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build instructions, tweeks, tips and links

Posted by pvsfa 
build instructions, tweeks, tips and links
March 10, 2020 05:39PM
The aim of starting this separate topic is to make the process of building your own Hangprinter faster, easier and to help future builders avoid many pitfalls (and there are quite some smiling smiley. For current users, this is space where you can share your tips and tricks directly related to building, configuring and setting up Hangprinter 3. Let's try to keep this concise so we don't create another "general hangrpinter 3" topic here winking smiley

Here are the sources I suggest you consult in this exact order to get the best and quickest idea of what Hangprinter is about:

1) watch instruction videos

Chris three part youtube tutorial. It is very well paced and quite comprehensive. Make sure to watch all three parts, as last once introduces retrospective tweeks to the previous two. It all takes about an hour.
building:
[www.youtube.com]
calibration:
[www.youtube.com]
wrap up and tips:
[www.youtube.com]

2) check official hangprinter documentation

Head to official hangprinter documentation site: [hangprinter.org]
Documentation is decent but not fully comprehensive. Nevertheless, if you watched full Chris's tutorial, it should make sense. Anyway, you are now kind of informed on what awaits you.

3) Bill of Materials (BOM), printing parts of hangprinter, electronics

Next, head to bill of materials (BOM) spreadsheet here:
[docs.google.com]

3a)
In the top of it are the links for actual 3d models (STLS) of parts of the printer you need to print yourself (no kits available as far as I known, although people've been asking recently).
My only top as far as parts go is that I found spool cores to be quite fragile (broke 3 of them and than gave up on it). Im talking about this:
[gitlab.com]
I found using 10mm thick long-ish (i think about 80mm?) screw work much better. attached it from under the plate and used one screw at its base and one on top of the pool. These are easily available at any hardware store and definitely wont brake. I belive Tobb uses them in his earlier bulds too.

3b)
Below that 3d models link, still at the BOM sheet, there is a link to layout of how the hangprinter parts and electronics should be positioned on a plate. If you have payed good attention to Chris's first video, this will only be a guide for you. Don't take it literally as you may have to redo it to adjust for your particular set-up (as I had to).

3c)
then there is a whole list of components (vitamins) you will need to buy and put together for the printer. Some of the links are still live, some not. You can just copy paste the names of the components and get any equivalents from anywehre online (i did my shopping on various aliexpress stores). Most parts are possible to source locally but some are definitely not. Take this into consideration if under time constrains. For example, I couldnt find 623 V-groove bearings anywhere outside of China but in UK. Same goes for atypcal M3,M2 screws.

The closest place where I could order the fishing line you will need was some german online fishing shop:
[www.fishingtackle24.de]
As for the RAMPS part, everybody seems to be using 1.4. I used 1.5 and there is 1.6 as well. As far as I understand you may go for any of these

As for the smart stepper, you need to decide if you want one or not as its not a must. Here are the pros of getting them:
- they will enable you to autocalibrate (more on that later)
- hangprinter shall not loose any step (eg if a phyisical bias is introduced - someone kicks your printer, it should be able to compoensate for it, by returning to original position)
- you can put the printer into torque mode which means it will create certain and sustain certain tension on all motors which is handy for "parking" printer in the ceiling position and is also necessary for autocalibarion.
The downside of it is opting for smart steppers are two:
- the whole build will become twice as expensice. (one stepper motor is 50usd)
- there is a bit more wiring and installing and tweaking to do

If you choose not to get smart steppers, buy four more stepstick drivers instead (so 5 in total, as you ll need one nevertheless)
If you choose to get smart steppers,l you got three options:

- buy mechaduino from tropical labs:
[tropical-labs.com]
- buy smart stepper from misfit electronics
[misfittech.net]
the above two are mostly similar (one being developed version of the other), and they both cost roughly 50usd (plus shipping if you re outside of US)
Torbjorn suggest that latter has more of a functionality (more on that later) but that it can be pushed to mechaduino too, with specific firmware he himself (I believe) wrote for it.
- 3rd option - buy smartstepper clone from makerbase shop on aliexpress. I have heared some people confirming that Torbjorn firmware works on these, but haven't tested myself. If you understand arduino code and can easily figure pinouts and wirings it should be possibly to make it work (as it is really mostly a chinese clone). This one costs about 20usd i believe

one more unclear item on a shopping list: extruder + hotend. It says anything will do, but you probably want to buy Volcano or Super Volcano from E3D (based in UK). These allow for thick layer printing (up to 1,4mm) which is what you want if you re building something big (otherwise it will take ages, literally)

