SG540 suddenly cutting strange

[CBilkes]

Hey everyone! Hoping for some insight as my SG540 started giving me issues in the cut phase of jobs. All of the cut paths are coming out very wavy, primarily towards the end of the cut path. I've attached a photo of a test cut for example. I spoke with my local tech and they said that it was likely that I needed to replace my cutting strip and/or the blade carrier. I've now replaced both and there is no change to this wavy cut pattern. I also tried resetting to factory settings on the machine but it still persists. Has anyone seen this before?

 

[CBilkes]

Something I've just discovered is that there seems to be an issue with the locking mechanism for the print head because during the cut phase the print head is coming out along with it. I've removed and examined the locking mechanism but I don't see any issues and when manually sliding it right to its lock position, it's clicking as normal and doesn't move when pushed left again.

 

[Rodge Roo]

Hi mate, I am having similar issues with my Mimaki CG160FX. Just started doing this to me too! Letters are terrible, did you ever find a cause for this?

 

[damonCA21]

Hi mate, I am having similar issues with my Mimaki CG160FX. Just started doing this to me too! Letters are terrible, did you ever find a cause for this?

Normally it is down to the cutting strip, when this wears it can get a groove in it that deflects the blade and makes the cuts wavy. If not, check your blade holder, Make sure the blade can spin freely in it, and that it solid in there with no side to side wiggling. The other option is dirty or worn pinch rollers, but this is less likely but worth cleaning them anyway

 

[Rodge Roo]

Normally it is down to the cutting strip, when this wears it can get a groove in it that deflects the blade and makes the cuts wavy. If not, check your blade holder, Make sure the blade can spin freely in it, and that it solid in there with no side to side wiggling. The other option is dirty or worn pinch rollers, but this is less likely but worth cleaning them anyway

Thanks so much for the prompt reply Damon,

I have just changed the strip but will have a look at the blade holder. the blade is spinning freely in it however I will grab another one and see if it fixes the issue. I bet the nip rollers have never been replaced on the old girl so will give that a shot too and report back my findings... Thanks again!

 

[damonCA21]

No problem, also give the grit rollers under the vinyl a good clean. Sometimes a stray bit of vinyl can get stuck to them or the pinch roller and cause the vinyl to slip.
Another thing that can help is lowering the cutting speed on older machines

 

[Rodge Roo]

Also would it be worth replacing all the springs including the leaf springs inside the actual carriage units? Not sure if the leaf springs actually wears or not. These are what apply pressure for the hi & low pressure settings on the nip roller clamps (From what I understand). Kinda wishing I never bought this old one but I did get a good price on it.

 

[damonCA21]

I would try the other things first. Not sure if you can get the springs seperately, it may be worth taking them off and bending them a bit so they give more downwards pressure.

I would look at the problem being more around the actual cutting carriage or blade holder though if you have already replaced the cutting strip.

Give everything a wiggle and see if you can notice any looseness or movement anywhere. There may be a small amount when the head isn't powered as the solenoid will take up some of this.

 

[weyandsign]

It can also be caused by the vinyl bunching up, or becoming wavy in the machine, due to temperature or humidity

 

[cornholio]

In the case of the SG-540, it's the locking mechanism. Take it out,(be carefull not to loose the spring loaded ball...) clean it, put fresh grease and reinstall it. Then, I'd do a limit position initialize as well. That should be it.

 

[2ny]

Something I've just discovered is that there seems to be an issue with the locking mechanism for the print head because during the cut phase the print head is coming out along with it. I've removed and examined the locking mechanism but I don't see any issues and when manually sliding it right to its lock position, it's clicking as normal and doesn't move when pushed left again.

We have a SG-540 too, and I have never seen the print head come out for the cutting operation. That has to be the issue here.

#Cornholio; that sounds fairly easy to do... is it though?

Good luck
Tony