@Artezio it might be that I’m not as strong as some people bit I also don’t want to push or pull it too hard and cause any damage to it lol.
But seeing as with the laser its creates perfect circles i think it is actually to do with this play as it needs to have an additional force to move the head in the play / wiggle direction. Hence this would only happen with the 3D print and CNC modules. 
@SophieSeal if it was bad it would be clunking back and forth just from moving along the rail, and would require no force from you to make it show any play. The play would also exist in the laser and cnc heads as well as the play is inside the rail and not the head. The extruder gears don’t really put extra stress on the rail at all, what’s inside the rail is a lead screw and an adjustable carriage slider, the carriage slider is what’s loosening but it’s not bad enough to justify opening the rail, which should only be done if Snapmaker tells you to open it. With laser doing perfect circles, you likely have a bad port on the 3D print head. I diagnosed this with extremely heavy detailed troubleshooting for someone else before, Snapmaker came to the same conclusion. You should update the firmware and see if it still happens, just to eliminate that as a possibility.
And yes it might not be as bad as some people, but you are now quantifying against other peoples issues, where as Im quantifying against the precision of the printer.
Also I always update and check the firmware every time before printing or using the snap maker.
I fully understand what your saying, but I still disagree with what you are concluding.
The wiggle in the head unit is not in the x direction its in a diagonal across it (Y/Z planes), therefore if it was pushing on a surface with enough resistance when the hot plate moves in the Y plane it causes the head to move in the diagonal causing the print nozel to be dragged off where it should be and therefore creating the flat spot on the sides of the circles.
The fact that the play is minimal means that it will only move a little, and also hence why it shows more prominently on doing smaller circles.
I have actually just found this on the SM page about play/looseness in the linear module and how to fix it?
A better circle test would’ve been one where the laser travels in a circle, instead of what’s in the picture - an image of a circle drawn horizontal lines.
The horizontal line method has the Y axis moving in the same direction, so the backlash is hidden.
The X axis does appear to not have backlash, but it’s hard to see because of the adjacent partially overlapping passes. A single line would be clearer.
Here’s when I did this with varying backlash compensation settings, you can see a distinct shift in the circle. In this case I had approximately 0.12mm of backlash in the X axis after a crash, worth correcting as normally it should be about 0.02mm.
That FAQ article you found would be the steps to follow if linear modules are found to be wobbling. I really don’t like how it’s phrased in the article, as it calls out numbers that are nearly impossible to measure. It’s more straightforward to adjust it until you can just barely insert the carriage between the rails (a small amount of preload required to force it in), but it rolls smoothly without effort once inserted. If there’s no force required to insert the carriage onto the rails then it will still have a small amount of slop.
I agree with Brent.
Lasering the circle at one round pass would give a better look.
I am not sure right now but I guess it’s vector mode to get circles like @brent113 .
@SophieSeal have you been able to figure it out?
Hey all sorry still working on this, things a little busy personally with work so not much time to play with the toys lol.
Iv been looking into the Backlash and reading up on this. I will run the single round pass test later when I get home or over the weekend.
Thanks again everyone for your support and help 
i love it when a community comes together.
Hi Sophie,
I am sorry for my late reply.
The engraving result seems to fine.
I uploaded a gccode here. Can you try to print it?
By the way, can you share your gcode and I will print it out? Thanks
Thanks Tracy, is this gcode Ill try this shortly as well. Just going to do the laser test tonight and then after Ill switch back and run this test.
And which one did you want me to share the circle i engraved or the buttons i was trying to print?
Hi Sophie, it is for printing. I am sorry that I did not mention it in my last reply. 
As you can see the gcode ending up with .gcode, so it can be only used for printing.
The gcode for laser engraving ends up with .nc. 
Can you share me the gcode of this one? Thanks
I just opened it up and saw it was a print, so was just editing my last reply.
And I never new that thanks thats really helpful to know.
I have added the gcode and the original button i was trying to print below.
button_white.stl (483.6 KB)
@brent113 @xchrisd
I have just tried doing two single line circles as suggested, and I got this result 
@Artezio with this new test result it changes my conclusion sorry for disagreeing with you earlier.
I think this might be the backlash you mentioned initially
@SophieSeal it’s not necessarily backlash, I was just explaining the backlash being a result of the innards of the rail and not the head. It’s still a possibility though. We will get this figured out for you and get you up and running again. The easy fix would be if it is a loose carriage, that’s what you want to be hoping for right now. Looking closely it’s as if it’s both the y axis and x axis are getting offset. I think I know what’s going on, and it seems to be happening more often lately. @Tracy what cable is interchangeable with the y cable going to the controller, it’s the tool head cable isn’t it?
@Tracy Iv finished printing the circle your gave. I have added some pictures below.
It still has a kind of flat side to it in the same places. It is also clear that it then trys to counter correct so it creates this like bulge.
I dont know what I should do now, any suggestions from anyone?
Thanks x
This is kind of a support issue.
There is a backlash test, but this is more like a work around if you are still on original settings…
Thanks, before I start this to find the back lash values, is there away to adjust the backlash values on the Snapmaker?
Or should I trying adjusting the eccentric nut on the carriage first?
Removing mechanical backlash by mechanical means is (almost) always preferable to compensating for it with modifications to the control method.
Caveat: Even removing as much backlash as possible with the mechanism inside the linear module may not eliminate all of it. You may still want some backlash compensation through software.
