Setting allowance for board packaging

[Helen Tan]

What is the norm percentage in board offset packaging printing as setting waste ?
Look forward for some sharing.

 

[aqazi81]

Depends on the run length, if a short run job, the percentage will be much higher and as the job run length increases , percentage will drop.
Type of jobs and number of colors also determine the wastage.

 

[ar17]

do you have some sort of matrix as reference? say for 1000, 5000, 10000 and onwards. also interested for the standard industry practise. thanks

 

[Magnus59]

Waste in sheetfed offset is calculated as fixed overs + running percentage.
We don't run packaging, but our allowance for sheetfed offset general printing 4 colour process 2 sides is 400 sheets fixed + 2% running waste

 

[turbotom1052]

One thing you can be sure of is that the waste allowance will USUALLY be borderline ridiculous. All pressroom employees know the standard reasoning behind these low waste allowances, but it seems that the bean counters haven't yet caught on to what happens when you don't allow for enough paper. So hear it is... Most Pressman would much prefer to make every sheet that the customer gets in as perfect register and perfect color, and as free of defects, as the process allows. When you don't allow enough waste for a job, you are in effect often FORCING a pressman to start counting sheets prematurely, and including marginal quality impressions to make it into the job. This results in at times, bad sheets being delivered to the customer. This only becomes a problem when a customer complains. As a result of customer dissatisfaction, someone has to be blamed. Ill give you one guess where that blame usually falls??? This is a management dynamic I've seen many times. It happens when instead of management dictating the companies standards, they allow their customers to dictate the companies standards. I don't think ive been to a single job interview in my almost 40 years in the printing industry where I wasn't told "we are a quality shop". So every company THINKS they are quality printers, but we all know there a bunch of not so great printers out there. Instead of management setting their standards and finding a customer base that's looking for that particular product, the quality control is allowed to be determined by the customer. They in effect roll the dice and hope that everything goes well and every sheet is sellable. This will often have good results but when the inevitable defective sheet or sheets eventually gets noticed then there's hell to pay. This same dynamic applies to production expectations. In order to fit 10 lbs of dung into that 5 lb bag compromises need to be made. Once again we have a situation where "the fish stinks from the head!!!" I would not expect for this post to get many likes as many who are not anonymous will be fearful for their job, but I can assure you bean counters this... many of your employees are fully aware of this and talking about it.

 

[Deleted member 16349]

One thing you can be sure of is that the waste allowance will USUALLY be borderline ridiculous. All pressroom employees know the standard reasoning behind these low waste allowances, but it seems that the bean counters haven't yet caught on to what happens when you don't allow for enough paper. So hear it is... Most Pressman would much prefer to make every sheet that the customer gets in as perfect register and perfect color, and as free of defects, as the process allows. When you don't allow enough waste for a job, you are in effect often FORCING a pressman to start counting sheets prematurely, and including marginal quality impressions to make it into the job. This results is at times, bad sheets being delivered to the customer. This only becomes a problem when a customer complains. As a result of customer dissatisfaction, someone has to be blamed. Ill give you one guess where that blame usually falls??? This is a management dynamic I've seen many times. It happens when instead of management dictating the companies standards, they allow their customers to dictate the companies standards. I don't think ive been to a single job interview in my almost 40 years in the printing industry where I wasn't told "we are a quality shop". So every company THINKS they are quality printers, but we all know there a bunch of not so great printers out there. Instead of management setting their standards and finding a customer base that's looking for that particular product, the quality control is allowed to be determined by the customer. They in effect roll the dice and hope that everything goes well and every sheet is sellable. This will often have good results but when the inevitable defective sheet or sheets eventually gets noticed then there's hell to pay. This same dynamic applies to production expectations. In order to fit 10 lbs of dung into that 5 lb bag compromises need to be made. Once again we have a situation where "the fish stinks from the head!!!" I would not expect for this post to get many likes as as many who are not anonymous will be fearful for their job, but I can assure you bean counters this... many of your employees are fully aware of this and talking about it.

Deming recognized that waste and lack of quality was 90% a management responsibility and not an operator one.

For all the time I have been interested in offset printing, it was my aim to solve these types of problems in a rational, predictable and low cost way. I have never found management types to be interested in any of what potential I had to offer. Managers are not leaders.

