Best posts made by sonderzug

By now, I have experience with both (Duet more than Bambu). My opinion is this: Bambu Labs have identified the key areas to innovate where an FDM 3D printer has to be really, really good to make an overall good product.

• motion system that is not overengineered (Raise) nor underengineered (Ultimaker), focus on lightness, with intelligently engineered, custom injection molded parts.
• very powerful extrusion system (ultra fast ceramic heater, short filament path, light weight)
• hype-worthy features: the print speed that results from the above, and multicolor printing that really works due to the AMS which is cheaply made but also rather well engineered from a functional PoV. The Lidar is innovative for sure, I find myself not using it too often.

aside from that, they just made some smart decisions/choices in terms of which slicer(s) to fork, which build plate system to use, etc. And they seem to have a lot of experience in UI/UX which shows itself in the touchscreen interface, unboxing/setting up experience, extensive documentation.

All in all I'd say the printers live up to the hype for a great part, as Frederick says. They definitely didn't do themselves a favor with the online/cloud first approach, which albeit handy when you want to remotely access your printer, is still a nuisance first for me as a commercial user (my IT has great trouble integrating the printer(s) into our network, obviously using the cloud servers is out of the question, and they don't have ethernet). They are expanding on the "LAN only" mode which should have been perfected first, so I think they are listening to the community.

For Duet to "perform on par" IMO it doesn't even take too much, the features are mostly there - it's just a task to perfectly tune them to a specific set of hardware, which would also include programming a lot of macros and integrating a lot of sensors. I'd go a step further and say that with the CAN ecosystem including closed loop drivers and such, Duet has the better foundation to build a bigger and more powerful, industry-ready Bambu competitor. The thing I see myself envying most in other systems is a sleek, polished and functional touch UI such as the Bambu's or (from the looks of it) KlipperScreen.

Just my 0,02$!

I've acutally written my master's thesis about designing and building a HT printer. In my case, HT refers to a build chamber temperature of about 160-200 °C and nozzle temperatures of 350-450 °C.

The main challenge was in fact to design a motion system that would either withstand the heat or be excluded from the heated and isolated build chamber. I chose igus drylin in a stainless version with HT capable gliding foils, as well as high pitch spindles with nuts from the same polymer (I work at igus and did my master's there, if someone wants to look at the design, do so here). In this case, the linear rails are kept in the build chamber while the spindles protrude through the isolation to the outside, where they are driven by the steppers.

Doing so allowed me to bypass the Stratasys patent which seemed to be the sensible thing at the time.
If I were to design one such printer again, I would change a few things over the last design (aside from general considerations like accessibility and manufacturability). Most notably I would consider changing to a belt-driven, maybe coreXY system that is isolated by bellows as suggested before. A design that incorporates this is shown here.

In contrast to some who commented before, I'm very much of the opinion that the higher the chamber temperature, the better. While you can certainly produce some nice parts at 70 °C (at which temperature most available belts start to go out) sneaking up to Tg of the polymer is ideal and will allow to freely print parts of any shape without problems. And while for most use cases, materials like PA and PC (natural or filled) will do the trick, if you want to process materials like Ultem or PEEK (that have not been highly altered to be suited for lesser temperatures), you need that 160-200 °C chamber temperature at least.

If it doesn't become clear from this, IMO it's not the main challenge to reach the required nozzle temps. A 60 W heater, maybe water cooling for the hotend and a berd-air system for part cooling (or pressurized air for both, which is available in most workshops) does the trick. In my setup I'm running an E3D setup with the standard heater cartridge. The standard temperature sensor cartridges are garbage in this application and have been replaced by a high quality, braided-line version.

Hi,

you're putting a lot of torque on the bearing blocks, which leads to a lot of binding (what you call "chattering"). This might work with stiff ball bearings, which still move under high load, but not with gliding bearings such as igus. The forces in the bearing surface become too high to allow a smooth gliding motion.

