July 27, 2018

Glass Manufacturing

Stewart Engineers builds high-quality float glass manufacturing facilities around the world. We use our considerable experience in float glass to design and build float facilities that maximize profit. Technologies like the StewartFloat® tin bath and AcuraCoat® CVD system combined with Stewart’s international project management and procurement experience result in float facilities that are built on schedule, on budget, and on quality. Beyond the initial project metrics, Stewart Engineers delivers a total solution by providing highly automated and robust solutions along with glass manufacturing process and business operations training.

Stewart Engineers specializes in helping new entrants to float glass manufacturing understand what they need to succeed. Determining ideal tonnage, staffing, product mix, glass recipes, and other critical design decisions can be tough for groups entering the float glass market. A feasibility study is the best tool for determining the market strength and market positioning. Stewart has been in glass for many decades and can assist customers in making the decisions that will determine their future success. Whether or not a customer purchases a feasibility study, Stewart Engineers advises our customers on the best paths to success.

Unlike other engineering companies, the facilities we build are designed first, and foremost, to be profitable.

Plant capacity, location, product mix, product quality, rebuild period, and equipment selection all affect profitability. We consider how every aspect of the plant affects profitability before finalizing it. One example is plant capacity. The higher the plant capacity, the lower the cost per ton of the glass produced. On the surface, it seems like plants with very high capacities would be best but other factors come into play like risk and market size. A float facility has a limited ability to produce less than its design capacity and as glass production is reduced the profit per ton drops precipitously. Even when only considering operating expense (OPEX) this means it is better is better operate a 600 tons per day (TPD) plant at 600 TPD rather than operate an 800 TPD plant at 600 TPD. The plant design must be carefully tailored to the local market and have the appropriate technology for the endeavor to be profitable. We have many decades of glass industry experience to guide the decisions that will affect profitability.

Properly designed workflow can be a significant advantage to a manufacturer. We develop our facilities to promote logical and efficient workflows. An example of a good workflow design is the placement of the quality lab. We place the quality lab directly beside the production line; this enables the Quality Control (QC) operators to pull samples and return to the lab to conduct their measurements speedily. Ultimately the efficient workflow empowers the production supervisors and operators to respond to process conditions more quickly—leading to higher quality and yields.

We use our experience and process knowledge to prequalify our sub-suppliers to guarantee the quality of our facilities.

Stewart Engineers guarantees and warranties our facilities. Most engineering companies will only guarantee the equipment; leaving the customer at risk of having functioning equipment but poor product yields or quality. Stewart can ensure not only correctly functioning equipment but also successful glass production because we have extensive experience in glass.

We have decades of experience with most of our suppliers, so we know how to deploy capital efficiently. Glass making suppliers can present customers with a wide array of options. Batching configurations can range from one to more than five times cost for exotic arrangements. Stewart has the glass manufacturing process expertise to select the best recipes for our clients.

Our team travels globally installing glass technologies. We ensure our systems whether built internally or purchased from sub-suppliers meet our rigorous quality and maintenance standards. We use the most straightforward technology that meets our production goals, ensuring replacement parts and knowledgeable technicians are available in any part of the world.


Continuous Improvement
  • We can transform a greenfield into a float glass facility in 24 months.
  • Our layouts are the most effective in the industry.
  • Our equipment uses the latest technology.
We use automated process controls when it makes sense.

We automate jobs where operators make errors. For example, as the molten glass floats atop the liquid tin in the float bath, the speed the glass is pulled from the bath is automatically maintained. By automatically controlling many of the variables involved in the forming process, product quality is improved.

We automate jobs that would be dangerous for an operator. Stacking glass by hand is a dangerous job, years ago it was common to have 100 or more people handling glass in our factories. As glass handling technology has gotten better, faster, and cheaper, we have reduced the number of people handling glass—leading to a considerable reduction in injuries.

We automate jobs where operators cannot keep pace. The feeding of all raw materials to the glass furnace is automated. Over 700 TPD of raw materials must be weighed to produce 600 gross TPD of glass, and it is common to have over 1,000 weigh-ups (weighing of raw materials) every day.

Let us be your trusted technical partner for float glass projects.

Our latest innovations

July 27, 2018

Feasibility Studies

Stewart Engineers can help you quantify risks and ensure financial feasibility before investing in glass manufacturing. Investing in float glass is challenging for new entrants. How can y... Read More→

July 27, 2018

Glass Manufacturing

Stewart Engineers builds high-quality float glass manufacturing facilities around the world. We use our considerable experience in fl... Read More→

June 19, 2018

Make CVD Part of your Future

Glass manufacturers began to use CVD for online coatings in the 1960’s. Pilkington was the first to develop a marketable product, Reflectafloat. Over the lifetime of the product, i... Read More→

May 07, 2018

History of Glass

How to turn Sand into Glass The raw material from which glass is made is silica, the most abundant of all the earth's minerals. Milky white in color, it is found in many forms of rock, including granite. And as... Read More→

May 07, 2018

Float Glass Cutting and Packing

The final online manufacturing process for float glass is the Cutting and Packing line. The cutting and packing conveyor is immediately downstream of the annealing lehr. It is comprised of special roller sections that... Read More→

May 07, 2018

Float Glass Annealing Lehr

What is a lehr? A glass annealing lehr oven- often just referred to as a 'lehr', is a long, temperature controlled, kiln. Lehrs are typically 6m wide and... Read More→

May 07, 2018

Glass Forming

Forming Technology Flat glass is manufactured using one of three processes: the sheet process, the plate process, or the float process. The float glass process has, almost entirely, replaced the sheet glass and... Read More→

May 07, 2018

Glass Materials and Batching

Glass contains three major categories of constituents - formers, fluxes, and network modifiers. Silicon dioxide (SiO2), or sand, is used as the former and basic constituent with soda ash (Na2CO3) as the flux. Lime (Ca... Read More→

May 07, 2018

Glass Melting Process

Melting The typical melting furnace is a Six Port Cross Fired Regenerative furnace with a capacity of 500 tons per day. Cross fired regenerative furnaces have been built for very small and very large melting ar... Read More→

April 10, 2018

Glass Coating Technology Comparison

A variety of techniques are available to deposit thin films onto flat glass. The most widely used of these for producing high-quality functional coatings can be subdivided into two classes: Physical Vapor Deposition (... Read More→