CHANGEOVERS IN A NAPKINS CONVERTING LINE
Changeover in a mechanical napkins folder takes at least two-three hours.
This is the real time you lose each time you replace folding head, embossing rollers, cliché cylinders and for doing all necessary adjustments (also with a waste of material, in consequence of it) plus another 30-60 minutes to replace size-parts of the napkins packaging machine.
Napkins folding machines which work by vacuum process are “multi-size” machines : by some simple adjustment you may convert napkins of all sizes between a range .
Unfortunately, one-line vacuum folders run up to 300-350 m/min while a mechanical folder runs up to 700 m/min.
Furthermore, you will have to replace edge embossing rollers and printing cylinders anyway, if you change napkin size.
You may easily understand which a vacuum folder is good for some application but not necessarily it solves matters of frequent changeovers.
Considering that, when daily capacity is an issue, the best choice is to use a napkins converting line (specially if the folder is mechanical-type) for one item only.
Obviously, not all converters have got so many lines, thus there is no choice than using a converting line for more than one napkins-size and packet-configuration.
Apart obvious advices like : schedule your job and do changeovers once per week, it is definitely better not to charge a napkins converting line by so many different folding heads, embossers, subjects to print, number of napkins to pack or the real capacity of that line will fell down dramatically.
If you have no choice, try at least to do it on a vacuum-type folder since in this machine changeover takes much less time.
Some other valid ideas are:
- add to the folder one or two additional embossing stations: in this way you don’t need to continuously remove embossing rollers but you will just pass the tissue from one or another embossing unit
- if you print many subjects in small quantities: buy a folder with 4 or 6 color units and always keep red ink in one unit, green ink in another unit, yellow, blue and so on in other units. In this way you will still have to replace clichés but you will have not to wash units to remove previous ink each time
- last but not least: modern packaging machines are servo-based: by operator panel you may adjust almost all parameters of your packer, cutting in this way the changeover requested time.