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??

@Surgikill Most stepper motors used by 3D printing enthusiasts are built using 'Class B' insulation for the motor windings. For 'Class B', the max allowable winding insulation temperature is 130°C, which often yields a max motor ambient temperature of 40-50°C (not stepper casement temperature).

http://www.drivesandautomation.co.uk/useful-information/nema-insulation-classes/

Example motor with specs on insulation, thermal rise, etc
https://catalog.orientalmotor.com/item/2-phase-bipolar-stepper-motors/42mm-pkp-series-2-phase-bipolar-stepper-motors/pkp244d08a2

Most of us skirt by this 'max temperature' limitation by running steppers at 85% or so of the rated current, that gives some margin for an elevated ambient temperature. Running with an ambient temperature higher than the spec'd motor ambient could result in reduce service life for the motor. Ends up most of us ignore what 'Class B' insulation means, or simply don't know (I have been ignoring it, been running ambients in the 60-70°C on my motors )

Without looking at a datasheet... the roto motor likely has 'Class B' insulation.

Speaking of datasheets, a lot of steppers used in printers seen here don't go into the detail manufacturer's like Oriental Motor use on their datasheets (example snippet from a popular stepper seen here):

If you read the specs above, and don't further research what 'Class B' means, you might assume the motor running at 130°C is fine... and by running at 130°C, one might think thats the easily observable casement temperature (they do get hot!).

With extruder motors, its often recommended to run them at a significantly reduced current (at least when they were using smaller NEMA17 motors) for two reasons:

1. The torque at full current was much greater than what was needed for extrusion force
2. The casement thermal rise at full (or 85%) current could soften the filament, depending on how the filament drive was connected to the stepper)

Its possible that, while the roto motor uses 'Class B' insulation, it doesn't need to run at rated current, meaning theres higher margin for ambient temperature (maybe, a good amount of conjecture on my part of the requirements of the roto motor )

As far as that LDO pancake stepper, LDO has been making a series of high temperature motors for the enthusiast community using higher rated winding insulation.

@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.

@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.

@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

@Phaedrux said in Power Supply Sizing:

Can you share the listing? Do they have a model number?

Consider shopping here instead so you can be sure of what you're getting.

https://www.omc-stepperonline.com/

I might be blind, but they don't publish rated voltage? Seems odd but I may have missed it. Plenty of other specs though.

(2.8A)^2 * 1Ohm *1.5(scaling)= 11.8W
Looking at some roughly equivalent Oriental Motor specs, I'd guess they're rated for about 3V or so
2.8A * 3V = 8.4W

The Nema23s I'm using are rated at 1.6V and .57ohm, at 2.8A/phase.
(2.8A)^2 * .57Ohm *1.5(scaling) = 6.7W
2.8A * 1.6V = 4.48W

I'd say the two methods (Voltage vs. Resistance) get pretty close (remove the scaling factor and they are actually nearly the same). Going bigger never hurt anything but your wallet!

Don't forget to add in fans, heaters etc.

@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.

@SanderLPFRG Cura will inject temperature commands in such a way to ensure the next extruder is (nearly) at the printing temperature when called via the Tx command. This behavior can be further tuned via the 'Machine Settings' plugin, which allows you to specify the 'heat up' and 'cool down' rates of your tool. Also has a nice setting to configure the minimum stand by time (at print temperature).

@Solv777 To activate all four extruders and nozzles at once, in your config.g you would define a tool using M563 that uses the applicable extruders, heaters, fans, etc. https://docs.duet3d.com/User_manual/Reference/Gcodes/M563

You could then use pretty much any slicer I believe, so long as it supports tools other than 'T0'. I use Cura, which in my experience has great support for printers with multiple tools (I use it with my IDEX printer). In the Cura printer settings you would tell it how many tools your printer has, and then when you want to slice a given model, you activate the tool(s) you would like to use.

