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Posts posted by jonnybischof

  1. Are you printing at a different layer height?

    It looks like underextrusion and bad layer adhesion.

    The underextrusion could be due to a higher layer height (?) which might be too high. For example with a 0.4mm nozzle, you don't want to go over 0.2mm layer height because your print lines won't be "square" anymore but more like "rounded out" which seems to be the case here.


    What material are you printing with?



    By the way, for strong and accurate mechanical parts I never print faster than 40 mm/s. Typically I'd print at 35mm/s (PLA). For some PLA brands, printing faster will give me a very brittle and easily delaminating result.

  2. "Print one at a time" needs to be set up carefully. You need to teach Cura (or any slicer software) the dimensions of your printhead and gantry so that it knows where it can go without hitting previously printed parts. If you're using a "brand" machine like an Ultimaker, this information is stored in the machine profile. For custom builds you'll have to set up the profile.


    You could set up your printer to automatically print a part, cool down, knock the part off the build plate (by deliberately hitting it with the printhead) and out of the printer, then heat back up and start over and over. But that requires some scripting I'm not familiar with. Has been shown by others though.

  3. Assuming that the top of your model is horizontal (parallel to the bottom, parallel to the build plate), the easiest thing to do in order to get uniform walls everywhere (and nothing else) would be to change the settings and the model a bit:


    The idea is to change the model from "tube" to "cylinder". Meaning fill out the internal space of your model so that it will have the same outer shape, but be solid inside.

    Simplified dummy for illustration:




    Then, you print the model with 3 walls (3x 0.4mm nozzle size = 1.2 mm), 0% infill and no solid infill top and bottom (uncheck boxes in Cura). This will get you the result you want. You can also make thicker or thinner walls by simply changing the settings. Always use a wall thickness that equals a multiple of your nozzle size.





    It only works with a flat (horizontal) top because if your top is not horizontal, it will be treated as a wall:





    So, what you wanna do is not print any infill (which is printed as what you called little bridges) at all, but just (outer) perimeter lines of the model and leave everything else away. That means, disable the according print settings, and remove the according features of the model (anything except outer contour).





    One important detail I forgot:


    As mastory mentioned, using this trick you will get variations in actual wall thickness, because Cura will always print the walls horizontally. A 90° wall will have the thickness it's supposed to have, but with increasing slope, the actual wall thickness will be reduced. You'll have to make a test print and check if that is acceptable or not.




    For some reason this forum will insert the last picture again at the end of my post o.O

    Please disregard...

    tube from cylinder 3.png

    • Like 1
  4. 1 hour ago, jasonatepaint said:


    This has not been the case, at least in my builds. My 2 aluminum extrusion printers are WAY more quiet than my official UM2. I use 4 big rubber feet on the bottom and it keeps the machine quiet. As far as motor noises/vibration it is minimal and as I said, worse on the official UM2 frame.  Vibration dampeners (rubber, cork) can be used as a thin interface between the 3D printed mount part and the frame, however I found that if tightened securely to the frame, I get no additional noise or vibrations. 


    Do you use the regular stepper motor drivers, or silent ones like TMC2100?

    I found that already manually moving the gantry made a lot of "aluminum" noise..

  5. On the note of aluminum frames:


    I must say that I don't like alu frames. They are strong and you can easily put stuff on them, but (precise) assembly is tricky because you have to put every beam together at the right point, check angles and so on. And the biggest disadvantage imo is the noise - aluminum frames seem to result in a more noisy machine overall. The stepper motor vibrations / noises get amplified by the aluminum (resonance). I don't like that...


    I have gone back to my initial idea of making a frame from HPL material (Trespa Virtuon 8 mm in my case). But for that I need a good CNC machine up and running. Takes time and money :(

  6. ...

    How did you managed to order from them? Did you order it on a company or from US?

    The european website says they only handle companies.


    I can make orders at Misumi from my workplace. Luckily, I do sometimes need Misumi parts at work so I can justify having an account there :)

    If there is a local FabLab near you, you could ask them if they can make orders. As long as they have a registered VAT number, they should be able to make orders.

    The easier way however is to just go for another brand / shop. There are several good aluminum extrusion systems out there.

    I dare say Misumi probably has the most extensive (maybe expensive, too) and most customizable range of aluminum extrusions in the world. But for the Ultimaker frame you don't actually need much more than a bunch of straight, accurately cut, standard extrusions with some mounting options.

  7. There's a 60T gear from misumi (or I think it was 58T) that has a inner dia of 12mm. With that you could insert the mk7 inside and align the screws so both are together in love :)

    I didn't went that path because I just found out after buying my 50T :D


    Do you mean GEFBB0.5-60-2-12-W7-H14-TPC3 ?

    This could be nice, and very solid because you can put the parts together using one long setscrew. But you can only connect the gear's hub to the MK7, not the gear itself. That's not quite the same as foehnsturm did.

