plate cylinder drifting forward on it's own?

[Bill Rothwell]

I have a Heidelberg 6/c sm/cd 102- 2004. when you make ready the register holds, but when you begin to run it will drift forward about 40 points on it's own on units 3 and 6 only. Also during a run if you move units 3 or 6 it will lock in and then drift a little later again. Has anyone experienced this? Heidelberg said that the engineirs said it was the clamps and rebuilt the clamps in unit 6, but we still have the same problem! It wasn't the clamps. This is driving me nuts because during short runs by the time you look at the fit and find that the cylinder has drifted the job is almost finished. Any thoughts or suggestion would be greatly appreciated. Thanks, Bill

 

[Cornishpastythighs]

Sounds Electrical to me

 

[Al Ferrari]

Sounds Electrical to me

Please explain how an electrical malfunction could cause this problem.

Al

 

[Cornishpastythighs]

Possibly getting an intermittent signal, computer board going bad, computer board overheating. I am a printer not an electrician I have seen some computer driven motors do some funky things when they get the wrong signal. Heidelberg dont seem to know either do they?

 

[Kaoticor]

Is the difference showing up on your display? Or does it move without indicating that it has moved.

Another thing: maybe good to check your blanket/packing thickness if you have changed those recently in those units.

 

[Bill Rothwell]

plate cylinder drifting forward on it's own?

the movement of the cylinder does not show on the screen, nor does it show on the pot at the motor of the unit. I hooked up a meter at the motor during a run monitoring the pot and when the cylinder moves it dosen't show that it moved on the pot (potentiometer) therefor, it looks like the cylinder didn't roll, but it is moving. Another strange thing that happens is if the unit rolls forward during a run and I roll it back to put the marks back into register it will then stay, but the very next job i put up, the first pull will show that the unit i moved back is 40 points beyond the rest of the colors on the register marks and then must roll it back down. This is really weird stuff! Thanx again for listening to my plea, Bill

 

[junker1984]

image drift

image drift

Hey Bill - The issue you posted is most likely wear in the pin/bushing configuration on the plate cylinder double gear. This is real common, and not real painful, you may even be able to accomplish it yourself with a little guidance. Send me an e-mail, [email protected]. Regards, Steve

 

[Bill Rothwell]

plate cylinder drifting forward on it's own?

Thanks for getting back to me guys! I'll shoot you a email Junker1984. I'll keep you guys posted on how I make out fixing this problem. Sounds like Junker1984 has the answer!
Bill

 

[turbotom1052]

some speedmasters have 2 different positions that the pin can be engaged. you might want to try the other engagement position just as a test before getting in too deep. The other thing you may want to check is the bolts going around the cylinder circumfrence just inside of the gear. Be sure they are reasonably tight. Sometimes guys will tumble the cylinder to fit a job on a diffent sized stock and not tighten up the bolts enough when putting it back!!!

 

[junker1984]

turbotom has a point, sometimes it's best to look at the simpler possibilities to resolve a problem. On that note, another thing to look at would be searching out the grease zerk on the outer plate cylinder gear face and give it a couple squirts of premium synthetic grease. Once the damage (wear) is done, no amount of grease is likely to help, but it's worth a try.

 

[Al Ferrari]

turbotom has a point, sometimes it's best to look at the simpler possibilities to resolve a problem. On that note, another thing to look at would be searching out the grease zerk on the outer plate cylinder gear face and give it a couple squirts of premium synthetic grease. Once the damage (wear) is done, no amount of grease is likely to help, but it's worth a try.

Is your second suggestion a preventive measure against a future problem, or a long shot possible cure for the current problem? Your own last sentence makes it useless as a cure, until you add "but it's worth a try." Which is it?

Al

 

[junker1984]

Al - As always, a little grease and attention to where the grease zerks are goes a long way. Seems whenever I've run into this problem over the years, pressmen have said "Geez, no-one ever mentioned that grease point". Hopefully this will serve not only as a preventive for many, but also a long shot cure for Bill. I will add, I can't picture in my mind what type of lube fitting you'll see on the gear face, but when I take the assembly apart, I apply the premium grade synthetic grease to all close tolerance surfaces. Again, "once damage (wear) is done, no amount of grease is LIKELY to help"...but it can't hurt to try it. Regards to all! Steve

 

[Kaoticor]

How is this problem going for you, any success yet? Were you able to check out to see if those bolts were tightened? I'm interested to see what happened with this problem

 

[Bill Rothwell]

plate cylinder drifting forward on it's own?

