exxos blog - random goings on

[exxos]

The BIQU printer was under the knife earlier as well.

Trying to work out if I could fix the linear rails directly side bracket things. Seems not as the bolts stick out, and don't fit etc

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After much duckduckgo'ing, it seems how others do it, is to have some L brackets which bolts on the back of the X-bar which allows the linear rails to bolt on top of it...

EG

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So had to order the brackets

Which then leads me onto the Z-axis "fix".

First off to remove the bars and fit the longer ones..

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To change the corner block for one which sits lower down so it aligns with the tensioner thing.

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Now people know why I wanted a longer belt..

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[exxos]

So this went from bad to worse fast!

The L-brackets came

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Where the holes didn't align to my bar Carried on anyway..

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Then the carriage plate adapter didn't align

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So did some metal editing..

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Then the carriage bracket didn't fit the bar either

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Thought I would slide the slidey thing off the bar and use it as a template to drill some holes , when loads of bearings fell out

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Now ordering the correct size bar... Hopefully it will come tomorrow.

[exxos]

New bar arrived this morning. So been busy trying to figure out how to get it all to fit together. This all literally took me 12 hours straight


First problem is of no surprise. This slidey bit was too wide, so I had to move the whole mechanism forward on some nuts and washers.

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I moved the L brackets to the front because I could space them out better this way.

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Next problem was finding more bolts to fit the idler mechanism. Also spacing that forward.

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Now I needed to flip the drive gear on the motor which proved practically impossible to undo the grub screws I eventually managed to get one of them three but the other one must have been rammed in there so hard at manufacturer it was just simply never going to come out. Basically I ended up just bashing the thing until it came off. It looked like it was plastic but it is as strong as metal.


Thankfully I had a spare which was the right size anyway.

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The problem with the head bracket is that it physically fits to far forwards now.So I could not use the clamp for the belt any more I ended up using the hole from the bottom idler wheel and placing a bolt there. I hacksawed a spare bracket down and clamped that to the bolt.

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The next problem was there was no way to clamp the belt onto this new plate. So I just had to order a longer belt. Then I can wrap it around and simply cable tie it together so it cannot move.

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Currently this is where we are at.

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The head is now mounted back on. I just need the belt to come tomorrow so I can hook up the X-axis again. I also need the Z-sync belt to come yet.

I have a new magnetic bed *somewhere* which I also need to swap out. Hopefully this will solve the two biggest problems with the printer overall.

[exxos]

The sync belt just come. If anything it is a fraction too long, but I do have a shorter one on order from China. This one is still very much usable. I'm not going to fit it properly just yet as I need to power on the motors to synchronise them properly and not at a point of doing that yet.

Amazon's "get it by tomorrow by 1pm" has let me down. Now it is not even dispatched and classed as arriving tomorrow by 10pm. So yet another let down by companies I'm not at home tomorrow, so assume it will be here Thursday when I am back at home.

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[exxos]

Managed to get it all back together and synced up and level. The x motor was stuck on some odd plastic pillars inside the motor cover. No idea why they are there but cut them off and x motor happy now.

The next problem is the x belt slipped I thought bending the belt on itself , that the teeth would lock the belt when cable tied together. But idea didn't work so ordered a proper belt clamp thing. Hope that will come in the morning. I'm pretty much ready now to start a calibration cube!

Been busy working on the wiki code all day. But hands are complaining now but I've been working on some bbcodes to port my website content over to the wiki easier. It's a bit of a nightmare overall as the forum has very limited formatting options. I've got a kind of mash up between phpbb stuff and my external pages which are emulation my websites HTML pages. While content can be edited on the forum, the pages don't display correctly because of all the custom stuff I've hacked in. But it displays fine on the external wiki pages.

Probably the most annoying thing is converting HTML tables over to bbcodes. As even a simple CSS style attribute I've had to create a custom bbcode for. Custom size images were also a problem as the forum has them all fixed. Also all the downloads have to be uploaded to the forum and all the direct download URLs changed to forum download ids . I got Dawn to do that bit

So I think it's official we will have our own wiki. Just taking a while to write a mutant wiki engine

[exxos]

Started doing test prints which were not going to bad overall. But I have now rediscovered another problem I had right from the start.

There is not actually any physical end stop switches on this thing It seems to use some new fancy technology called "stallguard". Which in a way is a good feature has because if the head hits something like the print some reason, the printer will turn off or whatever. But it seems they are using the same function to detect when the "end stop" is hit. The problem is, it does not actually work. Because the movement across the axis is not taking exactly the same amount of "power" , when it hits a slight " intolerance" on the wheels or runners or whatever, it seems to think it has stalled and hit the "end stop" when in actual fact is nowhere near. The only way I can avoid this is to slacken off the belts to the point where it just then causes other problems

I tried upping the motor current, but this does not seem to help either. And I cannot simply disable the feature because there is no physical end stop switches to fall back on. So now I am messing about trying to see if there is anything in the firmware to do anything about this. But I am honestly at the end of my rope with this printer now. The thing just does not function properly and has way too many issues. If you just had proper end stop switches and I think I could really get this printer working properly. But this is always the case, that there is always "one more thing to fix" and it just perpetually never ends.

I'm pretty much thinking all these printers are like dealing with old cars. When you start having issues with them, it is just time to get rid of and just not bother. But that logic falls apart as I do not really think there is any decent printers out there that spending megabucks and they probably have their own issues anyway.

So just thought I would ask if anyone else has had dealings with this stallguard crap ? or knows if there is anyway to make it less sensitive at least ?

[exxos]

Hmmm

M914 - TMC Bump Sensitivity

https://marlinfw.org/docs/gcode/M914.html


EDIT:

SENT: M914
READ: X homing sensitivity: 100
READ: Y homing sensitivity: 100

Setting to 50 was a bad idea. But 80 seems to work fine and the X axis not "hits" the end stop (and stops) .

[Badwolf]

My gut feeling would be to lower the current to the motors rather than increase it (I figure it'd be a bigger relative difference when it hits something), but know as much about stepper motor drivers as I do about the quality control process on a breakfast cereal production line.

BW

[exxos]

My gut feeling would be to lower the current to the motors rather than increase it (I figure it'd be a bigger relative difference when it hits something), but know as much about stepper motor drivers as I do about the quality control process on a breakfast cereal production line.

I went from 1300 to 500mA and didn't change anything.

I will just fiddle with those sensitivity values until it stopped breaking down.

[exxos]

So this seems to be the values which work reliably.

Code: Select all

M914 X82 Y91

Though I just noticed on the motor current page, when I home the values change from 1000mA ( is currently set) but momentarily changes to 350mA on X, and 400mA on Y.. odd!

So maybe the " motor current" is actually the end stop current and not the actual " drive current"

So I put 200mA now it "grinds gears" when homing X

EDIT:

So I will just leave the motors on 500mA.. and M914 X85 Y92... gotta get on with other stuff anyway..

EDIT2:

Actually there is another problem with this stuff.. In that when the head "pulls" the filament from the real, sometimes it will inherently be harder than others and this could actually create a false "stall" due to the jerk on the real itself