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General discussions. For specific printers / electronics / fabrication methods / softwares, please see other sections.
Re: MAKE SKEINFORGE AN EXE - 15 years ago
I am just saying, is it that hard to make it a little more user friendly? I am sorry that I offended you, I was just a little ticked off that I spent so much time trying to get it to work, and when it did, the stl files didn't load. I will upload some stl files and you can see if they work on your program, because they don't on mine, no matter how hard I try.The attached stl is a simple cube, soby galaxyman7 - Skeinforge
MAKE SKEINFORGE AN EXE - 15 years ago
Hi, I have had a lot of trouble with skeinforge, and I think the whole program needs to be a bit simpler. Why can't someone make it into an exe so that people don't have to download python and do all this nonsense before using it? I know it is supposed to be open source, but if no one can use it, what is the point? Also, I have tried to import stl files that I created with solid edge, but nothingby galaxyman7 - Skeinforge
Re: Polar Rep Rap - 15 years ago
Sure that sounds great. Tell me when it is up and running so I can move this project there.by galaxyman7 - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
Here are the ranges for a robotic arm type printer with two 6 inch arms (like the one in the photo I took). It is a kind of dog bowl type shape. This should be able to print its own parts easilyby galaxyman7 - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
That would be great if you could create a couple forums for cartesian, polar, and delta. Then we could expand on different ideas and they would all be in the same place. Is there a way to copy this topic over to that forum? Then we don't need to link to it, which is a pain.by galaxyman7 - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
Here are some pictures of the first linkage system I milled out. It seems to be pretty sturdy when I try to bend it downwards, but obviously it is wobbly back and forth. I need to make a base to hold two of these side by side, and then put bolts through both of them. That should definetly be sturdy enought to hold an extruder. I also need to make mounts for the motors on the arm and in the base.by galaxyman7 - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
One big thing is that the program needs to be user friendly. I have used Skeinforge and it is ridiculous how many other things you need to download to use it. Plus after all that, it wouldn't even load my stl files. So please, if you can, make a nice GUI interface with clear steps that anyone can understand. I will mill out the arm pieces today, out of some polycarbonate I have laying around. Iby galaxyman7 - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
Equations for angles a, B, and theta (plus some inbetween equations) B = arccos((R^2 + Z^2 -L1^2 -L2^2)/(2*L1*L2))_____-180 < B < 0 a = arccos(R/sqrt(R^2 + Z^2)) + C _____0 < a < 90 theta= arctan(y/x) Note: two answers for theta, pick right one in program supporting equations C = arcsin(L2*sin( B ))/sqrt(R^2 + Z^2) _____0 < C < 90 R = abs(x/arctan(y/x))_____ abs value bby galaxyman7 - Polar Machines, SCARA, Robot Arms
Re: Support material suggestion - Grease is the word! - 15 years ago
Interesting. I think playdough would stick to itself as long as the extruder was close to the surface. If it doesn't, I am sure you can make your own playdough that will. You can make your own playdough with flour, salt, water, and oil. This would be a super cheap support material, and it would be reusable. It is almost like bread dough.by galaxyman7 - General
Re: Support material suggestion - Grease is the word! - 15 years ago
How about playdough?by galaxyman7 - General
Re: Polar Rep Rap - 15 years ago
Yep, I had forgot about law of cosines and sines, mostly because things are usually right triangles. They are very usefull indeed. This should help a ton. Next probem- making a program to load the gcode and output step and direction code to the motors. This could either be done on the computer or on a microcontroller. I am thinking that the SX chip from parallax is a good option. They are onlby galaxyman7 - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
Wow, I just found a paper explaining the mathematics of robotic arms! This is exactly what I was looking for. I have attached it. It is in x, y coordinates, which for me is r, z coordinates. So I will still need to do some work on it.by galaxyman7 - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
By the way, stiffness should not be an issue because there is no cutting force. The weight of the extruder should make all of the motion fairly smooth even without bearings. The motors will be attached at A and B in the picture, and the other links will be attached with bolts.by galaxyman7 - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
Very interesting! I have done many calculations trying to solve the angles of each member in terms of x, y , and z. It has proved to be very difficult. I have attached a picture of what I am doing. It includes the equations. First I solve for r and z, which are fairly easy. All I have to do is add up components of the lengths using trig. This converts it to cylindrical form. -Each angle is posiby galaxyman7 - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
Ahh, ok. Credit goes to Beaglefury. I am going to do some calculations to find the relationship between the x, y, and z position compared to the angle of rotation for each joint. Then this can be used to position the arm. The only thing I am worried about is the motors overshooting their target. They need to be started and stopped exactly at each angle. Got any ideas? I know if you short the motby galaxyman7 - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
Here are some more pics with the base rotating. I also made the link at the base rigid. Obviously things would need to be thicker in order to hold the motors and extruder, but this just shows the basic concept. I think 3 linkages in parallel would probably be best, with the top linkages being thicker to hold the motors. Also not shown in the pics are the pins that connect the two linkages, whicby galaxyman7 - Polar Machines, SCARA, Robot Arms
Re: Polar Rep Rap - 15 years ago
Ok, it looks like Johnny Cooper's team has already thought of a dual rotating platform, which is interesting, but I do not see any z axis movement being very easy on that machine. The robotic arm will have no linear slides, only rotation. Plus it can rotate in a full circle, making parts anywhere around itself. This means it could theoretically print all of its parts in one go! I have experimenteby galaxyman7 - Polar Machines, SCARA, Robot Arms
Polar Rep Rap - 15 years ago
Hey, I was thinking that the best way to go in order to get rid of all the metal parts in a reprap is making it polar (or spherical coordinates). This would basically be a robotic arm with an extruder on the end. The mechanical part would hardly be complicated, just needing 3 motors for rotation in 2 directions, plus an extending arm. The tricky part would be programming. But it is much better toby galaxyman7 - Polar Machines, SCARA, Robot Arms