Hello Instructables .

Today i want to share with u how i solved one of the common problems in 3D printing, mostly in DIY reprap printers like mine , which is the layers getting shifted.

So, like every one, I went online for answers, and as u might, know the common answer was Check the belt tension, Tighten the pulley correctly, Adjust the current of the motor

But what if u were like me, checking all that list with no improvement. Well, guess u might thing like i did and decide that some parts need change completely, then the next question will be: What part do i need to get rid of, and will it solve the problem

Well, to prevent u ending up like me buying a new set of stepper drivers, wasting money and discovering that i wasn't the problem, we will take steps to identify whether the problem is electrical or mechanical like mine

Step 1: IS It Electrical

So first to start with is the motor itself. First though i would like to note that in my case the shift happens at the very first layer, the one which will be completely filled with plastic, so if ur layers slip in the mid of printing, this wont be a typical way to find put the source of the problem. It is not harmful though to try with me :D

Now with the steps, Fist grab a marker and draw a straight line on the motor pulley, mine had a small grove in it so i didn't need to mark it, this mark will simply be as an indicator for the motor slippage in steps

Mark the bed where the tip of the extruder is standing with X as in the picture

NOTE : when the tip of the extrude is standing on the bed mark, the mark on the pulley should be vertical

Now home the Z-axis, open pronterface, on the direction wheel i want u to do the following fast and quickly, remember fast and quickly

push the motor 100mm to the right, 100mm to the left,100mm to the right, 100mm to the left again, don't wait for the motor to finish its move, I want to see whether the motor can with stand the inertial caused by the sudden direction change, u might as well try the 10mm to the left and to the right, as long as u make the extruder shake this means u r doing in correctly

Now for the results, look at the marked line on ur pulley

-Is it still vertical : if the answer is yes then congrats, ur motor and the current supplying it is fine

-If it is not : this means that ur motor is the problem

to solve it try adjusting the current to the motor and repeat the step for results

Step 2: Another Cause for the Last Setp Results

It is important to note here that if the mark on the pulley didn't return to its vertical position there is another reason for it than just the motor or the motor driver, which is the pulley it self

There might be a chance that the pulley isn't perfectly tightened on the motor shaft and caused it to slip like this, so go ahead and check for the pulley too

Step 3: Is It Mechanical

As u can see in the picture, my problem was obviously a mechanical one, and it wasn't a regular mechanical problem that u will simply find it's solution on the internet - or it is and i couldn't find it - more into that later

Now ... how to know if it's a mechanical problem, simply from step 1 results, if the mark on the pulley is vertical and the extruder tip is not back on the X mark u left on the bed then its a mechanical problem, and its cause is the belt or the bearing

So tighten ur belt and lubricate the rods for smooth movement and repeat the test in step 1

Step 4: A Special Type of Mechanical Problem

After finding the hard way that my problem was a mechanical one, i couldn't solve it with just a lubrication or belt tension, mine was a rather complicated one

Description : when i look at the belt around the pulley as the motor spins, i noticed a strange ups and downs movement of the belt, like if the pulley was eccentric or something, but of course the pulley was perfect, and I have to figure out what caused it to go up and down like this. In the end i came up with a conclusion which is : the belt's teeth some how skips the pulley teeth - honestly i still didn't figure out why it is doing this - and no mater how i tighten the belt it still skips

With that known i decided to make something that will keep the belt on the pulley without it skipping the teeth, as u can see in the picture - though ur motor housing might not be handy in doing this solution - i assembled some parts of an old printed objects to make what u can see in the picture as something just hugging the pulley

If u have a problem like this, try to think of a way to keep the belt on the pulley. Use old parts like i did

That's it for my problem guys .... than u and happy printing :D

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