To eliminate the torque on the bearing block, either move the linear rail to the center of the bed's side (which would have been the sensible thing to do in the first place), or add another bearing block per rail that is spaced to the original one at least half of the distance between rail and the bed's center of gravity.

igus calls this the "2:1 rule", check out this document: https://www.igus.de/_wpck/pdf/global/2zu1Regel.pdf

HTH, Niklas

Good day,

IMO the duet 3 6HC is overkill if you're not planning on going super fast or high accelerations (to the like of Vez3D etc on youtube)

I've done the Voron 2.4 with a duet 3 mini + 2x expansion, as well as the 1LC toolboard which simplifies wiring the gantry a lot. I'm moving the print head around at up to 300 m/s comfortably (haven't tested for more).

Anyway, the 1LC toolboard is a recommendation no matter what main board you get

Hi,

I've used igus chainflex CF884.006 which packs the following cores into one cable of about 9 mm diameter:
3 pairs of 0,14 mm^2 twisted pair sensor wires (shielded)
4 wires of 0,14 mm^2 (for fans, LEDs)
4 wires of 0,22 mm^2 (for 1 stepper)
2 wires of 0,5 mm^2 (for 1 heater element)

there is another shield around the whole package. It's made for energy chains, so it allows for quite tight radii and is flexible enough so it won't break. I fit a print head with direct drive, heater, sensor, 2 fans and a bltouch (and even an optical endstop) with this cable, I can see if I can still find the according diagram later at home.

Best regards, Niklas

Hi all,

I've now equipped a few printers with Duet hardware, and lately with all the CAN expansions for tool boards and single (bigger) motor drivers, I've found that I'm using the actual main board connectors less and less.

Example: bigger FFF printer with NEMA 23 for motion all around, it might use a 3HC expansion for X,Y,Z and 1LC Toolboard, or even an IDEX with three 1HCL for XYU and a 3HC for 2-3 Z drives, as well as 2 1LC toolboards - there is very little else that needs to be connected to the main board, maybe some temp sensors and small mosfets for switching PSU relais or bed heater SSRs.

So wouldn't it be feasible to have a "hat" for the Pi that acts as the Duet Main board but only has 5V and CAN outputs, maybe a few other connections that might not be included with one of the expansions; this concept would make wiring much simpler in general, as mostly there only has to be CAN + Power. Think of otherwise selecting the matching cable for each heater/sensor/motor/... and the matching cable chain which is probably a must for machines of this size.

Benefits would include a cheaper main board without unused stepper drivers, SD slot etc., and it could even be mounted externally, for example within the "monitor and UI box" that can be seen on many bigger CNC machines or SLS printers. Writing all of this up I realize that this would mostly appeal to printer OEMs that have to look out for cost at scale, versus the hobbyist who can afford to spend some extra bucks on unused stepper drivers etc.

Thoughts?

best regards, Niklas

I've designed a mount that integrates the 1LC toolboard to the new Stealthburner print head. I can share it however it is based on the pre-release STL models, and it is possibly flawed in that it doesn't support the tooboard on all four mounting locations and might allow for some vibration which crucially can throw off the accelerometer for tuning input shaping. Aside from that it's tidy and works well.

@giblte535 did you watch some ThisOldTony during the last week?

Pressure Advance is a "mechanism" to better match the actual extrusion output to the output requested by the control, by means of anticipating the upcoming movements and changing the current extrusion speed before a change in flow is actually requested by the gcode (I hope I'm not totally mangling the actual mathematical model that is working under the hood to calculate PA).

in short, it's not so much a mechanism to keep extrusion constant, but to better match the actual output to the requested/calculated output.

If the extrusion output is varying, e.g. because of Arachne's variable line width, pressure advance should work just the same. I personally haven't had any unexpected results in the combination of both, however there might be edge cases where they might counteract.

also:
in my (personal) opinion, drylin is in fact a very good choice for a quiet machine. If done right as per my above recommendations, that is. The often advertised fact of its rust- and dust-proofness and lack of lubrication make it very easy to maintain, keep clean and in general enjoy.

