Hot Air and Media-Based Systems Offer Drying Options for Mass Finishing

With few exceptions, mass finishing processes require the addition of water and compounds to produce the desired results. That means finished work pieces discharged from the finishing machine are wet.

Since possible corrosion or problems with subsequent manufacturing steps are possible, the finished work pieces must undergo a drying operation. While not as complex as the mass finishing process itself, drying nevertheless requires careful consideration to ensure that the work pieces are completely dry and free of any water or dirt spots.

Rosler has extensive experience developing dryers for a wide range of work pieces and the expertise to assist with process parameters and settings.

Work Piece-Based Machine Settings

Machine settings for speed and temperature must be matched to the work pieces and their surface condition to ensure the lowest possible energy use to complete the task.

For work pieces with complex shapes, including undercuts and/or internal passages, the dryer speed may have to be lower for a longer dwell time in the machine. In addition, the temperature setting may have to be higher.

Work pieces with simple shapes can be dried at a higher speed and a somewhat lower temperature.

Machine Types

Dryers are categorized by their drying method, specifically based on whether they use a drying medium or hot air.

Rosler offers a variety of machine options in both categories, each with its own unique capabilities.

Rosler rotary dryer with supervelat

Rotary Vibratory Dryers

Known as the RT model range, rotary vibratory dryers utilize a drying media and are ideal for small- to mid-sized work pieces with relatively simple work piece shapes. Rotary vibratory dryers are the most common drying systems.

Rosler belt dryer

Belt Dryers

The BT model range of belt dryers uses hot air to dry work pieces. These machines are ideal for mid-sized to large work pieces with complex shapes. Belt dryers are also widely used, especially when drying media might get lodged or trapped in the parts.

Rosler drum dryer

Drum Dryers

Utilizing a drying medium, the TT drum dryer model range is particularly useful with mid-sized, cup-shaped work pieces as well as for parts that require gentle handling to prevent part-on-part damage.

Rosler drying centrifuge

Drying Centrifuges

The hot air drying and work piece handling of the HTZ model drying centrifuge is capable of processing very small work pieces that are too small to be treated in other devices. The centrifugal force in combination with heated air ensures efficient drying of parts that are processed in batches.

Special Rosler vibratory dryer

Special Rotary Vibratory Dryers

For drying operations that must be absolutely free of dust, such as polished coin blanks, special rotary vibratory dryers utilizing hot air are available. Determining the best options of various designs requires careful consideration of the overall process.

Drying Media

Maizorb drying media

Made from crushed corn cobs, maizorb is the most common type of drying media. Its granule sizes range from approximately 0.002 to 0.2 in (0.5 to 5 mm).

Regular replacement with new media is important to reduce the impact of residual contaminants, such as oil, media fines, and undersized media pieces, picked by the drying media. If not regularly refreshed, these contaminants can be transferred to work pieces.

Stampings, for example, carry large amounts of oil into the finishing machine, requiring media replacement every few days. Conversely, media used in die casting processes can be used for a few weeks before being replaced.

Work Piece Action Points

As with any manufacturing process, regular observation is advised even with automated systems.

For hot air and media-based operations, regularly check if the work pieces are dry when coming from the dryer. If not, change the machine settings (speed, temperature, airflow) to ensure that the work pieces are dry.

In machines utilizing drying media, check dried work pieces for dirt spots on the surface. If spots appear, quickly replace the drying medium.

The Rosler Way

Decades of experience and ability to design, service, and maintain machines as well as the consumables and accessories to get the finish you require make Rosler a well-rounded surface finishing expert. Contact us to discuss your drying and general mass finishing needs.