How Rings are Made
Although we use a number of different manufacturing processes with varying degrees of automation, the basic process steps are common to all ring types:
(1) the metal strip is cut into correct lengths (called blanks) and sharp edges on incoloy/steel rings are removed by barrelling.
(2) the ringing scheme name and address (e.g. BRIT.MUSEUM, LONDON SW7) is stamped on the blank.
(3) the number (e.g. AB00001) is stamped on the blank.
(4) the blanks are bent into the correct ring shape (forming the ring).
Special rings (e.g. Penguin rings) may require several forming stages.
(5) the rings are placed in sequence on a plastic tube.
(6) the rings are inspected, packed and despatched.
The exact nature of these six steps differs between ring types and are therefore described in more detail below.
Cutting the Blanks - Most rings used on small short-lived species are made from a magnesium aluminium alloy whilst incoloy (a nickel-chromium alloy) is used for most large long-lived species or where excessive abrasion, exposure to saline or alkaline water would shorten ring life. For cost reasons stainless steel is used for rings with a diameter greater than 12.5 mm. The raw materials are purchased in rolled strip form. Unlike the aluminium alloy which is relatively soft and easy to cut, the cutting of incoloy and steel gives rise to sharp edges which have to be removed through the process of barrelling. This involves the cut blanks being rotated in a centrifuge overnight with silicon chips to gradually wear off the sharp edges.
Stamping the Address - Although some customers require just a simple number to be stamped on the rings, most also require a unique name or address. The amount of information that can be stamped on a ring is dependent on the size of the ring, and is detailed in tables on the relevant product pages. Each address die is made for us by a specialist company, and is kept for use with any future orders.
Stamping the Ring Number - Unlike address dies which are unique to each customer, the ring numbers are stamped using standard numerator heads with a series of rotating wheels containing letters or numbers that automatically increment to give the correct number sequences. Porzana has 3 numerators that can produce a series of 7 letter/number combinations that are 1.6, 2.4 and 3.2 mm high, and a larger numerator that can produce a 5 letter/number combination that is 5.0 mm high. There are 4 types of wheel, one with numbers 0 to 9 and 3 with letters covering the alphabet from A to Z.
Forming the Ring - For most simple C or V shaped rings only one forming operation is required, however more complex rings such as clips, Guillemot, Razorbill and SOs require additional operations. For example, clip rings require 3 forming steps.
Plastic Tubes - The smaller aluminium and incoloy rings are placed in number sequence on cut lengths of plastic tube in 100s whilst larger incoloy rings are placed on tubes in 20s or 10s. The largest steel rings are sello taped together in 10s.
Inspection - Although the machine operators are all responsible for checking their own work, all rings are subject to an independent inspection before packing. Any errors are corrected and investigated to prevent recurrence wherever possible.
Although many of the smaller volume and more complex rings still have to be made on hand and kick presses, great improvements have been made in recent years to automate the manufacturing processes. Three aluminium alloy ring sizes, 2.0, 2.3 and 2.8 mm, account for about 66% of our production volume and therefore justify their own dedicated automatic machines. These machines name, number, guillotine and form the rings in one continuous operation. Once the machine has been set up for a particular order, the machine operator controls the process from the feed of the alloy strip into the machine through to the completed rings that are formed around the plastic tubing.
Larger aluminium alloy rings from sizes 3.3 to 5.25 mm are made on a semi-automatic machine (the Linear Machine) which can name, number and guillotine the rings but these flat rings then have to be formed by hand on kick-presses and placed in sequence on the appropriate sized plastic tubes. Whilst this manual forming operation is very time-consuming and slow, the quantity produced of these larger alloy rings does not justify the investment in separate dedicated machines.
All our standard V shaped incoloy and steel rings larger than 4.3 mm are made on a rotary machine. On this machine the operator feeds individual barrelled blanks into the machine which are then addressed, numbered and formed before dropping into a catch tray. The operator then places the rings in sequence on plastic tubes. The speed of the machine is determined by the rate at which the operator can feed in the blanks and handle the formed rings, however, changing the forming tools, the address dies and the numerators between each job can take several hours.
Although some of the processes used to make rings/bands are now fully automated, a number of the manufacturing processes are still very basic and require considerable manual work. Whilst human errors are kept to a minimum, an understanding of the manufacturing processes may help customers who use our rings to understand how problems can very occasionally arise.