@RockB For the US Digikey and Mouser are great options (there are more!)
https://www.digikey.com/en/products/detail/molex/0436450308/4247419
https://www.mouser.com/ProductDetail/Molex/43645-0308?qs=1uvhzzitxfhjsp6NZN%252BXjw%3D%3D

@SanderLPFRG You could try keeping the G91 + G1 Z1 in your tree, but then in tpost you could set up a restore point move?

https://docs.duet3d.com/User_manual/Reference/Gcodes#g1-controlled-linear-move

Example - G1 R2 Zxxx , with xxx being your Z-hop height, and then follow that with G1 R2 Z0. Likely would want both lines at the end of your tpost. This would restore the print head to the position stored before the tool change, but offset by Zxxx. Then it would restore down to an offset of Z0 from the restore point (thus completing the Z-hop).

@oliof Not sure I follow - the 1HCL is compatible with quadrature encoders like whats used by the OP.

@BenzinLord3 , read through on connecting quadrature encoders to the 1HCL here: https://docs.duet3d.com/Duet3D_hardware/Duet_3_family/Duet_3_Expansion_1HCL

You'll essentially connect the motor/encoders 5V, GND, A+, and B+ to the 1HCL 'Quadrature Input' +5V, GND, A_INPUT, and B_INPUT. The motor leads would then connect to the 'DRIVER 0' connection.

@SanderLPFRG said in On-device start gcode handling:

@jay_s_uk I have, but I do not see any issues. I have not used G, M, N, or T and I do not see a max specified

what do you mean exactly?

The section he quoted below regarding not using ‘P’

@achrn In the example you cite, best practice IMO would be to actually use an inline connector. You don't really want a soldered joint in a flexible connection (joint becomes brittle), and a nice connector at the end of pigtail means easy swapping of components (upgrades? replacing a bad motor?).

For chassis wiring, soldering would work well - the solder sleeves mentioned above are pretty awesome. https://www.newark.com/c/cable-wire-cable-assemblies/cable-management/sleeving-tubing/solder-sleeves

@DuetUser Using one of the Duet closed loop products is without a doubt superior to using an external driver/motor combo.

1. Simple hardware and firmware setup
2. Integrated closed loop tuning & control
3. Better handling of error states

There is a third (and even a fourth option) you don't mention, and that is using the 1HCL expansion board instead of the 23CL steppers. This allows you to pick nearly any stepper you need, combine it with a quadrature encoder, and get running almost as easily as using the 23CL. The fourth option would be to also use a 1HCL, but in conjunction with the Duet Magnetic encoder. Depending on the motor you select, you may need to engineer a mounting interface for the magnetic encoder, but that should be fairly trivial.

If the 23CL motors don't quite get you the motor specs you need, I definitely recommend option three or four. Going the native closed loop direction and tuning directly in RRF/DWC is the way to go. https://docs.duet3d.com/User_manual/Tuning/Duet_3_1HCL_tuning

@Jered No problem! You could likely use the same technique, combined with the bed scanner, to get an even quicker read of just the print area before each print.

@Jered said in Creating height maps only where the part is being built:

Interesting post, but not automated enough to matter for me. I think I will look into the scanning probes as they don't require a lot of time to use. My printer is a 500mm ratrig, so it is large and requires about 25min to probe

@Jered said in Creating height maps only where the part is being built:

. I was kind of hoping that, as a temporary fix, I could automatically have the area where the part is printed to be probed, but it looks like I would have to program this for every part made.

Not sure I follow, as the link @Phaedrux posted shares several (IIRC) entirely automated solutions. Typically you add a line or two to your slicer (PrusaSlicer, Cura, etc) start code, which will automatically pass the X/Y Min/Max values to either M557. Following that the start gcode would then call for that area to be probed and used as the height map. Linked thread goes into some elegant start scripts that use mesh.g, but some simpler methods below.

Not sure what it looks like for PrusaSlicer, but I think something like this in your start code would work:

M557 X{first_layer_print_min[0]}:{first_layer_print_max[0]} Y{first_layer_print_min[1]}:{first_layer_print_max[1]} 
G29 S0

In Cura, I have added a MeshPrintSize post-processing plugin (to handle the replacement of the min/max placeholders), and then have added the following to my start gcode:

M557 X%MINX%:%MAXX% Y%MINY%:%MAXY% P3:3
G29 S0

I'd recommend taking a closer look at the linked thread, you should find a nice automatic implementation that will work for you.