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Here's what I made, here's a photo, and here's a link to the [[page]] on RepRaps wiki!
Re: Tripteron Implementation - 2 years ago
Just finished reading through this whole thread. I believe that the arm joints would be easiest to make as a compliant hinge out of the material that was used for this KS: It is a project I backed, but just before it could be delivered the creator came down with cancer and never completed the last bits and shipped the project to the supporters. The hinge concept was great though and I thiby see3d - Look what I made!
Re: started designing a new mostly-plastic reprap SCARA with fishing line motion transmission and unorthodox winch for Z - 8 years ago
I see you got the main answer you needed before I could respond. As far as recirculating the air back up the arm, it all depends on the printing environment. If you are in a closed box where you want to regulate the temperature and air currents, then you may want to bring the cooling air back outside the box. This is why some bots use water cooling. Otherwise, it is better to just let it flowby see3d - Polar Machines, SCARA, Robot Arms
Re: started designing a new mostly-plastic reprap SCARA with fishing line motion transmission and unorthodox winch for Z - 8 years ago
The fan is a neat idea, but you have drawn in the wrong type of fan. To get high flow with a lot of back pressure, you need a squirrel cage blower. I use that type of fan for my part fan also because the air is much more directed to a small area.by see3d - Polar Machines, SCARA, Robot Arms
Re: Introducing: Reprap Ultrascale (Idea) - 8 years ago
The way an air bearing works is that air is pumped between two very flat surfaces. The air pressure is reduced because it has to speed up to get out of the small space. This means the the air gap is balanced between the 14 PSI air pressure and just enough gap to get the air out. If air is pumped into the puck with a flexible tube, then it should work (with proper engineering and very flat surfby see3d - Polar Machines, SCARA, Robot Arms
Re: Introducing: Reprap Ultrascale (Idea) - 8 years ago
Ever heard of air hockey? Hovercraft? No friction with air bearings.by see3d - Polar Machines, SCARA, Robot Arms
Re: Wally Z axis alternative linear designs - 8 years ago
I think it would be a good idea to mount the motors to the arms, but keep them in the same X,Y position (the center of the motor shaft at the center of the shoulder rotation). That way the steppers would just rotate about their center on the shoulder, which would keep the inertia very low, and the forces on the arm balanced above the strongest place (the pivot). I think it would be well worth tby see3d - Polar Machines, SCARA, Robot Arms
Re: Idea for magnetic joint - 8 years ago
Quotejaistanley Perhaps a ball end mill could be used to finish the surface of the magnet? Jai "20. Can I cut, drill, or machine neodymium magnets? The Neodymium Iron Boron material is very hard and brittle, so machining is difficult at best. The hardness of the material is RC46 on the Rockwell "C" scale, which is harder than commercially available drills and tooling, so these tools will heat upby see3d - Delta Machines
Re: Wally Z axis alternative linear designs - 8 years ago
If this is your main concern, then I would take a different approach. Have a removable bed surface that you can take away from the printer to remove the part. I supported a KickStarter for the Gecko print surface. It is just a thin steel plate with a special surface that parts will stick to, but give it a bit of flex and the parts fall off. I am expecting my 300mm x 300mm plate to show up anby see3d - Polar Machines, SCARA, Robot Arms
Re: Wally Z axis alternative linear designs - 8 years ago
Welcome DedeHai, You might find that square steel tubes of about 3/4 inch size can make a good external structure (instead of or in addition to the wood parts). Because of the reaction forces from moving the arms, it is easier to make a moving bed that is linear on Z rails. The bed has no reaction forces, so the rails do not see any. This will facilitate being able to use more massive armsby see3d - Polar Machines, SCARA, Robot Arms
Re: Parallel flexure test - 9 years ago
Were you planning on having a Z axis also?by see3d - Polar Machines, SCARA, Robot Arms
Re: Delta Scara - 3D printer design - 9 years ago
If you allow the motor to pivot at the back bracket, then you can spring load the worm into the gear and spring load the axis into the worm. That gets rid of the backlash. The Solidus Labs one uses gravity to load these.by see3d - Polar Machines, SCARA, Robot Arms
Re: Delta Scara - 3D printer design - 9 years ago
Rotating of the filament is less pronounced when you have arranged it like you did with the 90 degree bends. I was thinking of it if you came in from the top of the extruder and straight down. Unless you have a rotational axis on the extruder, the line going to the filament will keep changing the angle of entry to the extruder. This is what happens instead of the rotation that occurs in theby see3d - Polar Machines, SCARA, Robot Arms
Re: Delta Scara - 3D printer design - 9 years ago
Your filament must be a lot easier to bend than my filament. I have to run a gentle arc from the spool to straight down through the extruder. Perhaps a 2-3 inch bend radius for 1.75mm PLA would be ok if it went around a guide on a bearing. Without a guide, I would say 4-5 inch radius in free air is about what my filament wants to curve without too much strain. That is the only filament I currby see3d - Polar Machines, SCARA, Robot Arms
Re: Delta Scara - 3D printer design - 9 years ago
Take care about the path the filament will take in getting to the hot end. It looks like it could get all hung up on the structure and arms. Catching the table if it falls is not so hard. Just have a spring at the bottom to decelerate it. You can also have a can with a close fitting plunger to use as an air shock damper. I did this on a machine to catch a fast 15 pound arm X motion that waby see3d - Polar Machines, SCARA, Robot Arms
