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A History of Flat Glass Cutting
Written by: Bob Lang, Solution Specialist at Billco Manufacturing
As one recalls the progression of flat glass cutting from the early 1900’s to today, there has not been very many major iterations of equipment designs to get where we are today.
As glass producers changed from producing glass in large round cylinders, to flat drawn vertical or horizontal processes in the early 1900’s, scoring the glass surface with a small wheel or other hard item, held by a wooden hand tool was the order of the day.
Large lites of glass were cut (or “capped”) from the continuous ribbon of glass, placed on bucks (racks), and delivered to hand cutting areas of the factory. The hand cutting area looked like rows of horse stalls. In each stall was a man with a wooden hand cutting tool (usually diamond tipped), and a large table. The environment was dark and dirty.
As the racks of large glass lites were delivered to the stalls, the men scored and separated the lites into smaller squares or rectangles. The sizes they cut corresponded to the stock glass sizes that the glass producer sold to the local glass shops around the country. These stock lites were interleaved with saw-dust or paper, and were shipped in wooden boxes.
An interesting side note is that my company, Billco, at that time under the family name of Klages, had its beginnings in the early 1900’s making these diamond tipped hand cutting tools as one of its products for the glass industry.
The First Commercially Produced Cutting Machines
Machines for cutting shapes were developed in the late 1920’s / early 30’s, almost 30 years before straight-line cutting machines were produced.
The first shape cutting machines were designed for cutting circles and ovals, and were manually operated. My company began selling these circle and oval machines in the 1930’s to distributors selling supplies to the glass industry, as well as directly to companies who were producing clocks, mirrors, gauges, optical devices, and other items that required a glass cover plate. These machines could produce parts from 1” to 36” in diameter.
As automobiles began using glass in the 1930’s, and the automobile designers demanded windows in shapes other than rectangles, manually operated shape cutting machines were developed. These machines utilized a two-part arm assembly supporting a pneumatically operated head that held a cutting wheel. This assembly looked exactly like a person’s upper and lower arm, and hand. The assembly pivoted at the upper arm from a heavy post attached to the back of the cutting table. A template was made from wood or metal in the shape of the desired part. This template was suspended over the cutting table, just above the stock lite of glass lying on the table.
The cutting head was designed to follow this template as the operator moved the arm and head assembly around the template. The pneumatic head forced the cutting wheel down to the glass, which placed a score on the glass in the shape of the template as the operator moved the arm/head assembly around the template. After scoring, the glass was moved to an adjacent table for score separation. These shape cutting machines were not only used in the automotive industry, but in the mirror industry as well. Manually operated shape cutting machines ranged in size from 20”x 20” to 44”x 94”. An example of one of these machines is shown.
Even some large glass wholesale shops had at least one shape cutting machine, as well as one or two oval/circle cutters. In order to reduce operator fatigue in high production automotive shape cutting lines, a motor and belt assembly was introduced in the 1950’s, to power the cutting head around the template. These manual and powered shape cutting machines were prevalent until the late 1970’s, when a revolutionary new concept was introduced to the industry, as you will see later in this discussion. However, some of these shape cutting machines are still being used in factories in some parts of the world.
Straight-line Cutting Machine Technology Developed Slowly
Straight-line cutting can be defined as cutting of squares, rectangles, or trimming edges from the stock size glass sold by the glass manufacturers. Surprisingly, it took until the late 1940’s before any type of automated equipment for straight-line cutting became commercially available. Until then, straight-line cutting was done on tilting or stationary tables, with hand cutting tools and straight edges. There was one exception to this… the automation of the cutting (“capping”) of stock sheets from the continuous vertical and horizontal glass ribbons, after the glass was cool enough to be handled. Billco built this type of equipment for glass producers, and I assume other companies did as well. [Read more…]