 

[turbotom1052]

Deming recognized that waste and lack of quality was 90% a management responsibility and not an operator one.

For all the time I have been interested in offset printing, it was my aim to solve these types of problems in a rational, predictable and low cost way. I have never found management types to be interested in any of what potential I had to offer. Managers are not leaders.

Eric,
ive worked for a few companies that claim to live and die by Demmings philosophies. Problem is that they pick and choose the ones that they want to live by. Most upper managements love the philosophy where every aspect of the manufacturing process is controllable. Problem is that often they miss the part that says that the control they seek needs to work its way through ALL stages of the process. This is particularly true when it comes to resisting the temptation to buy sub standard substrates to print on. So a press crew is given crap to put in the feeder and expected to deliver Rembrandts, because Demming says so.

 

[turbotom1052]

Waste in sheetfed offset is calculated as fixed overs + running percentage.
We don't run packaging, but our allowance for sheetfed offset general printing 4 colour process 2 sides is 400 sheets fixed + 2% running waste

Fixed percentage allowable waste does not take into consideration complexity of job. You also make no mention of the OK process. If the pressman is permitted to do his own OKs, and flip the counter on at his discretion, on a very straightforward job with a decent amount of coverage then the fixed 400 sheets you say you allow is barely enough to print quality work. That amounts to 200 sheets per side. Throw in a customer Ok, or a tough form with crossovers, or something with very light coverage, and 200 sheets per side can be easily used up. What happens with the numbers you propose is as follows, even if the pressman will not admit it. See if you can follow this very possible scenario....Pressman encounters one of the above mentioned variables during the make ready process and is FORCED to exceed your allowable 200 sheets per side. At this point he or she is left with one of two options. He can, if permitted, opt to flip the counter on early, and begin the production run, before proper ink water balance is achieved, and color is matched. Or.... he can begin to dip a little into the allowable production waste. Then the inevitable problems arise during production that leaves the pressman with another one of two choices. He can either allow defects to remain in the job, that should have been pulled out if he had more paper to work with, or he can pull out the needed amount of sheets every time the press starts up, after a hickey removal or cleaning of some or all blankets, and risk short counting the job. Having gotten read the riot act for short counting jobs in the past the pressman rolls the dice and hopes that what he knows to be sub standard, sneaks through. This possible scenario becomes even more complicated with the very common practice of the estimator being forced to sharpen his pencil and buy job lot paper. This job lot paper on the surface looks like a very good deal. Too good to pass up. Fingers are crossed by everyone but upper management, in hopes that this job lot paper performs well on press and prints defect free. Upper management doesn't worry at all because if things go wrong he has plenty of fingers to point in various directions. At this point producing "QUALITY WORK" becomes more of a "Hail Mary" then a biznez model. So now the job is complete. The estimator and the pressman, because of the skimpy waste allowances say their "Hail Marys" and hope that the substandard presswork goes un noticed. The final verdict on the job is not known until perhaps a week later, when the customer accepts delivery. Thats a lot of lost nights sleep by the pressman over a problem caused by someone else. Heres where another of 2 scenarios occur... The company that always boasts of being a "QUALITY SHOP" now has a tarnish on its reputation because a substandard job (as defined by the customer) has gotten through, and the job needs to be reprinted or discounted. At this point tell me were the fingers are being pointed??? Or..... the job sneaks through, no harm, no foul, customer accepts delivery and all is wonderful at ACME QUALITY PRINTING CO. This just further fortifies managements willingness to buy crappy paper and less of it. Its not too long after that the paper gets crappier and the allowable waste gets less. Sounds to me like a real recipe for success in the wishful thinking world of "top quality printing!!!"

 

[Deleted member 16349]

Deming recognized that waste and lack of quality was 90% a management responsibility and not an operator one.

For all the time I have been interested in offset printing, it was my aim to solve these types of problems in a rational, predictable and low cost way. I have never found management types to be interested in any of what potential I had to offer. Managers are not leaders.

I will add here that my target allowance, with respect to getting to density targets and based on the theoretical and experimental work I have done, would have been about 50 impressions. This would have been independent of coverage.

