3D printer bed leveling

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PartierSP
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Re: 3D printer bed leveling

Post by PartierSP » Sunday 19th December 2021 1:12am

Here is the a shot of the bottom side. The one chip shown there does the USB to Serial communications for the board. Since my board did not have any proper solder mask, it was a bugger to get soldered on properly. At the top of the board are the traces that handle the current for the heated bed and hot end. It was recommended to add plenty of extra solder to assist with the high current.
Bottom side of Controller
Bottom side of Controller
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Here is a view of the bottom of the bed support. You can see the wing nuts and springs used to support the bed and allow for tramming. Its not completed yet. I was still working on making bushings or ordering linear bushings. I didn't make up my mind what I was going to do as original linear bearings were dang pricey. But looking on line I could probably pick something up for a decent price.
Bottom view of the bed support.
Bottom view of the bed support.
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Here is a close up of the extruder. Its a simple 3D printed extruder using herringbone gears. Personally I liked the look of the gears and thought it would add a bit of steam punk look to it.
Extruder
Extruder
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PartierSP
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Re: 3D printer bed leveling

Post by PartierSP » Sunday 19th December 2021 1:28am

In reference to the pic you posted of your end stop, my Ender uses the exact same end stop as your CR-10. All the way down to the circuit board and mount. It makes sense that Creative uses the same components for their entire line of printers.

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stevedee
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Re: 3D printer bed leveling

Post by stevedee » Sunday 19th December 2021 10:24am

Wow! Brilliant work Mike!

I do hope you find the time to complete this project, and maybe compare its performance with your Creality Ender.
But I know how difficult it is to find time for long term projects, with so may other demands on your time.

I have to confess that I have not used my printer since mid-October, and even then I was just demonstrating it to a mate that came over one evening. I haven't been able to find anything I wanted to print during the last couple of months.

PartierSP wrote:
Sunday 19th December 2021 1:28am
...It makes sense that Creative uses the same components for their entire line of printers.
I thought Creative made sound cards! :lol:

Those little micro-switches seem to do the job, its just that I would have thought the repeatability and hysteresis would have affected Z-zero, the very thing that needs to be spot-on. Also, I should imagine opto-source/sensor arrangements come with their own set of issues due to light-scatter, and maybe variations in sensitivity. Another consideration is how to ensure that if the motor drives through the detection point, the motor doesn't then get switched back on and damage something. At least with a micro-switch, once its operated, it stays operated. I also assume that they are wired in a relatively fail-safe manner, i.e. switch "open" stops the motor rather than "closed".

Your frame is a work of art (even the cat thinks so!). What is at the heart of your controller (...Arduino maybe?).

I'm really not sure about using wing-nuts for adjusting the bed, but I guess you are limited on space. The adjusters on my printer are at least 2" in diameter, and I still need a very gentle touch to make fine adjustments. I can't remember very much about screw threads from my days as an apprentice (...seem to remember UNF were the finest pitch) but I guess the finer the better.

Yep, I like the Steam Punk extruder gears too. I've no idea what the considerations are regarding wear.

Keep up the good work!

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Re: 3D printer bed leveling

Post by PartierSP » Sunday 19th December 2021 10:21pm

stevedee wrote:
Sunday 19th December 2021 10:24am
Wow! Brilliant work Mike!

