Worried about the 6 to 7 second X homing death rattle

I know the SV06 detects home positions by hitting the physical end stops. But is it normal that the procedure takes this long? It can’t be good for the longevity of the machine.

I got my machine on 12/18/22 from Amazon.

I have the same issue but it just fails to autohome after that time

No its not normal - Tighten your X-Axis belt - the stop should be firm and instant…if it grinds while homing - the belts should be tightened or you should increase (increase sensitivity) the value in the config menu for senseless homing.

Belt is already super tight. I noticed that in some operations it’s just a short blip. When starting a new print though, it goes for up to 10 seconds. I suspect something mechanical, but will look for the setting. Thanks for helping out. I’ll report back when I have something that works for me. Other than that, I am a happy camper - great printer for the money.

Actually, it is normal. The TMC steppers are using the “roof knock” or more officially referred to as “Sensorless Homing” to make up for minor inconsistencies in the horizontal leveling. It’s much like the old Commodore 1541 Floppy disk that used the track 0 stop to realign the heads after a disk change. In my experience over the last month, I’ve only needed to perform the operation 2 times - the first taking around 9 seconds before continuing and the second taking around 2 since it was still pretty well aligned, with over 11 filament changes and power cycles. You will also notice that you get a bit of a rattle in the X and Y planes when hitting limits as the drives use the stall guard feature to detect the physical limits in the horizontal plane of motion.

However, if you have a major difference between the two sides, you may need to go a bit more medieval on the lead screw(s) as Aurora Tech discusses here -

That may clear things up and allow the roof knock to take a more normal 2-3 seconds with your unit.

One additional consideration that I uncovered - my bench was not 4-square level (like that table in the restaurant that you have to put folded napkins under one leg to stop rocking) where I had the SV06 sitting and that gave me fits on anything outside of the center 80mm x 80mm print zone. Fixing that allowed me to use the entire print bad successfully.

Disclaimer - I’m probably more “new” to all of this 3D printing stuff than many of you, and I am just reporting my observations and experiences based on 46 years of mechanical and electronics engineering experience. I will gladly admit if I’ve made a mistake because of that

1 Like

Starting with a Datasette and then switching to a 1541 I know what you are talking about :wink: There is a lot of good information in your post. Much appreciated. When setting up for the first time, I noticed that only three of the four rubber feet were touching my workbench. So I’ll probably do a thorough examination of the mechanical setup in the next couple of days.

Wow - you got the trifecta - the 1541 alignment scare, potentially misaligned lead screws - AND an unlevel work surface. It’s fun getting old, huh!

Good luck and let us know how you turn out.

In advanced settings, TMC drivers, the default setting is 65. Try 67 or 68 for x. I don’t think we should have to do this but each stepper motor is slightly different in sensitivity.

1 Like

everyone commenting here is wrong, go to your printer, see your bed cable? yea it’s under the bed isn’t it? move it outside the square in the back of the printer. problem solved. so funny to see everyone get all ‘technical’ i’ve been reading like 1/5 of forums all have the same problem describing it different ways, but it’s all just the cable. ya see the cable being in the way offsets the bed and then the printer thinks the bed area is in a different place so it grinds itself against the gantry.

What you describe MAY be an issue is corner cases, but the 6-10 second “death rattle” is normal for aligning the two screws to keep the X axis level and square with the top of the frame (which SHOULD be parallel with the bed).

This is normal. I repeat - this is normal and part of the design. The process is:

Go to the sensor Z access stop
Continue driving both sides into the stops built into the frame top for 4-10 seconds

Why? If the two sides of the Z access are not level, the side that is low will continue turning until it also hits the gantry frame point on its side. At this point, the X axis rail is now level/perpendicular to the bed.

BTW - I’ve been designing synchro/servo systems since 1984, so this is not a guess.


Why then does it continue to exhibit this behaviour until the warning comes up to reset the printer? I’ve power cycled 20 times today already. Nothing is out of line. The last time I printed was yesterday where the printert did a fine job of an intricate desigh. Today, turn it on and do an auto level and all I get is loud buzzing in X-axis, enough to wake the neighbours. It sounds like a jack-hammer. Tried the homing settings, had them all over the place, from 50 to 100, with no change.