Z-axis and end stop issues

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do-it-for-science-
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Z-axis and end stop issues

Post by do-it-for-science- » Tue Feb 24, 2015 3:59 pm

So first of all the kittaz is great, stout, and wonderfully documented. Everything went smoothly in the build and it took far less time than I anticipated that it would, about four hours of build time, perhaps a bit less. the only snag I encountered was a defunct power supply, but the wonderful people at Lulzbot quickly sent me a new one and I got everything up and running except a couple little hiccups.

-the Z-axis motor on the left side of the frame next to the electronics case does not want to turn, I can not tell if it is an issue with the stepper motor or if there is too much friction on that side, however it makes a horrible grinding noise when I try to move the z axis up or down.
-the other issue I am having is that when I try to home any of the axis they do not sense the end stops and just keep try to push the carriage along and the belts skip like mad while I franticly look for a stop button on pronterface. I am not sure how to check and see if it is a hardware issue or if there is a software issue or if it is wiring. I don't know how to check and see if the end stops are sending anything to the computer at all, is there a way to get into the raw data?

thank you for any advice you might have! I'll just keep trying to figure it out, but I thought the intelligent and experienced people of the Lulzbot community might have some ideas!
open source, open heart,

Jeff Hunt,
Renewable Energy Engineering student OIT

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Re: Z-axis and end stop issues

Post by mhackney » Tue Feb 24, 2015 4:13 pm

Cool, my KITTAZ is on the FEDEX truck and due to be delivered on Thursday. I'm collecting the various upgrade components for later. The only non-stock thing I'll do on the initial build are stepper dampers (I love these things, much quieter machine).

Question on the documentation, did you use one of the online build manuals or did something come with the kit?

On the Z stepper, one quick test to eliminate the driver or a firmware misconfiguration is to swap the Z1 and Z2 connectors on the RAMBo. Please make sure to unplug first so you don't do nasty things to the RAMBo. If the same thing occurs on the same side, then it is likely the stepper or something mechanical as you surmised. I suspect it is mechanical binding. With the machine powered down, you can slowly turn the screws by hand on each side (of course you will then have to re-calibrate the Z steppers) and feel for roughness or tightness.


The homing issue sounds like you may have the stops miswired. I'm assuming that the RAMBo is already loaded with a configured Marlin, is that correct? If so, then it is probably wiring related. If not (i.e. you have to compile and upload Marlin to RAMBo, you could have an endstop misconfiguration). Each axis has a Min and a Max connector on the RAMBo. Could it be as simple as you connected to the wrong set?

Prontorface doesn't have an e-stop button unfortunately.

There is M119 to get endstop status. You can learn about it and all the other supported Marlin g- and m- codes here: http://reprap.org/wiki/G-code

M119 is excellent to use to diagnose exactly these sorts of issues.
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Re: Z-axis and end stop issues

Post by do-it-for-science- » Wed Feb 25, 2015 6:58 pm

mhackney,

greetings, first I want to say that I admire your work.

secondly, I am so exited to see a community (small be it though), springing up around the KitTaz. I think that building the thing from near ground up give you such an excellent feel for how the printer mechanically goes together and gives, at least me, much more grandiose ideas about how I am going to modify and upgrade it in the coming months. I'll have to check out the dampeners, they look like a nice upgrade. so far (and I know I'm not even done calibrating, but I cant stop myself, Upgrade all the things!) all I have done is put a PEI sheet on it and hook up a raspberry pi for octoprint. soon though I plan on building an integrated box with heating and ventilation, ordering some metal bearing for all of the linear movement or perhaps going with linear motion rails in place of the smooth rods, still more research to do, and then of course dual head printing and flexstruder. also I'll eventually upgrade my pi to a bbBlack just for the sake of keeping the entire build as open source as possible.
as far as the build instructions, I used the online guide from ohai-kit and that is it. there were a few confusing spots, but not enough to make me stop and take note, I worked through them quickly.
thank you for the advice on the stepper problems, I'll try that on monday.
and as far as the end stops go, I am 80% sure you are spot on, I was blazing through the build and so it is entirely likely that I swapped the end stops and just need to switch the X and Y end stop plugs on the Rambo board.
also, Prontorface needs an E-stop fo-real!
thank you for the heads of on M119 that is just the thing I was looking for!

peace be to you,
Jeff Ironwood-Hunt
open source, open heart,

Jeff Hunt,
Renewable Energy Engineering student OIT

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Re: Z-axis and end stop issues

Post by Orias » Thu Feb 26, 2015 1:37 pm

also, Prontorface needs an E-stop fo-real!
Don't forget that commands and button presses in Pronterface stack, so anything you send now, won't be processed until after the commands that are in memory are processed. for an E-stop type situation, turn the printer off using the power switch. Your print will not be recoverable, but...

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Re: Z-axis and end stop issues

Post by do-it-for-science- » Thu Feb 26, 2015 2:23 pm

I think that as the speed and power and multi functionality of the reprap machines increase the need for a quickly accessible E-stop will only increase. the potential to damage the machine or even the operator will become a reality, if not already, in the near future.
I don't have any skill in the software side of things as of yet but I wonder how difficult it would be to integrate a "big red button" into the design that would pause everything regardless of what was going on at the moment. no stacking, just bypass everything and stop, but without powering down. not sure if it would be very useful in situations where an e-stop would be necessary except to see what part of the G code was executing at the time in order of trouble shoot it.

have a great day!
Jeff Ironwood-Hunt
open source, open heart,

Jeff Hunt,
Renewable Energy Engineering student OIT

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