The reason for choosing 50 impressions as the target was based on the results of computer simulations of our Chambon offset press back in 1990 or 1991 at Tetra Pak Canada. Several things were tested with this simple simulation program. One was how the print density would react when going from low to high coverage or from high to low coverage and both runs started with an uninked plate. With high to low coverage, the density over shot a small amount but then trended to its steady state target value.

We also investigated density variation in the machine direction due to printing intermittent patches on the plate. We also compared this to how an ideal press roller train would reduce this variation. Interesting results.

50 impressions might seem too low and unrealistic but it can be improved even more. As a real world example, the Anicolor press is said to be able to get to colour in 20 impressions and it is a lithographic press. I don't think it is the right direction for press design but it shows what is possible.

 

[turbotom1052]

I will add here that my target allowance, with respect to getting to density targets and based on the theoretical and experimental work I have done, would have been about 50 impressions. This would have been independent of coverage.

The reason for choosing 50 impressions as the target was based on the results of computer simulations of our Chambon offset press back in 1990 or 1991 at Tetra Pak Canada. Several things were tested with this simple simulation program. One was how the print density would react when going from low to high coverage or from high to low coverage and both runs started with an uninked plate. With high to low coverage, the density over shot a small amount but then trended to its steady state target value.

We also investigated density variation in the machine direction due to printing intermittent patches on the plate. We also compared this to how an ideal press roller train would reduce this variation. Interesting results.

50 impressions might seem too low and unrealistic but it can be improved even more. As a real world example, the Anicolor press is said to be able to get to colour in 20 impressions and it is a lithographic press. I don't think it is the right direction for press design but it shows what is possible.

The problem with these numbers are that they are theoretical. These numbers come from printing under laboratory conditions, with tight controls on every conceivable variable. The control of such variables are OFTEN beyond the willingness of the average printing company. For many of the bean counters such tight control of these variables will simply be viewed as "too costly" This unwillingness to occur the additional costs of controlling these variables, come from the bean counters shortsightedness. The controls needed would require at times a monetary commitment, and change of mindset, with a ROI thats projected a bit too far out for comfort.
Ive been witness to this very dynamic on numerous occasions. Picture this.... Someone at the big chair in a company decides that his or her company is not making what he or she perceives to be enough money. Or there is too much waste. Or bad sheets are slipping through and making it to the customer. The possible scenarios are endless. Little hope is had for the companies existing employees to come up with solutions to these problems, so a "consultant" is hired to do a full plant audit. All employees are told to fully cooperate with the auditor. The auditor comes in a spends a week or 2 observing operations. Upon completion of audit, a report is submitted outlining a bunch of issues that can be improved upon. Often these issues are things that regular front line employees have been suggesting all along. Just like the employees suggestions, it soon becomes apparent that to implement these changes commitment is required. New procedural changes take a bit more time, or cost a bit more money. Or perhaps the audit shows that the job lot paper that the companiy has been buying, is really no bargain, when all things are taken into consideration. Within weeks things go back to biznez as usual. The guy in the big office convinces himself that his employees are the problem. What he fails to acknowledge is that perhaps he promoted his pressman off the broom a little too quickly to save $4 bucks and hour. Sound familiar???

 

[Deleted member 16349]

The problem with these numbers are that they are theoretical. These numbers come from printing under laboratory conditions, with tight controls on every conceivable variable. The control of such variables are OFTEN beyond the willingness of the average printing company.

Yes, the numbers are theoretical but IMO are achievable. If the theories are correct, they represent reality more than what one might get from experience. That is the basis of the modern age. So if one wants to make improvements, one needs to start with a theory. Otherwise, one is just doing trial and error.

Yes, variables do have to be controlled and the theory tells one, which ones need to be controlled. Not all variables need to be controlled so much. Testing theory does require modification of existing equipment but I would not say it needs to be under laboratory conditions.

I would also not expect the average printing company to do too much. They would not tend to have the engineers or scientists required to think through the problems of validating theory and innovating solutions. But very large printers could and of course press manufacturers should.

Back to the theory topic. Think about an existing press printing during a run.

On each revolution of the plate cylinder, the form rollers are reinking the plate to reproduce the printed image of the previous impression.
So one is reproducing an image with only one impression.

