simple trick for leveling bed

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adamtimm1
Posts: 11
Joined: Sun Jan 14, 2018 9:28 pm

simple trick for leveling bed

Post by adamtimm1 » Sun Oct 21, 2018 8:28 pm

The only thing I hate about 3D printing is the obsessive compulsive nature required for leveling the print bed. As a woodworker I use jigs for everything and today it occurred to me to use one for the x-axis. Use a short piece of wood say 64 mm (about 2 inches) long to level the axis on both sides. Now without having to determine whether or not your eyes are failing because you live in a state that condones marijuana use :lol: you simply have to place the bottom of the wood piece on the aluminum part of your build tray, then turn down the drive rods until the 500 mm smooth rods of the x-axis touch the wood firmly without pushing down the aluminum plate below.

Do you remember 7th grade when the science assignment was to measure something with a yard stick and no one had the same measurement? This should take out the guess work. I realized this when I was printing 20 mm blocks. I am at an age where my vision is a bit slow but If I simply cut a 20 mm or so block and place it under the nozzle, I can adjust the build plate up or down as required. I can do it on both the two rear corners and the two front corners. Viola!

I have found that the thickness of business cards can vary from 0.27mm to 0.33 mm so unless you keep the same business card it will be difficult to achieve the same distance between the build plate and the nozzle. A feeler guage works very well but judging how tight the nozzle is pressing down on the build plate can be somewhat non specific. Using a block of a specified thickness which you know and lowering the nozzle to the block from either the LCD screen or the slicer 1mm at a time should give the perfect space from the build plate when the block is removed and the machine is homed-all. It should be an easy peasy to adjust your PEI sheet up or down as needed at the corners of the build plate and a level x-axis.

If someone wants to tell me that my idea is stupid I will take the criticism. Being wrong is a great way to learn. On the other hand I would like to cut down the time it takes to level my bed. Don't we all have better things to do?

kcchen_00
Posts: 1695
Joined: Thu Feb 19, 2015 12:42 am

Re: simple trick for leveling bed

Post by kcchen_00 » Mon Oct 22, 2018 12:15 am

Any idea to help with leveling the bed is worth consideration. :)

Using the aluminum plate is a good idea. Its a better reference than the table which the printer is resting on... since the y-rails sit on printed parts with heat inserts (which could vary). Using the LCD (I use Octoprint, and don't use the LCD much) to finalize the leveling is where I lose you... I guess if you're using the LCD to get the initial left hand corner (home position) height, then the right-hand lead screw to match the height of the wooden block... that would work. Well, as long as the block doesn't deflect or material doesn't compress.

My process is to finalize leveling the bed:
- To get the initial nozzle height start point, I start with feelers or a business card... specifically my business card (which I know I need a few turns on the z-endstop).
- Then (digital) dial-gauges on either side of the toolhead to ensure the print bed is level.
- To finalize the nozzle height, I print a set of calibration print to check for extrusion width consistency and "squash".
- The first calibration print is a pattern of concentric circles to check for a consistent extrusion width.
- The second is a 10x10x5mm square to look at the bottom and judge how I like the squash - the gap between extrusions. And evaluate top and bottom dimensions for deformations (elephants foot).

I usually stop there (the prints I make don't require that much precision, and some point ). But to get more precise, I've used the Z-offset G-code setting in my slicer (S3D). Then translate the offset value into # of turns or partial turns of the Z-endstop screw pitch (TAZ 5). I think its a M5 with a pitch of .8mm, which means half a turn is .4mm and quarter turn is .2mm... etc. Markings on the adjustment screw helps... I have a multi-colored thumbcap.



Sounds like you're on the right track with the jigs!

adamtimm1
Posts: 11
Joined: Sun Jan 14, 2018 9:28 pm

Re: simple trick for leveling bed

Post by adamtimm1 » Sun Jul 07, 2019 5:12 pm

For anyone reading this the point is that trying to line the "x" axis up with a "tick" mark on a mm ruler is a pain as you already know. When the axis just touches the "jig" you know it's where it needs to be and you can even feel it which means you don't have to rely strictly on your eyes. The absolute certainty that your X is level relative to the aluminum bed takes a lot of stress out of the bed leveling process.

adamtimm1
Posts: 11
Joined: Sun Jan 14, 2018 9:28 pm

Re: simple trick for leveling bed +spring constant

Post by adamtimm1 » Sun Jul 07, 2019 5:39 pm

The thing I don't like about a spring loaded bed leveling system is the inherent displacement of the springs brought on by heat and it's effect on the spring constant of the springs themselves. By example, if one wanted at one time to build a "low rider" you simply heated the springs till they were red hot. The problem is that the same spring constant which follows Hooks law, http://www.softschools.com/formulas/phy ... ormula/60/ can vary from one spring to another as they wear thus the frustration with keeping the bed level or having to replace the shocks in your truck or car.

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