This guide is the beginner’s guide to mass finishing.
So, if you are entirely new to this, then you can learn everything about it here.
The mass finishing process mainly deals with parts made of three types of materials- metals, plastic, and ceramic.
All these parts are manufactured using various techniques.
This guide covers the importance of mass finishing in a manufacturing business, the complete process, different techniques, and the various types of machines.
You will also understand the importance of different types of tumbling media and the role of polishing compounds in a finishing process.
1. Importance Of Mass Finishing
Let us have a look at the various benefits of mass finishing in a manufacturing business.
1.1 Time Saver
It will take a lot of time if the parts are finished manually.
A machine can clean and polish multiple parts at a time.
Thus, you can save a good amount of processing time.
1.2 Cost Saver
You need to make a one time investment on the mass finishing machine.
It can do all the finishing processes with the help of the right tumbling media.
You will need only one person to operate the entire machine.
So, you can save on the labor cost.
The machine doesn’t need any additional investment for maintenance.
So, there is no additional maintenance cost involved.
1.3 Better Finish Quality
You will have different finish requirements for different parts.
Some parts will need a glossy finish, and others will need a matte finish.
The finish levels also vary for these two types of finishing.
You need to select the right type of tumbling media to get the desired finish level with the machine.
The quality of the finish will be excellent in a machine based finishing process.
1.4 Parts free of Damage
The manual finishing process is prone to human error.
So, it may damage the parts.
So, the part rejection will be more in a manual process.
The finishing machine ensures damage free finishing if you use the right type of tumbling media.
Thus, you can get more finishing yield.
1.5 To Get Consistent Finish Quality
You need to have consistency in finish across all your parts.
It is essential in the manufacturing business.
Inovatec machines will help you to achieve finish consistency across all parts.
1.6 Safe to Use Parts
The final finished parts must be safe to use.
It should not have unwanted sharp edges or corners.
The finishing machine will ensure that the part is safe to use with the help of edge breaking procedure during the finishing process.
1.7 For Proper Surface Preparation for Coating
If your final part demands a coating or painting, then you need to prepare the part surface accordingly.
A machine based finishing process will help you to finish the part surface for coating.
The surface preparation will be consistent across all the parts.
1.8 For Efficient Cleaning and Deburring
The machine based finishing will help to improve the efficiency of the cleaning and deburring process.
2. Different Mass Finishing Process
The mass finishing of parts will include the following process.
The unwanted raised edges on the surface of a part are called a burr.
Deburring is the process of removing the burr from the parts.
It is essential for the proper use of the part.
2.2 Cleaning and Degreasing
Manufactured parts may have unwanted powder deposits or oil/grease on its surface.
The machine based finishing helps to clean and degrease the parts.
2.3 Surface Smoothening
The parts after manufacturing will not have a very smooth surface.
Some will have a very rough surface, and some will have machine marks.
So, you need to remove these to smoothen the part surface.
You can get it done by using the finishing machine.
2.4 Edge Breaking
Edge breaking involves the process of breaking unwanted sharp edges in the part that can harm the user.
Some metal parts will need a coating or painting at last after the finishing process.
So, you need to remove the oxide layer or rust from the part surface.
You can do the surface preparation of the part using the finishing machine.
Polishing is the last step in the finishing process.
Here, the parts will get polished inside the finishing machine to get the desired level of shine.
You can do both dry polishing as well as wet polishing.
3. Mass Finishing Process Explained
The whole process happens inside a finishing machine.
The machine will have a container in the shape of a tub, drum, or a barrel.
You need to fill this container with the tumbling media and the parts for finishing.
When you run the machine, the tumbling media will always be in contact with the parts.
This container is made to vibrate or rotate to make the tumbling media act on the surface of the part for finishing.
So, the abrasive action of the tumbling media on the parts is responsible for the entire finishing process.
You will get the finished parts as the output.
The time duration of finishing depends on many factors like the finish requirement of the part, type of tumbling media, type of machine, and the part material.
If you are looking for a high end gloss finish, then you will have to run the machine for a long duration.
4. Mass Finishing Machines
Let us have a look at the commonly used mass finishing machines.
Inovatec machinery offers multiple variants of these machines.
So, you can choose any based on your finishing requirements.
4.1 Vibratory Finishing Machine
The vibratory finishing machine works on the vibratory principle for finishing parts.
Here, the parts are made to vibrate along with the media using the vibratory motion of the container.
This container is connected to an unbalanced motor and is resting on a set of springs.
Cost effectiveness and low labor requirement make vibratory finishing machine a popular choice amongst many businesses.
