New Delta Printer - Look Ma, no rails!

I have no objection to posting your project here Linkreincarnate (of course its not my thread to decide)...but I think you would better serve yourself and the community to create a thread of your own so that interest in your ideas and achievements would be easier for others to find and comment on in the future. Best of luck with your design...TP.

Edited 1 time(s). Last edit at 10/12/2015 02:05AM by simspeed.

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Linkreincarnate
Ok, thanks a lot for all the advice! I am going to redesign the cable routing and body tonight. I'll just keep posting my progress to this discussion if you dont mind. (if you do I can make a new thread)

No objections on my part either, but I agree with simspeed - you'd be better served with a thread of your own.

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NEATman
I just saw this crazy motion simulator:
[www.youtube.com]

I know it is much more complexity with 8 winches, but I thought it may inspire more ideas.

Keith

6 motors is enough. The "Spike" printer from a few years ago is a 6 line masted winchbot. Meet Spike.
Anatoly Makarevich proposed a parallelgram based version that lowers the motor count further, and these inspired the Sky delta.

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LoboCNC

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ekaggrat
super cool... What firmware are you using?

I am using Marlin set up for a Delta printer, but I had to modify the calculate_delta() function in Marlin_main.cpp as shown below. In Configuration.h, the parameter DELTA_DIAGONAL_ROD is normally the fixed length of the pivoting arms. In my implementation DELTA_DIAGONAL_ROD should be set to the initial length of the diagonal strings when the carriage is at the zero position.


void calculate_delta(float cartesian[3])
{
float z_squared;

z_squared = sq(delta_z0 - cartesian[Z_AXIS]);

delta[X_AXIS] = sqrt( z_squared +
sq(-cartesian[X_AXIS]-delta_tower1_x) +
sq(-cartesian[Y_AXIS]-delta_tower1_y)
) - delta_diagonal_rod;
delta[Y_AXIS] = sqrt( z_squared +
sq(-cartesian[X_AXIS]-delta_tower2_x) +
sq(-cartesian[Y_AXIS]-delta_tower2_y)
) - delta_diagonal_rod;
delta[Z_AXIS] = sqrt( z_squared +
sq(-cartesian[X_AXIS]-delta_tower3_x) +
sq(-cartesian[Y_AXIS]-delta_tower3_y)
) - delta_diagonal_rod;
}

I too am now working on a fairly similar delta design, and while I have an old Rambo board using Marlin (from a Mendelmax 2.0), I want this setup to run on my new smoothieboard 5x (it is wired to it now). In the versions of Marlin that I have, I can find the section that you changed, but the versions I have use different variable names, and as I'm translating (replacing) the variable names from your version of Marlin to my version of Marlin I can then see how to change the Smoothieboard firmware. The updated Smoothieboard firmware compiles and runs, and will still control my robot for "Home" and will make the first movement (-Z) for "Probe", but I can no longer make independent X, Y or Z movements.

Hopefully this is still just an easy question.... I can easily see (translate) all variable names but one, that (after tons of searching), I just made a wild guess on..... I can not find variable "delta_z0" anywhere in any copy of Marlin that I can lay my hands on! Can any one tell me about, or help me find, "delta_z0" in any Marlin version?

Thanks in advance, I will post more info later today if needed.

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RichardMenasco

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LoboCNC

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ekaggrat
super cool... What firmware are you using?

I am using Marlin set up for a Delta printer, but I had to modify the calculate_delta() function in Marlin_main.cpp as shown below. In Configuration.h, the parameter DELTA_DIAGONAL_ROD is normally the fixed length of the pivoting arms. In my implementation DELTA_DIAGONAL_ROD should be set to the initial length of the diagonal strings when the carriage is at the zero position.


void calculate_delta(float cartesian[3])
{
float z_squared;

z_squared = sq(delta_z0 - cartesian[Z_AXIS]);

delta[X_AXIS] = sqrt( z_squared +
sq(-cartesian[X_AXIS]-delta_tower1_x) +
sq(-cartesian[Y_AXIS]-delta_tower1_y)
) - delta_diagonal_rod;
delta[Y_AXIS] = sqrt( z_squared +
sq(-cartesian[X_AXIS]-delta_tower2_x) +
sq(-cartesian[Y_AXIS]-delta_tower2_y)
) - delta_diagonal_rod;
delta[Z_AXIS] = sqrt( z_squared +
sq(-cartesian[X_AXIS]-delta_tower3_x) +
sq(-cartesian[Y_AXIS]-delta_tower3_y)
) - delta_diagonal_rod;
}

