Industry

If you have decided on a table plasma cutting machine for your projects, you would be hard-pressed to find a better tool. Plasma cutters produce high-quality finishes on cut pieces of metal and do so within a relatively short period if done right.

That, right there, is the main issue; doing it right. Some people venture into plasma cutting with little or no experience and then start to count the losses; loss of time, money, maybe even damage to property in extreme cases. So apart from learning how to operate a plasma cutting machine, there are a couple of things to consider before you even buy one and you better stick around to find out.

Types of Table plasma cutting machines

There is quite some variety when it comes to plasma cutters. But the major types of plasma cutters are manual plasma cutters and automatic alternatives which can also be referred to as Computer Numerically Controlled (CNC) plasma cutters. Manual cutters are simply that. Manual. They are small handheld cutters that have a lot of different uses.

CNC plasma cutters on the other hand are guided by computer software to produce precision cuts, over and over again. They’re mostly used in handling large scale work on industrial production lines. However, if you do a lot of metalwork yourself, a table plasma cutting machine would be a great addition to your workshop.

There are different sizes and ratings of plasma cutters that handle different metal plate sizes and thicknesses so be sure to think about the projects you’ll be handling and choose accordingly. Speaking of sizes…

Space

Table plasma cutting machines aren’t small. There’s no other way to put it. So you’ll need to at least plan how and where to set up your plasma cutter. Some plasma cutters are 5 meters by 2.4 meters, while slightly smaller ones are 4 by 2 meters.

You’re also going to want enough room to move around the machine, as well as for the control unit. You should try to place your plasma cutter away from other items, the reason for which will be mentioned in the next point. If you are getting a table cutting machine, it’s a good idea to invest in a sturdy table that will support the weight of the machine and then some.

Safety

You should pay attention to this because just like any tool; if a plasma cutter is used carelessly, it can result in harm to both life and property. Wear sufficient and appropriate eye and face protection, because the UV rays coming off the plasma cutter can cause injury to the unprotected eye.

A good welder’s helmet wouldn’t hurt, because it protects your eyes from the radiation, and your face from debris coming from the machine. Protective equipment such as aprons, a jacket, leather gloves, and strong laced boots will be necessary for anyone operating the machine to prevent burns from flying sparks.

The leather gloves also help protect your hands from the plasma arc. You also want to ensure there is no material near the plasma cutter that could start a fire if exposed to these sparks.

Conclusion

Plasma cutters are great tools, but only if you do the right things. Learn as much as you can about them, choose the right one, set it up properly, and follow the safety information. That way, you’ll get the best value out of your plasma cutting machine.

Amazon SFP runs one of the largest fulfillment centers in the world. The company takes on inventories from several other companies and takes on their fulfillment roles. A fulfillment center is a company that helps eCommerce merchants to outsource their shipping and warehousing duties. They are essential for online businesses because they relieve them of the required physical space to store all products. They also come in handy for companies that do not have enough space to cater to their inventory level. In this post, we discuss how fulfillment centers work.

How do fulfillment centers work?

Online companies have to employ a fulfillment center. After that, the company has to ensure that the fulfillment center has enough inventory to take care of all orders. This means that if the company manufactures the products sent to clients, it will have to send the products to the factory’s fulfillment center. On the other hand, if the company gets the products from a separate manufacturer, they have to make sure the products are sent directly to the fulfillment center. In simpler terms, the fulfillment center functions as a warehouse for the online business.

Therefore, it is the business’s role to make sure that the inventory is always sufficient because they know their client habits. The last thing a company wants is to receive too many orders only for clients to be disappointed.

Once the fulfillment company received the products from the online company, they log in the items into their database. This helps keep track of all the products. The database also helps online businesses know when and how they need to stock up again. Most fulfillment companies allow online businesses access to their inventory in real-time. This means that the center does not have to keep sending records to the business or requesting restocks.

Afterward, when customers make purchases from the online business, they send the orders to the fulfillment center. This is done once the products have been paid for. The fulfillment center takes on the role of processing the orders. Note, the fulfillment centers do not require any input from the online businesses at this point.

The fulfillment center will make sure that the clients get the products. When preparing products for delivery, the companies have to make sure they meet the personalization or customization requests as agreed upon with the online business. For instance, if the business wants custom packaging uses, then the fulfillment center will make this happen.

