Vibratory Finishers and Mass Finishing Machines Information

Vibratory finisherVibratory finishers and mass finishing machines use loose abrasives or tumbling media combined with cleaning or polishing compounds to bulk-finish parts. A mass finishing machine or mass finisher can be used for finishing, cleaning, coloring, brightening, deburring, burnishing, deflashing, polishing, refinishing, or stripping production parts. Mass finishing machines vary in terms of performance specifications such as aggressiveness and finishing speeds. Finishing systems can be designed to operate as:

  • Continuous systems — where parts enter at one end and are continually discharged at the exit in the finished state.
  • Batch systems — where parts are added, processed, and removed in single groups of multiple parts.
  • Sequenced process — involves running the parts through multiple mass finishing processes to produce a final finish.
  • Single part systems — in which large parts are processed individually

Types

There are several types of mass finishing machines. Each part finish requirement will determine the type of equipment needed: 

  • Centrifugal disc — Centrifugal disc finishers consist of a large disc rotating at high speeds at the bottom of a round tub. The centrifugal force throws the parts and media out and up against the stationary inner wall of the tub, where the media and parts slow down and fall back onto the rotating disc. 
  • Centrifugal drum — Centrifugal drum finishers consist of several part-holding drums mounted on a table or turret rotating at high speeds. The smaller containers or drums counter rotate slowly. 
  • Drag/spindle finisher — Parts are mounted on a spindle or fixture that is dragged through the finishing media contained in a fixed or counter-rotating drum. 
  • Rotary barrel/tumbler — Parts are tumbled with media and finishing compounds in rotary barrel finishers to burnish, polish, or debur part surfaces. Rotary barrel tumblers or finishers tend to be less aggressive and slower than other processes.  
  • Vibratory — Vibratory tub, elongated tub, round bowl, spiral, or racetrack finishers use a vibration or shaking action to agitate media and compounds against the part surface and impart a finish.

Specifications

Selecting mass finishing machines requires an understanding of finishing processes. Mechanical driver details, voltages, speeds, and part capacities will all need to be addressed. Typical specifications differentiating vibratory finishers and mass finishing machines are:

  • Power — This is the mechanical power provided by the driver or power source. 
  • Current — This is the device's rated current. 
  • Driver Technology — Can be electric motor, pneumatic, or combustion engine.
  • Motor Voltage and Phase
  • Part Capacity — Volume — The volume of parts that can be processed in one batch or cycle. 
  • Part Capacity — Weight — The weight or mass of parts that can be processed in one batch or cycle. 

Vibratory finishers and mass finishing machines lend themselves to a full spectrum of automation. Depending on the production requirements and operator training, several levels of automation can be included in system design.

These include:

  • Manual — Devices require manual loading and then manual setup and operation. Users must change abrasive products and adjust machine parameters such as speed, applied load, and coolant/lubricant flow. The user interface may include push buttons, foot switches, pendants, a touchscreen, or a graphical user interface (GUI). 
  • Automatic/indexing — Devices load parts automatically and can be operated without user intervention. Machines change or adjust abrasive product, workpiece, and other parameters such as speed, applied load, or coolant/lubricant flow rate in a pre-programmed manner. They also index the cut depth or position to achieve the required material removal, geometry, and/or surface finish. 
  • CNC — Devices include automated computer numerical control (CNC) machine tools. These can be as simple as point-to-point linear controls or can perform highly complex algorithms that involve multiple axes of control. CNC controllers use a programming language called G-code that is downloaded from the controller to operate the machine. M-code is a standard set of machine tool codes that are normally used to switch on the spindle, coolant, or auxiliary devices. 
  • PLC — Devices include a programmable logic controller (PLC) for programming and controlling a sequence of machine operations. 
  • Windows®/PC control — Devices are controlled or programmed through a personal computer (PC) interface that uses an operating system such as Microsoft Windows®. Machines change or adjust grinding wheel or abrasive product, workpiece, or other parameters such as speed, applied load, or coolant/lubricant flow rate in a pre-programmed manner. Both Microsoft and Windows are registered trademarks of Microsoft Corporation. 
  • Conveyor/continuous feed — Parts are loaded or continuously fed. Often, a belt, roller, or specialty conveyor is used to load and present parts to the abrasive tool.  
  • Loader arm/robot — Parts are loaded and presented to the abrasive tool with a loader or robotic arm. 
  • Vacuum loader — Parts are loaded and presented to the abrasive tool with a vacuum device. Vacuum devices are useful for handling small, thin, or delicate parts. 

Features

To further customize a mass finishing system, many features may be available to improve equipment performance. Spindle orientation is an important feature in many abrasive systems:

  • Multiple heads/spindles — Devices have multiple heads that can be used to carry abrasive products with a range of grit sizes. Multiple head machines often enable part dimensioning and finishing with just one pass. 
  • Orbital/planetary — Devices use an orbital or planetary motion during finishing or grinding. 
  • Variable/multi-speed — Motor speed can be adjusted continuously or set at discrete speeds within an operating range. 
  • Vibratory/oscillatory — Devices use a vibratory or oscillatory motion during finishing. 
  • Horizontal — The machine has a horizontal spindle orientation. 
  • Vertical — The machine has a vertical spindle orientation. 

Other special features may address the specific needs of the parts being produced. These features may improve the process effectiveness or provide greater safety for the operators and other workers.

  • Dust collection/filtration system — Devices have an integral or optional dust collection or coolant filtration system. 
  • Media separator — Mass finisher with an integral media separator as commonly found on spiral or racetrack vibratory mass finishers. 
  • Superabrasives — Devices are designed to use superabrasives or diamond or cubic boron nitride (CBN) abrasives. Very rigid or high-stiffness machines make better use of superabrasives in precision grinding applications. 
  • Wet grinding/finishing — Devices are waterproof and designed or suitable for grinding or finishing with a water or water-oil coolant mixture. 
  • Cabinet/enclosure — Devices include an enclosure or cabinet that shields the user and surrounding area from dust, sound, coolant or debris generated during the grinding, sanding, or finishing process. 
  • Chemically accelerated/isotropic — Machine is designed to utilize chemicals to accelerate the material removal or finishing process. Isotropic superfinishing and electrochemical grinding are examples of chemically accelerated processes. 
  • Cleaning/spray nozzles — Machine has integral spray nozzles for cleaning, cooling, or washing parts during or after processing. 

In the world of metal parts, burrs, spurs, rough finishes, and sharp edges are a product of the techniques used to produce the part. Mass finishing allows many parts to be processed at once, reducing throughput time and manpower requirements. From drum finishers to tumblers to vibratory finishers, very specific process methodologies have been developed to get the best finish results at the lowest cost. Depending on part size, shape, and material, deburring, polishing, smoothing, super finishing, cleaning, pre-plate finishing, ball burnishing and barreling or tumbling needs can be met with the right system.

Related Information

Engineering360—The Role of Abrasives in Woodworking

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