Are you looking for a way to improve productivity in your inserting operation? Okay, that's a dumb question who wouldn't want improved productivity? It allows you to meet SLAs better, gives you more time for quality control, frees up capacity for accepting more work and might even lower your labor costs.


Mail center managers are always looking for ways to push more mail through the shop on every shift. There are many ways to accomplish this: better scheduling, more efficient material movement, more operators, more equipment or faster machines, etc.


An area that is frequently overlooked is the envelopes used in the shop. While the other measures can certainly make a difference and may be appropriate steps to take in some situations, improvements in envelopes are something that can make a big difference with little or no cost.


How Envelopes Are Related to Productivity

Fixing problems with materials often results in improvements that exceed the performance bumps that you can expect from the investments in new hardware with little or no expense. The key to higher productivity is keeping the inserter running at the highest speed manageable. Anything that stops the machine on a repetitive basis is going to have a big impact on the throughput statistics. Poorly running envelopes have opportunities to cause problems in multiple places during the inserting operation: Envelope feeding, insertion of material, flap opening, flap closing, sealing, metering and stacking.


Operations managers have a tendency to blame the equipment first for the downtime that takes a big chunk out of the finished-pieces-per-hour statistics. But, in fact, there are many factors that can have an effect on those numbers. The machinery itself is one factor, but often the envelopes running on them could very well be the real problem.


When you do decide to invest in higher speed inserting equipment, the demands put upon the envelopes are even greater. Not all envelopes are designed for the stresses of a high-speed environment. In fact, some managers have experienced initial disappointment in their new equipment because the output is actually LESS than their old machine at least until they work out the material problems and their operators become more efficient at setting up and running the machine.


There are a number of things that can happen to envelopes that will cause the inserter to stop or jam. If this occurs too often during a shift, the productivity of your department can decline. Inline material or inserts can jam as they are fed into the envelope for a number of different reasons. Here are some things to consider:


1. Insufficient clearance Check your inserter manufacturer's specifications for the minimum clearance. This is measured from the edge of the widest piece of material to the edge of the envelope. The material should be centered when taking this measurement. For most inserters, less than 1/8-inch clearance is going to cause problems. The more clearance (without experiencing material shift that causes address info to not be visible through the window), the better.


2. Material catching on envelope seams or glassine Diagonal seams usually work better than vertical seams. But if the seam glue is inaccurately applied, then the front and back of the envelope can become glued together or the seams can buckle, stopping the material before it is fully inside the envelope. Glassine must be sealed all the way around so that the plastic doesn't lift up and prevent the material from entering the envelope smoothly.


3. Not enough thickness capacity Again, check the specifications to make sure you are not exceeding the inserter's maximum package thickness rating. But also make sure the envelope can expand far enough to accommodate all the material that the equipment is attempting to shove into the envelope. Problems sometimes pop up with envelopes that are just fine most of the time, but a special run may have one extra page that is just enough to make the thickness exceed the capacity of the envelope.


4. Flap won't open Flaps that are too long or too short will keep the mechanism from being able to properly pull it open with suction cups or other methods. Flaps with diagonal sides that are too steep or too gentle will cause parts such as guides that are supposed to slide under the flap to miss the mark.


5. Flap won't close properly In addition to the conditions discussed above, a non-closing flap can be the result of:


6. Material too tall for the envelope You may need to adjust the folds, or reduce the size of the inserts. If this isn't possible, a taller envelope may be necessary. Make sure you are still within the aspect ratio of height to width specified by the USPS for machineable mail.


7. Inadequate glue If the glue on the flap isn't applied consistently, the flaps will pop open, causing envelopes to jam at the meter, the exit conveyor or to stick together in the mail trays.


Poorly Running Envelopes Have a Financial Impact

In many companies, the purchasing department controls what envelopes get used in the inserting operation. It is the nature of the job of a purchasing agent to focus on the price paid. Envelopes are viewed as a commodity and are understood by the purchasing department from their perspective of regular office use. Few purchasing agents will have insight into the important differences that exist in a high-volume mail shop without getting some guidance and input from operations.


The purchasing departments are good at making sure they order envelopes that meet the specifications they have been given for size or window placement, but may not be so aware of the importance of quality criteria that will impact productivity. To make matters worse, they may be making replenishment purchase decisions based on the best available price each time, resulting in sourcing the envelopes from multiple vendors. Using envelopes that vary in design, materials, quality or packaging is even worse than dealing with one envelope that is consistently causing problems.


In the high-speed inserting world, envelope problems that increase jams can quickly erase any savings realized by a slight reduction in the price of the material. Besides the productivity lost while the operator is clearing jams, there is also the very high cost of reprinting and manually mailing damaged pieces. In consumer billing applications, where the highest percentage of customers pay their bills the day they receive them, a day or two delay caused by lower productivity or manual reprints can have an effect on cash flow as well.


I've been in lots of shops where, if an operator starts having repeated problems after loading envelopes from a newly opened case, they toss the whole carton into the trash. It's just not worth it to keep fighting what is perceived as a "bad box." What happens to the purchasing savings then?


There are also costs that lack objective measurements but definitely impact productivity, such as the damage done to morale and motivation of employees. Inserter operators generally are more satisfied and productive when they can do their work faster. They are proud of their statistics and may even be compensated on the number of finished pieces they produce. Having to sort through envelopes to find good ones, continuously clear jams or record account numbers for reprints tends to drive their personal productivity down even if the problems eventually work themselves out.


Here are some ideas that will help to ensure that your envelopes are part of the reason for high productivity instead of the cause for disappointing results:


  • Avoid manufacturers that produce envelopes with only die-cut production techniques. With die-cutting, it is difficult to maintain consistency.


  • Use diagonal-seam envelopes. Side-seam designs have a tendency to cause inserts to catch, and the seam glue can sometimes cause the inside surfaces of the front and back of the envelope to become glued together.


  • Provide the purchasing department and your vendors with the material specifications for your inserter. These should be available from your equipment vendor.


  • Ask your equipment vendors for advice or referrals to envelope manufacturers. They probably know which vendors' envelopes work well on their machines and which don't based on the experience of some of their other customers.


  • Inspect envelopes for damage. This can be caused during delivery, from being stacked too high in the warehouse, run into by forklifts, etc. If material is consistently arriving from the vendor in poor condition, you may have to insist on better packaging. If it is getting damaged after being received, you may have to discuss the problem with the warehouse people.


  • Store envelopes in a climate-controlled warehouse. Humidity change is a major problem. Paper warps when the moisture content changes. Also acclimatize envelopes planned for the next day's use by moving them into the production room the day before.


When looking for ways to improve the productivity of your inserting operation, don't overlook the obvious. Envelopes and material can be a huge factor and one that can be easily corrected with little or no expense. Even if you eventually do invest in new equipment, the improvements you make in the quality of envelopes will continue to pay off.


Mike Porter is President of Print/Mail Consultants, an independent consulting firm that helps companies nationwide be more productive, adapt to changing requirements and lower costs in their document operations. For more information about Print/Mail Consultants, visit or email