Electroplating is a process which metals pass through to bond a compound or another metal on them so that their conductivity capacity will improve as well as provide protection against corrosion and wear. If you want to preserve your metal parts before using them for fabrication, you must plate them accurately to achieve a good finish.
There are many methods of electroplating metal parts, using racks, barrels, vibration and more.
Among all the available plating methods, the most common are barrel plating and rack plating, so we’ll focus on them in this article.
It is not always easy to choose the best electroplating method for your project but if you do, be assured that you will get optimal results while minimizing the risks of damages on your finished product.
Before I go ahead to give you in-depth information comparing barrel and rack plating, consider the following:
Let’s say that you have hundreds of parts for electroplating in the shortest time within a tight budget, what will you do? One of the things that will make anybody’s services efficient and impressive for continued patronage is your ability to deliver quality results promptly within a cost-efficient framework.
If you want your clients to return for more work amd recommend your services to their colleagues and friends, you must always impress them with continued quality result rendition.
Therefore, before you start any electroplating project, you must sit down and ask yourself, “barrel plating or rack plating? Which is the best option for this project?"
So what is barrel plating?
It’s as obvious as it sounds: electroplating metal parts using a barrel. The barrel used for this plating is always constructed of polypropylene material. Inside the barrel, there are center bars that are in charge of conducting sufficient electrical current which will make the whole process to work as expected.
This plating process involves a slow rotation of the barrel immersed in an electrolytic solution which is required for the plating. This rotation will result in a cascading or tumbling movement of all the metal parts in the barrel. As this process continues, the coating will attach to the parts to provide a uniform finish.
This method helps you to finish metal parts in a way that makes them resistant to wear and tear. It increases the aesthetic appeal of the electroplated parts and also enhance their capacity to resist corrosion.
If I start from the most common benefit, it will be that you can use it to handle high volume projects in the shortest time possible. Yes!
If you are choked up with work or the pressure to deliver electroplated parts for item fabrication is making you stressed, barrel plating is the best thing that can happen to you at this point.
When you make use of this plating method, you will not only save time, but you will save money as well.
Advantages of Barrel Plating
Below we’ll cover some of the other benefits of using this method of electroplating.
1. You will use a single vessel
With the right sized barrel, you can handle every plating need for your project. Be it parts cleaning, rinsing, parts pickling or even sealing, all you need is one single vessel, and that’s it!
2. It handles variety well
With the barrel method, any parts you have will be electroplated in the barrel. So when you have varieties of parts to electroplate, there is no need for various equipment since your barrel can take any part that can fit into it.
3. Be sure of a uniform finish
Using this plating method is a sure way of achieving a uniform engineering finish on all the electroplated parts.
A plating machine rotates and causes metal parts to tumble. This cascading makes a bipolar contact among parts possible and result in a uniform finish. This electroplating method is popular for achieving this result after metal parts plating.
4. You will spend less
Barrel plating provides a low-cost dual benefit if you use it for your project. It benefits both you and your customers. This method will help you to minimize your operational costs which will result in low-cost service rendition to your clients as well.
In some cases, you may not even need additional fixtures, part carrier or agitation equipment, further reducing costs.
5. Barrel plating require minimum labor
Labor cost is one of the things that increase your service costs. You will need fewer hands to carry out the operation or the processes involved in the method. All you need is a set of barrel equipment, and that’s all.
Other plating methods may require many people to work together in the plating process.
6. The method utilizes little space
Barrel plating happens in one barrel. You don’t need to create a large space like if you are using rack plating. You can set up the barrel plating equipment in whatsoever space you have and still achieve the same wonderful results.
No matter how wonderful barrel plating is, there are some downsides to this plating method, which you should be aware of when comparing barrel plating vs rack plating.
1. Low current requirements can cause issues
Due to the low current requirement of barrel plating technique, the metal parts are exposed longer than necessary.
2. It can’t handle all the parts
Sometimes, there are very large and complex metal parts that will not fit properly into your barrel plating equipment.
When this scenario occurs, your choice will no longer be barrel plating. Also, some parts can fit in the barrel, but they are too delicate to withstand the cascading that occurs during the barrel plating process. At this point, you will have to use other plating methods.
