In April 2000 I visited the Miyuki glass bead
factory in Japan. My tour was fascinating and the
information below is what I gleaned from my tour.
I was not invited to photograph most of the
process, sorry, and any factual errors are my
fault.
Miyuki, by the way, started to make glass beads right after the end of WWII, in 1949. However, Miyuki Shoji as a company was not established under that name until 1974. This year they shortened their name to Miyuki Co., Ltd.
How Miyuki Makes Glass Seed Beads
Step One: Raw materials and recycled glass of the same color are mixed and melted in the furnaces. The Miyuki factory has both automatic and manual furnaces operating 24 hours per day. They are on the 2nd floor.
Step Two: When ready, molten glass from the furnaces falls through a hole. The shape of the hole determines the shape of the glass tubes.
Step Three: After dropping to the first floor, the vertical tube of falling glass passes under a thick chunk of wood and turns at a right angle to become horizontal. Imagine a vertical length of rope passing under a pulley and then being pulled sideways. The scene in the glass factory is much more dramatic, however. For starters, the glass "rope" is still extremely hot so that it is slowly burning its way through the smoking piece of wood. In addition the tube of glass is actually being pulled over a series of metal troughs by a machine which not only pulls the glass but also cuts it into one meter lengths. The speed of the pulling determines the diameter of the glass tubes. A faster pull makes thinner tubes; a slower speed makes them thicker.
Step Four: The cooled tubes are sorted to make sure that they are the correct diameter for the size beads being produced. Any tubes which are not the correct size will be recycled and remelted to make new glass.
Step Five: The tubes are cut into beads. As the cutting room is not open to any outsiders, I can't offer further information. I did learn that one Delica cutting machine can only cut 4-5 kgs per day, which is one reason for their high cost. (And contrary to some rumors, Miyuki cannot run the Delica cutting machines faster to keep up with increased demand, with an accompanying decline in quality. Instead high demand just leads to longer waits for production). Delicas are not cut by lasers, by the way, another occasional rumor.
Step Six: Cut beads are mixed with carbon black and reheated to make them round. Delicas are only slightly heated; round beads are heated more.
At this point the beads are washed. Those which need no additional work—plain crystal, plain opaques or transparents—are then ready to be weighed and packaged.
Fancier beads, for example matte finishes, AB coatings, color-lined beads, etc. may go through one, two, or even more additional processes before they are finished. Each additional step takes time, equipment, and adds to the cost of the finished bead.
Amazing!
Miyuki, by the way, started to make glass beads right after the end of WWII, in 1949. However, Miyuki Shoji as a company was not established under that name until 1974. This year they shortened their name to Miyuki Co., Ltd.
How Miyuki Makes Glass Seed Beads
Step One: Raw materials and recycled glass of the same color are mixed and melted in the furnaces. The Miyuki factory has both automatic and manual furnaces operating 24 hours per day. They are on the 2nd floor.
Step Two: When ready, molten glass from the furnaces falls through a hole. The shape of the hole determines the shape of the glass tubes.
Step Three: After dropping to the first floor, the vertical tube of falling glass passes under a thick chunk of wood and turns at a right angle to become horizontal. Imagine a vertical length of rope passing under a pulley and then being pulled sideways. The scene in the glass factory is much more dramatic, however. For starters, the glass "rope" is still extremely hot so that it is slowly burning its way through the smoking piece of wood. In addition the tube of glass is actually being pulled over a series of metal troughs by a machine which not only pulls the glass but also cuts it into one meter lengths. The speed of the pulling determines the diameter of the glass tubes. A faster pull makes thinner tubes; a slower speed makes them thicker.
Step Four: The cooled tubes are sorted to make sure that they are the correct diameter for the size beads being produced. Any tubes which are not the correct size will be recycled and remelted to make new glass.
Step Five: The tubes are cut into beads. As the cutting room is not open to any outsiders, I can't offer further information. I did learn that one Delica cutting machine can only cut 4-5 kgs per day, which is one reason for their high cost. (And contrary to some rumors, Miyuki cannot run the Delica cutting machines faster to keep up with increased demand, with an accompanying decline in quality. Instead high demand just leads to longer waits for production). Delicas are not cut by lasers, by the way, another occasional rumor.
Step Six: Cut beads are mixed with carbon black and reheated to make them round. Delicas are only slightly heated; round beads are heated more.
At this point the beads are washed. Those which need no additional work—plain crystal, plain opaques or transparents—are then ready to be weighed and packaged.
Fancier beads, for example matte finishes, AB coatings, color-lined beads, etc. may go through one, two, or even more additional processes before they are finished. Each additional step takes time, equipment, and adds to the cost of the finished bead.
Amazing!
Glass-melting furnace at the Miyuki factory