Re: Delta Scara - 3D printer design - 9 years ago
Nice approach to the design. If it were me, I would relocate the elbow drive motor close to the shoulder to reduce the swinging mass. This will speed up the motion and increase the resonant frequency of the arm. I like that you have the extruder with the hot end, rather than a Bowden tube.by see3d - Polar Machines, SCARA, Robot Arms
Re: Wally Z axis alternative linear designs - 9 years ago
@Feign: Interesting approach to the Z. I like the concept. Not exactly a Wally, but interesting none the less.by see3d - Polar Machines, SCARA, Robot Arms
Re: Wally Z axis alternative linear designs - 9 years ago
Quotecreativeautomaton would like to assist in building a linear x crane bot using alot of the concepts of wally. Can you make a sketch of what you have in mind?by see3d - Polar Machines, SCARA, Robot Arms
Re: Wally Z axis alternative linear designs - 9 years ago
Simpson has nothing to do with this thread. Wally was a concept with a first cut at implementation by Nicholas. It has not had full followthrough while Nicholas has been busy with his job, but Nicholas did demonstrate a working Wally, you can't say Wally does not work, just because some others have not made their variations work from his open source alpha design. Working on an Alpha design takby see3d - Polar Machines, SCARA, Robot Arms
Re: Wally Z axis alternative linear designs - 9 years ago
Wally as designed by Nicholas had that as an initial goal, but it was never a limiting goal in my mind, even though I supported this goal for the first Wally version. This thread is about alternative Z axis designs for linear motion. There are no limitations in the possible designs, but goodness criteria are: low cost, accurate, easy to build, scalable, etc. QuoteFeign Practically, there areby see3d - Polar Machines, SCARA, Robot Arms
Re: Wally Z axis alternative linear designs - 9 years ago
So far, I have not seen anything more simple that the original top post suggestion I made. It is only 4 bearings and two square, rectangular, or "L" shaped rods as linear guides. I would like to see some ideas for improving this design concept also. What are the limitations or concerns about that approach? How can the rods be constructed to make them more economical? Should they be supporby see3d - Polar Machines, SCARA, Robot Arms
Re: Dual-arm SCARA robot - 9 years ago
It has a singularity to program around in the centerline. It has a bar in the way for filament overhead. If using only half of the area to remove these problems, it becomes similar to other 3D printer mechanisms like Wally and others. So, my answer is no for the configuration shown in the video, plus, the MSRP is $7K for what was shown.by see3d - Polar Machines, SCARA, Robot Arms
Re: SAPE Single Arm Printer Experiment - 9 years ago
Too Funny! I just finished rebuilding my DIY tractor backhoe attachment last week. I never though about putting a seat on the bucket and running the joysticks out to the seat and taking it for a joy ride. QuoteA2 Very cool! Am I the only one that see's it evolving into a backhoe Remotely, and pragmatically dig holes in the yard, scale it up and dig a pond, or a basement, switch the bacby see3d - Polar Machines, SCARA, Robot Arms
Re: SAPE Single Arm Printer Experiment - 9 years ago
Great fork of your previous design.by see3d - Polar Machines, SCARA, Robot Arms
Re: Modified CoreXY Geometry - 9 years ago
This is a good arrangement for more Z resolution and keeping the same X speed. It mimics the functionality of other designs that use dual Z lead screws to have a separate Z resolution, but it eliminates the high cost of precision lead screws, as well as the Z periodic errors of low cost lead screws.by see3d - Mechanics
Re: New Arm Design - 9 years ago
QuoteA2 Idea: Instead of using a mass for the boom crane, create a tensor using a stepper motor with a pretensioned cable. You could even preprogram it to control for the catenary drop. Picture pleaseby see3d - Polar Machines, SCARA, Robot Arms
Re: Tri-Polar Bot Concept -- Wally Chrome - 9 years ago
Congrats! You have come a long way in a short time. Now on to perfection!by see3d - Polar Machines, SCARA, Robot Arms
Re: Wally Z axis alternative linear designs - 9 years ago
I had the same thoughts about a solid aluminum backboard. My concern about a plastic roller is that if it has cantilevered loads, the plastic tires will develop flats. Metal rollers though, I would have no problem with, as long as it is not a small point contact on aluminum.by see3d - Polar Machines, SCARA, Robot Arms
Re: Wally Z axis alternative linear designs - 9 years ago
This thread should be about throwing out all kinds of ideas to spark the creative juices. After we run out of different ideas, then we can focus on the pros and cons of each one. Often times, identifying a weakness in a design, just inspires a creative way around it. I am using a 300mm Z travel as my design center for evaluating different ideas for size, cost, durability, precision, etc.by see3d - Polar Machines, SCARA, Robot Arms
Re: Wally Z axis alternative linear designs - 9 years ago
Quotenicholas.seward BTW, this design uses 32 608's. That sounds like a lot and it is but the overall costs are right around $10 for this z stage when the bearings are less than 25 cents a piece. It would be hard to get 1 metal rod for that price. A 0.75 inch square 304 SS tube (0.065 wall), would run about $9.62 for 36 inches. That is about right for a 12 inch (my goal) Z travel. That was juby see3d - Polar Machines, SCARA, Robot Arms
Re: Wally Z axis alternative linear designs - 9 years ago
@Gomez.Marcos -- Yes, a scissor jack would not allow the Z to fall, which could happen with the current Wally design if the motor detent was too weak, or the string broke. OTOH, having the Z drop in a controlled way is a way to set the end stop without needing switches. A scissor jack might need a switch. It has very poor resolution at the bottom and very fine resolution at the top. You alsby see3d - Polar Machines, SCARA, Robot Arms