DTC Dynamic Tolerance Control Retrofit

Volume Oriented Control Retrofit for all Engravers

DTC gets the best out of your engravers.
In the Packaging Gravure process, we assume that all engraving machines perform the same, as they all get the same TIFF file, but tolerances are inevitable, and cylinders with high tolerances cause issues in the press.
The tolerances sometimes level each other out, but when they add up, they can cause noticeable density differences in printing. DTC prevents that, especially on older engraving machines.

Before DTC and Volume Test Cuts, we had to accept unpredictable results.
Modern engravers address the Unpredictable Tolerances Issue with CellEye or Volume Test Cuts, and for older engravers of any brand, DTC provides an even better result, as also Copper conductivity, Head linearity and Amplifier linearity are compensated

DTC with its Volume Oriented Control brings the impact of all mechanical tolerances in the engraving of half-tone cylinders down to maximum of 0.4 Dot% on all engravers.
This graph (GIF) displays measured printed densities. Most measurements are off-target. DTC moves them all close to on-target.
Mar-12-2018 23-03-35

How does DTC work?

DTC collects information about all tolerances that play a role and optimises the engraving data dynamically for each cylinder.
After entering all parameters, the DTC Software does its magic.
You can then copy the earmarked file to the local disk in the engraver and start production engraving as usual.

This two minute keynote explains DTC

What is DTC?

DTC is an Application that makes sure that all half-tone gravure cylinders print perfectly, regardless of
  • Stylus Wear (increasing Stylus Angle over time)
  • Stylus Chips (damaged Stylus cutting edge)
  • Copper Quality (Copper structure influences the cell symmetry)
  • Copper Quality at the edges of the cylinder, where the test cuts take place. The engravability of the copper there differs from the rest of the cylinder
  • Test Cut Tolerance (a tolerance of a few microns from the target can be compensated)
  • Head Characteristics (Engrave Heads are profiled for their deviation in linearity and the difference between Test Cuts and Production Engraving)
  • Amplifier Linearity (Machine characteristics)
  • Cell Measuring Instrument tolerances (including operator error)

DTC is compatible with Hell, Ohio, Daetwyler and DMA engravers and doesn't change anything to the engraver itself, the file server, or to the gradation used.
It is an addition to the workflow which changes the engraving pixel-data on HelioDisk, DLManager, Collage, GravoComplete or JobCreator. The DTC server is added as a data source.
Also with some modern Twain engravers with two engrave heads, it can be beneficial to use DTC for halftone cylinders, making both heads produce the same result in print.
Intelligent algorithms are used to calculate the compensation, stored in a database, not in the engrave-head.

DTC is a client-server application. Operating is done on an iPad, at each engraver, or with each operator.
The DTC Server is connected to your data server. A document with a detailed explanation of the configuration you find in the download section below.

An example in numbers on how DTC works:
An area in a package is meant to be tone of 25%. Because of mechanical tolerances, it prints like 23%.
DTC optimises the data in that area to 27% with the engraved result printing like the targeted 25%.

Operating DTC on an iPad

The engraving operator enters all relevant parameters in an App on the iPad just after measuring test cuts and before production engraving.
Besides the obvious parameters like cell sizes and the Engrave Head used, there's a Cell Quality Star Rating were the operator 'Star-rates' the shape of the test cut cells for Symmetry, Stylus Chips and Copper Quality.
A 'five star' cell is perfectly symmetrical and a 'three star' cell will not release ink so well, and therefore will be compensated more.
The latest software includes the Copper Structure measured in IACS percentage to evaluate the 'engrave-ability' and the conductivity difference between the edge and the centre of the cylinder.

A three minute movie about how to operate DTC on the iPad.

Logging and tracing

As DTC already stores all parameters for each cylinder in a database, you can trace when each cylinder was engraved, on which engraver and how it was optimised.
The green values in the screenshot below will show up red when the compensation reaches its limits.
With this feature of DTC you can also monitor the cylinder production from home.
DTC query-squashed

Sustainability and Economic Advantages:

  • DTC is saving setup time and waste in the press and the costs that come with that, making you a preferred supplier of cylinders.
  • Time saving. With DTC you can almost always do with One Test Cut.
  • DTC extends the Stylus Life.
  • With DTC you can concentrate on producing cylinders and less on costly proof printing.
  • DTC protects your investment in engravers. No need to buy the latest engravers for quality or stability reasons
  • Replacement cylinders print the same as the original ones.
  • DTC uses your existing cell measuring devices and conductivity measuring devices (not included)


Since we run DTC operational we observed that the life time of standard styluses increased from averaging 110 hrs to >230 hrs.
At the same time we observed zero stylus breakages as well as zero color deviation from test engraving jobs and following production jobs.
We also observed that the test cut process is greatly reduced.
DTC is so easy to operate via its user friendly operational app surface as well as the handling of various engraving machine with one single mini iPad.
As part of our QM system we are even able tracking back our jobs if there should have been an engraving issue.
All over anyone using older engraving machines or even new ones we highly recommend DTC as the tool for consistent engraving quality, increased stylus life time and true color output.
Kind regards,
Dominik Michalek
General Manager
Helio Asia


As DTC is combatting the consequences of mechanical tolerances, Hell K500's CellEye and Ohio's Volume Test Cut on new machines are doing that too. Here is a document that compares similarities.
This configuration document shows that DTC is an addition to the workflow, does not change anything to the engraver or its gradations, and it does not interfere with the current configuration.
A YouTube movie with technical details about DTC.

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