Hi Y'all,
I worked for Ball for 20 years. The machines that make glass containers are simply amazing to watch! If any of you EVER have the chance to tour a glass factory, do so. It will be something you won't soon forget. When collectors came to visit us here, I always gave them a tour of the Ball plant. They may not remember my jar collection, but I'll bet they still remember that tour!
How jars are manufactured has really changed little in the past 100 years. The basic principle is still the same although the speeds have increased dramatically. A few years ago, I wrote an article explaining glass forming machine operation for another jar forum. I thought you folks might be interesting in reading it.
Bob Clay
Glass Forming Machine Operation
A modern glass forming machine is a true wonder to watch! Usually the machine consists of 8, 10 or 12 sections, with each section actually an independent machine. Each section can make either two, three or four containers at a time (cycle) depending upon how many gobs, blanks and moulds are on each section. There are machines that easily put out 700 containers per minute in use right now. These machines are run by compressed air and usually computer controlled now, as far as the timing goes. A very minute change in the timing can make a world of difference!
Let's start with the glass itself. Today's furnaces are what is known as continuous flow furnaces, in that raw materials are continuously being purged in at one end and glass extruded from the other. This is crucial for a 24 hour operation that draws as much as 500 tons of glass per day. Once the melted glass (at around 2700°F) leaves the furnace, it is distributed to the forming machines in channels called forehearths. Temperature is critical here. At the end of each forehearth right above a machine is what is called an orifice ring, which the glass is pressed through to make a flow of glass in a specific diameter. The glass is then cut into "gobs" of a specific size and precise weight by the "shears" . Depending upon how many molds are to a section, determines how many gobs are cut at one time.
Once the glass is cut into gobs, these fall a few feet into a gob distributor, which swings wildly about and makes sure the gobs are distributed to each section of the machine in a perfectly timed manner. The gobs of glass go through delivery tubes which align them and stop any wobble as they are falling. This is all simply gravity controlled. Once they leave the delivery tubes, the fun begins.
The gobs fall into the back side of the forming machine, called the "blank" side. Most of the machines I worked with were called double gob machines, as two gobs were distributed to each section at a time. Triple gob and quad gob machines have three and four respectively. The gobs drop into the closed blank mould. As soon as the gob hits, a plunger comes up from the base and through the finish ring and presses the glass into the finish ring, forming the lip and threads of the container and actually preshapes the glass into a longer, more cylindrical form, hollow in the middle and now with a threaded finish and finish side down. At this point it is called a "parison". Then the blank mould opens and the invert arms remove the parison by the finish ring and flip it over to the other side of the machine to waiting, open, final blow moulds. These are the moulds which actually form the container. They consist of two halves and a bottom plate. As soon as the invert arms release the container, they flip back over to the blank side and another gob falls immediately into place, while the rest of the job continues on the front side of the machine for the parison just released.
On the front side of the machine, immediately these moulds close, which leaves the finish ring above their surface. Then a "blowhead" swings over, sets down over the finish ring and blows a specific amount of carefully controlled temperature air directly into the parison. Now you have a completely formed container. Then the blowhead swings back, the mould swings open and the "take out jaws" grab the jar by the threads, remove it from the bottom plate and suspend it above the "cooling plate" momentarily. As soon as the take out jaws remove the container, another parison swings over from the blank side ready to be blown. Then the take out jaws open and release the container. For a split second it sits on the cooling plate being circulated with cool air to make it set up. (the container is still glowing red hot at this point) then the "push out paddles" push the container out of the machine and onto a fast moving flat chain, which carries the containers through a coating hood, where gaseous compounds are applied to improve the lubricity of the container. They exit the hood and move into where the "stacker" positions the containers in rows in what is called a "lehr" which is the tempering oven. Here the container is heated back up to around 1000°F and then cooled to about 250° in about a half hour process. The lehr is similar to the ovens seen for cooking pizza, except they are MUCH larger; maybe 20 feet wide and 150 feet long or longer. As the containers exit the lehr, they are then moved onto high speed chains which take the containers through many electronic inspection machines, to the case packers or palletizers.
All this sounds EXTREMELY complicated, and it is. And this is for just one section. Imagine if you will, 10 or 12 of these sections all working in unison and timed perfectly so the containers exit the machine about 2-3" apart. This was describing just ONE cycle of ONE section, and depending upon the size of the container and the speed of the machine, only takes a couple or three seconds. It was amazing to watch. And even if you can imagine a machine that can produce 12 bottles per SECOND, you really have to actually see it to believe it!
Somewhere around here, I have a tape that shows a forming machine in operation, and the operator swabbing each of the blanks. Incredible to watch. A dangerous job, but the forming machine operators are fully aware of the dangers, and concentration is critical. One wrong move could result in your hand being burned off or crushed beyond belief. I got to work with some of the best of them, and learned much over the years. It truly was a big help in understanding just how the jars we love to collect, were manufactured years ago. The speeds have increased greatly, and the quality has as well, but the principle behind their manufacture hasn't really changed much in 100 years.
