Current estimates that three trillion dollars have been wiped off shares in the continuing stock market ‘correction’ does not bode well for investment generally. Add to this the problems with BSE and FMD and the leather industry seems to be especially hard hit.

So, how do you persuade tanneries to invest in new equipment? Well, if you are Antonio Galiotto, sales manager of Erretre, the chemical milling drum manufacturers based in the Veneto region of Italy, you prove that without their drums and un/loading system, the tannery’s production will not be as consistent.

‘Tanners didn’t mill because they were unsure about the all the variables they had to control’, he said, showing me the new computer controlled drums Erretre have developed. Chemical milling is, in fact, a difficult process to get right. The variables include controlling the humidity, temperature, speed and chemical additions.

Erretre have simplified the system for the tanners by taking the guess work out of milling. This is achieved by controlling the parameters through using a sophisticated computerised automation and programming system.

It permits the automatic control of the work cycle, control of the times, even control of the unloading of the drum, which is as important as the milling.

All this leads to an improvement in productivity and in the quality of the leather produced. The advance in technology has taken ten years to come from concept to fruition, but the dividends are now paying off with a number of firms interested in using this technology.

Not that Erretre have been sitting still, they have secured big orders for their chemical milling drums from the likes of the Mastrotto and the Dal Maso group.

Their drums are an elastic construction bolted together in stainless steel, which ensures that the serious structural problems that are found if a completely welded stainless steel drum is used, are overcome.

They also shied away from wood because as Galiotto pointed out: ‘How do you know where the humidity goes? Does it go into the leather or the drum?’

They also studied, and solved, other problems such as:

* air recycling for dust removal and to control the internal air temperature and humidity

* the internal movement of the leathers in the drum, ie the choice between shelves and pins, dimensions and speed

* what actually happens in the milling drum? As a result of exhaustive data collection, relating the various parameters of air, temperature and moisture, from tanneries all around the world in all kinds of climates and with all kinds of leather, Erretre are able to accurately control the results from the milling drums they produce

Returning to the computerisation of the milling process, having completed exhaustive trials, they developed a software package which would allow the tanner to control precisely what is going on inside his drum.

This means that the process control is out of the hands of the operator, who is left to load and unload the drum without the worry of ensuring the process will start on time etc.

A trained technician decides on the formulation to be used with the help of the computer and a clever bit of programming that stores all the previous history of milling in the drum.

The advantage of this history is that it is a record of what actually happened rather than what was in the initial recipe. This helps the technician to decide on the correct process to use. More information means that the process can be better controlled.

The system also allows the technician to completely disconnect the computer if necessary or if there is a system failure. A control panel attached to the drum allows the operator to manually control the important parameters.

At the other end of the scale individual drums can be connected to a control system, which will control several drums by means of a host computer.

Graphic display

The graphic display of the various functions allows the machine to be programmed easily and precisely. This is achieved by grabbing the particular icon which may, for instance, represent the loading of the batch, and dropping it into the schedule bar. There is also a process list and an unloading list. When these are also dropped into the schedule bar the recipe is complete and the process can begin. However, before it does, the computer checks the recipe is capable of doing the job, that the drum’s capacity is suitable and it reconfirms the chemical additions required.

If there are any problems the technician can modify the process. Another important feature, which appears on the background of the screen, is whether the operator is available to load the drum, and not on a tea break when the process is about to start. If he is, then the computer will wait until someone is available to carry out the necessary operations.

There is a ‘real time’ line on the computer and when the bar crosses that line it becomes ‘history’, and the data of what really happened is stored for future reference. Another feature is a single screen analysis of what is due to happen next, much in the same way as a screen in an airport tells the onlooker which flights are due to take-off and when that event will occur.

The system is also provided with auto-diagnostics for signalling any problem in any part of the machine and there are back-up discs that ensure that if there is a failure, no data is lost.

Returning to the first statement about what makes a tannery invest in an expensive milling drum, Galiotto said: ‘when leather production is critical, quality is important. The value of the machine is small if buying a cheaper machine means that a lot of grade 1 upholstery leather is ruined in the milling because there is excessive pebbling due to poor process control.

‘Thus, spending an extra 10k on the best machine is actually a good return. The more difficult the conditions, the better for us.’

Even with difficult trading conditions Erretre are investing million of lire in a new facility to expand the current operations. The new factory will be opening later in the year in Arzignano, and Erretre intend to move their head office there, although they are keen to point out that the original factory will remain part of the scheme.

Ruggero Galiotto, the founder and director general of Erretre, said: ‘we are in the middle of the race. The first ten years took us the time to develop and grow the ideas. Then there was a big jump and this [new factory] is the start which allows us to grow. There are new projects in the pipeline, so this building is important.’

Also at the new site are BER Chimica. They are Erretre’s partners in developing the chemical milling products. The chemicals are produced by Biar and sold in a JV agreement between Erretre and BER. Chemical milling is important in improving certain leather properties such as hydrorepellency, crock fastness and feel/touch of the leather. The addition of chemicals at the milling stage means that the properties can be modified and different effects achieved.

Conceria Ambra

One tanning group that have been impressed with Erretre are the Dal Maso group. This group includes Conceria Arianna, Tigre, Dal Maso Callisto and the tannery I visited: Conceria Ambra.

The Ambra tannery have two units, one for wet production and one for finishing. They produce around 3 million ft² per month of leather for upholstery, car seats and steering wheels, all precut.

The automotive leather manager, Alberto Silvagni, agreed that there was a growing non-chrome market, especially non-metal wet-white production. However, he did point out that there was no scientific or ecological reason for this: ‘it is what our customers want.’

Generally, although there are the problems with raw material supply, business for Ambra is good, with production going to the US markets and Europe.

He said that they used Erretre drums for milling because they had been with Erretre from the beginning and started with their simple milling machines before advancing to the computer controlled types. The computer handling of the drums in the automotive upholstery business is important because the quality has to be right. Chemical milling, he said, is important because it gives a product that is difficult to surpass in a normal processing way.