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 The standard temperature sensor cartridges are garbage in this application and have been replaced by a high quality, braided-line version.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

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,

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 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

@bricoletout Hi, unfortunately it isn't at this point, but the downloadable CAD model goes a long way in explaining the principles.

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

Hi all,

as i mentioned before i orered new sensors to replace the e3d cartridge type ones. A german shop i found stocks both PT100 and Type K sensors in cartridge configuration:
PT100 click
Type K click

the only drawback is that the Type K variant is only available as 4 mm diameter. They are not even expensive however and (to my experience) of much higher build quality than the e3d types. The lead length is variable and they feature ferrule ends matching the Duet Daughterboards perfectly (as opposed to the e3d types which have to be fitted). Last but not least they are specifically rated for 400 °C and 550 °C respectively. I am running the PT100 type right now and am finally able to print again.

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)

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

I second @droftarts opinion; circles with horizontal and vertical flat spots (i.e. corresponding to the direction change of the x respectively the y axis) indicate mechanical backlash, quite noticable in your case.

@bricoletout Hi, unfortunately it isn't at this point, but the downloadable CAD model goes a long way in explaining the principles.

I second @droftarts opinion; circles with horizontal and vertical flat spots (i.e. corresponding to the direction change of the x respectively the y axis) indicate mechanical backlash, quite noticable in your case.

Hi,

most people who I've seen build printers with this kind of capabilities (myself not included, unfortunately - my high temperature print bed still uses paper clips), actually opt for vacuum tables. They seem to work well at elevated temperatures and give you a set of options for print surfaces (different polymer sheets, aluminium / glass plates, etc). You can use your mill for that, too

best regards, Niklas

propably has to do with the availability of 2mm ID and 3mm ID pneumatic tube back in the day when there were no 3D printing specific products, at least this would be my guess.

...aside from the bondtech QR there's also the bondtech DDG that is an upgrade for the Ultimaker but should be able to be used separately?

Hi,

https://blog.igus.eu/do-it-yourself-build-your-own-3d-high-temperature-printer/ We've posted about it on our company blog, and we offer the CAD data as download. It may be that this model still has the "sandwich" plate heated bed, just imagine one instead of two of the shown plates and the Al plate clamped down on top.

The steppers are outside the print volume and the print head/gantry is driven by high pitch lead screws. They are standard steppers, however they directly incorporate the lead screws instead of shaft and coupling. Could be done otherwise.

@bearer with a 1,5 kW heater (from a baking oven) the build volume heats up to 170 °C in under an hour.

Hi Frédéric,

I've built a high temperature, enclosed and actively heated 3D printer that does just what you are suggesting - heating up the print volume with a chamber heater, without a heated bed. When I started out I had a heater for the bed installed, but I found that it only accelerated the time for heating the build volume by a little bit. No wonder since it was around 200 W while the chamber heater is about 1,5 kW. So I took out the bed heater.

I'm using exchangable, plain Aluminium plates which I can coat with tape for adhesion. Others are using vacuum plates to hold down print sheets (e.g. PEI sheets), which aren't heated either of course.

Hello Gentlemen,

I've had the chance today to play around with my setup today.
In regard to my questions above, I can report the following:

• the igus controllers in fact seem to be happy with the "unadultered" output of the EBOB. They have a separate +5V/- input for logic level connection with external controllers such as the Duet, which I connected to the same 5V/3A PSU as the Duet itself. Accordingly I've only connected the S-, D-, and E- pins to the respective inputs of the igus D1.
• I've gone with the recommended setting of M569 P5 T20:20:10:10 which in turn seems to work fine. I've not tried to go any lower yet (is anyone interested in this experiment?)
• regarding resolution, I've set the Duet and igus D1 up at 1/32 stepping at the moment. Considering the 20T HTD 3 mm pulleys I am using resulting in ~ 106 steps/mm and at 25 kHz max. step frequency this gives about 235 mm/s in movement speed which is totally acceptable. Moving the one motor I'm experimenting with seems to work even at higher speeds. We will see in the final application how well this works.

thank you again for your support.

Best regards, Niklas

Hello David and Tony,

thank you both for your input, I will try this as soon as possible.
Interesting mention about the low maximum frequency. I might discuss this with the developers of the igus controller.

Hi all,

I'm building a bigger than usual 3D printer at the moment and would like to clear some things before moving along.

Setup:
Duet 2 Ethernet @ RRF 3.1.1 + Expansion Breakout Board
3x igus D1 motor controllers to drive NEMA23 Motors in closed loop setup (for X, Y, U axes)

My question is how you would interpret the instructions from the manual regarding the options of M569.

from the igus D1 manual, page 81:

1. I assume I'll have to tweak the Expansion Breakout Board to deliver 5V on the respective Pins for the D1 to take the signals properly?
2. How would I have to set up the M569 T parameter in order to meet the instructions?

from the documentation:
Minimum driver step pulse width, step pulse interval, direction setup time and direction hold time, in microseconds

My uneducated guess:

• minimum pulse width = minimum period = 40µs
• step pulse interval = inverse of frequency = 40µs
• direction setup time = "10 µs after the last negative edge and 10 µs before the first positive edge" = 10µs
• hold time = infinite?

Any input would be appreciated. Please note that I didn't try to drive the motors with this setup yet, but plan to do so next week, so at this point we're talking hypothetically ...

Have a great weekend everyone!

best regards, Niklas

No you're not, I've requested this feature in the past along with others. As of now I'm using the bed heater controller to set my chamber temperature (I don't have a bed heater).

@T3P3Tony good to know that this will be included in the new firmware!