Hi all,

I'd like to present to you my self-designed, own built printer that has been conceived and created over a year ago.

Short overview:

• Duet Maestro mainboard

• genuine E3D v6 gold hotend (why yes, I do consider myself a fancy individuum), mounted to a genuine Bondtech BMG with a 0.9° 1.2 A stepper motor from Stepperonline (17HM08-1204S)

• custom 160 x 210 mm heatbed (5 mm cast aluminium) with custom 200 W 24 V silicone heater with a PT1000 temperature sensor, powered directly by the Duet

• highly integrated motion system based on igus Drylin W linear rails (6 mm square profile, more on that later), belts on all axes, driven by About3D (RIP) 1.8° stepper motors

• optical endstops for y (x not implemented yet), BL-Touch for bed leveling

• black 2040 extrusion frame with bamboo base plates

• Separate 5 V and 24 V power supplys by Mean Well, the 24 V supply is switched by M80/M81 via relais

• all of the wiring is hidden in the mysterious black box that makes up the base of the frame. It's connected to the network so it doesn't need an own control interface, however I will propably dedicate an old smartphone as a seperate touch screen to control the printer when the PC is off.

Some of you might find the design somewhat familiar; the use of the Drylin linear rails in the way that I did it was inspired by the Protoworx Tiny, which is a precious little machine that is capable of some very nice prints when it's properly set up. Check it out here. I'm not affiliated with the creators, but I felt it necessary to mention the design because credit is due. I did however route the belts very differently.

some pics of the build process:

itsy bitsy sample print:

The hotend mount has been upgraded to mount a 40 mm Noctua fan for absolutely silent operation. The heated bed is "mounted" (read: laid down) Mark Rehorst style on two ballhead screws and a flathead screw. There should be springs holding it down, but you can see the tip of the broken thread tool still sticking out of the base plate from whence this operation failed and the motivation left me to fix it permanently. It works at low-ish speeds due to the weight of the cast aluminium plate, but you can hear it flapping around a bit when it moves to quickly.

The bed surface is actually quite nifty, I bought plain black PEI sheet from a german distributor, and glued it to magnetic foil that is temperature stable to >100 °C. This "foil" is rather flexible but is held down to the build plate quite strongly. I haven't worked with warp-heavy materials though, there I would deem it possible that the part lifts this foil off the bed. I might also look into getting a spring steel sheet that would work better.

So this is the printer as it exists up until now, but won't for much longer. At the moment it's printing parts for its next big upgrade. I'm using Colorfabbs XT-CF 20 filament for structural parts, which seems to yield very strong parts yet is somewhat easy to print.

In the next post I will explain the upgrades that are going to happen to this machine, which will for the most part change its appearance radically. I'm ditching the igus Drylin rails - not because Drylin isn't suited for 3D printers, but because I chose the wrong type (I have to say this, because I work at igus and am somewhat a fan of the components).

I hope you enjoy this thread, I will post updates here on the remodelling that is happening, and show some sample prints once it's done.

oh yes: @wilriker you were interested.

Best regards, Niklas

Hi all,

I wanted to share my experience in connecting and configuring the Creality CR-Touch Z-Probe. There is some information here and there in various threads and the docs, but I felt a complete and comprehensive guide was missing (existing threads are help posts by users because they couldn't make it work, and then they just post "oh yeah I made it work" when someone asks and don't say how). I also want to provide some guidance since I destroyed my first CR-Touch due to switched wires which can be avoided. I thought it worth the effort to write up this little guide as the CR-Touch seems to be a more sturdy and precise alternative to the original BL-Touch probe.

