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Paul Murphy

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See that unevenness on x and y. I would have thought that was stack belts, but they seem pretty tight. PLA. This is a moving bed (x) printer.

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The uneven sides seems like it would be insufficient belt tension. Is that right? X and y seem pretty tight....

Hi all,

I have a new bike with Shimano gears. I am adjusting the front derailleur (three cog), and adjusting the h stop to get the outside edge of the cage as close as I can to the chain when on the biggest cog.

I have tightened it as far as it will go, but it is still around 4mm away. Do I need to move the whole mechanism over a bit or is there something else I should do?

The inside of the cage lines up nicely with the small cog using the other stop.

I modified my Little Monster X axis to use rails instead of wheels.

I cleverly took hardly any photos. Mostly because I was figuring it out as I went - I didn't have a design as such. I can get photos and details if anyone is interested.

The benefit is that it is now silky smooth. But also, because I built a frame to attach to the linear bearings, I am using compression springs to mount the aluminium bed and so I can level it now.

My printer has the z gantry supported only on one side. I am planning to add a second leadscrew at the other end, with a timing belt connected to the current z stepper.

There doesn't seem much chance I am going to get this to be exactly at a distance that would make a standard timing belt the right length. And I have read that cutting and joining them is difficult - no surprise.

What would be the right way to tension the belt while still having a continuous loop? Would you have an idler in the loop that is adjustable to "push out" the belt to tighten it?

+ANTCLABS Hi, could you give me some advice. I am trying to work out if my bltouch needs adjusting or something else isn't right.

What I am doing is G28 to home everything. I have SAFE_HOME on (this is Marlin 1.1 rc7 on RAMPS 1.4) so my home is the centre of the bed. Then I do Z0 and adjust Z until it is paper thickness to the bed. Then this becomes my zoffset. I set it with M851 and save with M500. I even reboot RAMPS to make sure it is set correctly and saved. But next time I home, the zoffset is off by -0.19 mm, or a similar amount. Some times it is fine. Over a the course of a few days, I might need to adjust it more than 1mm from its original offset, then suddenly it needs a positive adjustment.

The hotend and nozzle are attached to the same aluminium plate, so they cannot actually be moving relative to each other.

The rod is clean, and the action seems to be right. The nozzle/bltouch offset is ~8mm as per spec, and the nozzle is 19mm away along the x axis, and inline on y.

Any tips?

I have a bltouch that works well, except that I seem to need to adjust the z-offset a lot.

For example, I'll G28 Z in the middle of the bed, then G1 Z0 and then apply a z-offset that puts the nozzle paper width above the bed. If I G28, and go back to the middle of the bed and Z0, the nozzle ends up where I expect. M500 to save.

But then if I print something, and check this again, I find that I need to set z-offset again. Sometimes adjusting by .5 mm up or down.

I am struggling to understand how this can be. It seems to me that no matter how messed up my bed is, the distance between the bltouch and the nozzle tip should be static. They are both solidly connected to the same aluminium plate - there isn't that much give.

Is there something I am not understanding about this? How can it vary?

Is the most likely reason for my ramps 1.4 rebooting mid-print a lack of power?

I have a usb desk fan pointing right at it too cool the capacitors and anything else that might get hot, but perhaps that is not enough and it is a thermal thing.

The Octoprint logs just say contact was lost - I am not sure where to look for diagnostic info.

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Is this corruption on the bow still a cooling issue? It looked pretty much like this before I added a proper part cooler.

My printer has a (moving) 250mm x 290mm aluminium plate at the base - this is not flat, it has screws in the middle of it.

Currently I have a 214mm x 214mm PCB heated bed, with a glass sheet of similar size on top, and a layer of cork board between the PCB and the aluminium. So:

Aluminium -> Cork -> PCB -> Glass

This is all sitting on top of each other, with foldback clips holding everything together. No levelling (I am using bltouch to deal with the lack of levelling right now). So the build area is maybe 190x190mm taking into account the clips encroachment.

I'd like to do two things - put in proper levelling, and increase the build area.

I am hoping for some advice as to a good approach. I can drill three points into the alum plate, and so add some levelling screws/springs.

But I am not sure on what to do next. If I want to use the existing PCB heater, then I'd need an aluminium spreader. So lets say I get a 250x250x3mm aluminium sheet. I can mount that on the three points, and put a 250x250mmm glass sheet on top of that, but I still need to somehow get the heater to affix to the underside of it.

And then I am wondering if two alum plates + glass + PCB is going to be too much for the NEMA17 + belt that moves the bed back and forth.

I am thinking that none of this is new, and so you might be able to give some tips?
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