Volume 42, Issue 3 - March 2007

Small-Budget Building Building Up to Fully-Automated Insulating Glass Production
by John Bridgen

Most manufacturers entering the insulating glass (IG) production business do not have the luxury of investing the capital for a fully-automated system right away. While these lines may represent the ultimate goal for any IG plant interested in consistent quality and high throughput, they simply are not always a viable option. Building up to a fully-automated IG line over time provides manufacturers with a cost-effective solution, while still providing advantages in flexibility and risk mitigation.

Modern glass production facilities often incorporate a range of processing and fabricating lines, including those for IG assembly. While it is easy to develop “equipment envy” of plants that can afford starting with a fully-automated line, there are advantages to building the line over time. 

Selecting a fully-automated line is often dictated and limited by the spacer technology that a plant can provide to customers. As the spacer technologies rapidly advance, being locked into a specific spacer does not offer a company the ability to leverage break-through advancements in either spacer cost or performance. Companies with semi-automated lines are often more nimble in adapting to changes in product technologies, or, at a minimum, incur a much smaller loss in the product changeover.

Line Orientation
Before any single piece of equipment is purchased for an IG line, the company needs to decide whether it wishes to operate a horizontal or a vertical line. Understanding the trade-offs between the two is the key.

The main advantage of a horizontal line is its glass flow capabilities. In a horizontal arrangement, multiple lites can be staged through the system in the parallel position, with the top and the bottom lites moving down the line side-by-side. The expected advantage of the parallel processing can increase throughput by 40 - 70 percent. 

The biggest disadvantage of the horizontal line is that it requires a greater amount of floor space. In fact, for the same throughput a vertical washer can have a 145-percent smaller footprint than a horizontal washer. And, since glass is often received in stock form in the vertical position, processing glass horizontally requires more movement and handling than processing vertically.

Hybrid Line Concept 
Consider an IG line that consists of the following processes: washing, spacer application, gridding and topping. A plant wanting to optimize throughput would be best served by selecting a line that is not strictly horizontal or vertical, but rather a hybrid. This involves optimizing the layout based on each orientation’s advantages and the IG process requirements. The IG unit consists of two individual lites of glass until it is topped. Therefore, any processing that occurs after topping does not benefit from horizontal’s biggest advantage: parallel processing. Taking into consideration that the gridding process is often regarded as best performed in the vertical position, this could be a logical break point for the horizontal to vertical transition.

Depending on the line’s exact processes, a hybrid may not offer any substantial value. However, the ability to develop a line with a mixed orientation is worth considering. While such a fully-automated hybrid line is not currently an option from IG equipment suppliers, by building a line over time from best-in-class components, the hybrid concept is at least a possibility. 

Case Study
As in the case with horizontal or vertical processing, it is impossible to apply a recommendation on a single-best approach to producing IG units that applies to all manufacturers—one IG line layout does not fit all. Regardless of the path chosen to produce the IG, understanding the consequences of decisions will allow plants to be better prepared to deal with them. 

Let’s say, for example, you decide to enter the IG market, but have only a small existing customer base. You are located, though, in a region where 400-percent growth over a two-year period is very attainable. Let’s also say you’re working with a flexible spacer product (i.e. the line does not require roll-forming equipment). With a limited amount of capital available for equipment, the first round of equipment you purchase needs to focus on the basic needs of the operation. Consider the following rules when determining your purchase. 

Rule one: Maximize the value of the equipment. This takes into consideration the cost of the equipment verses the ability to complete the process while affecting the quality of the unit. For example, most glass washing equipment is available for well under $100,000. A person’s ability to safely and repeatably clean both surfaces of a glass lite is a significant risk for performing this process manually. Further, the shear amount of handling required for a person to flip the unit to clean both sides represents an added level of risk, both to the operator and the unit quality.

Rule two: Consider the universal nature of the equipment. A glass washer can be used for any flat glass manufacturing process (tempering, laminating, etc.) On the other hand, gas-filling equipment is only used in IG production and is not done by all manufacturers. The washer’s equipment flexibility will allow you to adapt your business model and reapply existing capital equipment if necessary. Additionally, should you need to sell the equipment, the universal demand for the process ensures a higher re-sell price [compared to gas-filling equipment], further minimizing risk.