(Disclaimer: this only applies to the CR-Touch Probe by Creality and their supplied cable connectors etc., I won't be responsible for any damage that might occur. My working setup is with the "Model AL T04" version of the CR-Touch, as printed on the probe)

There are some pointers in the docs as to the pinout. Notably there seem to have been different versions of the BL-Touch Z-Probe in a Creality version with varying pinout, but there is no explicit mention of the CR-Touch by Creality themselves. Maybe this can be added after this @T3P3Tony

I've started out by measuring which cables would be the ground connection, since there seem to be two (one for the servo output, one for the sensor input). On the CR-Touch cable, the White and Red wire are the GND connections and can be combined into one crimp when pinning the connector (contrary to a user's statement in one of the aforementioned threads). As mentioned in the docs, Black is 5V+, Yellow is the servo control input, and Blue is the sensor output.

Important: don't mix the red and blue (GND and sensor output), since it will probably short out and destroy the measuring circuit for the optical sensor. In my case, this happened while the probe was still operable with M401/M402, but didn't put out any reading anymore. It also made the toolboard reset itself but luckily didn't damage it. I measured for continuity between the white and red cable to make sure these hold the same GND potential.

I wired the probe to the IO0 port of the 1LC Toolboard, I presume it must work the same if wired to the mainboard directly. I took the liberty to modify the 1LC wiring diagram to make it extra clear:

my shortened and pinned-for-duet connector cable:

as installed on my print head:

As per the configuration, I did it like described in the docs:
from config.g

M950 S0 C"121.io0.out"   ; 121 is my toolboard CAN ID
M558 P9 C"121.io0.in" H5 F120 T6000
G31 P500 X0 Y31 Z1.18   ; since the pin protrudes past the nozzle, the trigger height is positive

plus the deployprobe.g and retractprobe.g macros in the /sys folder.
from here on out, the deployment of the probe is like described for the BL-Touch in the docs.

hope this will help one or two people that might find themselves in the position I was in two days ago.

best, Niklas

@dizzwold Hi, thanks for reaching out, interesting. May I ask where you're based? (not that I want to run to my colleague and pin them to the wall just curious)

When looking at different drylin types, it's important to know what you're doing - designing a new printer or retrofitting an exisiting one.

For designing a new one, drylin W is in fact a good choice, there are carriages that can be adjusted in play which makes it fairly straightforward to set up. It should be the most robust and versatile as well, e.g. the WSX profile offers a lot of options for integrating functions, mounting points etc.
I do not recommend the square WSQ however, since it does have more play but can't be adjusted. I've gone that route with the first version of my DIY printer (pics can be found around here), but have since replaced the drylin alltogether.

For retrofitting, I'd not look at drylin W because it seems rather difficult to integrate. I suggest drylin T (replaces ball bearing linear rails 1:1 and many types can be adjusted) or drylin R (replaces round rods and bearings, there are types with minimized tolerances but not 8 or 10 mm diameter as far as I'm aware). Bearing blocks based on R can be 3D printed and made adjustable, for example by using a slotted bushing (can be cut easily) and clamping screws. There is the typical "japan style" bearing + housing that replaces the Misumi style round linear ball bearing, used for example in Prusa printers.

Some things have to be considered:

• sliding bearings with zero play are basically blocks clamped to a rod meaning they don't exist. So the (minimal as it can be) play has to be taken into account. In my experience and opinion this doesn't have to be a problem, but can be especially in more dynamic systems. Printers with high velocities and accelerations are (again, IMO) not suited to be equipped with drylin, subject to change. I for one wouldn't equip a Voron with drylin T, for example.
  This also has to be considered when replacing Hiwin Style linear bearings, e.g. with drylin T: if you have just one bearing block to support the print head, it will wobble due to play. Two parallel rails should be used to get rid of the wobble.
• also, most if not all drylin bearings or systems are susceptible to misalignment and/or torque loads on the bearing, resulting in high wear and friction, probably what @cosmowave was experiencing. This is different in comparison to linear ball bearings. Drylin W guide blocks for example, when bought as a complete unit, mostly have 4 bearing blocks installed to them to alleviate. Translated to our 3D printers this means:
• minimize torque on the bearing, e.g. gantrys have to be driven at both ends/bearing positions. This applies to the x-axis of i3 style printers, and cartesian as well - coreXY when done right should have this effect.
• the fixed/floating bearing princible should be applied, e.g. when two bearing locations are connected by a longer component, one bearing should be fixed and one should have some play. Mark Rehorst aka the digital dentist has some good posts about this on his blog. Seizing due to elevated friction levels can be avoided thus, and aligning parallel rails is more easy because it doesn't have to be perfect.
• in general look at possible over- or underconstrained assemblies, if it is perfectly constrained it should work well with drylin

hope this helps!