I do hope you find the time to complete this project, and maybe compare its performance with your Creality Ender.
But I know how difficult it is to find time for long term projects, with so may other demands on your time.
Thanks. A lot of hours have gone into it so far. The frame and all the plates are made with Stainless Steel. Except for the floating portion of the bed. That's aluminium. The stainless didn't do me any favours as it can be a bugger to work with. But it also welds so nicely.
I have to confess that I have not used my printer since mid-October, and even then I was just demonstrating it to a mate that came over one evening. I haven't been able to find anything I wanted to print during the last couple of months.
Yeah I wonder where I will be with it in another 6 months. Hopefully still at it. Right now I've got a couple of projects I'd like to try for my DSL and for my telescope. I found this Bokeh Mask on Thingiverse and gave it a print. Its a cool effect but would like to remix the design to work better (falls off too easily and the masks drop out if you move the camera). I'd also want to mount a camera to my telescope. It'll make it easier to show the kids the planets if we can do camping this summer.
I thought Creative made sound cards! :lol:
I know right! :P
Those little micro-switches seem to do the job, its just that I would have thought the repeatability and hysteresis would have affected Z-zero, the very thing that needs to be spot-on. Also, I should imagine opto-source/sensor arrangements come with their own set of issues due to light-scatter, and maybe variations in sensitivity. Another consideration is how to ensure that if the motor drives through the detection point, the motor doesn't then get switched back on and damage something. At least with a micro-switch, once its operated, it stays operated. I also assume that they are wired in a relatively fail-safe manner, i.e. switch "open" stops the motor rather than "closed".
Well technically the way Creative mounted these limit switches are wrong. You never want your flag to come down onto your switch. It should move across it. This way if the switch is not set properly, or say a motor/actuator is wired backwards, or the response time of your actuator is slow, you never crush your switch. But this orientation they are using will give them better response from these type of switches.

[/quote]Your frame is a work of art (even the cat thinks so!). What is at the heart of your controller (...Arduino maybe?).[/quote]I enjoyed working on that frame. I cut and coped all the tubes by hand in the mill. I had to make an aluminium insert to stabilize them as I did this. Otherwise the sides would just bend and be a mess. I was really pleased how they turned out. The plates were all cut on a CNC mill. I just took all my CAD drawings and imported them into BobCAD (think Cura for machinist ;) ). I used our TIG welder to weld the frame. I had a horrible time with the tubes. They are SO THIN! :( I originally was going to to complete welds all around each joint. But I was having so much trouble I just stitched welded them in stead. Now that I have a few more years of practice on that welder, I wonder if I can do a better job or not. I think its best to leave sleeping dogs lie.

The controller is a ATMEGA 128 (I think) which if memory serves me is what's used on the Arduino Mega. Its just this chip does not have the Arduino boot loader installed on it. This Arduino program allows users to store programs on the chip without needing to play with the chip's 'fuses'. Thus the Arduino code makes it more convenient for the average person to program these chips at the expense of some lost memory. And Merlin doesn't rely on the Arduino code so its not there. But otherwise its the same chip and has a lot of similarities to the design of the Arduino Uno/Mega boards.

Our Creative boards don't use ATMEGA based boards. The ATMEGA are slower. So I will be limited in the half stepping I due for the steppers. Essentially these stepper motors take 200 pulses to rotate one full turn. But using half/quarter/etc stepping technique, you can increase that by 2x, 4x, 8x, etc. This produces smaller motion per pulse and also reduces the motor's noise levels.
I'm really not sure about using wing-nuts for adjusting the bed, but I guess you are limited on space. The adjusters on my printer are at least 2" in diameter, and I still need a very gentle touch to make fine adjustments. I can't remember very much about screw threads from my days as an apprentice (...seem to remember UNF were the finest pitch) but I guess the finer the better.
Yes after working with my Ender, I think this will be an area that will need improvement.

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Re: 3D printer bed leveling

Post by PartierSP » Monday 20th December 2021 5:25am

I think I used 1/4-20 UNC screws and wing nuts for the adjustment. This will give me about 1.27mm of height adjustment per revolution. I probably will need to replace them with 1/4-28 UNF or maybe even 10-32 UNF. They would give me 0.91 or 0.79mm adjustment respectfully. I'm not sure what they used on my Ender, I expect they are 1mm pitch or less. They are a pretty small diameter screw.

The thing I don't like about the ones on my Ender is that they are a pretty light spring holding everything up. Mine are significantly stiffer. But I'm wondering if they did that in case you crash into the bed with the head. The springs would absorb the impact so nothing else gets damaged. After seeing how easily I scratched my printing surface that came with the Ender I wouldn't be surprised if this is the idea behind that. I also think a stronger spring would make the adjusting knobs easier to control as they move to the slightest touch right now.