So, if one can set the ink conditions of the form rollers to the same condition as existed during the print run, pre-ink the plate and blanket, then one could theoretically have a start up run of one impression that reproduces the target impression.

OK, this is demanding but the thinking process to understand what needs to be changed in the process to approach this performance, certainly gets you close and greatly improves what you have now.

 

[turbotom1052]

In theory if a presses inker could work like a continuous flow dampening system, as opposed to a reciprocating ductor type system, and the roller train only had the storage capacity for a single impression, as opposed to enough capacity for multiple impressions, then we may be on to something. Unfortunately such a short ink train lacks the ability to lay down a smooth and even film of ink onto the plate with the current technology that's in place.

 

[Alois Senefelder]

Hello Erik,


What about the Water(F.S.) that ...... Trespass onto the Image Areas ?


Regards, Alois

 

[Deleted member 16349]

Hello Erik,


What about the Water(F.S.) that ...... Trespass onto the Image Areas ?


Regards, Alois

Explain why it should? I have tested positive ink feed on four presses and in all cases, the solid ink density is quite consistent and independent of the amount of F.S. being applied. One can flood the plate so much that it is soaking wet but that does not affect the amount of ink that gets printed. One can not wash out the print. And surprisingly for those tests it has not affected the print much at all. This maybe due to the specific inks. When running a UV ink, between normal F.S. levels and very high F.S. levels, the dot gain did not change which was actually a surprise to me. Only in one case, when printing on plastic coated substrate, the quality of the print was affected by high levels of FS. But one would not normally print at those test levels.


I have said this so many times over the years but you don't believe it. You can't understand it. Trying to explain this to you is like trying to describe a sunset to a blind person. Almost pointless. You will not believe it until you finally see the result of a positive ink feed. Your past experience is no help with this situation.

 

[turbotom1052]

Explain why it should? I have tested positive ink feed on four presses and in all cases, the solid ink density is quite consistent and independent of the amount of F.S. being applied. One can flood the plate so much that it is soaking wet but that does not affect the amount of ink that gets printed. One can not wash out the print. And surprisingly for those tests it has not affected the print much at all. This maybe due to the specific inks. When running a UV ink, between normal F.S. levels and very high F.S. levels, the dot gain did not change which was actually a surprise to me. Only in one case, when printing on plastic coated substrate, the quality of the print was affected by high levels of FS. But one would not normally print at those test levels.


I have said this so many times over the years but you don't believe it. You can't understand it. Trying to explain this to you is like trying to describe a sunset to a blind person. Almost pointless. You will not believe it until you finally see the result of a positive ink feed. Your past experience is no help with this situation.

Eric, you seem to insist on viewing people as stubborn and unwilling to accept your theories, or findings. I personally think, based upon past conversations that your patent had some merit. I don't believe in your idea that, with your system you could flood the form with fountain solution and show no ill effects. It seems to be your expectation that because you were able to achieve certain outcomes during your testing, that everyone should have the same results, and that the technology should immediately be embraced. It seems that there is no consideration for the fact that your very controlled testing may not be that feasible in the real world we work in every day. You are in effect telling people that I am a press engineer, and your personal experiences on the front lines of the industry mean nothing, because you don't have the engineering degree that I posses. We are talking here of some people that could very well be industry leaders. We are talking about people here that have practical experience with the day to day running of multicolor presses often under very adverse conditions. People who don't have the luxury of applying your product to just a single retrofitted unit on a multicolor press but to perhaps up to 10 printing units at the same time. People who's requirements for ink control may just be beyond the conditions you tested your product under. I can assure you of this... The narrow operating windows of a sheetfed press running complex, fine screen multicolor images, is leaps and bounds different than a single unit of a press that's printing simple line work. I don't know the nature of the sort of work others here on the forum are a part of, but I do know the history of my career. And based upon the description of your testing in your very own words it would appear that your product just might be better suited for a less sophisticated duplicator style press running simple line work.

 

[Alois Senefelder]

Gentlemen, Erik Nikkanen.


Being a member of this forum gives us all - "The Virtues of Engagement, Scrutiny and Scepticism"



Regards, Alois