Now that you have seen the make-up and capacity of barrel plating let’s consider its counterpart.
Another common method of electroplating parts is the rack plating method. This method involves plating metal parts by hanging them on a metallic fixture which supplies the galvanic cell circuit necessary for the electroplating process.
On the rack, there are wires, pins, and screws which ensures that there will be less electrical contact during the process. As a result of the minimal contact, the finishing that will be achieved on the metal parts will be a high-quality coating.
Rack plating process starts from hanging the metal parts on your plating rack. When you are done, use bonds or hooks to keep the parts in the right position. Afterwards, dip the parts in either the Chrome or Nickel solution and apply your electrical current. The best way to enjoy this plating method is to use it for selection or partial coating.
However, some specific coating requirement for metal parts may necessitate the use of rack plating. Apart from the requirements, some applications that need rack plating service like copper alloys and nickel-silver, Steel, aluminum steel, Inconel and Monel, Stainless steel, etc. Also, there some kinds of plating that will only pass through rack plating like copper plating, bright nickel plating, silver plating, electroless nickel plating, gold plating and electrolytic plating.
One good reason for using rack plating is because some of the parts that pass through electroplating are delicate. Sometimes, they come in complex geometry which may hinder a uniform finish result through other plating methods. As a result, the only plating method that can efficiently provide smooth finishing to these parts with complex contours is rack plating method.
So if you know that the metal parts you want to electroplate will suffer damages if they are agitated in a barrel, you will pick the rack plating method. Also, some parts are larger than others. When any metal part is large and cannot pass through any other plating method, your best option is to plate it on a rack.
With the rack plating method, you can carry out the following types of plating, Zinc and Aluminum plating using Chrome and Nickel plating solutions. Rack plating comes preferred to single parts plating where you will have to plate your metal parts one by one. Talk about time killing and cost building. Instead of handling every part differently, take as many as the rack can carry and start the electroplating process.
There are many advantages to using rack plating method of electroplating metal parts:
1. It can plate any size or shape
Using this method you can plate any size of metal part you may have to electroplate. Since you are not putting them in a barrel, you can hang them on the rack and go ahead with the process.
Some parts that have complex geometry which you must plate the contours can still get a uniform finishing through rack plating method. All you need is to do is to customize the rack to fit the needs of the project and also use engineers who are experienced.
2. It handles fragile parts very well
Fragile parts that are easily damaged are best suited for the rack. Sometimes, when you may need to electroplate metal parts that have sensitive tips, don’t try other methods; just head straight to your racking equipment and protect these parts from damage.
3. Consistent, scratch-free results
In preparing the metal parts for electroplating, all you will do is hang them and hold them in place with hooks or bonds. Each of the items is purely on their own with little or no contact with other parts. After passing through the plating process, you will notice that they will be smooth without any scratch. In rare cases, you may notice little scratches that are not detrimental to the use of such part.
4. There will be uniform finish
One great benefit is that you can achieve a uniform finish for all the parts even those of complex geometry. It produces an overall good result.
There are also some limitations to using the rack plating method.
1. High equipment cost
Rack-based plating equipment is more costly to fabricate than other equipment. You may need to spend more to get the size that will fit your budget for the whole process.
2. It takes longer
Before plating the metal parts on the rack, you will have to hang them manually. If you have hundreds of metal parts to electroplate, I don’t have to tell you how long it will take you to finish.
3. Your volume is limited
You can only plate as many parts that can hang on the rack for each batch. Unless you have a large plating operation that can carry as many units as possible but it will still be limited to the length of the rack.
4. It is labor intensive
It will take many hands to handle huge projects. One man or few cannot rack plate hundreds of parts and finish it as per client’s deadline. So with this method, you will have to use many people.
5. The method is costly
Due to the large requirement of human resources and the time required, this method becomes very expensive to operate. People who have a large volume project often spend more especially if they have parts that can only pass through the rack plating method.
6. It’s harder to achieve a uniform finish
If you want to electroplate parts that have complex geometry, you must use anodes or rubbers to improve the efficiency of the whole system. If you don’t want to use anodes, you can customize your equipment to fit the part geometry for better results.