On the other hand, if clients decide to ask for refunds on a purchase, then the fulfillment center has to receive the product and inspect it to make sure it is in perfect condition before issuing a refund. If the product is still sellable, then the center will log it back into the inventory.

Conclusion

Fulfillment centers help eCommerce businesses reduce their workload. They help make their work easier and also influence the prices of the products. This is because the company does not have to incur the costs of hiring warehouse and shipping employees.

Custom machining is CNC machining in various forms, i.e., CNC milling, CNC turning, etc. Custom machining creates custom machined parts for companies in different industries. However, the kind of machinery required to make specific custom machined parts depends on the size, shape, and desired materials. Custom production of parts is easy and fast to make; this article will educate you on custom machined parts and custom machining in general.

The basics of custom machining

Ordering custom machine parts online is as easy as picking out parts from a catalog. Remember, custom machining is needed when desired products are not standard. Custom machine parts are also needed when a client is making an original item or product whose parts do not exist in the market yet. Secondly, custom machined parts can be anything from a simple button to a complicated gear.

Custom machining might be required for a commonplace product but required special detailing such as texture or engraving. The result of CNC machining is a high-quality custom machined part that will outperform its function.

To get a customized product, clients have to do at least one of the following

Clients create a CNC digital design from an idea. The design is a 3D or 2D object that can get turned into a program for a CNC machine.

For clients who cannot make their designs, CNC machine shops with a design department can collaborate to create the desired digital design. But note, an interaction, collaborative development between the department and the client is critical for producing an outstanding custom design.

Another way to make a custom design part is to have the manufacturer make a base part for the client to design. This approach makes it easy for the manufacturer but limits the freedom of the client’s design. Adaptive customization allows the manufacturer to make many products with a degree of accuracy without losing time readjusting the machines.

Cosmetic customization is the process of creating a standard product in several different styles. The different styles are not significantly different from the standard part. The products vary in minor ways, color, size, and shape. This is by far the easiest way to make custom parts for mass production.

Instances when custom machining is used

Custom machining is used when;

• The available standard parts do not match the design the client wants
• The desired design is not on sale from any supplier
• Good quality machined parts can get produced on instant notice
• Small quantity manufacturing is applicable in machine shops
• Machine shops can combine multiple elements into one single machined part

Basic machine shop requirements

If a CNC machine shop aims to manufacture single customized parts for their clients, it needs to be set up differently for production. Custom production involves the implementation of new tools and procedures with each item production. The constant change keeps the employees involved and the work enjoyable.

Decreasing lead time is the main issue that the machine shop has to solve. Since each product requires a fresh set of materials, the machine shop must have a constant supplier of materials. An efficient storage system needs to be set up as there can be thousands of tools and parts in a machine shop.

Types of custom machining

High precision CNC machining is the fastest way to produce custom parts and has quickly gained popularity in the manufacturing industry. High precision and less human input make the process virtually error-free. Increased accuracy in measurements makes the finished custom machined part high quality and high precision functioning. Custom machining can involve machines with five or 6-axis CNC machining centers to better manipulate workpiece materials.

1. CNC millingis a popular type of custom machining service. Parts are formed from a solid block of material. The preferred material for this process is metal, which is drilled until the final product is obtained. Lastly, plastics can also get used for CNC milling.

2. CNC latheand CNC turning are popular machining services that are useful in creating a 3D shape or mold. A computer with little human input controls the CNC machine. The finished product from this process can get blasted to create a more attractive finish.

3. CNC Router technologyis best for precision cutting and etching complex designs out of metal sheets. CNC routers can be used for composite, plastic, foam, glass materials. Because CNC routers are robust, they are suitable for large scale custom machining of parts. Items that CNC routers are used to make include wood boards, panels, molding, furniture, and frames. In reality, CNC routers are used for hobby work, to make prototypes, and product development.

4. Plasma and Laser cutting machiningoffers a fast and effective way to cut and shape 2D models and shapes. Plasma cutters are stronger than laser cutters, but laser cutters have a more accurate finish. CNC plasma cutters use less energy compare to laser cutters, which are preferred for wood and plastic.

The HVAC industry makes significant use of CNC plasma cutting services. The advantage of using CNC plasma cutters includes increased productivity and output. This machining service is also responsible for decorative metalwork and signage. For a more affordable solution, CNC laser cutting is used for high precision cutting and engraving. A CNC laser’s typical use is to create barcodes on items we used in our day-to-day lives.