Hi all,

"next weekend" turned into a few weeks, but with the holidays and everything I only had limited time to work on this project. However, the remodeling is more or less completed.

I announced that I would be ditching the igus linear rails. I did so in favor of used/new old stock THK linear rails that I obtained from ebay. In particular, I bought RSR12 (ZMUU) and RSR9 (WVM - double wide rail) rails, which will help this build achieve a much higher mechanical quality but will also be carried over to future builds (the lenghts allow for a bigger build volume than this has).
The problem with the igus rails was, as mentioned, that I chose the square profile rails which are not tensionable. The round profile drylin W rail has options for setting the tension of the gilder with a screw.

For the new rails, I obviously had to account for the missing structural components of the drylin rails. The easiest and most precise thing for me was to have aluminium sheets lasercut for my purpose. So this is what I did.

I further wanted to eliminate the cheap chinese belt idlers, which I replaced with 608zz bearings on which the backsides of the belt run. Obviously there are no flanges to guide the belt, which is a bigger problem than I anticipated, so I will have to replace some of those with flanged bearings.

I opted for genuine Gates GT3 belt, to eliminate further influence from cheap components. So far the print results are way better than before, regarding the quality aspects that can be traced to the mechanics of the printer.

Pictures:

the x-axis plate has mounting options for the rail, idler, motor and optical endstop. The stepper motor is mounted in a seperate printed part that allows it to be pivoted around the lower mounting hole, allowing to tension the belt.

This arrangement is copied for the y-axis. The heatbed will be mounted like before.

assembled and running:

right now the printer is printing some parts for itself, namely the cooling ducts for hotend and part.

A short glimpse under the hood:

Why the board hasn't been mounted with it's edge facing outward to easily connect the ethernet cord, I can't tell I didn't deem it too important at the time, unfortunately.

I still have to tidy up the cabling of the hotend as well; the cables are connected with two 8-pin connectors for which I want to design plug housings and strain reliefs as well.

On the topic of the x-axis falling down when the power is taken off the steppers.... yes it will of course, and unfortunately also when the stepper's coils are shorted. I will design a little lever that the x-axis can run over at the z-max end, which will snap into place to keep the x-axis up after power-off; I have a RC servo lying around which I will use to release it automatically.

I'm overall happy with the rebuild and hope I'll be able to use the printer for railway modelling etc. in the future.

Best regards, Niklas

@miller-spec Hi, I could see either the print head connectors (ie motor cables) coming loose due to insufficient strain relief and/or wiring length, or the filament becoming stuck in the tube when the print head moves to a location where it pulls on the tube and puts a kink in it or the bending radius becomes too small. The "phase disconnected" warning might point to the former.

@DocTrucker if you haven't started to migrate to Cura, I suggest you don't. IMO they're moving forward implementing useless and Ultimaker-centered features (which is their right of course) such as the multi-material-blending stuff, while neglecting the very real usability and feature weaknesses such as slow and laggy interface or the inability to place seams in any way that is logical and/or aesthetic.

