Dwell time plays an important role in tablet manufacturing processes. Understanding how dwell time works can help improve the results of the manufacturing process for many types of tablet products. In this blog post, we’ll discuss what dwell time is, its impact on tablet compression, and how certain tools can affect dwell time in these applications.

Tablet Manufacturing

What Is Compression Dwell Time?

Dwell time in compression is the amount of time it takes for the punches to stop moving vertically and to achieve maximum penetration in the die under the primary compression rollers. Dwell time takes place when the compression rollers make contact with the punch head flat. The punch head flat dimension divided by the turret tangential velocity will give you the tablet press dwell time calculation.

The Importance of Dwell Time in Tablet Compression

As a core parameter, dwell time greatly impacts the overall quality of many tablet products. Specifically, it affects the tablet’s strength and facilitates the transfer of product between tablet presses. Subsequently, increasing or decreasing dwell time could significantly affect the results of tablet manufacturing processes.

Increasing dwell time helps minimize the risk of air entrapment as it expels air from within the tablet. Failure to sufficiently compress the air out can negatively impact the tablet’s tensile strength and increase the risk of delamination or tablet capping. Certain granules will require a longer dwell time under peak compression due to their challenge of effective compression. The longer dwell time enables the tablet to acquire the necessary hardness and eliminate the risk of sticking and other potential issues.

Longer dwell times also mean the area of the available punch head flat could play a bigger role in the general profitability and success of the tablet manufacturing process. 

Tooling & Dwell Time

Many types of punches exist with various head configurations. Some of these punches increase dwell time, while others lower the risk of premature wear. Compression tooling punch heads consist of a head flat, which provides a consistent strain to the powder bed when beneath the compression rollers. Tools with longer heads will require longer dwell times.

Applications may also require a longer dwell time depending on strain rate sensitivity and powder deformation characteristics. Slowing turret speeds can increase dwell time; however, this will cause a decrease in production rates.

Tablet manufacturing processes may also use one of two widely recognized tooling configurations: the European ISO standard and the American TSM standard. Both of these standards allow for interchangeability of tablet press tools, streamlined inventory and inspection processes, and consistent quality across tooling vendors. Both configurations most commonly use “B” and “D” type tooling. 

“B” tooling features a smaller body that enables a higher number of punches in a turret, which is ideal for high-volume tablet production. “D” tooling, on the other hand, features a larger body that facilitates the production of tablets up to one inch. Naturally, “D” tools’ larger heads and flats make for longer dwell times during tablet production.

Get the Tooling You Need for Tablet Manufacturing at Fette Compacting

Depending on desired dwell time, different tools can meet the needs of your individual application. With more than 65 years of experience and knowledge, Fette Compacting is the world’s leading supplier of solutions for industrial tableting technology.. We can provide our customers with integrated equipment solutions based on their specific requirements, along with extensive customer support in order to generate maximum performance for users.Our strategically located facility in Rockaway, New Jersey, gives us the ability to provide reliable support to customers throughout the U.S., Canada, and Puerto Rico.

For more information about our tablet press machines and tooling, and to get started on your next project, request a quote from Fette Compacting today.

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