Hangprinter version 2 This thread is for discussing Hangprinter version 2, presented here: https://salt.bountysource.com/teams/hangprinter https://reprap.org/forum/read.php?1,738858,738858#msg-738858 Wed, 15 Apr 2026 09:59:34 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,738858,801029#msg-801029 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,801029#msg-801029
You will prooobably be first to be able to compare the v2 and v3 builds first hand. I'm looking forward to that!]]> tobben General Sat, 16 Dec 2017 09:19:23 -0500 https://reprap.org/forum/read.php?1,738858,800988#msg-800988 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,800988#msg-800988
Thanks Torbjorn and Tom, the live streams are awesome.

Tom's first hang live stream


]]> brotherchris General Fri, 15 Dec 2017 23:39:34 -0500 https://reprap.org/forum/read.php?1,738858,796056#msg-796056 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,796056#msg-796056 tobben General Sun, 12 Nov 2017 04:55:10 -0500 https://reprap.org/forum/read.php?1,738858,796034#msg-796034 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,796034#msg-796034 brotherchris General Sat, 11 Nov 2017 22:17:46 -0500 https://reprap.org/forum/read.php?1,738858,795904#msg-795904 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,795904#msg-795904 brotherchris General Fri, 10 Nov 2017 16:08:31 -0500 https://reprap.org/forum/read.php?1,738858,795902#msg-795902 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,795902#msg-795902 tobben General Fri, 10 Nov 2017 15:39:14 -0500 https://reprap.org/forum/read.php?1,738858,795846#msg-795846 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,795846#msg-795846 brotherchris General Fri, 10 Nov 2017 10:13:05 -0500 https://reprap.org/forum/read.php?1,738858,795460#msg-795460 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,795460#msg-795460 brotherchris General Tue, 07 Nov 2017 20:37:31 -0500 https://reprap.org/forum/read.php?1,738858,795429#msg-795429 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,795429#msg-795429
With vertical distance, I mean the distance that is marked C_Z in this picture:


You must imagine a cartesian (xyz) coordinate system and measure along the X-, Y-, and Z-axes separately.
The direction of the Z-axis can be found by using an aiming plumb or any other object hanging in a line.
The "vertical" direction, or the Z-direction, is the direction of gravity.

The Y-direction is the same as the (horizontal part of the) direction of your A-lines when your printer is in origo.

When you calibrate anchors, you must first place your printer in origo.
Then imagine a translated cartesian coordinate system which has its (0,0,0) fixated in a fish ring.
With this new coordinate system, describe the position of the other end of that line (the end fixated at the anchor point), using x, y, and z-coordinates.

Here's a picture of me taken yesterday, where I measure along X and Y to find distances marked ANCHOR_C_X and ANCHOR_C_Y in the image above:
(The table is there to help me get a 90 degree angle between my X-measurement tape and my Y-measurement tape.)


This is hard to explain in a forum post and I can imagine that it's even harder to understand via forum post.
Please ask questions where you get stuck.
]]> tobben General Tue, 07 Nov 2017 14:38:50 -0500 https://reprap.org/forum/read.php?1,738858,795383#msg-795383 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,795383#msg-795383 brotherchris General Tue, 07 Nov 2017 09:15:31 -0500 https://reprap.org/forum/read.php?1,738858,793415#msg-793415 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,793415#msg-793415
Do you know the vertical distance between the starts and the ends of your suspended A-lines?]]> tobben General Mon, 23 Oct 2017 17:44:34 -0400 https://reprap.org/forum/read.php?1,738858,793366#msg-793366 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,793366#msg-793366 brotherchris General Mon, 23 Oct 2017 11:19:45 -0400 https://reprap.org/forum/read.php?1,738858,793297#msg-793297 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,793297#msg-793297
How long are your A-lines when your printer is in origo?]]> tobben General Mon, 23 Oct 2017 04:40:09 -0400 https://reprap.org/forum/read.php?1,738858,793256#msg-793256 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,793256#msg-793256 brotherchris General Sun, 22 Oct 2017 17:55:59 -0400 https://reprap.org/forum/read.php?1,738858,793122#msg-793122 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,793122#msg-793122
Cool that you're working on the Maslow! I've been wanting to try one for ages.

The extra lines on each axis are there to constrain the rotational degrees of freedom. Jonas Forsell's Hangaround design uses 1 line on ABC. It works, but it always wobbles around Z.

The math is really not complicated since the mover never rotates. Forward kinematics is simply Pythagoras'. The moving part is treated like a point mass in the firmware.]]> tobben General Sat, 21 Oct 2017 16:49:01 -0400 https://reprap.org/forum/read.php?1,738858,793109#msg-793109 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,793109#msg-793109
Another option to consider is to simplify the math a bit by changing the mountings so that the lines are always pointing at the extruder (or at least at the axis of the extruder). On the maslow CNC project, we were suspending the sled holding the router from two chains at fixed points, and as we move around, the sled tilts. the math to calculate this is a nightmare. We are now trying a couple different approches (one attaching lines to bearings on a ring, and the other with pantograph arms, and that is drastically improving our accuracy as well as simplifying the math.

