@jason.fisher Build log: What should I do, start a new thread? You'll have to point me in the right direction. Belt/Conveyor: I was thinking along the same lines as you. Placing a belt/conveyor under the print head would allow me to run the machine in a production operation. There are examples on YouTube of this already with delta robots. With a belt/conveyor you can dump the parts into a bby A2 - Delta Machines
I bought a 4 foot driveway marker to use as a pulley shaft between the gear drives. $1.99 USD, fiberglass rod. If the O.D. is not an odd size, I will use a Nylon spacer or bushing as a pulley for the string to slide over. Surgical SS tubing would probably work well as a pulley, and it has an electropolished surface. A2by A2 - Delta Machines
@quickness HBot has a routing similar to what you have. Hbot [3dprinterhell.blogspot.com]by A2 - Mechanics
@morphos Nice work! What firmware, and microcontroller are you using? A2by A2 - Polar Machines, SCARA, Robot Arms
Interesting dual motor setup to get the end effector to tilt. 6 D.O.F. Hexa - Parallel Mechanism - Ege University Mech. Eng. Dep.by A2 - Delta Machines
Delta robots can have up to 6 DOF's.by A2 - Plastic Extruder Working Group
Guizmo, I like the ratchet idea, and I can see how each part could be printed, and integrated. But because the string is inelastic it will require very fine detentes to achieve the correct tension, this could prove difficult. A2by A2 - Delta Machines
@nicholas.seward Spider wire fishing line can cut through plastic, and your hand like a razor blade. Bushing would have to roll for a plastic to work. "The metal Line Roller was sliced into 2 by the braided line. On post mortem, it was always because of the plastic bushing inside the Line Roller that had gotten a little sticky, thus the roller could not keep pace with the line speed." In thby A2 - Delta Machines
@nicholas.seward At the local hardware store I found a lot of things that might be useful for the MA shafts within the gear drive, such as nylon/steel bushings, spacers, roll pins, cotter pins, dowels, etc that could be used as a shaft and roller bearing for the gear drive. Thin walled hard nylon bushings on a dowel like surface would work well as a bearing surface for the string. But I worby A2 - Delta Machines
I'm building a wooden H.A.I.B. version of Simpson (made from discarded items), I started a few days ago Today I was at the hardware store looking for a timing belt to replace the herringbone gear. What I found potentially useful was the HEAVY duty anti slip sandpaper for steps (black, not gray). With a little force it felt like no backlash and no axial/transverse slippage, and there's adhesivby A2 - Delta Machines
I need to hack a 3D printer together so I can make prototype bearingless Simpson's on the cheap. 3D printer part quote: This past weekend I got a quote for the upper arm using makeXYZ.com. It was way too expensive for the scope of this project. So I redesigned the arm, and shaved off 90 cm3, and reduced the cost to $45.00, it's probably still too volumetric (fat). Everything needs to be reby A2 - Delta Machines
@Nicholas, I didn't think any one would consider building a Simpson this big, I was wrong I've been designing a 9' 6” long print envelope, which requires about 16' long arms. Clues of it being constructed larger are hidden in the pictures that I posted of the bearingless Simpson I was attracted to the Simpson platform because I could see that it could easily be scaled up in size, and it doeby A2 - Delta Machines
String crash, Install an optical sensor around the string to detect it's disappearance. Micro switch pressed against the string. Optical CCD mouse camera could be used for crash detection.by A2 - Delta Machines
@Nicholas, Zip tie looks OK, but I don't like the idea of tugging against the device to tighten it. A SHCS, and nut with a hole through the head of the screw. Turn the screw to take up the slack, then lock it down with the nut. I like the SHCS because I can easily adjust it if I felt it needed inspecting. An eccentric cam. A leaf spring, low profile, light weight, high force. You could alsby A2 - Delta Machines
Micropositioning using cheap mouse cameras with Arduino Library 2D position finding using the “Christopher Carter Algorithm” Absolute 2D position encoding/decoding using a Gray Code pattern. Position is resolvable generally to 1 pixel, in this case measured at about 2.4 mils (about 70um). I can envision using the tracking device to verify the printing process. If in front of the fusion paby A2 - Delta Machines
