D-Bot 3D Printer

[Dr_Ju_ju]

I was also having issues with auto bed levelling and wide variations on height across the bed, but with this system I'm down to +- 0.6 mm

[tekkydave]

I have yet to implement auto levelling on this printer. I haven't decided on proximity or servo/microswitch. Any thoughts?

[Dr_Ju_ju]

As you are going to be using a glass bed, I'd shy away from capacitive\inductive sensors as they won't have enough sensitivity with glass in the way (I was having fun just trying to get them to work through a PEI sheet), so I'd recommend using a BLTouch or its knock off variant the DLTouch, which will work with any surface, also in the latest Marlin firmware (1.1.5) all the code is built in, so just needs to be enabled, as long as you have enough 'spare pins' on the Arduino.

edit:

I forgot to add, I'm currently using an LJ12A3-4-Z/AX NPN NC device, it has an 8mm sensitivity range, but is still a little flaky through the PEI sheet, so I'll probably switch to a DLTouch when I upgrade the extruder, as I don't like the Bowden 

Edited September 17, 2017 by Dr_Ju_ju
Added info

[tekkydave]

Thanks, I'll have a look at those

 

[Dave_D]

If you're using 3 lead screws for the bed then surely autolevelling won't be an issue once it's all set up. can't speak for the coreXY design, but since i rebuilt my A8 using 2040, i've been using 15mm spacers between the bed and h-plate and haven't had to relevel the bed for going on 6 weeks now.

[tekkydave]

1 hour ago, Dave_D said:

If you're using 3 lead screws for the bed then surely autolevelling won't be an issue once it's all set up. can't speak for the coreXY design, but since i rebuilt my A8 using 2040, i've been using 15mm spacers between the bed and h-plate and haven't had to relevel the bed for going on 6 weeks now.

I'll have to see how it goes I think

 

[Gina]

I use inductive sensors on my 3D printers.  They have a range of 4mm so since the glass is already 3mm, metal (eg. kitchen foil) under the glass means the sensing would be very close to the glass.  I get round this by using patches of self adhesive copper foil on the top surface of the glass.  Of course, you could cover the bed with copper foil but I place around 20mm squares of foil just where the probe operates.  Using the Marlin auto-bed levelling routine works very well.  I use fast and slow probing with the second probing at a quarter of the speed of the first.  This provides very accurate auto levelling.  I use a 9 point grid which overcomes any curvature as well as levelness.

[Jamie16v]

I too have built the d-bot. Since changing the z axis to linear rail and linking the motors with a belt I have no need for auto bed levelling. It has to be the best mod I've done to the printer.

[tekkydave]

I discovered I had a complete servo/microswitch assembly left over from when I experimented with bowden on the Prusa. I printed a modified fan mounting to accomodate the assembly then fitted and wired it all in.

The orange coloured parts are the ones from the Prusa.

I have amended the Marlin config to suit and it just needs calibrating now.

I also assembled & fitted the power switch/SSR enclosure.

 

[Stub Mandrel]

LOL I like the idea of using a servo.

[tekkydave]

I have added an extra piece to support the front of the platform. This has allowed me to put wheels in all 4 corners of the platform to better support the weight. At the same time I have changed the 4-wheel carriages to 3-wheel. These are much easier to align. The carriages I used from Thingiverse also have an M3 bolt to adjust the tension. I have also moved the leadscrews to the centre of the platform as this is now the centre of gravity. I'm still considering an upgrade to a 3 leadscrew system  powered by a single motor.

 

[Gina]

My new 3D printers have the platform held at all four corners - works a treat   Also, means 2 wheel carriages are fine since they are not required to hold the platform level just correct in the XY plane.

[tekkydave]

Santa's bringing me one of these for Christmas (don't ask me how I know ) - Can't wait to go 32-bit and quieter stepper drivers etc. Will have to wait till Christmas to open it though .

I've also ordered one of these to try this new way of probing the bed. The servo arm with microswitch method I'm currently using just isn't reliable enough.

[Gina]

Interesting   I shall be interested to see if you find the 32bit processor any better.  I find the induction Z probes quite adequate - bed levelling works very well.  I too found servo arm and microswitch very unreliable too and gave up on that ages ago.

[tekkydave]

The Precision Piezo kit arrived so I spent this afternoon putting it together following their instructions on Youtube. Then connected it up to the DBot Ramps to calibrate and test. It only needs the standard 3 endstop wires (Gnd, +5v, Signal) and will work on 5v or 3.3v.

The video below shows the unit triggering (blue LED)

 

 

Edited December 2, 2017 by tekkydave

[Dave_D]

On 26/11/2017 at 11:56, tekkydave said:

Santa's bringing me one of these for Christmas (don't ask me how I know ) - Can't wait to go 32-bit and quieter stepper drivers etc. Will have to wait till Christmas to open it though .

hope we get a review of this... my extruder driver just turned it's toes up and of course being a cheapo chinese affair, the whole mobo is now useless :/

[tekkydave]

At some point, yes. I won't get my paws on it till Christmas Day so you will have to be patient

 

 

[Dave_D]

5 hours ago, tekkydave said:

At some point, yes. I won't get my paws on it till Christmas Day so you will have to be patient

 

 

well, i just pulled the trigger on one so it should be here in a day or 2... and now to play with the big boys

[Gina]

I've had no problem with the Arduino Mega - what difference will these microprocessors make?

[Dave_D]

should be a lot more future-proof than the atmega range (which to be honest is getting very long in the tooth now being only 8 bit) better drivers, better interface, better firmware etc etc etc...

[Gina]

But I'm thinking "If it ain't broke, don't fix it"   That part of my printers gives no problems.  Much more critical is the hardware.

[Dave_D]

5 minutes ago, Gina said:

But I'm thinking "If it ain't broke, don't fix it"   That part of my printers gives no problems.  Much more critical is the hardware.

mine IS broke though 

[Gina]

O-I-C

[Dr_Ju_ju]

... but if you want to make the most of your new 32 bit boards, and you use Marlin firmware, then you may need to use the 2.0 bugfix branch that now supports most of the newer boards, see https://github.com/MarlinFirmware/Marlin/tree/bugfix-2.0.x ....

[tekkydave]

Once I've had a chance to try it hopefully I can give a good reason to upgrade. I've read reviews on FaceBook of people who have switched from RAMPS to Duet. They say it is capable of higher speeds and are much quieter due to the TMC drivers.