Layer shift on Y axis

I’ve been printing only one model with my X5 and the parts were coming out reliably. All of a sudden, there was a layer shift in the Y axis about 0.5-1mm. Everything else in the part was normal except a small step in it.

I had not loaded a new model for a week, so the code was the same as when it was coming out correctly. I’m thinking that this might be a problem with the physical Y axis. I turned off the machine and moved the Y axis back and forth and everything seems fine. The belt is moving properly, except that during printing, at the same exact layer height, the axis shifts… not at any other height.

Before I start going in and taking things apart, does anyone know what this problem could be?

On the one hand I thought the problem could be the code, but then how could this happen to a print that I was running all week?
On the other hand, I thought the problem could be with the belt, but then how could this only happen at one layer height only once during the print?

Update:

I updated the software on the machine from 1.4.7 to 1.4.9, but to no avail. Still same exact problem at same exact layer height.

The print worked at first, but when I added the parts to be printed using the machine’s touch screen, that’s when the problem seems to happen.

In summary:

  1. The first print that printed from my computer using Up Studio came out fine
  2. I printed 4 more of the same unit from selecting the print jobs from the touch screen on the machine and they all had the step problem in the print at the same layer height.

Also, it was the same layer height as with the older version.

Update:

I updated Up Studio to the latest version which came out earlier this week and ran the X5 on the product I was having issues with.

I ran:
Batch of 3 - no issues
then Batch of 5 - no issues
Batch of 10 - no issues
Batch of 10 - 2 layer shifts
Batch of 10 - 4 layer shifts (one of the layer shifts was at a different layer height)

At this point I’m thinking the stepper motor may have a slight issue and needs replacement. Running a couple prints, the stepper motor can handle it, but doing many prints it may not be able to hold up.

Update:

I contacted Tiertime support and they got back to me the next day. Here’s what they wrote:

could be the speed is a little too high when printing thin features.
The print head has rapid back and forth movement will printing the infill. You may try slow the print speed entirely or specifically decrease infill speed or acceleration for parts that has thin wall features.

The parts I am printing do have 2mm thick walls (which would be the thin features), so I slowed down the speed from “normal” to “fine”.

The result was really good. At his point I’ve printed several 10 piece batches and have gotten only 1 defect (layer shift in a part). The defect happened on the last part in a 10 part batch… which leads me to believe it definitely has to do with the stepper motor performance. Perhaps it’s getting too hot. A solution may be to let the machine shut down and cool off for a few hours after running each batch. Or perhaps in the future they can offer higher performance stepper motors.