Compared to the injection molding industry, custom plastic machining for the production of prototypes is cost-effective and efficient. In the manufacturing industry, pricing is a deal-breaker: lower prices are always preferred as long as the quality is unaffected.

Conclusion

Manufacturing automation has made way for the development of innovative machines that solve day to day problems. The computerization of CNC machines makes custom machined parts easy to use, fast, and precise. The highlight of industrial development is the awe-inspiring flexible manufacturing system designed to create multiple unique custom machined parts in mass production and low volume production. All these advances in technology have made it possible for production costs to lower considerably. Custom machined parts are the future of engineering and manufacturing.

You can find gaskets used in different industries, such as food processing, construction machinery, pharmaceutical, and more. With different gasket manufacturers, you can be guaranteed to get a variety of custom and standard gaskets on the market. As you know, your application determines the type of gasket you should use. For instance, some applications use Teflex Barium Sulfate Filled PTFE Sealing & Gasket. These are some of the tips to help you get a gasket that suits your needs.

Specifications

It is advisable to take into account all gasket specifications and the area where it is used. In this way, you can narrow down the features to look for. For instance, is the gasket going to handle corrosive chemicals and extreme temperatures? Does the chemical or fluid in question have properties that can reduce the lifespan of the gasket? Remember that some gaskets can easily be damaged because of pressure and chemicals.

Select Material

Remember that gaskets can be made from different materials. Moreover, the material is quite important in determining optimal performance. You can find gaskets that are ideal for different applications and operate in different environments, such as containers, pumps, and pipelines. Materials used to manufacture gaskets can be classified into non-metallic, metallic, polymer, and fiber. It is advisable to consider materials such as rubber, silicone, graphite, and Teflon or PTFE.

Some gaskets have multiple layers to improve the features and performance of the gaskets. For instance, you can find rubber gaskets with metallic inserts or rings. Selecting an appropriate material is necessary as it ensures the gasket you choose can last longer and needs minimal maintenance. In this way, you can be assured to get value for your money.

Testing

There are different tests undertaken to determine the safety and performance of gaskets. As a result, you can find certified gaskets ideal for certain applications and requirements. Different tests ensure that you can find a gasket that matches your needs. In this way, you can make an informed buying decision.

Reputation of Manufacturer

It is advisable to consider a gasket manufacturer with experience and expertise to make quality gaskets and sealants. An experienced manufacturer can even make custom gaskets to suit your requirements. For instance, they can be bent or welded to meet the needs of clients.

Resistance Requirements

In industrial operations, mishaps can happen. That is the case when people fail to consider different features and specifications of gaskets before they can use them. Therefore, you need to consider your application and choose a gasket that can handle specific chemicals, temperatures, and pressure. When you deal with an experienced manufacturer or supplier, you can get custom and standard gaskets that can provide the perfect sealability, pressure resistance, and even other functionalities.

Gaskets can be used as sealants for different applications, such as thermal, refinery, and chemical. The quality of the material and design determine the performance of your gasket. When choosing a gasket, you want to ensure it has the features needed to meet the requirements of a given application. Also, ensure you choose an environmentally-friendly gasket at a fair price.

Rapid prototyping is an important product development technique that allows designers and engineers to reduce lead time by creating a production-ready design. There are different techniques used to accomplish rapid prototyping goals. These include 3D printing, CNC machining, and more. Remember that you need to find reputable Prototype companies to work with. These are some of the benefits rapid prototyping offers.

Speed

Usually, rapid prototyping refers to components or products made through additive manufacturing techniques such as 3D printing. However, some prototypes are made through CNC machining. All these processes help reduce lead time depending on the geometries involved and materials used. Usually, the 3D printer acquires data from the CAD model without the setup time as the case with conventional manufacturing techniques.

The truth is that rapid prototypes can be ordered online, made, and then delivered to you. As a result, you can finish your projects sooner than anticipated. In this way, you can deliver products to the market faster.

Cost-Effective

The truth is that 3D printing is more cost-effective as compared to other manufacturing processes. Conventional manufacturing methods have extra associated costs, such as material procurement, configuring setup, and surface finishing. When it comes to 3D printing prototyping, the machine prints the CAD model.