3d)
Wiring loom. I didn't bother preparing one, but I can suggest two things. If you are planning to use cables longer than 2 meters (which you most probably are) I'd suggest using separate quality lower gauge number (eg18awg, which is thicker than 28awg rainbow wire you ll be ordering) wires for some of the connections. The definite one is for the heater element. It surely does need something thick. In my case i also suspect increased resistance reaings on thermistor beacuse of the long and thin wire, so I got a thicker cable on that too.

4) Physical build of the printer

By now you should have a decent understanding of what and how you will need to do, print and buy. Head back to hangprinter.org documentation and follow the step by step instructions. Torb also includes instructions for build with smart steppers and witsh stepstick drivers. The wiring diagram is a bit hard to tackle, but dont get intimidated, just make sure you connect all the connections exactly as they are. If in doubt, perhaps go back to Chris's first video (although he only uses stepsticks setup)

5) Uploading Marlin code to RAMPS and arduino

Once, you've built the printer, you will need to upload the code to it. Go to Torb's gitlab here:
[gitlab.com] and click on hangprinter category.
Here, most of the project information is concentrated. Most of it will be irrelevant to you by now, as you'd already have printed the parts and build the physical body of the printer.
What you are looking for is the code for the printer. There are two - one for RAMPS and Arduino Mega, which is referred to as Marlin, and one for Smart steppers (if you're using them). Than there is also autocalibration code, but we'll get to this later.
Now, download the whole directory (there is download button somewhere in the upper right corner). In „Marlin_subtree“ there is the folder called Marlin. You need to open that folder and find a file called Marlin.ino. If you double click that file, your Arduino IDE will start. You will need that to install the firmware and your RAMPS and Arduino Mega. If you don’t have it installed yet, google it and download it. It will ask you to save the new sketch in a folder called Marlin, so go with that, but make sure to copy all the other files there, so that the new Marlin folder looks just like the one which you downloaded from gitlab. Next, in Arduino IDE head to Tools and choose your board (mega) and port in arduino ide (smthing like COM* on Windows or /dev/tty.usbserial* on MacOS). If you have a chinese clone of arduino, you may need to install additional driver for Arduino IDE to recognise them, plus you may need to choose „Old bootloader“ at Processeor menu (also in Tools). More on the chinese drivers here:
[arduino.stackexchange.com]

Now the sofrware should be uploaded to your arduino. you may need to tweek some variables (especially direction of stepper motors, as those seem to be opposite to what they need to be by default (in my case of mechaduinos)). If you are using Volcano, that is preconfigured as default extruder. If not, you need to configure that as well. Most of these are done in config.h file which is one of the many tabs that opens together with Marlin.ino file as its dependencies. If you feel lost, watch Chris’s second video, as he covers most of the basics.

5b) smart steppers code

if you are using smart steppers, you need to upload code over arduino IDE to these as well. they use different code than main RAMPS board though. it is to be found at two places - one is official mechaduino website (tropicallabs.com) and other is Torb’s gitlab - in smartstepper_subtree folder. The first one will definitely work for mechaduinos. The latter one is somewhat tweaked version and should work on both misfits and tropical labs hardware. I used mechaduino’s official firmware, but i may try torb’s in future as its ment to have more features.
In any case, you need to upload the code to every single smart stepper one by one. This process is similar to what is described in previous paragraph, just with different files. So go find stepper_nano_zero.ino or mechaduino.ino (you re basically looking for .ino file) open it, copy remaining files to newly created folder, and upload the code. You than need to calibrate the steppers to work properly. The process of wiring the smart steppers (mechaduinos specifically) and prcoess of calibration (mechaduinos) is covered fairly well on hangprinter.org documentation site at the end of the page, so just follow that. On gitlab, Tobben’s got another mechaduino repository, that seems to be more up to date. you may want to try using that, not sure if there is any big difference. Or try the one for misfits steppers. (someone can clarify?)

