ReturnChinese-European co-operation in electronic testing for raw silk yarn
Italian programme
-----------------------------------------------------------------
May 15, 2008
(Varese)
(Tarcisio Mizzau, Stazione Sperimentale per la Seta)
Ladies and gentlemen,
taking the floor as the Chairman of Stazione Sperimentale per la Seta, the Italian research institute for textiles, I’m happy to welcome all of you in Italy to discuss, among various
items, the latest progress on the subject of electronic testing for raw silk yarn starting to consider a new raw silk Classification System.
A particularly warm welcome to the Chinese friends, whose presence gives substance to our discussion, since an appropriate control of raw silk meets its ceiling result when applied in filatures; and filatures are mainly present in China. The subsequent control,
when the goods are traded, is naturally useful, but only to promote a fair business, not to
help production operations and have better lots.
We note with pleasure that the Hangzhou CIQ report underlines the need for an entirely reproduceable Electronic Test, so that exactly the same instrument, same accessories, same yarn path should be used by all surveyors and that upgrades and improvements
should be adopted at the same time by all inspecting institutions around the world.
The second essential condition for international recognition of a testing instrument and
method is repeatability of the test with consistently similar results.
We have as long experience of Classifault tests as Hangzhou CIQ, because all Jiaxing Idea data is available to us, we visit there regularly and took active part in suggesting
system upgrades. However from the beginning we tested raw silk after soaking and drying
(in the condition it reaches our users), while Hangzhou CIQ tested unsoaked raw silk, just
as with the seriplane test. We learnt from Keisokki that CIQ results were not repeatable
and we witnessed the failure of Keisokki engineers to start testing with the new
TrichordFlex winder at the State Standards Committee last October. When Hangzhou CIQ
announced they were going to make comparison tests with soaked silk, we thought it was
fair that we should study at our side our common instrument performance with unsoaked
raw silk.
The TrichordFlex system lately developed does not bar use of unsoaked silk, albeit at a
speed of 500mt/min against 1000mt/min of soaked silk. The Slub, Thick and Thin, both
capacitive and optical, do not show significant variation, just IPM are understandably
slightly higher. A great improvement in consistency between optical and capacitive results
will be found compared to the present CIQ system.
As Mr. Dong explained, cohesion defects can only be detected by the optical sensor and
only after soaking. However the optical sensor cannot distinguish flat silk from defective
cohesion: it is necessary to cut and retrieve Thick defects and put them onto a blackboard
for visual examination. The operator can easily do this during the test, as the number is
fortunately limited. This is the only way to directly rate silk for cohesion; the other way is
indirect and arbitrary, as it must take into account number and difference between optical
and capacitive result of Slub in the 80% and 100% class.
The second reason for which we recommend testing soaked silk relates to repeatability.
While we have succeeded to obtain consistently repeatable results with soaked silk (noting
that if you adopt ±15% for Thick and Thin the result will be reversed each time you rewind
due to the zero point of calibration), we have been unable to obtain repeatability with
unsoaked silk, especially with Thin and Thick, even adopting ±30%, because the
deterioration of the unprotected sericin surface is much faster.
The key point in TrichordFlex winder testing is that the sample is not destroyed but can be
delivered, together with defects blackboard, with the lot, so that a retest at destination on a
similar instrument can confirm the test result, in case of claim. In our experience this is
possible with soaked silk but will be very difficult to achieve without soaking.
Cost (due to double winding speed but also to faster wear of the drums and feeders with
soaked silk), cohesion detection and repeatability are arguments in favour of soaked silk
testing. However both ways are possible and the silk community can take a decision after
adequate study.
Coming now to the research programme we’ve planned for the near future, I’m happy to
inform you that a big advance has been decided: in fact, we will now be able to make
some autonomous lab work, studying the matter in parallel with Hangzhou CIQ and Jiaxing
Idea, whereas in the past years we used to pay attention to the lab work of the others,
contributing with our consultancy only.
In Como, in the Centro Tessile Serico lab, we’ll install a complete, updated Classifault
equipment, in order to test a considerable number of samples coming from different lots of
raw silk. Dr. Francesco Gatti, who has been dealing with this matter in the last five years,
will lead a group of researchers. The aim of the project is to gather enough data,
comparable with the data produced by Hangzhou CIQ and Jiaxing Idea, to enable our
group to take part in the dialog when the new Classification System for raw silk will be
established.
The programme is supported by Regione Lombardia, Stazione Sperimentale per la Seta,
Centro Tessile Serico and Ufficio Italiano Seta.
Let me underline the three steps of our plan, and the necessity to open a co-operation
among European and Chinese researchers to achieve the final goal.
First: we’ll install the equipment in Como before the end of this year and we’ll be assisted
by Keisokki in starting the operations.
Second: we’ll make one hundred to two hundred tests on different samples of raw silk,
gathering the data and studying them. In this case we need to agree, in a preparatory
phase, with the parallel groups – say Hangzhou CIQ and Jiaxing Idea – all the details of
lab operations, so the data of the three labs are comparable. This phase will be completed
during the first half of the year 2009.
Third: together with the Italian firms buying Chinese raw silk, and having the gathered data
in our hands, we’ll prepare our proposals to contribute to the elaboration of the new rules
for raw silk new Classification System.
This way we hope that the new Classification System will finally come out with such
characteristics that can convince the Chinese Standardization authorities to approve it,
and the European Standardization authorities follow the same track during the year 2010.
Having this programme in mind, we hope that the contacts with the Chinese friends will
continue after the present meeting. There’s a lot of work to be done together.
We call also our European friends to take part in this adventure, so important for our
sector. We’ll open the work plans and the collected data to all of them. We would be
honoured to have some French, Swiss or other countries’ technicians working with us.
We start to see the light at the end of the tunnel, after long years of talking. It’s nice to
work, finally, with a positive perspective ahead.
Thank you for your attention.