If you were able to do a 3D version of something like this [lang.hm] you would make it so that the lines are always pointing at the end of the extruder.
(the links make it so that the small hole in the arms is always a constant distance from the center of the bit, and a line extended from the chains will always point at the bit)]]> dlang General Sat, 21 Oct 2017 13:39:21 -0400 https://reprap.org/forum/read.php?1,738858,792878#msg-792878 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792878#msg-792878
See fsr branch of auto-calibration-for-hangprinter repo (particularly in simulation.py) for the my lastest attempt at doing this using force sensing resistors to sense tightness of lines. The script can also be used to test if keeping the probing points in a plane would actually create an ill-conditioned system (by simulating those data points and trying to solve).]]> tobben General Thu, 19 Oct 2017 11:10:56 -0400 https://reprap.org/forum/read.php?1,738858,792871#msg-792871 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792871#msg-792871 dc42 General Thu, 19 Oct 2017 10:23:49 -0400 https://reprap.org/forum/read.php?1,738858,792853#msg-792853 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792853#msg-792853
The only way to find out is to double check the values you got from the calc by doing manual measurements along the xyz-axes individually, like in the image above. Based on the large amount of slack you are getting, I think you will find an > 1 cm error somewhere (or everywhere).

The calc has defined your y-axis to go straight through your A-anchor.
Measure the y-distance along one suspended A-line first (when printer is in origo and all lines are tight).
For measuring y-distances and x-distances along your B- and C-lines, I recommend using a big 90 degree ruler and drawing lines with pencil or tape on the floor if your floor and all its users are ok with it.

While this process can teach users a bit about how Pythagoras' theorem is used inside the firmware, I really wish users (and myself) didn't have to go through it.
Robust one-click anchor calibration is possible in theory.
Most of the possible ways to implement it also gives us automatic homing almost for free.]]> tobben General Thu, 19 Oct 2017 06:14:53 -0400 https://reprap.org/forum/read.php?1,738858,792841#msg-792841 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792841#msg-792841
Thanks for the reply. I have eeprom commented out.

Chris]]> brotherchris General Thu, 19 Oct 2017 03:43:03 -0400 https://reprap.org/forum/read.php?1,738858,792837#msg-792837 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792837#msg-792837
do you use the EEPROM?
If your answer is "Yes": Are you using M502 to load the Firmware defaults after uploading your edited firmware?
After that you should use M500 to store that new values.

If your answer is "No": Sorry, i can't help you :(]]> siggi60 General Thu, 19 Oct 2017 02:40:48 -0400 https://reprap.org/forum/read.php?1,738858,792826#msg-792826 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792826#msg-792826
Next I commented out the line compensation. It doesn't change anything, the A B and C still feed out line on the way up and retract it on the way down. Not sure how that has happened.

I am commenting out this line, #define EXPERIMENTAL_LINE_BUILDUP_COMPENSATION_FEATURE

I have made sure all the D lines are the same and all the A B and C lines are equal.

I have been using the calc.]]> brotherchris General Wed, 18 Oct 2017 18:29:10 -0400 https://reprap.org/forum/read.php?1,738858,792822#msg-792822 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792822#msg-792822 G92 X0 Y0 Z0
G8 A50

If this releases 50 mm of line, then your machine has control of how much line it's letting out, and buildup compensation works (at least on the A-axis). Its equivalent to what we did with G8 before. If buildup compensation works when used with G8, it also works during print.

It is correct that a wrong spool radius will have much the same effect as a mistuned buildup compensation. The above test also accounts for erronous spool dimensions. An erronous spool radius can even be perfectly compensated by tuning the LINE_ON_SPOOL_ORIGO values :)

There's always the option to disable buildup compensation by commenting out line 435. I'm a bit curious of what happens if you disable buildup compensation, reflash firmware and try the G1 Z100-movement again.

Factors that could mess up anchor location calibration a little bit:
  • D-lines not perfectly vertical when printer in origo.
  • Paralellograms not perfectly paralell (like one A-line being longer than the other, or one A-lamp hook being placed closer to origo than the other).

Did you use the online calibration calculator, or did you measure ANCHOR_ABC_XYZ directly, or both?]]> tobben General Wed, 18 Oct 2017 17:16:51 -0400 https://reprap.org/forum/read.php?1,738858,792809#msg-792809 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792809#msg-792809 dlang General Wed, 18 Oct 2017 14:32:24 -0400 https://reprap.org/forum/read.php?1,738858,792795#msg-792795 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792795#msg-792795 brotherchris General Wed, 18 Oct 2017 12:27:14 -0400 https://reprap.org/forum/read.php?1,738858,792779#msg-792779 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792779#msg-792779
The best thing I can give you for now is the following illustration:



... and the info in the calibration manual.
]]> tobben General Wed, 18 Oct 2017 10:49:46 -0400 https://reprap.org/forum/read.php?1,738858,792773#msg-792773 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792773#msg-792773 brotherchris General Wed, 18 Oct 2017 09:59:05 -0400 https://reprap.org/forum/read.php?1,738858,792736#msg-792736 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792736#msg-792736
I still suspect that either some rapid Z-lifts makes the D-motor loose steps, or that anchor locations are not perfectly calibrated, or a combination of both factors...

If you place the printer in origo, tighten lines and move to Z100 like this:

G1 Z100 F150 ; F150 sets a low speed of 150 mm/min so no steps will be skipped

Does it still result in slack lines?
If it doesn't, then skipped steps during print time is probably the issue.
If it does, then anchor positioning is the issue.]]> tobben General Wed, 18 Oct 2017 05:47:13 -0400 https://reprap.org/forum/read.php?1,738858,792691#msg-792691 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792691#msg-792691 brotherchris General Tue, 17 Oct 2017 19:38:46 -0400 https://reprap.org/forum/read.php?1,738858,792201#msg-792201 Re: Hangprinter version 2 https://reprap.org/forum/read.php?1,738858,792201#msg-792201 brotherchris General Fri, 13 Oct 2017 19:02:36 -0400