If you got misfits steppers you’ll probably have similar wiring (although pins may be located in different positions). To be honest, Im slightly confused here as Tobben seems to have two depositories for smart steppers on his gitlab (maybe someone can clarify?). the one that seems to be tiny bit more detailed in text description is this one (firmware files seem to be the same at both cases): [gitlab.com]

6) Calibration

if you are using stepstick drivers, your only option is manual callibration. Best calibration tutorial is, again, Chris’s second video. He also explains bit of maths behind and gets you some clear formulas and tips to get you there.
If you are using smart steppers (Misfits’, Mechaduinos, or chinese clones) you can try autocalibration method deviced by Torbjorn (or stick to manual calibration). it basically consists of python script that collects data points of the printer as you move it (in torque mode) from one point to another to another. Torb’s instructions are, again, on his gitlab:
[gitlab.com]

if you re on mac like me, you need to run this script over terminal. you also need python 2.7 to run it. and python needs numpy, scipy and mystic. Im not going to go into details here, but if you ve got no clue what im talking about, try asking someoen geeky smiling smiley or google installing python and packages over terminal. Thats what i did and i managed eventually, but honestly, im not confident explaining how. if you re on windows, i wouldnt know, but googling will. I assume, something to do with command line winking smiley Tobben’s instructions are actually written for Linux machines, so MacOS is a bit close to that but it might be quite different on Windows.
Once you have all the dependencies installed follow the instructions on gitlab. It should eventually generate the calibration table for you, like the one you would have calculated yourself with manual callibration.
Personally, I managed to get the script going and had it compute the coordinates but only got trash data out of it. Not shure why that was (someone has a deeper insight into this?) but im assuming my set up of anchors was a bit too uneven. So I think you pretty much need to set it up as neat as you can - ie as Chris would have you do it for manual calibration and than having set everything precisely, you can try auto callibration script.

those are my two cents. I hope this will help people who dont have degree in engineering but are intrigued by possibilities this machine offers. Im definitely one of those smiling smiley
and yes, this was my first 3d printer built ever ;P

If anyone feels this is inappropriate, or has questions to few questions raised here, please feel free to comment or send me a message and i ll update it.
Peace
Re: build instructions, tweeks, tips and links
March 12, 2020 01:12AM
Hey

This is a great summary!
Now, that I have about two years of experience with the Hangprinter, I can make some suggestions in addition to your list.

1. You should go with Nema 23 or beefy Nema 17. I'm using standard sized Nema 17, and they are completely underpowered for a printer this size. This manifests in geometry distortion, once the print passes a certain size. It has definitely to do with a miscalibration, but near the print volume perimeter the line tension get so high, that the Nema 17 won't do it anymore.

2. You should invest in a cross line laser level! It makes positioning the anchor points so much easier. Pick one, that has also a laser dot pointed straight up. That dot should be aimed at the center of the D-spool. The best experience yet was a small turn table beneath the laser level, that makes it so easy!

3. When calibrating/positioning the anchor point, bear in mind the levelness of the ceiling, the floor and the print surface. Again, place the laser level on the turn table (which stands in the middle of the print surface) and check that the anchor points are on the same level.

4. Don't use the V-groove bearings! The shape is not optimal for the dyneema line. The bearing flanges will shear the line, and eventually it will snap, leading to a quite catastrophic print failure (most likely a huge plastic blob around your extruder)

5. Documentation on the calibration process could be more precise. For example, I'm not sure if you should home the print head to origin and reset the the counter between each data point collection or not. At least, it seems to produce better calibration data. Also, I was only once able to get some data with the default calculation setting. I wasn't able to reproduce it, so I don't know what went wrong. The alternative (slower) calculation method produces data.

6. When winding the line on the spools for the first time, try to not twist the line. Otherwise the line will shear at the top line deflection bearing and it will also have an effect on the print quality.

7. If you print the spools in PET, they will squeak quite nasty smiling smiley It's annoying, consider using some crease for lubrication.

8. I will be releasing the frame design for Hangprinter v3 soon. Just need some time to go through the files, but I will get back as soon as possible.


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