When building a line over time, selecting equipment that can be used with any spacer technology will also reduce risk. For example, if the initial line purchase will have only a limited number of automatic processing stations, consider focusing those first investments into universal solutions. Not every type of spacer requires an automatic secondary sealant machine, whereas a press is required with every spacer on the market today.

Exact Specifications
With the basics of the production line in place, you will next need to select the exact models for a washer and press. To properly select the units, you need to understand throughput and product mix. Let’s say your company currently is producing units that range in size from 16- x 16-inches to 58- x 48-inches with a required output of 300 units per day. 

For the selection of the washer, a variety of sizes and speeds are available. Using existing product specifications, you could choose to order a 60-inch washer with a convey speed of 15 feet/minute. While this configuration may serve you well today, it does not provide the flexibility or speed desired to create a high-volume, fully-automated line in the future. With this configuration, if the sales department presents an opportunity to the production department for a customer requiring a mix of products including 70- x 50-inch units, your company could not consider quoting the job. However, if you increase your investment in the washer by 60 percent, with an 84-inch washer running at 36 feet/minute, you would be able to provide a quote on the job.

Now consider the spacer. Let’s say your current spacer technology does not require a heated press. However, when the time comes for you to select an automatic press you may still want to consider purchasing one that is heated, as it can be operated without the heat option for the current spacer. The additional cost of the heated press is likely to be 40 percent more than otherwise, but adding the option provides flexibility for the future.

Though your initial equipment investment exceeds your current needs, you have added a level of capacity and flexibility that will serve you for years to come. Focusing the line’s financial resources into a select group of equipment allows you to purchase best-in-class machines, rather than trying to spread the same resources into all of the equipment at the same time. 

If, however, you decide to invest the minimum in these components, any future growth would result in having to re-purchase the same equipment to support the added capacity. Not only is the initial capital investment wasted, the time spent on learning the nuances of the equipment operation would be lost. 

Future Growth 
While your automated solutions may only be a washer and press, they still allow you the ability to meet your initial production needs. After investing in the equipment, companies are often motivated by a combination of quality, throughput or staff reduction issues to increase their plants’ level of automation. With the manual line in place, you are positioned to increase business and fully understand customers’ needs—both existing and potential.

During the line expansion, several existing pieces of equipment could likely be re-used (caster decks, etc.). However, during the reconfiguration, you can also address some of the known bottlenecks, quality issues and operator head-count issues. Perhaps your company has a labor force that is excellent at handling glass carefully, but is not able to apply spacer or secondary sealant consistently. The production line expansion could then include considerations for automating these processes. Based upon the performance of the vendor that supplied the initial pieces of equipment, a level of qualification is already completed. For example, if the washer vendor was unsatisfactory, you could select a new vendor. As the level and complexity of automation increases, the dependency on the vendor becomes more important. 

Planning Ahead
The key to succeeding with any automated solution is taking the time up-front to plan for the future and understand customers’ needs. Ensuring a few simple features are available with each piece of equipment selected will go a long way to ensure the long-term success of the operation.

IG manufacturers often feel unable to enter the market without investing in a fully-automated line. Though some of the most productive plants feature fully-automated lines, the path to success does not have to start with one. Building up to a fully-automated line over time allows for greater flexibility and allows the plant to efficiently adapt to the ever-changing business environment. 

Follow Through: Defining and Measuring Throughout 
Throughput is the amount of work that can be performed by a system in a given period of time. When coupled with efficiency and actual product mix information, throughput numbers allow you to accurately predict the output of the system over the desired period of time. Production downtime, waiting for materials and supplies, operational errors, etc., are all factors that can contribute to lower-than-published throughputs.

When purchasing equipment, it is important to understand the different assumptions that are used to calculate the published throughput. For IG lines, large variances in stated equipment throughputs are often seen when grids, for example, are added to the unit and/or patio doors are being produced.  

Depending on the product being produced, different companies and industries can choose different variables by which to measure throughout. One common mean for measuring throughput is recording the total number of parts or pieces produced in a 7.5 hour shift.

the author: John Bridgen is the product development manager for Billco Manufacturing in Zelienople, Pa.


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