home it
if !move.axes[0].homed || !move.axes[1].homed || !move.axes[2].homed || !move.axes[3].homed
  G28

; tpost0.g
; called after tool 0 has been selected

M106 R2           ; restore print cooling fan speed
M116 P0 ; wait for tool 0 heaters to reach operating temperature

G1 E26 F900 ; extrude 20mm
G4 P1000

G1 F2100 E-1
G1 X{move.axes[0].min} Y{move.axes[1].max-80} F18000

M83 ; relative extruder movement
M106 S0           ; turn off our print cooling fan
G1 E-1 F2100
G91 ; relative axis movement
G1 Z1 F1200 ; up 1mm
G90 ; absolute axis movement
G1 H2 X{move.axes[0].min+20} Y{move.axes[1].max} F18000 ; move the X carriage to -240mm
G1 H2 X{move.axes[0].min} Y{move.axes[1].max} F6000 ; park the X carriage at -260mm

G1 E-25 F1500 ; retract 12mm

@martin7404 No worries! And thanks for the comment.

You're right that for mirror and copy modes, you want the nozzles to be closely aligned in the Z axis. Unfortunately I did not design in any provisions to mechanically level the two nozzles, as my BMG extruders essentially directly mount to my X & U rail blocks. This hasn't been too much of an issue for me, as I typically print in 'normal' mode (build tool and support tool, dual color, etc), but I could deal with any Z variance by printing in mirror/copy modes with a raft.

If I were to do IDEX again, I would definitely make my tool heads a two-part system - I would have the motion carriage, and then the tool plate. The tool plate (extruder, hotend, fans, etc) would mount onto the motion carriage, and could be mechanically adjusted at least in the Z axis. I'd then use something like the door knob "KnobProbe " to check Z offsets, and also improve how I've used TAMV to align the X/Y and Y axes (I've also seen this product, but haven't given it a try https://www.emberprototypes.com/products/cxc).

Some other recommendations I have

• Design a fully fleshed tool head before committing to and detailing the rest of the printer build. I essentially did the opposite - started from the outside, ending my design+build with the tool heads (I thought they would be easy). Quite the opposite
• Make sure your tool heads can be easily worked on. I would not put significant effort into making them compact, with lots of fiddly screws.
• Design mounts for input-shaping accelerometers close to/on the tool extruder. (Can be accomplished with the Duet 3 tool boards). You want the accelermoter as close to the nozzle as possible, and rigidly mounted near it to truly characterize the motion+vibrations.
• Have a thermistor/thermocouple mounted on each tool to measure the ambient/chamber air - maybe near the hotend cooling fan inlet. Helps you keep an eye on what the chamber temperature of the build volume is.
• Try to insulate as much of the frame as possible from the chamber air.
  
• Really put effort into the 'parked' positions for each tool head. You want space to purge material, perform nozzle wiping activities, etc.
• Ensure all belts, pulleys, shafts are in double shear. You don't want to put massive radial loads on stepper motors while getting the belts to the correct tension (in fact, it likely cannot be done). My X and U motors are in single shear, I would absolutely either do like I did on the Y axes and isolate the motor from the Y-axes motion belts, or use a shaft coupler, with the secondary shaft+pulley in double shear.
• Definitely research magnetic/removable build sheets. Initially I went with a 5mil PEI sheet, which worked pretty well for all the materials I used, but that thickness is delicate. I recently switched to a 40mil PEI sheet which is significantly more durable. Heck, I'd be curious if I could go thicker (of course, 40mil was expensive, like $160 USD).
• Put some thought into what cables you use (motion rated, bend radius) you use for each toolhead, and how you manage their motion (energy chains, etc). Make sure that for each printing type (normal, copy, mirror) you don't run into any physical cable routing issues (cables getting caught on framing, or pushing into each other, bending into belt paths, etc).
• Look into an equivalent of https://sendcutsend.com/ for your area, and design to their capabilities. Their prices, lead times, material options are amazing, and can make cost-effective alternatives to using pure aluminum extrusion (and the associated t-slot nuts, etc).

I'm reading this forum daily, feel free to reach out if you have any other questions or ideas!

@Proschi78 said in SIMPLIFY 3D V 5 IS NOW OUT:

@sebkritikel What software are you using to display the gcode?

I'm using Craftware
https://craftbot.com/craftware

Can open GCODE files. I'm using an older version, but the newer one is still quite similar.

@Proschi78 Oh wow, I see what you mean in PS. Weird!

@Proschi78 Thank you! To be clear, I'm not digging on S3D, I just nerd out and dig into whats going on 'behind the scenes'.

A couple of interesting things stick out - S3D is varying both the print speed/feedrate and extrusion amount along the model's height.

From bottom to top, the S3D print speed varies from 6.0mm/s -> 9.1mm/s -> 2.8mm/s -> 4.4mm/s - this is likely to achieve a minimum layer time. In contrast, PrusaSlicer prints at a consistent 15mm/s (difference in speed is also evident from print duration).

Whats more interesting is the variation in extrusion amount occurring in S3D. PrusaSlicer is again consistent, but S3D increases the extrusion amount during the more vertical sections of the vase. There doesn't seem to be varying layer heights during this vase-mode print?

Thanks for sharing!

@Proschi78 Can you upload the GCODE file for the vase print? Certainly looks great, but I can't imaging they're doing anything special in that print file.

Better yet, upload a comparison GCODE file from another slicer (where you attempt to match the settings as closely as possible).

@lormal Check out these threads - they converted some Stratasys machines over to Duet 2 Wifi +Duex. Drove the extruder servo with a Geckodrive G320X servo motor controller.

https://forum.duet3d.com/topic/12647/another-stratasys-uprint-retrofit/42
https://hackaday.io/project/186419-dueprint

May be of some help. On my project list to do one of these days...

@coseng If you want to go further down the rabbit hole, some other discussions I had on a user in regards to BCN3D's forks (and slicer/IDEX compatibility in general):
https://forum.duet3d.com/topic/19167/creating-a-new-idex-3d-printer-with-duet-2-wifi/31?_=1670003869964