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General discussions. For specific printers / electronics / fabrication methods / softwares, please see other sections.
Re: Arm length calculation help on own-design delta needed - 7 years ago
QuotehercekThat seems to be what people seem to call forward for reasons I newer understood. Why it should be called forward when the direction we primarily need is the other one? Well, forward is defined from actuators to cartesian space; same notation is used for robots. But your're right, this is mainly the IK we are interested in.by fma - Delta Machines
Re: Metal corner drawings - 7 years ago
Quotedougal1957If you can wait till later today or early tomorrow I can sketch one out for you with some measurements on the sketch for you? That would be great! It is not urgent at all, so, I can wait longer... Thanks.by fma - Delta Machines
Re: Metal corner drawings - 7 years ago
Thanks! I think what is important is the position of the concurrent points of the horizontal arms relative to the center of the vertical arm (upper and lower dimension on the drawing).by fma - Delta Machines
Metal corner drawings - 7 years ago
Hi! I plan to use metal corners to build my future Delta 3D printer, from robotdigg company. Unfortunately, they don't provide any top view of there products, which is a little bit strange, as it is mandatory to determine horizontal length profiles. So, does anyone have top view (as DXF or just image with dimensions) of these products: (for both NEM17 and NEMA23, but I think they are the saby fma - Delta Machines
Re: Arm length calculation help on own-design delta needed - 7 years ago
Nice maths! Are there curves, somewhere, showing the resulting errors on the movements, depending on the different errors that can be encounters, as described above (for standard vertical towers, not titlted ones)? I've no idea of the order of magnitude of all this...by fma - Delta Machines
Re: Basic considerations about Delta printers - 7 years ago
Thanks for sharing!by fma - Delta Machines
Re: Basic considerations about Delta printers - 7 years ago
Compared to the standard profiles, like 2020 Motedis I-profile, is Openbuilds profile better? It has maybe a better contact whith the wheel? BTW, I also plan to use excentrics...by fma - Delta Machines
Re: Basic considerations about Delta printers - 7 years ago
Quotefma Like these? Are these profiles better, in combination with the above wheels?by fma - Delta Machines
Re: Arm length calculation help on own-design delta needed - 7 years ago
QuotefmaWith tilted towers, it seems that arms remains more // to the towers in every point (didin't check with maths), so accuracy should not change as much as with vertical tower, from center to edge of bed. This may also be better to prevent effector tilt? Especially under lateral load (spindle usage)?by fma - Delta Machines
Re: Arm length calculation help on own-design delta needed - 7 years ago
So, it will be more a calibration machine than a 3D printer With tilted towers, it seems that arms remains more // to the towers in every point (didin't check with maths), so accuracy should not change as much as with vertical tower, from center to edge of bed. But as you explained, other problems make this point irelevent. I agree with metal corners; I will also use them, rather than printedby fma - Delta Machines
Re: Arm length calculation help on own-design delta needed - 7 years ago
I understand.by fma - Delta Machines
Re: Basic considerations about Delta printers - 7 years ago
Quotehercek[...]If you are very advantageous then go for about Ø 1.5 mm steel cable. But in this case you need big diameter drums to minimize impact of the errors because of varying position on drum. And that means you probably need a speed reduction from stepper to the drum. What accuracy do we need on the axis?by fma - Delta Machines
Re: Arm length calculation help on own-design delta needed - 7 years ago
Sounds good!by fma - Delta Machines
Re: Basic considerations about Delta printers - 7 years ago
Quotedc42I have only even used Delrin wheels on aluminium profiles, and they work well for me. Like these?by fma - Delta Machines
Re: Basic considerations about Delta printers - 7 years ago
And what about such solution:by fma - Delta Machines
Re: Basic considerations about Delta printers - 7 years ago