@nicholas An impressive demonstration of the proportional gear drive joint. What I like most about this drive is that it powers the arm in both directions, without backlash, and it doesn't use springs, or gravity. I'm going to adopt your design as it's a more elegant solution, tks! Now I understand why you had the surface of the cam hanging below the arms. This was to allow for the string toby A2 - Delta Machines
That's cheap, I would feel sad for the distributor if you got them for less... lol A2by A2 - Delta Machines
To eliminate purchasing a gear, and to increase tension on the spring, tie a metal ring (or loop) on the tag end of the string and hook it over an array of detents. Or wrap the string around a small peg with straight flues, and place it into a hole (array holes to increase tension). A2by A2 - Delta Machines
That's really neat! Print 4 more parts, and lets see it in action. Looks like a diameter of 22.1 mm for a 608 bearing is a slip fit. How much press fit has been used successfully with 3D printed parts (PLA,ABS)? I'm not using bolts to retain the bearing in a pocket.by A2 - Delta Machines
Looks good, and a Zip tie is holding the two halves together? About how long does it take to print one arm? Questions: 1. What is the standard stepper motor shaft coupler used on reprap machines for NEMA 14, 17, 23 motors? ans: Coupler NEMA 17 stepper motor 5 mm flexible shaft 5 mm diameter round shaft at both ends Length: 1" Diameter: 0.75" Material: Aluminum 2. What bore diameter are the 6by A2 - Delta Machines
I'm going to make the bearingless Simpson 3D printer, I'm working on it now I'm amazed at the part reduction I got with a compliant joint, and I see a few other areas where I can further simplify, and integrate purchased hardware, that's what I'm working on now. But that is a ton more work for me, integrating all the bit's and bobs into one part. In addition, I'm was able to reduce the quantby A2 - Delta Machines
I'm pricing electronics now. Do you have a date when will you have your Simpson electronics kit ready for shipping, the contents of the kit, and pricing? A2by A2 - Delta Machines
@Nicholas Seward, Nice looking pair of robot arms! Tks for the explanation, and for stating that the cam form is circular, so your goal is to calculate a radius. Roughly to my unaided eye, it looks like the radius of the cam is 20% to 30% of the length of the arm. I have estimated that the cam radius for my 6 inch arms to be 1.5 inches. I'm going with 1.5 inches until I understand the maby A2 - Delta Machines
All components that are dark yellow can be printed, (see attached images). It appears that the hardware part count will be low. I'm designing this robot to fit on existing reprap beds, this will allow the smaller 3D printers to breed larger 3D printers. I'm going to limit the max part size to 6 inches x 4 inches x 4 inches, moreover it's cheaper to mail a smaller lighter package of parts to yby A2 - Delta Machines
Double lamina compliant joint (DLCJ). I believe that the hinge that you and Nicope have drawn up has another name, and I'm unable to find a picture to help my memory. This joint is often assumed to be related to the rolamite bearing. But because there is no box or sliding action it is different. I thought of it when I saw the DLCJ joint constructed with thread on Wally, and I was curiousby A2 - Delta Machines
Nice looking render, and solution Nicholas! There is a name for this style of frictionless joint, but the name escapes me. Nylon Zip ties have been successfully 3D printed, and would be a natural first choice, as it's some thing a 3D printer can replicate. I like the idea of using thin steel shim stock for the ribbon. Thin shim stock can typically be cut with a pair of scissors, or with a handby A2 - Delta Machines
Nicope> Clever idea, it reminds me of the Rolamite bearing. Were you able to adjust the tension of the ribbon? Thanks for sharing. A2by A2 - Delta Machines
Guizmo, Nicholas Seward: I like the combination of the zero back lash of the Double Lamina Compliant Joint (DLCJ) bearing/joint, and the non linear toothless elliptical gear or cam correction as it affords weight, and part count reduction, moreover it works with the Simpson firm ware without further modifications! I believe I have a solution (or a starting point for discussion) that incorporby A2 - Delta Machines