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 The standard temperature sensor cartridges are garbage in this application and have been replaced by a high quality, braided-line version.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

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

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 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

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

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.

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

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.

thank you, I've been able to buy a replacement in short term and will make use of your replacement offer afterwards.

best, Niklas

FWIW I've left the setup powered up for the hours since my last post, and the 3HC did not eventually come alive unfortunately....
@dc42 I hate to "summon" you like this, but this machine is supposed to be exhibited at formnext next week, and I'm getting a bit nervous. Any thoughts?

thank you,
Niklas

Hi,
I have a problem commissioning my duet 3 setup on my DIY printer.
The setup is as follows:

• duet 3 mini 5+ on FW 3.4.4, in SBC mode connected to an RPi 4
• duet 3HC expansion v1.0
• 2x duet 1LC toolboards v1.1
• separate 5V and 24V PSUs as well as original RPi PSU for the SBC

where the CAN daisychain looks as follows: mini5+ -> 3HC -> 1LC -> 1LC (termn.)
right now, only one 1LC board is implemented and terminated.

My issue is that the 3HC board is completely unresponsive:

• all power rails seem to be OK, so 3.3V, 5V, 12V and VIN LEDs on the 3HC are lit up
• the CAN status LED is off and as far as I can tell never comes on
• the 1LC that is further down the CAN bus is responsive, I've already updated its firmware successfully, which tells me the CAN connection should be good (the termination jumpers on the 3HC are not fitted).
• every M122 poll to the 3HC is answered by "response timeout"
• I've tried setting different CAN adresses
• I've tried updating the firmware to no avail (CAN response timeout)
• I've tried updating the bootloader to no avail (CAN response timeout)

I've come across this thread where David Crocker mentions some firmware problems with earlier versions.
The boards were purchased back in february '22 through a german reseller, the mini 5+ was on FW 3.2.2 and the 1LC toolboard was on 3.3b - is it possible that the 3HC is on one of the FW versions that is mentioned in the above thread?
What are my options aside from force updating the bootloader using the Atmel ICE which I don't own?
Any other ideas?

thank you as always,
best, Niklas

@Dizzwold oh, I see. No, I don't think this rotational play can be eliminated by adjusting the bearing block. The problem is that between its point of rotation and the tip of the nozzle, a minimal amount of play in the bearing will be amplified to become really problematic.

I'd do it like this:

the bracket or printed part can be installed without problems, it doesn't have to have too tight tolerances since the mount is not overconstrained. And wobble in the nozzle is minimized because there is no rotation like in your sketch.

@Dizzwold since the TWE can be adjusted in all directions separately I wouldn't do one floating bearing, but two non-floating. Seeing it's an open frame and the x-axis is probably max. 500-600 mm long, it should work out with the tenths of millimeters of adjustability in the bearing blocks to eliminate binding.

Don't really understand your point about the x-axis rail, my suggestion still stands.

@Dizzwold Hi, for the y-axis you can probably do this. The TWE-04-12 + TS-04-12 are suitable, and can be adjusted in play. However I'm not 100 % confident that in this configuration, there isn't any rotational play around the x-axis. If you want to use T for the x-axis, I recommend two rails on a 20x20 profile to eliminate play (can be opposite sides or 90° offset, e.g. top and front facing sides of the profile).

Please note that I haven't tested this, which is why I'm a little cautious here...

@dizzwold I'm in Cologne, Germany. On one hand, I think these considerations are valuable for everyone thinking about using drylin, on the other hand I want to point out that my suggestions represent my personal opinion and are not to be mistaken for a manufacturer's recommendation (and I'm not knowledgeable enough to acutally present such a one).

I've just now taken a look at the Tronxy printer you mention. No, I don't think drylin T would be the most suited, price is one thing but I'd recommend it as the easiest solution when replacing "Hiwin-Style" (for lack of a better word in our 3D printing universe) linear rails, because they have the same overall mounting dimensions.

Seeing that the Tronxy printer has those "rod-mounted-to-extrusion" style of linear rails with roller bearings, AND they're at the same time a structural component, I'm actually not sure what to do, it seems like a very involved redesign. If I were to choose components to loosely replicate what Tronxy has designed here, I'd go as follows:

• drylin W rails for the y-axis, e.g. left and right (WS-10 single rail). Mounted horizontally. The beauty of this is that you can choose between a range of bearing blocks to match, e.g. with or without (adjustable) pre-tension, or even as a hybrid roller-slider bearing configuration. The rail can be bought without holes, and it could be bored and/or tapped manually to allow mounting of the z-axis rails.
• I recommend two blocks on each side, adjustable on one and standard on the other, this should already fulfill the fixed/floating bearing requirement - seeing that we don't have much elevated temperatures. It should work to repurpose the plates that come with the Tronxy printer.
• the height of the belt arrangement might change, so it might be neccessary to adjust the motor mounts.
• for the x-axis, the easiest and at the same time possibly cheapest and probably still best solution (in terms of precision, play, weight), could be to redesign it entirely, using two parallel 10 mm steel rods (drylin R) and matching bearings.
• these might be, depending on your machining or manufacturing capabilities, bearings that replicate round linear ball bearings with aluminium case, e.g. RE7UM-01 - this should be the easiest solution again. They are available with tighter tolerances or in a split version that's easy to mount (not both, unfortunately - I'd go for precision over ease of maintenance). 3 or 4 such bearings should be used, compare how Prusa does it.

OK, I think that is all I can contribute to this. If you really decide to go down this route, please contact a sales rep at igus UK, if questions arise reference this thread.

@mrehorstdmd (couldn't remember your handle - drmrehorst? digitaldentist? mrehorstdmd it is ) thanks for your input, this wasn't the post I was looking for but it should be relevant nonetheless. I was referring to your method of mounting the floating side of the x axis to another bearing block that is fixed to the carriage, a perfect rendition of a fixed/floating setup...

best, Niklas

@o_lampe most drylin rails and profiles are hard anodized aluminium (dark brown-grey appearance), the iglidur materials that the gliding elements are offered in are well matched to this. The more "standard" round shafts - iglidur R - are available from Cf53, stainless steel or HC aluminium (amongst others), they might offer better longevity but tbh I'm no expert on that. In general we take good care in testing and selecting the right materials for each application.

Spelling it out I realise that in fact, the ground/polished R rods (Cf53 or stainless) and matching injection molded bushings might be the best option if maximum precision, i.e. minimal play is the goal. However I haven't personally tested this out. Another thing to consider is that the standard bushings require to be press fit into a H7 tolerated bore to achieve the tolerances that are given in the documentation.

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.

@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!