Delta 4th axis length and limits?
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@Munce31 I have not got any recent pictures and I am not near my machine for the week. I will take some if I remember next weekend. I can tell you that I still use something very similar to the picture I posted above.
The arm has gotten way more complicated (and heavier) since I added a full blown water cooling setup on there. At the moment I a working on a simple counterweight systems to offset the ~2.2kg of mass that the moving arm carries.
If you are interested in the water cooling part you can check out the ongoing project in this thread.
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Here is what the latest iteration looks like in CAD.
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Wow that looks like a fantastic piece of engineering. I guess you're printing in a heated chamber environment.
I see that your tower is driven by belt, so how do you prevent it from falling down with all of that weight on it?
Also, am I right in saying that you can have the 4th tower's end stop lower than the end stops of the delta towers?
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Also, I'm wondering if there is a way to make the 4th tower move simply as an offset of the Z height?
My understanding is that the current coding in RRF is for flying extruders, so it tries to maintain 'X' amount of distance between the extruder output and the hot end's entry point, effectively the length of the bowden tube.
The scenario I'm thinking of is for cameras, where you want the field fo view to remain at the same level or offset of where the print head currently is in the Z orientation.
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@Munce31 said in Delta 4th axis length and limits?:
Also, I'm wondering if there is a way to make the 4th tower move simply as an offset of the Z height?
My understanding is that the current coding in RRF is for flying extruders, so it tries to maintain 'X' amount of distance between the extruder output and the hot end's entry point, effectively the length of the bowden tube.
The scenario I'm thinking of is for cameras, where you want the field fo view to remain at the same level or offset of where the print head currently is in the Z orientation.
As I said in another thread, you can achieve this by pretending that the 4th tower has a very long rod length.
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@Munce31 said in Delta 4th axis length and limits?:
Wow that looks like a fantastic piece of engineering. I guess you're printing in a heated chamber environment.
I see that your tower is driven by belt, so how do you prevent it from falling down with all of that weight on it?
Also, am I right in saying that you can have the 4th tower's end stop lower than the end stops of the delta towers?
Actually I do not have a heated chamber. I incorporated water cooling, because I could
and to avoid 'tiny fan noise' where possible.The whole system is indeed belt driven. During operation the power of the motor is enough the overcome the weight, albeit just. The stepper I had laying around when I started working on this is not terribly powerful, I might swap it later but it is fine for the time being.
In its current form the issue arises when the power is switched off. For now I have written a shutoff script that moves the head to the edge of the bed at Z=0, so the 4th axis is as low as I can be. Only then is the power actually turned off. This minimizes the distance the carriage will drop. To resolve this, I have started working on a simple counterweight system. On the cad picture I posted you can spot the wheels where the cable will run over at the top (in a upside down 'U' shape). I have not completed everything I need for this to work, so no pictures yet.
With regards to the 4th axis endstops. Unless I am mistaking, you can place them at any height you want. The only thing RRF requires/assumes is that when the machine is homed on all axis, the (vertical) distance between the 4th axis endstop and the attachement point at the other end is the correct distance you specified in the config.g file. It as to assume this as there is no way to probe this similar to the actual printhead.
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@Nxt-1 said in Delta 4th axis length and limits?:
With regards to the 4th axis endstops. Unless I am mistaking, you can place them at any height you want. The only thing RRF requires/assumes is that when the machine is homed on all axis, the (vertical) distance between the 4th axis endstop and the attachement point at the other end is the correct distance you specified in the config.g file.
That's correct.
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@Munce31Here are some crude pictures I took yesterday. Sadly no video yet, I hope to get some things completed in the coming month or so before I make a clip.
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@Nxt-1 Wow! looks great. I'm surprised the stepper motor can handled all of that equipment on the one axis.
Just one question: Why not have the radiator and pump outside? Then you could close up the sides and retain more heat for warp-prone plastics.
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@Munce31 Well, the stepper motor cannot really handle the weight
At least not comfortably, if it is too cool in the room, the water cooling tubes are somewhat stiffer and that adds just enough resistance so the stepper cannot reliably function. This is also the reason I have not posted a video yet. As I said, I do plan to resolve this with the counterweight.There is no real reason the water cooling components are inside the build volume, just did even come up I guess. It is something to look into if I ever feel the need to enclose the machine.