Test Different Designs

With rapid prototyping, it is possible to test even complex designs that may be time-intensive and costly. Ideally, prototyping makes it possible to make items that cannot be made with conventional manufacturing practices. Components with sharp corners can be made by additive manufacturing techniques. It is advisable to make prototypes with different geometries to help engineers test functionality and other parameters.

Component Consolidation

You should note that rapid prototyping makes it possible to test different parts and components before they can be made for end-use. Remember that consolidating different fabricated or machined parts during prototyping is cheaper and helps engineers to explore various designs. There are also some prototyping techniques that can be used to make end-use products. These include carbon DLS, SLS, and DMLS.

Testing of Materials

Rapid prototyping offers designers and engineers the freedom utilize various materials. Some of the materials used include nylon, metal, plastic, and composites. The choice of material depends on the product application or where it will be used. For instance, metals can withstand high pressure and stresses that are common with automotive applications. Ideally, with rapid prototyping, you have a huge combination of materials, finishes, and colors.

Mitigates Risk

In any business, you need to mitigate the risk. The ability to determine the risk level before manufacturing a component gives a business a competitive edge over its rivals. Most manufacturers use 3D printing to make prototypes because of the minimal resources required, and it is cost-effective.

With rapid prototyping, it is easier to minimize the time of the idea formulation to production timeline to a few weeks. For instance, it can take a few days to make prototypes and test them. This allows you to test different materials and component geometries. Also, you have the freedom to choose the method to be used to make rapid prototypes. Some of the common methods include injection molding, casting, 3D printing, and CNC machining.

If you are in the metal finishing industry, you’d definitely know all about tumble finishing and vibratory finishing. These two finishes are part of the bigger mass finishing. They are usually used to remove scale and rust removal. They are also used to deburr as well as for burnishing processes.

In this article, we’ll be looking at tumble finishing and vibratory finishing. We’ll also be explaining why the vibratory finishing system might be the right choice for you.

If this is a topic you’re interested in, you should probably stick around.

The differences between tumble and vibratory finishing

The very first difference between most terms can be seen in their definition. The vibratory finishing system consists of media, parts, and compounds. These items are placed into a tub or bowl that is vibratory in nature.

These parts then grind together which in turn helps to polish various parts. The tumble finishing refers to the placing of parts along with a barrel. The parts are joined by abrasive media and other forms of compounds. The barrel then rotates which helps in creating friction.

This friction combined with other movements helps to perfect the deburring action of the surfaces of the parts.

How the vibratory finishing system beats the tumbling finishing

In the world today, the vibratory finishing system seems to be more favored than the tumbling finishing. One of the main reasons for this is because of its compatibility. It is compatible with automation processes.

This makes it easy to work. That’s not all. It also helps to reduce costs and labor. This helps to save money in the long run.

When dealing with parts that are delicate or large, the vibratory finishing system is also the preferred type. Its tolerance levels are well suited to this form of finished.

Vibratory finishing is also liked because of the ability to provide a smoother finish. This is done without the usual wear and tear that might result.

The production of a smoother finish is important as it helps to make the product and parts more durable.

The Argument for the tumbling finishing

The argument for tumbling finishing is quite clear. They are simpler than the vibratory finishes. This makes them cheaper to get. The tumbling finishing is the best finishing to get when you are on a budget.

The downside of being simpler means that you are going to take a longer time to actually finish. Also, your parts face the risk of being indentations.

How do I know which finishing to get?

If you are still confused about how to approach your mass finishing, then it might be time to actually see an expert on the finishing system. You would get a complete explanation of how each finishing system works.

Verdict

So which vibratory system should you use? To us, we feel that the vibratory system should be your first choice. However, if you are on a budget, then you might find it easier to actually use the tumbling finishing.

The truth is no matter which finishing you choose, make sure that you are making an informed choice.

Anemia is a medical condition associated with the lack of vitamin B12 and low red blood cell count. It is a condition that can be either subclinical or clinical which is way worse. Each person diagnosed with anemia/b12 deficiency is prescribed a custom treatment. Nowadays, there are all sorts of formulations designed to help people battle their anemia. 

Here is an overview of salcaprozate sodium and how it compares to other formulations designed to treat B12 deficiency. 

Formulation

Cyanocobalamin, which is the most popular form of vitamin B12 comes in all sorts of formulations such as nasal spray, sublingual, intramuscular injection, tablet form, and solution. 