OrcaSlicer was mentioned as the open source project that tries to find the best in Prusaslicer and Bambu Studio (which in turn is derived from Prusaslicer and incorporates some Cura features, such as an alternative slicing engine). It's more aimed towards open source printers and tinkerers such as ourselves, and it seems to be the spititual successor to Superslicer which also seems to have been all but abandoned. I've had very good results with little tweaking from OrcaSlicer.

best, Niklas

I like this idea, I think this is something that can already be done in SLS job-prepping software (aka slicer), for example.

inb4 new RRF feature:
printing text (on XY-plane)
Gnnn S"string" Xnnn Ynnn Dnnn Hnnn Lnnn Tn.n Fn Nn

where X, Y are the starting coordinates (of the base line of the text), D is the direction (0 - 360° or 0 - 2pi, where 0° is parallel to the x axis), H is the font height, L (optional) is the maximum allowed length unto which the text needs to be compressed in length, F (optional) is the selected font
Edit: N (optional) is nozzle size so that it can be somehow avoided to print unreadable letters
T (optional) is the layer thickness, not sure if this is a value that is usually passed on to RRF by the slicer.

did I miss anything?

all this would require is, as you implied, a pre-sliced alphabet. And the slicer must somehow pass the starting coordinate, the rest can be done by RRF.

looking forward to the discussion on this topic!

Hi everyone,

thanks for the replies. The tap end is stuck there for sure, but it's not a big problem as 1) the position of the spring is variable as long as it's in the proximity of the respective support screw and 2) I have a second base plate left over. The only slight nuisance was that I had to go back to the hardware store to get another M3 tap.

@mrehorstdmd ,
the heater was custom made to my drawing. I had every component (well, the critical ones) designed before I ordered the first part for this build.
the bearings are not adjustable, which is my big concern with these rails. That's the wrong choice I was referring to earlier. The Drylin W rail is also available with round guides (which is actually the standard variant). For the round rails, there are bearing blocks with pre-tension by spring or screw available.

The play in the bearing blocks plus not perfectly tensioned belts lead to backlash which leads to un-round holes (at least that's my theory).

@Phaedrux ,

see below the setup of the z axis. There is a 8 mm rod underneath that connects both belts, which is driven by the stepper with a 2:1 reduction for extra resolution and torque. There are standard pulleys on each end driving the belt. There are little idler plates at the top of the frame, which are also used for tensioning the belt by pushing these upward (a screw through the upper frame member would propably be the more elegant solution).

Edit: the obvious disadvantage is that the x-axis drops like a stone when the steppers have no power applied. I'm thinking about a little servo with a lever that will support the x-axis in the upmost position, once the print has finished. Another Idea would be to add a relais that could short-circuit one or two coils of the z-axis stepper motor, which would be controllable by G-Code, with the short-circuited coils having enough holding torque to steady the x-axis. Has anyone tried this? Problem could be that this acts like unplugging the stepper from the board while on, which is a no-go...

Best regards, Niklas

@mrehorstdmd said in Behavior of drivers at high speeds:

I milled some teflon bearings for the X axis yesterday

albeit a little late (and slightly OT), I'd like to point out Igus filament for this kind of application... since we're 3D printing around here the I150-PF type is the easiest to print and should be sufficient for your bearings.

Best regards, Niklas

(disclosure: I work for igus)

@curtisb1986 Hi, research the "pebble wiper" as an active solution with an additional servo arm, and/or how Stratasys and Bambulab do it as passive solutions. Stratasys use a purge bucket with a silicone lip and brass brush, Bambu use a purge bucket and a short piece of PTFE tube that is flexibly mounted and that the nozzle brushes against after purging. With both solutions the "smart" is in the way the purging and brushing is being done. Both sell the brushes as consumables which points to the fact that there is wear on the brush and the nozzle.

For the parked nozzle it might make sense to have a little piece of spring steel sheet pushing against the nozzle orifice and keeping it shut which should all but eliminate material oozing out. It should still be purged when the tool is picked up since the material will degrade and change viscosity when it stays in the nozzle for even only a short time (some materials are more resistant to this than others, and moisture [see below] is a big factor in any case).

Aside from that, my recommendation from years of experience with multi material printing is to take great care of drying the material properly for printing, as this already helps a lot with unwanted ooze from the nozzle (however it will not eliminate it when the nozzle is parked, just for retractions etc.)

hope this helps,
Niklas