Thanks, DC42; I'll dig that solution... O_lampe, I plan to use 40x20 aluminium extrusion as vertical arms, and put the rods on each side of the 40mm lenght. So, I will have more than 80mm between rods...by fma - Delta Machines
Re: Arm length calculation help on own-design delta needed - 7 years ago
I'm wondering: does this design reduce the non-linearity, and so simplify the tuning?by fma - Delta Machines
Re: Basic considerations about Delta printers - 7 years ago
What are the feedbacks on the linear systems using plastic wheels on aluminium profiles? I see that on some commercial 3D printers, but I wonder if it provides good long term accuracy... It is a very simple design, and very cheap compared to rods/ball bushing.by fma - Delta Machines
Re: Basic considerations about Delta printers - 7 years ago
Quotehercek In my opinion, the only reason to prefer delta to coreXY is the high printing speed. Otherwise delta has only disadvantages. It needs more powerful/expensive controller, it is harder to calibrate, and it is taller. But if you want a delta for the fun/challenge of it then go on Well, I find it simpler to design: only 1 axis, repeated 3 times. About controller, I'm waiting for a Repliby fma - Delta Machines
Re: Basic considerations about Delta printers - 7 years ago
Quotedougal1957The Arms should not be less than 20 degrees to the bed at the farthest extent of there travel and should be as wide apart as you can get but aim for no less than 45mm (that is around 40 mm wide fixing points on the effector/carriages which is the std for the Kossel if you can go wider then you will have greater rigidity) Thanks for the tips!by fma - Delta Machines
Re: Basic considerations about Delta printers - 7 years ago
No, the gonio is under the bed, not on the effector... About the spindle, I'm thinking using a little brushless motor, like used in quadcopters... Anyway, these are possible options only, and I really want to build a Delta For now, I need to determine the global size, so arms geometry is an important factor.by fma - Delta Machines
Basic considerations about Delta printers - 7 years ago
Hi! I'm thinking to build a Delta printer from scratch (moslty for fun), and I would like some advices. Here are some infos about the printer I plan to build: - no need fo high speed printing; quality is the main factor -> must be rigid - metal parts as much as possible (aluminium profiles, lasercut plates...) - diam. 10mm (mini) for rods/linear ball bushing - normal build volume (~diam. 25by fma - Delta Machines
Re: Another Remote Extruder 
- 8 years ago
QuoteTHE_SHRUB Quotethe_digital_dentist I think it can be made to work. Even if mechanical losses are high, you can use a bigger motor and more current to drive it. If you had to you could mount a set of bearings in the gear to reduce sliding friction along the square rod. It may not be necessary to make the square hole in the gear all that close fitting on the square rod. The whole carriageby fma - Mechanics
Re: Another Remote Extruder - 8 years ago
Just to say that I'm also trying both technics described here (square shaft and flexible shaft). I designed the ChickenStruder, using a square shaft: I still need to make the motor fixation, but I successuflly printed a part. The idea, now, is to use IGUS filament to print the little gear, or at least the square part sliding of the shaft, to decrease friction. This allows to put multiple extrby fma - Mechanics
Re: filament igus - 8 years ago
Yep, j'ai lu, mais je cherche plutôt un retour des gens qui en ont imprimé...by fma - RepRap Groupe d'Utilisateurs Francophone
Re: filament igus - 8 years ago
Salut, Tu as refais des essais, avec le filament IGUS ? Peux-tu donner plus d'infos sur ses caractéristiques une fois imprimé : - a-t-il du retrait à l'impression (comme l'ABS) ? - Colle-t-il bien au lit ? - Faut-il le ventiler comme le PLA ? - Tu dis qu'il es cassant : mais est-il quand même résistant ? Se rapproche-t-il du PLA, comme propriétés mécaniques ? Merci d'avance. PS : j'envisageby fma - RepRap Groupe d'Utilisateurs Francophone
Re: Fire Hazard - 8 years ago
Did you try to run such overheating condition, to check how it works? Hotend manufacturers should include a support (simple hole) for these fuses, near the top of the hotend; using a 100°C fuse should do be OK.by fma - Safety & Best Practices