I worked for Ball for 20 years. The machines that make glass containers are simply amazing to watch! If any of you EVER have the chance to tour a glass factory, do so. It will be something you won't soon forget. When collectors came to visit us here, I always gave them a tour of the Ball plant. They may not remember my jar collection, but I'll bet they still remember that tour!
How jars are manufactured has really changed little in the past 100 years. The basic principle is still the same although the speeds have increased dramatically. A few years ago, I wrote an article explaining glass forming machine operation for another jar forum. I thought you folks might be interesting in reading it.
Bob Clay
Glass Forming Machine Operation
A modern glass forming machine is a true wonder to watch! Usually the machine consists of 8, 10 or 12 sections, with each section actually an independent machine. Each section can make either two, three or four containers at a time (cycle) depending upon how many gobs, blanks and moulds are on each section. There are machines that easily put out 700 containers per minute in use right now. These machines are run by compressed air and usually computer controlled now, as far as the timing goes. A very minute change in the timing can make a world of difference!
Let's start with the glass itself. Today's furnaces are what is known as continuous flow furnaces, in that raw materials are continuously being purged in at one end and glass extruded from the other. This is crucial for a 24 hour operation that draws as much as 500 tons of glass per day. Once the melted glass (at around 2700°F) leaves the furnace, it is distributed to the forming machines in channels called forehearths. Temperature is critical here. At the end of each forehearth right above a machine is what is called an orifice ring, which the glass is pressed through to make a flow of glass in a specific diameter. The glass is then cut into "gobs" of a specific size and precise weight by the "shears" . Depending upon how many molds are to a section, determines how many gobs are cut at one time.
Once the glass is cut into gobs, these fall a few feet into a gob distributor, which swings wildly about and makes sure the gobs are distributed to each section of the machine in a perfectly timed manner. The gobs of glass go through delivery tubes which align them and stop any wobble as they are falling. This is all simply gravity controlled. Once they leave the delivery tubes, the fun begins.
The gobs fall into the back side of the forming machine, called the "blank" side. Most of the machines I worked with were called double gob machines, as two gobs were distributed to each section at a time. Triple gob and quad gob machines have three and four respectively. The gobs drop into the closed blank mould. As soon as the gob hits, a plunger comes up from the base and through the finish ring and presses the glass into the finish ring, forming the lip and threads of the container and actually preshapes the glass into a longer, more cylindrical form, hollow in the middle and now with a threaded finish and finish side down. At this point it is called a "parison". Then the blank mould opens and the invert arms remove the parison by the finish ring and flip it over to the other side of the machine to waiting, open, final blow moulds. These are the moulds which actually form the container. They consist of two halves and a bottom plate. As soon as the invert arms release the container, they flip back over to the blank side and another gob falls immediately into place, while the rest of the job continues on the front side of the machine for the parison just released.
On the front side of the machine, immediately these moulds close, which leaves the finish ring above their surface. Then a "blowhead" swings over, sets down over the finish ring and blows a specific amount of carefully controlled temperature air directly into the parison. Now you have a completely formed container. Then the blowhead swings back, the mould swings open and the "take out jaws" grab the jar by the threads, remove it from the bottom plate and suspend it above the "cooling plate" momentarily. As soon as the take out jaws remove the container, another parison swings over from the blank side ready to be blown. Then the take out jaws open and release the container. For a split second it sits on the cooling plate being circulated with cool air to make it set up. (the container is still glowing red hot at this point) then the "push out paddles" push the container out of the machine and onto a fast moving flat chain, which carries the containers through a coating hood, where gaseous compounds are applied to improve the lubricity of the container. They exit the hood and move into where the "stacker" positions the containers in rows in what is called a "lehr" which is the tempering oven. Here the container is heated back up to around 1000°F and then cooled to about 250° in about a half hour process. The lehr is similar to the ovens seen for cooking pizza, except they are MUCH larger; maybe 20 feet wide and 150 feet long or longer. As the containers exit the lehr, they are then moved onto high speed chains which take the containers through many electronic inspection machines, to the case packers or palletizers.
All this sounds EXTREMELY complicated, and it is. And this is for just one section. Imagine if you will, 10 or 12 of these sections all working in unison and timed perfectly so the containers exit the machine about 2-3" apart. This was describing just ONE cycle of ONE section, and depending upon the size of the container and the speed of the machine, only takes a couple or three seconds. It was amazing to watch. And even if you can imagine a machine that can produce 12 bottles per SECOND, you really have to actually see it to believe it!
Somewhere around here, I have a tape that shows a forming machine in operation, and the operator swabbing each of the blanks. Incredible to watch. A dangerous job, but the forming machine operators are fully aware of the dangers, and concentration is critical. One wrong move could result in your hand being burned off or crushed beyond belief. I got to work with some of the best of them, and learned much over the years. It truly was a big help in understanding just how the jars we love to collect, were manufactured years ago. The speeds have increased greatly, and the quality has as well, but the principle behind their manufacture hasn't really changed much in 100 years.