Today I was able to take some time and look @ everything inside the unit and see how it comes apart as per junker1984's guidance. (thanks again Steve!) We are going to get the parts and go from there. In the mean time I will tighten the bolts and grease the fitting and check out locking the pin into the other position. Thanks again to everyone for all your input. This forum is great because of all of the knowledgeable people involved willing to help out and teach others!! Thanks everyone!
Bill

 

[turbotom1052]

Today I was able to take some time and look @ everything inside the unit and see how it comes apart as per junker1984's guidance. (thanks again Steve!) We are going to get the parts and go from there. In the mean time I will tighten the bolts and grease the fitting and check out locking the pin into the other position. Thanks again to everyone for all your input. This forum is great because of all of the knowledgeable people involved willing to help out and teach others!! Thanks everyone!
Bill

bill the spring loaded pins are just for the purpose of locating the cylinder so that they can all wind up in the same position. Its the bolts around the cylinder that lock the cylinder into position.

 

[Bill Rothwell]

plate cylinder drifting forward on it's own?

today I checked the bolts to see if they were locked down and they were. then I greased the zerk in the zero position around the cylinder and greased them again at the farthest position on each side of zero. then i let the press run and ran the circumference to maximum position in one direction then maximum in the other direction five or six times. We were getting ready to put a job up on the press at the end of my shift so the second shift will see if these procedures have any impact on the problem. the job is 110,000 sheet run, so if the cylinder is going to drift, they should be able to see it. I'll post the findings tomorrow. thanks again everyone for your input!
Bill

 

[Al Ferrari]

The idea that greasing that zerk fitting is going to help defies all logic. The purpose of lubrication is to reduce friction in order to allow parts in contact to move past each other without binding.

If the cylinders move it is because some parts somewhere are in fact already moving past each other without binding. They don' need more help doing that. On the contrary, they need to be prevented from moving past each other without binding, and that's not what more lubrication is going to do.

Al

 

[junker1984]

Logic is one thing, practical experience is another. What is not being taken into consideration is that there are two sets of close tolerance concentric surfaces being utilized to make the image change circumferentially by compressing/decompressing considerably high spring pressure. This is accomplished by commands from the CPC/CP2000, servo drive moves the outer gear laterally on the inner gear, helical cut of the gearing lends to the image moving up or down. I strive for clarity in my posts, and I ask for nothing in return for the sharing of a bit of knowledge. If I notice a post that seems to be inaccurate, I make a suggestion to try a different tack, but in that I don't criticize the previous poster as I may not posess the expertise he may. Anyway, I stand by my previous posts. Regards, Steve

 

[Bill Rothwell]

Al, I appreciated your input and everyone else's input on this forum. As I posted earlier, what is so great about this forum is that everyone brings there knowledge and experience to the table to try to help one another out with there problems in this trade and I for one am very grateful for anyone's offering to help me out. I have tried to do what everyone has offered from there experience and knowledge to cover all the bases on my press problem. I have been running a press for 34 years, made some pretty extensive repairs along the way, along with the help, knowledge and expertise of others. Please offer me some avenues of information to help me with the problem and not criticism.
Thanks, Bill

 

[Al Ferrari]

Bill and junkler,

I have tried to write carefully so as to make my criticisms constructive, and I apologize if I came across otherwise.

Junkler's last response is actually very useful: he posits that taken as a whole, the system is trying to make a correction that is not completely achieved at first due to friction, but that it is achieved after some number of impressions. The value of the greasing suggestion then is to facilitate the initial system correction so that there will not be subsequent movement. I see the logic of that now.

Unfortunately I have no specific knowledge of the equipment involved, so I cannot offer concrete suggestions. Let's wait to see if the night shift reports an improvement after Bill's lubricating procedure.

Al