Barrel Plating vs Rack Plating
After considering these methods of electroplating metal parts, the decision now remains, which method is suitable for my project?
So I am going to make it easier by pointing out some things you should consider before deciding to use either method for your electroplating project.
No matter how tempting it is to finish your project on time, you can’t just use barrel plating without making sure that it can provide a perfect finish for the metal parts. To make sure that you are on the right track, consider the following things:
1. The size of the parts
The general rule of thumb is, if the part can fit into the barrel, you can electroplate it. Now, what are sizes of the metal parts in your project? Can they fit into the barrel or will they be better on a rack? This has implications for plating automotive products, where items such as strut bars can be very large.
When you check out the size, and they can fit the barrel, go ahead and use it! But if the sizes of the parts means they are too large to fit, opt for rack plating to ensure a uniform finish especially on the contours of the metal parts.
2. Nature of the parts
This process involves a lot of tumbling or cascading. Some parts that are too delicate to withstand such tumult will just suffer damages thereby leading to increased production costs.
Or maybe the parts you need to plate are made of materials like copper, nickel or stainless steel.
When you are working with these types of parts, it is best to use rack plating equipment, but when the parts are sturdy and wouldn’t feel the brunt of other metals on their surfaces, opt for the barrel to save on time and cost.
However, there are some cases where you might notice some rack marks on the electroplated parts but no cause for alarm since it will not cause any harm.
3. The cost of production
Rack plating takes time to finish. The process is somewhat rigorous and demanding, and as a result, it is always an expensive method of electroplating both for the owner of the project and the person handling it.
When your service cost is high, it will also increase the operational costs of your client. If you have a high volume of metal parts to be electroplated, where possible avoid the rack method of plating. This way you can handle the whole process quickly and efficiently.
4. Labor requirements
When plating in a barrel, everything happens in one vessel. You don’t need many hands to put the metal parts into the electroplating barrel. After loading the parts, you watch as the parts move about to get the plating solution coated on their surface.
You will hang the parts manually before you start the process. You will also monitor the movement of the crane depending on the equipment you are using.
This whole process will require a lot of people so that you can finish the project within the planned time frame.
5. The project deadline
If you have an urgent project to handle, the best electroplating method to use is barrel plating. It will electroplate volumes at once and finish the project quickly.
6. The volume of the job
When you have many parts to electroplate, unless the parts are delicate, the barrel method is the way to go. If the volume is small, it’s still a good way to go. Barrels can plate thousands units in a few batches.
If you’re working with large volumes of parts, this is the best option.
7. Initial investment
Quality barrel machines isn’t expensive. These machines are affordable and still serve your needs. Rack plating equipment, however, is much more expensive and will also require more workspace as well, as the equipment takes up more space.
8. The processing time
Though plating in barrels can produce many electroplated parts at once, the equipment only uses low DC current. As a result, it takes a lot of time for each batch to process.
Even though rack plating cannot finish as many parts at once, you can still achieve a good volume depending on how fast you are.
9. The quality of the finishing
If you are working with an industry that requires high-quality finishes after electroplating, plating on a rack will likely be the best option for you. Some parts like medical, automotive, electronics, military parts, etc. are best suited to this method as it provides the highest quality, decorative finishes.
But if you want to electroplate parts that don’t require decorative finishes like fasteners, utilize this low-cost plating method.
Barrel vs rack plating, which is better?
Given what we have seen so far, there are no grounds to conclude that either of the plating methods is better than the other. Both methods are compatible with different finishing technologies. Each one of the methods can electroplate precious metals such as gold and silver. Also, you can electroplate metals like copper, tin, zinc, and nickel using either barrel or rack plating.
The decision to choose either of the two plating methods depends on the project you are handling. You can easily decide if you consider the shape, nature, size, cost, budget, labor, specification, quality of finishing, etc. The requirements of the project you are handling will determine which method to use.
To make your plating services operation legendary, it may mean needing to house both sets of equipment, so you have the option to cater to each projects’ needs.
As each project comes, follow our tips to decide on which method to utilize. Neither of these two electroplating methods are better than the other. Each has unique characteristics that make it suitable for different projects.