QMDI CLASSIC Won't print

I have a QMDI Classic and am having an issue with the press. When you engage the impression to print the press shuts down like a missed sheet but there is none. It also restarts the compressor if anybody can help let me know

 

It could be the X7 plug connection in the main electrical panel. Give it a clean.

Regards.

 

It sound like you have and air leak which will cause the press to shutdown on low air. I would check air cylinders for leaks.

Rick

 

I agree with Rick, probably one of the short stroke cylinders is defective.
To be sure look in SF 56 and switch the impression, unit per unit.
Observe error 15-06, low pressure.
rgds
Jan

 

I found that the X7 plug was burned and am in the process of replacing plug, i noticed that during the shutdowns the 15-06 error code was on do you think it is related to the plug or a separate incident

 

Yes, you have two issues.
X7 bad contact, cause the press is reseting. In the display you see init classic and Ametek blowers are going high.
It is due to the higher power consumption during switching to impression.
At the same moment, you are activating stroke cylinders (Y5-Y8) and at least one of those 8 (OS & DS) is leaking.
The pressure fall down under 6 bar, error 11-06 occurs, press stops, compressor restarts.
rgds
Jan

 

I have same problem how do I switch individual units in and out to check leaks?

Regards

eric

 

To test Y5 - Y8 go to our console press S 3+7 then 15

Now enter the channel number for the individual cylinder you want to test.

200 = Y5
201 = Y6
202 = Y7
203 = Y8

Press the + button to extend the pneumatic cylinder. Press the - button to retract it once more.

Repeat this for each of the listed numbers until you find your leak.

Hope this helps
Andy

 

Here is another piece to the puzzle when troubleshooting air leaks on the short stroke cylinders.

You will notice they have two 6mm air lines running to them. This is a binary set up in effect, one is on the other is off. They never both have air going to them at the same time. This is important because it is where alot of people get confused when troubleshooting which cylinder is bad.

Typically what happens when you manually activate each cylinder you eventually come across the one air circuit that has the bad cylinder. When you do you will initially hear the air leak coming from the 5/2 way valve which releases the air to either side of the cylinder depending on whether you are going on impression or off impression. DO NOT REPLACE THIS 5/2 WAY VALVE! It is not the problem. People tend to think because they hear it leaking it is the problem. I'll get back to why you hear sound coming from it in a minute.

Once you isolate which circuit is bad, it is very easy to find out what cylinder is non-functional. Go to either one of the cylinders on either side of the press. It does not matter which one. Take the air line loose that has no air going to it from one side of the cylinder. It is easy to tell which one will have no air as it is the one that will have the end of the ram farthest from it. (Where the lever being activated attaches to.) When you remove this air line one of two things is going to happen.

1. You will hear air leaking out of the air cylinder in front of you. If this is the case that cylinder is your culprit.

2. You will hear air leaking through the air line you are holding in your hand. If this is what is happening it means the cylinder on the other side of the press is the bad one. This also explains why you hear air coming through the 5/2 way valve, the air is looping back through the circuit and not allowing the 5/2 way valve to move fully to one position or the other, as a result the air leaks around the chambers in the valve making it sound like it is leaking.

It is extremely important when replacing these air pistons that you measure exactly the stroke length from the old one and adjust the new one exactly the same before installing. These pistons are responsible for not only the printing pressure but the alignment of the drive gears to the impression cylinder gears and plate cylinder gears. Being off just 2mm in length can affect the pitch of the gears. Most people think this is an easy replacement and mechanically it is, but a year down the line when you are experiencing axial streaks in your printing that will require a blanket cylinder gear replacement to fix or worse if you damaged the impression cylinder gear which can't be replaced, then you will understand how difficult this job actually is when not performed correctly.

If you have any doubts in your mechanical abilities when doing this, spend the money to have someone who has done it properly before come out and do the work. A knowledgable person can perform this job in an hour or less and will save you lots of money in the long run if you were to do it incorrectly.

 

Activating the off side cylinder quite a few times by using above codes solved this problem and taking the pressure switch off on the drive side and swopping with another appeared to solve this unit.

thanks again for your help

Regards

Eric hyde

 

leak in Long Stroke Cylinder unit 2

Hi Paul, I hear an air leak in Long Stroke Cylinder Unit 2. please advise what to do..?

Thanks

 

The long stroke piston only has one air line going to it. Replace the cylinder you hear the leak coming from. Also be sure to measure the shaft on this one. It is important to get the measurement correctly.

 

leak in Long Stroke Cylinder unit 2

Thanks for reply Paul, if you do have a picture for this shaft I think it will be easy for me to understand it.

Do you mean the shaft when it's completely opened?

thanks

 

Yes, when it is completely opened. Measure from the center of the holes that mount to the press and lever.

My apologies, but I do not have a photo.

 

after I purchased the new Long Stroke Cylinder, i didn't hear the air leak from the one on the machine any more. is it possible to leak and after few weeks (machine was not working) then the leak stops.?

 

Hi,
We have had the same experience just this week. We started running our 2nd QMDI which was not used for a few months due to an air leak on one of the short stroke cylinders/pistons. When we replaced the cylinder that was initially leaking we came across a few others with issues. Some of these would leak intermittently and then work properly again. We eventually changed a few of them and on some - only the valve needed changing. At last - by yesterday evening, we got the press running well with just one issue - we sometimes had loss of pressure on start up and then the problem would just as suddenly go away when we started again a few minutes later. We finally spotted the problem this morning by running the press with the doors open and keeping an eye for any leaks. I put small pieces of masking tape over the exhaust ports of each of the long stroke cylinders and on one of the start ups when we had loss of pressure I noticed the masking tape fluttering on one of the cylinders/pistons. This was the caus of the loss in pressure on strat up - the blanket to plate cylinder/piston on unit two was leaking (not every time though - just now and then). Without the doors open and the tape on the cylinder, it would have been almost impossisble to spot the leaking cylinder/piston as it would otherwise function normally.

So there you have it - they can sometimes work and sometimes leak. When we tested using the codes this particular cylinder/piston tested perfectly fine yet it was faulty!!

Hope this answers your question.

Kind Regards

Shawn

 

Shawn, thanks for reply
I opened the door and worked but i didn't hear any air leak, also the machine stops while the compressor is on 8.5 and 7.5 anc never go below.
I will test again now as it was wotking perfect two days ago.
Do u know the codes to test long strok cylinder?

 

I mean i opened the door and run the machine but still stops after 5 or 6 sheets

 

Hi,
Please see the codes in the attached picture. When the machine stops while the pressure is still high, what ERROR CODE do you get when you press S56 on the main panel?
Take a pic of the ERROR code and upload it so that we can see what ERROR is causing the machine to stop - it does not sound like a pressure problem if the pressure is still above 7,5 Bar

You can use the attached codes to test the cylinders but first you need to check what the error code is. It may not be the cylinders at all. Maybe something else??

Let me know!

Regards - Shawn

 

The error code is 12-10. But i checked everywhere between feeder and delivery no papers. Also the machine is running for 5 to 8 sheets before stopping