    Anyways, you could try Misumi's Nylon gears (GEABM0.5), drill out their hub to fit it onto the MK7/8 and glue the parts together. The Nylon is easy enough to drill through even with "toy grade" tools.


    GEABM0.5-90-3-B-9 has a 9mm bore. But 90 teeth (min for that bore) is quite a lot. Would of course be great for torque, but that gear has a 45mm diameter.

  8. That is really a nice system!

    I bet it's not cheap though..

    The way I described above is pretty much the same, except it works using only M8 screws instead of the connector. It is less flexible because you need pre-drilled holes in the profiles positioned where you want the profiles to connect. And there's only 90° angles, nothing more advanced like this Maytec system offers.

    Would be interesting to get a full price comparison for an UM frame made with the Maytec system.

  9. It depends on how you mount the extrusions to that plate. Note that the usual profile nuts have a huge amount of play. I didn't find a way to reliably mount my (large, 2mm steel) brackets to the profiles without manually aligning them while tightening several screws at the same time.

    If you can hire a few extra hands to help, then it works. Also, a large 90° angle tool helps a lot. But it's really not cool if you have to do it alone..

  10. This is an automotive part. The datasheet says 24..30V input voltage -> UMO power supply is 19V (Maybe UMO+ has a different one, don't know...).

    So that's out of spec. Output voltage is 13.8V which is also out of spec for a 12V fan.

    I would use a normal 24V to 12V DC/DC converter (5-10W) for a single fan, if you want it to run from the UMO power supply.

    One of the cheapest methods however is to just use some cheap 12V power supply. For example, an old external harddrive power supply adapter. These have more than enough power for a fan.

  11. This is a chinese clone of the actual SilentStepStick. No clue how it compares to the original... If they're actually using the same parts, then there shouldn't be any difference. But you never know with the Chinese...

    You can get the Original here: http://www.watterott.com/en/SilentStepStick



    Looking at the pictures on aliexpress, you can see three things:

    1. it's a different layout than the SilentStepStick (but not necessarily electrically different!)

    2. There actually is a trinamic IC on the picture (good sign)

    3. The soldering quality is HORRIBLE. This is really painful to watch, being an electronics engineer... The components look like they were thrown onto the board from a distance. The amount of solder is very uneven with lots of short-circuits on some and missing solder on other pads. This is definitely POOR workmanship. My advice: Do not buy.

  12. M1 gears are huge! This is a (module) 1 worm next to a m0.5:


    The M1 gears weigh like... I don't know. 100 grams?


    I chose a 13t m0.5 gear with 5mm shaft from veroma-modellbau.eu

    IIRC, that link came from foensturm in this very thread.

    I didn't want a heavy steel gear, so I'm pairing it with Misumi's GEABM0.5-50-3-B-5.

    Yes, that gear is insanely expensive (12.70 EUR) but the quality is great. Btw Misumi doesn't have small gears. 20 teeth is minimum, so a combination is highly recommended.



    Here's the two gears. I've already mounted the M1 gears, so I can't add them to the picture. But you should get the idea: These gears are tiny. And the Misumi Nylon gear is light as a feather.




  13. Well, Trespa is a very nice material. But it proved impossible for me to machine on our local FabLab's CNC router. I bought expensive, and (seemingly) well-suited mill-tools, but they all broke after just a few minutes of use.

    I suppose that router was just too crappy (vibrations, or maybe just the unbelievably stupid router settings that couldn't really be changed).

    Aluminum extrusions plus brackets is awesome on paper, but a real PITA to get squared in real life. I would never ever do such a thing again. Took my prototype apart before I had even tightened the last bracket. It was obviously never going to work the way I wanted it to.

    My latest attempt uses Misumi extrusions with the right mounting options. This works really well and I now have a frame that is built like a tank. See this thread:


    Btw, the UM black edition is on ice for now. I'm trying out a different gantry style, and overall a different concept entirely so it wouldn't make sense to call it an Ultimaker clone.

    • Like 1
  14. It depends on your CAD system, and how you (or, the CAD) interpret what an "M..." thread is.

    M thread sizes are specified in some ISO standard (or something alike) and given exact manufacturing parameters. There is no such thing as an M30.2x1.5mm nut. The standard already defines these threads to be matching (IF they are made from metal, which is what the standard was intended for).

    I don't know many different CAD systems, but I suppose most will not let you define "odd" "M" threads. They will only let you make "standard holes" (SpaceClaim term) according to the underlying standard.

    I would try to solve that problem by making the screw, then subtracting it from the part where I want the nut to be. Then adding an offset to all faces in the nut - how much of an offset I'd have to determine by trying out a few different values...

  15. That makes sense, because it wouldn't be an M30x1.5 thread, but M30.2x1.5 instead.

    Would be nice to have some feature implemented into CAD programs that would account for that. Such as "offset standard holes / threads by xx to account for material shrinking".