4.2 Barrel Tumbling Machine
Barrel tumbling machines are also called rotatory tumblers.
Here, the rotatory movement of the tumbler is used for the finishing process.
It is a slow process that is best suited for delicate parts.
It is easy to use and cost effective solution.
4.3 Vibratory Tubs
It is best suited for big and complex parts.
It also comes with the option to transform the compartment into separate chambers.
Thus, you can finish multiple complex parts separately in each chamber.
4.4 Centrifugal Barrel Finishing Machine
Centrifugal barrel machines will usually have four barrels that work on the Ferris wheel principle.
Here, you have the option to load each of the barrels with different parts and media.
A centrifugal force will act on the tumbling media due to the rotation of the turret in the centre.
It makes the abrasive media rub against the parts for cleaning.
This machine is suitable for parts with holes and crevices.
4.5 Centrifugal Disc Finishing Machine
The centrifugal finishing machine is suitable for finishing small and medium parts.
Here, the finishing happens through the to and fro movement of the media and parts from the centre to the walls of the container.
The processing time is very less for a centrifugal finishing machine.
If you want to minimize the amount of human intervention in a mass finishing process, then you can go for an automatic finishing system.
You have the provision to automate any of the machines mentioned above.
The automation is available at various levels.
So, you can customize the machine according to your needs.
5. Role of Tumbling Media
Tumbling media are substances that are added along with the parts into the finishing machine.
They are a fused mixture of abrasives with different types of materials.
It will be in contact with the part during the entire process.
So, the constant rubbing of the tumbling media with the part makes it clean, degrease, descale, smoothen, and polish.
You can get the same type of tumbling media in different cutting rates.
So, if you are looking for aggressive material removal, then go for media with a higher cutting rate.
It helps to bring down the processing time.
But, there will be more material wastage.
All these mass finishing media are available in different shapes and sizes.
Some of the standard shapes offered by Inovatec include ball, pyramid, cylinder, tristar, cone’ etc.
Different media shapes offer various services.
If you want the tumbling media to reach and finish difficult areas like holes or crevices, then shapes like tristar and cone are good.
Shapes like ball and cylinder are suitable for outer surface polishing.
All these shapes are available in various sizes.
If you have a part with holes, then you will have to use a small media which can go inside the hole.
The size of the media must be less than one-third of the smallest hole size in part.
Otherwise, you will end up cleaning the holes for removing the stuck media.
5.1 Different Types of Tumbling Media
5.1.1 Plastic media
If you are dealing with a soft metal part like aluminum, then plastic media is the right choice.
You can use it for deburring, cleaning, and polishing.
You can also use it for the surface smoothening of the part.
But, the shine will be less.
5.1.2 Steel Media
If you are looking for a heavy metal burnishing, then you need to apply more pressure.
In this case, steel media is the best choice.
They are made from stainless steel and carbon steel.
They are mostly used to burnish and polish steel parts.
Steel tumbling media has a very long life.
So, you can use it for many years.
5.1.3 Ceramic Media
Ceramic tumbling media is a mixture of aluminum oxide with abrasives.
They are sturdy and durable.
It is best suited for the deburring and finishing of heavy metals.
Ceramic media is also best when you are looking for a small size media with excellent cutting performance.
5.1.4 Porcelain Media
Porcelain tumbling media is one of the best polishing media.
It is more effective when you use it in the wet polishing process.
You can use it with water or any other polishing compounds.
It doesn’t contain any abrasives.
5.1.5 Organic Media
Organic media is mostly used for drying of parts after wet polishing.
It is also used for polishing parts.
Walnut shell granules and corn cob are the two popular organic media used by most of the manufacturers.
Organic media will have less life when compared to the inorganic ones.
5.1.6 Special Media
Zirconia media is the best choice for high end polishing and smoothening.
These media are suitable for hard parts.
They have a long life due to its superior strength and wear resistance features.
6. Role Of Polishing Compound
Some parts demand a wet polishing process.
Wet polishing will be done at the last stage of the finishing process.
Here, the polishing compound is added along with the tumbling media into the finishing machine.
Thus, the polishing compound, along with the polishing media, will act on the part to create the shine.
The commonly used compound is water.
You need to ensure that the pH level of the water is within the prescribed range of the part.
Otherwise, it may damage the part.
Certain parts that demand high gloss finish can make use of special polishing compounds.
So, now you know all the steps involved in a typical mass finishing process and the various finishing machine options.
So, if you are using manual methods for finishing a large number of parts in your business, then you can consider switching to one of these machines from Inovatec.
If you combine it with the right type of tumbling media, then you can see some cost and time-saving in the long run.