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stevedee
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Re: 3D printer bed leveling

Post by stevedee » Monday 20th December 2021 3:15pm

PartierSP wrote:
Sunday 19th December 2021 10:21pm
...Yeah I wonder where I will be with it in another 6 months. Hopefully still at it...
I'm sure you will be. You seem to be a very keen and active Maker.

A few years ago I'm sure I would have found plenty of use for my printer, but I seem to have lost much of my enthusiasm. I think my chemo sessions have knocked the stuffing out of me, but who knows, I may get back to it in 2022.

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stevedee
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Re: 3D printer bed leveling

Post by stevedee » Monday 20th December 2021 4:01pm

PartierSP wrote:
Monday 20th December 2021 5:25am
I think I used 1/4-20 UNC screws and wing nuts for the adjustment. This will give me about 1.27mm of height adjustment per revolution. I probably will need to replace them with 1/4-28 UNF or maybe even 10-32 UNF. They would give me 0.91 or 0.79mm adjustment respectfully. I'm not sure what they used on my Ender, I expect they are 1mm pitch or less. They are a pretty small diameter screw.
The screw diameter on my CR10 is 4mm. The photo below may give some clue to the pitch.
The thing I don't like about the ones on my Ender is that they are a pretty light spring holding everything up. Mine are significantly stiffer. But I'm wondering if they did that in case you crash into the bed with the head. The springs would absorb the impact so nothing else gets damaged. After seeing how easily I scratched my printing surface that came with the Ender I wouldn't be surprised if this is the idea behind that. I also think a stronger spring would make the adjusting knobs easier to control as they move to the slightest touch right now.
I think I'd prefer soft springs, rather than risk more severe damage to the bed, nozzle, or extruder assembly.

When is a scratch, not a scratch?

Several times, in the early days, I thought I'd scratched my nice glass bed during bed-leveling. Do you remember that bead of cold PLA I mentioned in an earlier post?

It turns out that I'd simply made a PLA mark. These PLA marks were quite tricky to remove, but by cleaning the bed with IPA, I think most of them have now gone (Memo to self: check next time I pass the Man Cave).

Is a brass nozzle hard enough to scratch glass? ...I'm not sure, but I suspect you have the answer.
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Re: 3D printer bed leveling

Post by PartierSP » Tuesday 21st December 2021 8:21am

If that is a standard M4 thread, then it would have a pitch of 0.7mm (which looks about right based on your photo). So I'm looking at about double the travel per rotation on the set up I have now.

I don't expect you'd be able to scratch a glass bed with a brass nozzle. Break it, yes. But scratch no. Brass is way too soft. That's why its used for mallets. Brass is heavy but soft enough that it wont damage steel. Copper and Aluminium are even softer still, but they wouldn't stand up to wearing from running over the extruded plastic let alone having the plastic extrude through it.

I wonder how Bronze would stand up. I'd have to check to see it's thermal conductivity but it should be in the range of brass. Its slightly harder then Brass but has much higher wear resistance. There's probably a good reason they don't make them for 3D printers. Yes they'd be more expensive (both material costs and also manufacturing costs), but I can't see it being by much. Bronze is used as bearing surfaces in stead of using roller bearings. Under the right conditions, a proper Bronze bearing will give you less resistance then a standard roller bearing.

edit: Thermal conductivity Brass vs Bronze are about equal. So I really don't know why they don't use it. Probably doesn't stand up much better then Brass.

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Re: 3D printer bed leveling

Post by PartierSP » Tuesday 21st December 2021 8:53am

Ok I just went down an internet rabbit hole filled with 3D printer nozzles. :shock:

Backing up a bit tho...When you showed me that worn nozzle on your website, jokingly my mind immediately went to "Why don't they make them out of tungsten carbide?" hehe. I use tungsten carbide tools all the time to cut steel (even use it to cut hardened tools). And well guess what, yep, they sell tungsten carbide nozzles. I'm sure one nozzle would last you a long time. Just don't hit your glass bed...it WILL scratch the glass!

I'm sure if you don't crack one of these Carbide nozzles, it would last a LONG time. Carbide tends to be more like glass then steel. Very hard but brittle.

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