    Note that circles usually shrink when printing because the printhead drags the plastic inwards a little while circling. It seems to be less of a problem with cylinders, which makes fitting a printed cylinder into a printed hole a very interesting thing...


    It "can" be a solution to scale your model in Cura (note you can scale X, Y or Z independently of each other). However, with anything more complex than a threaded cylinder, this will quickly become impractical because you'll ruin all the other dimensions...

    I usually make threads myself. In SpaceClaim, there is a "rotate helix" function which lets me make threads (inner or outer) very easily, with any specified parameters. Maybe Fusion has something similar?

    It takes a bit of genius / experience to make 3D printed threads which will work well even when someone else prints them with different printer / settings / filament / talent...

    I usually work around that by using standard metal hardware :p

  16. I'm not using Atmel chips - they're expensive and I have some kind of personal aversion against them :p

    The 32.768 kHz crystal (commonly referred to as the "real time clock crystal" or "tuning fork") is very useful if you need any kind of precise timing. 32768 is 2^15, so you can make a timer that counts seconds very precisely.

    Many MCUs have an internal "low frequency oscillator" which can be used for that purpose, but their accuracy is very low. Usually good enough for timings like "wait for the LCD to be initialised", but definitely not useful for counting time.

    About the capacitances:

    I don't know why Atmel bothered making a difference between Cxin32 and Cxout32. That makes no sense because no one will use two different caps there. Manufacturing costs...

    These oscillator driving circuits usually work the same for most MCUs. You have a "rather" high frequency signal, so circuit impedance is important. You have to match your crystal's impedance to the input impedance of the driver, in order to get them to work together reliably.

    If you don't, it will either not work at all, or at a shifted frequency, or it might stop or stutter at times. Or it might run fine, but draw more power than it should.

    I said "rather", because 32kHz isn't really a high frequency. These clocks usually work without problems, but you need to match the impedance closely if you want the timing to be precise.

    Either way, the MCU's datasheet should tell you how to connect it (Some do that better than others). The most common external circuit is a crystal with a capacitor to GND on both pins (I'm not using the correct terms like "shunt", "parallel" or so because I always mess them up.. o.O).

    You got the correct formula for deriving these capacitors. Cpara is the MCU driver's parasitic capacitance. They used the average value from Cxin32 and Cxout32, which makes sense.

    Cshunt is a property of the crystal, but many parts don't specify Cshunt (I don't know why, and I only buy the ones that are fully specified...). This is probably why Atmel gives you a typical value.

    I suggest looking for a crystal that has Cshunt specified, and use that value.

    Cpara (Cxin32 and Cxout32) are the parasitic capacitances of the pins. As I mentioned above, you want to match the circuits' impedances. The (parasitic) capacitances are part of the impedance calculation. There's also parasitic resistances and inductances, but by keeping trace lengths very short you can ignore these.

    CLext (external load capacitors) are the actual components, derived from all the capacitances in the circuit that you'll be using to match the impedances. "Every" parameter ultimately figures into this CLext, because these are the only components that you'll be using to match your selected crystal to the driver.

    There may be rules of thumb, but the calculation is really not that difficult once you dig through all the names and can connect the crystal's and MCU's datasheets together.

    I wouldn't generally say that the values aren't critical. It depends on the crystal, it's frequency, and most of all, the driver. Usually, 32kHz crystals are quite uncritical, unless you really get the load caps way off. But with high frequency oscillators this can become critical really fast.

    Ultimately, the most important thing is to select a crystal that goes well with your MCU.

    I preferrably use one of these:

    Abracon ABS07-32.768KHZ-7-T (very small package)

    Abracon AB26TRQ-32.768kHz-T (This is Abracon's derivative of the "popular standard" Micro Crystal MS3V-T1R)

    Mouser typically has these in stock.

  17. Naja, theoretisch hat PTFE eine Einsatztemperatur bis 260°C. Es ist jedoch vielfach dokumentiert und beobachtet worden, dass die Teflon-Teile in 3D Drucker hotends bei Temperaturen über 230°C sehr viel schneller kaputt gehen als sie eigentlich sollten.

    A propos Sammelbestellung - Ich bin letzte Woche umgezogen und werde auch diese Woche noch ziemlich beschäftigt sein mit Ein- und Aufräumen. Ich melde mich dann aber nochmals deswegen.

  18. This is a ferrite bead, not a resistor. For the DC supply, it has a very low resistance (around 0.01 Ohms iirc), but it filters out any AC noise that might be on the supply line. 470 Ohms is the impedance at 100kHz.

    The M0 has some advantages over some 8bit MCU. First of all, it's not really more expensive than an 8bit MCU. But it has better programming support (code libraries from suppliers, and better IDE) and it supports multiple communications interfaces, which is usually not found on the smaller 8bit MCUs. 8bit is dead...

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