Cyanocobalamin/salcaprozate sodium is one of the newest tablet formulations on the market. Unlike other B12 supplements and medications, it features an absorption promoter that goes under the name salcaprozate sodium (SNAC). The thing with SNAC is that it acts as a chaperone for vitamin B12, taking it from the gastric lining to the bloodstream.

Thanks to that, Cyanocobalamin/salcaprozate sodium is classified as a medical food. 

Because medical foods have been classified as food, are not subject to any drug regulation. Yet the FDA has its medical food standards that need to be met before the medical food can be cleared to be sold on the market. Furthermore, the medical food needs to have a label that is not misleading in any way. Prescription in some cases might be needed. Plus, all ingredients that are part of the medical food need to be acknowledged as safe to use. 

So, bringing medical food to the market might not be as rigorous as bringing a new drug, but at the same time, it sure ain’t easy as introducing a dietary supplement on the market.

Cyanocobalamin/salcaprozate sodium efficiency

The goal of every formulation for treating vitamin B12 deficiency is to increase the B12 levels within the bloodstream. Patients that needed an immediate boost mainly depended on IM injections. A cyanocobalamin/salcaprozate sodium tablet can deliver a fast bioavailable response as efficiently as an injection. That’s just one pill of cyanocobalamin/salcaprozate sodium per day and vitamin B12 can be set within their normal levels.

In Conclusion

The thing with vitamin B12 deficiency is that it can be mild when discovered on time. If untreated, or late discovered, it can lead to anemia or even nerve damage. Therefore, the sooner is diagnosed and corrected the better. 

As a result, some people will need to be treated with IV or IM injections which can be somewhat unpleasant and even painful. At least for a big group of people. 

On the other hand, cyanocobalamin/salcaprozate sodium seems to get the same job done, normalizing B12 levels, via a single tablet taken daily. As mentioned earlier, that’s due to the absorption profile of cyanocobalamin/salcaprozate sodium. So far, cyanocobalamin/salcaprozate sodium has proven to be very effective with every patient that used it. 

In comparison to IV or IM injections, it had the identical effect. Yet the fact that it is used orally makes it way more convenient for all users. 

Your manufacturing company needs a big boost. You finally decide that you need some CNC machines to do the trick. While you are excited, you realize that you have a tight budget. You also don’t have a clue on what a CNC machine shop charges for CNC machining. That can be a bummer.

Finding out how much you have to pay is important. It helps you plan for the unexpected. So, in this article, we’re going to look out certain things that influence how much a CNC machine shop will charge for your order.

Let’s begin!

How Does a CNC Machine Shop Calculate Costs?

When dealing with CNC machine shops, you should know that several things affect the final price. I have found at least four things that can sway your price higher or lower. They include

• The cost of labor
• Extra costs incurred during completion
• The particular order that you place
• The cost of the various machines
• The rate at which the CNC machine shops charges for each order.

Now, let’s break it down better.

The Cost Of Labor

We all know that one of the benefits of CNC machining is the reduced labor staff. However, this does not mean that you won’t have to pay for any labor at all. CNC machining has some labor that you just cannot ignore.

One of them is the labor costs as regards to the digitalizing and designing process. No matter how you intend to cut costs, you will need to get an expert to do the design.

If you have a lot of complication designs, chances are that the CNC machine shops are going to charge you more for the design setup.

Other labor costs which you will probably get charged for will include the salaries of the operators. The exact amount that you will spend will be determined by how long your production is going to last.

Finishing costs and assembling might also mean more labor costs. It’s always a good thing to analyze what needs to be spent when making a budget.

Extra Costs Incurred During Completion

Once the project is completed, you will be thrilled to finally get your CNC machines. However, you might need to pay for this. For example, if you use a CNC machine shop that is located in China, you will have to pay shipping costs for it.

The exact shipping costs will determine the urgency of the delivery. The particular material that is used in the production of the machine will also have an impact on the costs of shipping. A good material to go for will be aluminum. Using stainless steel might incur future costs.

The Particular Order That Is Placed

The specific order that you place will also play a very big role. For example, the more complex a design is, the more money will be needed to pull it off. It will also take a long time to do the programming of such a design.

Sometimes, it could more about finding the parts of the design that fit than the programming. The digitalizing part of the order will also incur more operating costs.

In effect, this part of CNC machining takes the bulk of the cost.

