GCC Spirit LS x-axis freezing on boot

[Andy Evans]

Hi all,

I'm not able to get my Spirit to boot and saw some good advice being offered here previously and thought I'd give it a shot.

The issue seems to be with the x-axis. When I switch the machine on, it will boot normally up to the point where it starts to move the x-axis, then it will travel for about 3cm and stop, then nothing else happens. The same thing happened about a year ago, but after some basic cleaning and moving stuff around, it started worked again.

I figured this would be because of a problem with the motion system and checked and cleaned everything, and oiled all bearings. I found that one of the bearings on the tension pulley was pretty badly seized (clicking when rotated), but it became much smoother after I oiled it (but maybe not 100% good). But the problem still persists.

I can boot into the test mode after holding down the auto-focus key and I am able to move the x-axis using this - but the motion looks a little jerky and laboured.

I've checked every test and they are all fine, the limit switches respond as normal.

Could it be this one tension shaft bearing causing the boot process to lock up? It seems strange that it would stop working altogether when presumably its performance must have been poor for a while, and now it moves reasonably fluidly after oiling. Plus, isn't it normal for the unit to display a motor error if the motion system is impaired?

Thanks for any advice. I've called support from the place I purchased it in the UK, but as usual with them, no one is calling me back, and it normally takes a couple of weeks to get an engineer to visit (by which time I will be half out of business! - I've always been forced to fix issues myself in the past due to this).

[Richard Rumancik]

. . . I found that one of the bearings on the tension pulley was pretty badly seized (clicking when rotated), but it became much smoother after I oiled it (but maybe not 100% good). But the problem still persists. . . .

So you think that the bad bearing is good enough that it will/should operate? Maybe . . . I assume that you plan to replace the bearing right away. Hard to guess how much resistance it is causing. I don't know what kind of feedback loop is present but if it detects (for example) that the drive current is too high for the resultant motion perhaps it is giving up and shutting down to protect the x-driver.

On this machine you can move the carriage in the x and y manually in unpowered condition, correct? If so, what are you feeling when you move in the x and then in the y? Do they act the same or is one axis showing more resistance?

Is there some way of disconnecting the x-pulley and let it slip on the motor shaft (or remove the belt entirely?) In this case the friction would be gone. You should be ready to trip the end switch manually in order to stop the motion at the end of your test (otherwise the motor may turn indefinitely trying to find the switch.) So think this through before you try it. It seems to me that if the pulleys are out of the loop and only the motor is turning then you will be able to identify the cause. If the motor is happy with no load (ie. turns indefinitely trying to home) then there is too much drag in the bearings. But if it stops after a few seconds with no load then it would seem to be the motor or driver. Just my thoughts.

[Martin Reynolds]

You might try reseating the motor connectors. If the rotational sensor is not reading correctly, you'll get that symptom.

[Andy Evans]

Thank you for the reply Richard, all good advice.

Unfortunately/fortunately I must make this an embarrassing 'note to self' - always check that the emergency stop button is not set before you dismantle your machine! Turns out that the earlier Spirit models didn't inform you that the stop is down :/ The x-axis halting after a couple of cm is a sign of this, apparently.

At least this has allowed me to swap the x servo with the y to balance the workload a bit (I cut 99% of my work raster) and I've identified a bearing that needs replaced!