I too am now working on a fairly similar delta design, and while I have an old Rambo board using Marlin (from a Mendelmax 2.0), I want this setup to run on my new smoothieboard 5x (it is wired to it now). In the versions of Marlin that I have, I can find the section that you changed, but the versions I have use different variable names, and as I'm translating (replacing) the variable names from your version of Marlin to my version of Marlin I can then see how to change the Smoothieboard firmware. The updated Smoothieboard firmware compiles and runs, and will still control my robot for "Home" and will make the first movement (-Z) for "Probe", but I can no longer make independent X, Y or Z movements.

Hopefully this is still just an easy question.... I can easily see (translate) all variable names but one, that (after tons of searching), I just made a wild guess on..... I can not find variable "delta_z0" anywhere in any copy of Marlin that I can lay my hands on! Can any one tell me about, or help me find, "delta_z0" in any Marlin version?

Thanks in advance, I will post more info later today if needed.

The variable delta_z0 may have been something I added - it's all a bit hazy now. In my code, I have a section where it looks like I edited out the variable delta_diagonal_rod_2 and maybe added in the variable delta_z0:
:
#ifdef DELTA
float delta[3] = {0.0, 0.0, 0.0};
#define SIN_60 0.8660254037844386
#define COS_60 0.5
// these are the default values, can be overriden with M665
float delta_radius= DELTA_RADIUS;
float delta_tower1_x= SIN_60*delta_radius; // front left tower
float delta_tower1_y= COS_60*delta_radius;
float delta_tower2_x= -SIN_60*delta_radius; // front right tower
float delta_tower2_y= COS_60*delta_radius;
float delta_tower3_x= 0.0; // back middle tower
float delta_tower3_y= -delta_radius;
float delta_diagonal_rod= DELTA_DIAGONAL_ROD;
//float delta_diagonal_rod_2= sq(delta_diagonal_rod);
float delta_z0 = sqrt( sq(delta_diagonal_rod) - sq(delta_radius) );
float delta_segments_per_second= DELTA_SEGMENTS_PER_SECOND;
#endif

did you use line or braid????

---

Check my rubbish blog for my prusa i3

up and running
[3dimetech.blogspot.co.uk]

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chris33
did you use line or braid????

I used 30# test braided Spectra line that is about 0.010" dia.

This forum thread ispired me to build something similar. I probably will settle with the same design, but yet I'm just experimenting with materials and other kinematics. I bought some dyneema line, which is similar to spectra, and tried different materials to guide it. The best so far is enamel wire (originally for coil windings). This hard, slippery coating is better than just polished copper you seemingly used. Closest to ceramics.
However I have another bold idea for this: the guide rings for fishing rods usually have ceramic inserts. They worth a try, and are more accessible than sewing machine parts (I think).

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besenyeim
This forum thread ispired me to build something similar. I probably will settle with the same design, but yet I'm just experimenting with materials and other kinematics. I bought some dyneema line, which is similar to spectra, and tried different materials to guide it. The best so far is enamel wire (originally for coil windings). This hard, slippery coating is better than just polished copper you seemingly used. Closest to ceramics.
However I have another bold idea for this: the guide rings for fishing rods usually have ceramic inserts. They worth a try, and are more accessible than sewing machine parts (I think).

I ended up settling on running the Spectra line through PTFE sleeving (see the photo at the top of page 3 of this thread). No sign of wear on the Spectra line. In fact I suspect the line ends up picking up a thin coating of PTFE which makes everything more slippery as it gets worn in.

How long will it take before the PTFE sleevings need replacement? From what you have observed so far, do you think it will be closer to 100 or 1000 or 10 000 print hours?

It's a neat and cheap solution, I've been considering it for the Hangprinter =)

---

torbjornludvigsen.com

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tobben
How long will it take before the PTFE sleevings need replacement? From what you have observed so far, do you think it will be closer to 100 or 1000 or 10 000 print hours?

It's a neat and cheap solution, I've been considering it for the Hangprinter =)

That's a good question. It doesn't seem like the PTFE is showing significant wear, but to be honest, I've probably printed less than 50 hours on this printer. Note, however, that only a tiny spot on the PTFE sees any wear, and you can easily shift the sleeve to a new spot without having to do any disassembly. You could probably shift and rotate the sleeve a dozen or so times before needing to replace it.