If you are trying out CNC machining for the first time, it might be wise to go with a design that is so much simpler. This will save you a lot of cash. It might also be the best option if you are unsure of what you really want.

CNC machine shops will also take into account the volume of your order. Generally, you are going to spend more on a larger order than a smaller order. However, with a bigger order, the price for every individual item you purchase will much lower.

The Cost Of The CNC Machines

Another aspect that is sure to affect the costs will be the CNC machines that you use. Generally, the 3 axis machining and the multi-axis machines are the two popular choices.

If you wish to hire a machine, you’d be charged using an hourly figure. If you want to buy a machine, there are several ways in which the cost can be calculated.

For 3- axis machines, the average price per hour has a range of $30-$50. An example of this machine is the milling machines. The CNC turning machines will also fit into this category.

For the multi-axis machines, it will cost you anything from $75-$150 per hour. This makes sense as the machines are much more expensive than their counterparts. Sometimes, it can even surpass this figure. It’s always a good thing to consider your options before making a deal.

CNC Machine Shop Rates

The CNC machine shops also have their individual rates which they charge. This is up to the particular shop you decide to use. The rates will vary based on certain factors. One of the primary factors will be how long it takes to get it up and running.

To get the best deal, you have to compare more than one CNC machine shop. While it can be difficult, it is essential especially if you run on a tight budget.

Most CNC machine shops will be available or can be contacted for their quotes or inquiries. Also, make sure you do some research yourself to make sure the company you choose is real.

It’ll be disastrous to get scammed without getting the actual value for your money.

So Where Should I Start?

The first step before getting the right CNC machine shop is to do a quick assessment of what you really need. Also, make sure that you have the budget to accommodate these needs. Once this has been done, these tips above should help you find a good financial outcome.

Final Thoughts

Getting familiar which a CNC machine shop and how much they charge will be great for your company. It will help you balance your books as well as get value for your money. With some luck, your CNC machines might last for a long time.

Without a doubt, there is confusion when it comes to stating the noticeable differences between contactors and relays. All too often, the two terms are used interchangeably. The defining differences are often not apparent to users of contactors, especially. In this article, you will find relevant answers to your questions.

According to experts at the prestigious Institute of Electrical Engineers, a relay is referred to as a device with a single contact circuit, which is often operated by a viable change in the conditions within the same circuit or other associated units.

A contactor, on the other hand, refers to a device used repeatedly to establish and interrupt an electric circuit in the normal conditions.

What are the unique features between contactors and relays?

There are unique textbook definitions that seem to be similar enough, even though not so helpful.  From these excerpts, both devices perform the same task, which entails switching the circuit.

So, what really is the difference really?

The load capacity

A relay is generally classified as a device that can carry a load of about 10A. On the other hand, a contactor is defined as a device that can carry a rather higher load than the standard 10A.

While this definition may look simple, it gives an accurate picture of the picture ultimately.

At the same time, it does not capture the standards and physical differences of the devices like in the next paragraph.  

Auxiliary contacts

For those who feel a bit confused about the operating mechanisms of a contactor, the device is often fitted using an auxiliary contact, which may be NO or NC.

But these are often utilized in performing various additional functions that are related to the control of the contactor.

For instance, the DC contactor can transmit power to a motor, even though the auxiliary contact is situated in the motor’s control circuit.

Safety Features- The Spring-Loaded Contacts

The arc suppression is another safety feature found in multiple contactor types. Magnetic arc suppression extends the path a DC contactor’s arc is suppressed.

Because relays are not tailored for high loads, the arcing is not really a concern. So the suppression is somewhat less common on these relays.

Safety Features- Overloads

Contactors are most of the time linked to overloads, which can interfere with the operations of the circuit precisely if the currents exceed a threshold for some time.

This plays a significant role in protecting the downstream of the equipment from damage. On the contrary, relays do not have overloads.

Applications of Relays vs. Contactors

When it comes to their applications, contactors are built and then used in about 3-phase applications. Relays, on the other hand, are commonly used in 1-phase applications.

A contactor will join two poles without a circuit in between. A relay comes with a common contact which connects to the neutral position. Besides, contactors are rated for about 1000V. 

On the other hand, relays are rated to about 250V only.

Final Thoughts

In practice, you need to look at the functionalities of the two devices too. For circuits with an overload condition, a contactor could be the best option. In cases where there is a need for lower switching to power, then a relay is more of an economical choice.